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HIGH-SPEED 16K X 16 DUAL-PORT STATIC RAM
Features

IDT7026S/L
True Dual-Ported memory cells which allow simultaneous access of the same memory location High-speed access - Commercial: 15/20/25/35/55ns (max.) - Industrial: 20/25/35/55ns (max.) - Military: 20/25/35/55ns (max.) Low-power operation - IDT7026S Active: 750mW (typ.) Standby: 5mW (typ.) - IDT7026L Active: 750mW (typ.) Standby: 1mW (typ.) Separate upper-byte and lower-byte control for multiplexed bus compatibility

IDT7026 easily expands data bus width to 32 bits or more using the Master/Slave select when cascading more than one device M/S = H for BUSY output flag on Master, M/S = L for BUSY input on Slave On-chip port arbitration logic Full on-chip hardware support of semaphore signaling between ports Fully asynchronous operation from either port TTL-compatible, single 5V (10%) power supply Available in 84-pin PGA and 84-pin PLCC Industrial temperature range (-40C to +85C) is available for selected speeds
Functional Block Diagram
R/WL UBL R/WR UBR
LBL CEL OEL
LBR CER OER
I/O8L-I/O15L I/O0L-I/O7L BUSYL A13L A0L
(1,2)
I/O Control
I/O Control
I/O8R-I/O15R I/O0R-I/O7R BUSYR A13R A0R
(1,2)
Address Decoder
14
MEMORY ARRAY
14
Address Decoder
CEL
ARBITRATION SEMAPHORE LOGIC
CER
SEML M/S
NOTES: 1. (MASTER): BUSY is output; (SLAVE): BUSY is input. 2. BUSY outputs are non-tri-stated push-pull.
SEMR
2939 drw 01
DECEMBER 2002
1
DSC 2939/12
(c)2001 Integrated Device Technology, Inc.
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
The IDT7026 is a high-speed 16K x 16 Dual-Port Static RAM. The IDT7026 is designed to be used as a stand-alone Dual-Port RAM or as a combination MASTER/SLAVE Dual-Port RAM for 32-bit-or-more word systems. Using the IDT MASTER/SLAVE Dual-Port RAM approach in 32bit or wider memory system applications results in full-speed, error-free operation without the need for additional discrete logic. This device provides two independent ports with separate control, address, and I/O pins that permit independent, asynchronous access for reads or writes to any location in memory. An automatic power down
Description
feature controlled by CE permits the on-chip circuitry of each port to enter a very low standby power mode. Fabricated using IDT's CMOS high-performance technology, these devices typically operate on only 750mW of power. The IDT7026 is packaged in a ceramic 84-pin PGA, and a 84-pin PLCC. Military grade product is manufactured in compliance with the latest revision of MIL-PRF-38535 QML, making it ideally suited to military temperature applications demanding the highest level of performance and reliability.
Pin Configurations(1,2,3)
11/16/01
SEML
R/WL
I/O7L
I/O6L
I/O5L
I/O4L
I/O3L
I/O2L
I/O1L
I/O0L
GND
A13L A12L
A11L
A10L
OEL
VCC
CEL
UBL
LBL
INDEX
11 10 9 8 7 6 I/O8L I/O9L I/O10L I/O11L I/O12L I/O13L GND I/O14L I/O15L VCC GND I/O0R I/O1R I/O2R VCC I/O3R I/O4R I/O5R I/O6R I/O7R I/O8R 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
5 4 3 2 1 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 IDT7026J J84-1(4) 84-Pin PLCC Top View(5) 66 65 64 63 62 61 60 59 58 57 56 55
A9L
A8L A7L A6L A5L A4L A3L A2L A1L A0L BUSYL GND M/S BUSYR A0R A1R A2R A3R A4R A5R A6R A7R
,
54 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
I/O14R GND LBR A13R A12R A11R R/WR GND SEMR I/O11R I/O15R A10R CER OER UBR I/O12R I/O10R I/O13R I/O9R A9R A8R
2939 drw 02
NOTES: 1. All Vcc pins must be connected to the power supply. 2. All GND pins must be connected to the ground supply. 3. Package body is approximately 1.15 in x 1.15 in x .17 in. 4. This package code is used to reference the package diagram. 5. This text does not indicate orientation of the actual part-marking.
6.42 2
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Pin Configurations(1,2,3) (con't.)
11/16/01
63
61
60
58
55
54
51
48
46
45
42
11
I/O7L
66
I/O5L
64
I/O4L
62
I/O2L
59
I/O0L
56
OEL
49
SEML
50
LBL
47
A12L
44
A11L
43
A8L
40
10
I/O10L
67
I/O8L
65
I/O6L
I/O3L
I/O1L
57
UBL
53
CEL
52
A13L
A10L
A9L
41
A6L
39
09
I/O11L
69
I/O9L
68
GND
VCC
R/WL
A7L
38
A5L
37
08
I/O13L
72
I/O12L
71 73 33
A4L
35
A3L
34
07
I/O15L
75
I/O14L
70
VCC
74
BUSYL IDT7026G G84-3(4) 84-Pin PGA Top View(5)
32
A1L
31
A0L
36
06
I/O0R
76
GND
77
GND
78
GND
28
M/S
29
A2L
30
05
I/O1R
79
I/O2R
80
VCC
A1R
A0R
26
BUSYR
27
04
I/O3R
81
I/O4R
83 7 11 12
A3R
23
A2R
25
03
I/O5R
82 1
I/O7R
2 5
GND
8
GND
10
SEMR
14 17 20
A6R
22
A4R
24
02
I/O6R
84 3
I/O9R
I/O10R
4
I/O13R
6
I/O15R
9
R/WR
15
UBR
13
A12R
16
A9R
18
A7R
19
A5R
21
01
I/O8R A
I/O11R B
I/O12R C
I/O14R D
OER E
LBR F
CER G
A13R H
A11R J
A10R K
A8R L
2939 drw 03
Index
NOTES: 1. All VCC pins must be connected to power supply. 2. All GND pins must be connected to ground supply. 3. Package body is approximately 1.12 in x 1.12 in x .16 in. 4. This package code is used to reference the package diagram. 5. This text does not indicate orientation of the actual part-marking.
Maximum Operating Temperature and Supply Voltage(1)
Grade Ambient Temperature -55 C to+125 C
O O
Pin Names
Left Port CEL R/WL OEL A0L - A13L I/O0L - I/O15L SEML UBL LBL BUSYL CER R/WR OER A0R - A13R I/O0R - I/O15R SEMR UBR LBR BUSYR M/S VCC GND Right Port Chip Enable Read/Write Enable Output Enable Address Data Input/Output Semaphore Enable Upper Byte Select Lower Byte Select Busy Flag Master or Slave Select Power Ground
2939 tbl 01
GND 0V 0V 0V
Vcc 5.0V + 10% 5.0V + 10% 5.0V + 10%
2939 tbl 02
Names
Military Commercial Industrial
0 C to +70 C
O O
-40 C to +85 C
O O
NOTES: 1. This is the parameter TA. This is the "instant on" case temperature.
Capacitance(1) (TA = +25C, f = 1.0mhz)
Symbol CIN COUT Parameter Input Capacitance Output Capacitance Conditions(2) VIN = 3dV VOUT = 3dV Max. 9 10 Unit pF pF
2939 tbl 03
NOTES: 1. This parameter is determined by device characterization but is not production tested. 2. 3dV represents the interpolated capacitance when the input and output signals switch from 0V to 3V or from 3V to 0V.
6.42 3
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Truth Table I - Non-Contention Read/Write Control
Inputs(1) CE H X L L L L L L X R/W X X L L L H H H X OE X X X X X L L L H UB X H L H L L H L X LB X H H L L H L L X SEM H H H H H H H H X Outputs I/O8-15 High-Z High-Z DATAIN High-Z DATAIN DATAOUT High-Z DATAOUT High-Z I/O0-7 High-Z High-Z High-Z DATAIN DATAIN High-Z DATAOUT DATAOUT High-Z Mode Deselected: Power-Down Both Bytes Deselected Write to Upper Byte Only Write to Lower Byte Only Write to Both Bytes Read Upper Byte Only Read Lower Byte Only Read Both Bytes Outputs Disabled
2939 tbl 04
NOTE: 1. A0L -- A13L A0R -- A13R.
Truth Table II - Semaphore Read/Write Control(1)
Inputs CE H X H X L L R/W H H OE L L X X X X UB X H X H L X LB X H X H X L SEM L L L L L L Outputs I/O8-15 DATAOUT DATAOUT DATAIN DATAIN
______ ______
I/O0-7 DATAOUT DATAOUT DATAIN DATAIN
______ ______
Mode Read Data in Semaphore Flag Read Data in Semaphore Flag Write I/O0 into Semaphore Flag Write I/O0 into Semaphore Flag Not Allowed Not Allowed
2939 tbl 05

X X
NOTE: 1. There are eight semaphore flags written to via I/O0 and read from all I/O's (I/O0-I/O15). These eight semaphores are addressed by A0 - A2.
Absolute Maximum Ratings(1)
Symbol VTERM(2) TBIAS TSTG IOUT Rating Terminal Voltage with Respect to GND Temperature Under Bias Storage Temperature DC Output Current Commercial & Industrial -0.5 to +7.0 -55 to +125 -55 to +125 50 Military -0.5 to +7.0 -65 to +135 -65 to +150 50 Unit V
o o
C C
mA
2939 tbl 06
NOTES: 1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. 2. VTERM must not exceed Vcc + 10% for more than 25% of the cycle time or 10ns maximum, and is limited to < 20mA for the period of VTERM > Vcc + 10%.
6.42 4
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Recommended DC Operating Conditions
Symbol VCC GND VIH VIL Parameter Supply Voltage Ground Input High Voltage Input Low Voltage Min. 4.5 0 2.2 -0.5(1) Typ. 5.0 0
____ ____
Max. 5.5 0 6.0(2) 0.8
Unit V V V V
2939 tbl 07
NOTES: 1. VIL > -1.5V for pulse width less than 10ns. 2. VTERM must not exceed Vcc + 10%.
DC Electrical Characteristics Over the Operating Temperature and Supply Soltage Range (VCC = 5.0V 10%)
7026S Symbol |ILI| |ILO| VOL VOH Parameter Input Leakage Current
(1)
7026L Max. 10 10 0.4
___
Test Conditions VCC = 5.5V, VIN = 0V to VCC CE = VIH, VOUT = 0V to VCC IOL = 4mA IOH = -4mA
Min.
___ ___ ___
Min.
___ ___ ___
Max. 5 5 0.4
___
Unit A A V V
2939 tbl 08
Output Leakage Current Output Low Voltage Output High Voltage
2.4
2.4
NOTE: 1. At Vcc = 2.0V, input leakages are undefined.
AC Test Conditions
Input Pulse Levels Input Rise/Fall Times Input Timing Reference Levels Output Reference Levels Output Load GND to 3.0V 3ns 1.5V 1.5V Figures 1 and 2
2939 tbl 09
5V 893 DATAOUT BUSY 347 30pF DATAOUT 347
5V 893
5pF*
2939 drw 04
2939 drw 05
Figure 1. AC Output Test Load
Figure 2. Output Test Load (for tLZ, tHZ, tWZ, tOW) * Including scope and jig.
6.42 5
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
DC Electrical Characteristics Over the Operating Temperature and Supply Voltage Range(1) (con't.) (VCC = 5.0V 10%)
7026X15 Com'l Only Symbol ICC Parameter Dynamic Operating Current (Both Ports Active) Test Condition CE = VIL, Outputs Disabled SEM = VIH f = fMAX(3) Version COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND S L S L S L S L S L S L S L S L S L S L Typ.(2) 190 190
___ ___
7026X20 Com'l, Ind & Military. Typ.(2) 180 180 180 180 30 30 30 30 115 115 115 115 1.0 0.2 1.0 0.2 110 110 110 110 Max. 315 275 355 315 85 60 100 80 210 180 245 210 15 5 30 10 185 160 210 185
7026X25 Com'l, Ind & Military Typ.(2) 170 170 170 170 25 25 25 25 105 105 105 105 1.0 0.2 1.0 0.2 100 100 100 100 Max. 305 265 345 305 85 60 100 80 200 170 230 200 15 5 30 10 170 145 200 175
2939 tbl 10
Max. 325 285
___ ___
Unit mA
ISB1
Standby Current (Both Ports - TTL Level Inputs)
CEL = CER = VIH SEMR = SEML = VIH f = fMAX(3)
35 35
___ ___
95 70
___ ___
mA
ISB2
Standby Current (One Port - TTL Level Inputs)
CE"A" = VIL and CE"B" = VIH(5) Active Port Outputs Disabled, f=fMAX(3) SEMR = SEML = VIH Both Ports CEL and CER > VCC - 0.2V VIN > VCC - 0.2V or VIN < 0.2V, f = 0(4) SEMR = SEML > VCC - 0.2V CE"A" < 0.2V and CE"B" > VCC - 0.2V(5) SEMR = SEML > VCC - 0.2V VIN > VCC - 0.2V or VIN < 0.2V Active Port Outputs Disabled, f=fMAX(3)
125 125
___ ___
220 190
___ ___
mA
ISB3
Full Standby Current (Both Ports - All CMOS Level Inputs)
1.0 0.2
___ ___
15 5
___ ___
mA
ISB4
Full Standby Current (One Port - All CMOS Level Inputs)
120 120
___ ___
195 170
___ ___
mA
7026X35 Com'l, Ind & Military Symbol ICC Parameter Dynamic Operating Current (Both Ports Active) Test Condition CE = VIL, Outputs Disabled SEM = VIH f = fMAX(3) Version COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND COM'L MIL & IND S L S L S L S L S L S L S L S L S L S L Typ.(2) 160 160 160 160 20 20 20 20 95 95 95 95 1.0 0.2 1.0 0.2 90 90 90 90 Max. 295 255 335 295 85 60 100 80 185 155 215 185 15 5 30 10 160 135 190 165
7026X55 Com'l, Ind & Military Typ.(2) 150 150 150 150 13 13 13 13 85 85 85 85 1.0 0.2 1.0 0.2 80 80 80 80 Max. 270 230 310 270 85 60 100 80 165 135 195 165 15 5 30 10 135 110 175 150
2939 tbl 11
Unit mA
ISB1
Standby Current (Both Ports - TTL Level Inputs)
CEL = CER = VIH SEMR = SEML = VIH f = fMAX(3)
mA
ISB2
Standby Current (One Port - TTL Level Inputs)
CE"A" = VIL and CE"B" = VIH(5) Active Port Outputs Disabled, f=fMAX(3) SEMR = SEML = VIH Both Ports CEL and CER > VCC - 0.2V VIN > VCC - 0.2V or VIN < 0.2V, f = 0(4) SEMR = SEML > VCC - 0.2V CE"A" < 0.2V and CE"B" > VCC - 0.2V(5) SEMR = SEML > VCC - 0.2V VIN > VCC - 0.2V or VIN < 0.2V Active Port Outputs Disabled f=fMAX(3)
mA
ISB3
Full Standby Current (Both Ports - All CMOS Level Inputs)
mA
ISB4
Full Standby Current (One Port - All CMOS Level Inputs)
mA
NOTES: 1. 'X' in part numbers indicates power rating (S or L). 2. VCC = 5V, TA = +25C, and are not production tested. ICCDC = 120mA (Typ.) 3. At f = fMAX, address and control lines (except Output Enable) are cycling at the maximum frequency read cycle of 1/tRC, and using "AC Test Conditions" of input levels of GND to 3V. 4. f = 0 means no address or control lines change.
6.42 6
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
AC Electrical Characteristics Over the Operating Temperature and Supply Voltage Range(4)
7026X15 Com'l Only Symbol READ CYCLE tRC tAA tACE tABE tAOE tOH tLZ tHZ tPU tPD tSOP tSAA Read Cycle Time Address Access Time Chip Enable Access Time
(3)
7026X20 Com'l, Ind & Military Min. Max.
7026X25 Com'l, Ind & Military Min. Max. Unit
Parameter
Min.
Max.
15
____ ____ ____ ____
____
20
____ ____ ____ ____
____
25
____ ____ ____ ____
____
ns ns ns ns ns ns ns ns ns ns ns ns
2939 tbl 12a
15 15 15 10
____ ____
20 20 20 12
____ ____
25 25 25 13
____ ____
Byte Enable Access Time (3) Output Enable Access Time Output Hold from Address Change Output Low-Z Time
(1,2)
3 3
____
3 3
____
3 3
____
Output High-Z Time (1,2) Chip Enable to Power Up Time (2) Chip Disable to Power Down Time
(2)
10
____
12
____
15
____
0
____
0
____
0
____
15
____
20
____
25
____
Semaphore Flag Update Pulse (OE or SEM) Semaphore Address Access Time
10
____
10
____
12
____
15
20
25
7026X35 Com'l, Ind & Military Symbol READ CYCLE tRC tAA tACE tABE tAOE tOH tLZ tHZ tPU tPD tSOP tSAA Read Cycle Time Address Access Time Chip Enable Access Time Byte Enable Access Time
(3) (3)
7026X55 Com'l, Ind & Military Min. Max. Unit
Parameter
Min.
Max.
35
____ ____ ____ ____
____
55
____ ____ ____ ____
____
ns ns ns ns ns ns ns ns ns ns ns ns
2939 tbl 12b
35 35 35 20
____ ____
55 55 55 30
____ ____
Output Enable Access Time Output Hold from Address Change Output Low-Z Time
(1,2) (1,2)
3 3
____
3 3
____
Output High-Z Time
15
____
25
____
Chip Enable to Power Up Time (2) Chip Disable to Power Down Time(2) Semaphore Flag Update Pulse (OE or SEM) Semaphore Address Access Time
0
____
0
____
35
____
50
____
15
____
15
____
35
55
NOTES: 1. Transition is measured 0mV from Low or High-impedance voltage with Output Test Load (Figure 2). 2. This parameter is guaranteed by device characterization, but is not production tested. 3. To access RAM, CE = VIL and SEM = VIH. To access semaphore, CE = VIH and SEM = VIL. 4. 'X' in part numbers indicates power rating (S or L).
6.42 7
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
WAVEFORM OF READ CYCLES(5)
tRC ADDR tAA (4) tACE tAOE OE tABE UB, LB
(4) (4) (4)
CE
R/W tLZ DATAOUT
(1)
tOH VALID DATA
(4) (2)
tHZ BUSYOUT tBDD
(3, 4)
2939 drw 06
NOTES: 1. Timing depends on which signal is asserted last, OE, CE, LB, or UB. 2. Timing depends on which signal is de-asserted first CE, OE, LB, or UB. 3. tBDD delay is required only in cases where the opposite port is completing a write operation to the same address location. For simultaneous read operations BUSY has no relation to valid output data. 4. Start of valid data depends on which timing becomes effective last tAOE, tACE, tAA or tBDD. 5. SEM = VIH.
Timing of Power-Up Power-Down
CE tPU
50%
ICC ISB
tPD
50%
2939 drw 07
,
6.42 8
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
AC Electrical Characteristics Over the Operating Temperature and Supply Voltage(5,6)
7026X15 Com'l Only Symbol WRITE CYCLE tWC tEW tAW tAS tWP tWR tDW tHZ tDH tWZ tOW tSWRD tSPS Write Cycle Time Chip Enable to End-of-Write
(3)
Parameter Min. Max.
7026X20 Com'l, Ind & Military Min. Max.
7026X25 Com'l, Ind & Military Min. Max. Unit
15 12 12 0 12 0 10
____
____ ____ ____ ____ ____ ____ ____
20 15 15 0 15 0 15
____
____ ____ ____ ____ ____ ____ ____
25 20 20 0 20 0 15
____
____ ____ ____ ____ ____ ____ ____
ns ns ns ns ns ns ns ns ns ns ns ns ns
3199 tbl 13a
Address Valid to End-of-Write Address Set-up Time (3) Write Pulse Width Write Recovery Time Data Valid to End-of-Write Output High-Z Time Data Hold Time
(4) (1,2) (1,2)
10
____
12
____
15
____
0
____
0
____
0
____
Write Enable to Output in High-Z Output Active from End-of-Write SEM Flag Write to Read Time SEM Flag Contention Window
10
____ ____ ____
12
____ ____ ____
15
____ ____ ____
(1,2,4)
0 5 5
0 5 5
0 5 5
Symbol WRITE CYCLE tWC tEW tAW tAS tWP tWR tDW tHZ tDH tWZ tOW tSWRD tSPS Write Cycle Time Chip Enable to End-of-Write (3) Address Valid to End-of-Write Address Set-up Time Write Pulse Width Write Recovery Time Data Valid to End-of-Write Output High-Z Time Data Hold Time
(4) (1,2) (1,2) (3)
Parameter
7026X35 Com'l, Ind & Military Min. Max.
7026X55 Com'l, Ind & Military Min. Max. Unit
35 30 30 0 25 0 15
____
____ ____ ____ ____ ____ ____ ____
55 45 45 0 40 0 30
____
____ ____ ____ ____ ____ ____ ____
ns ns ns ns ns ns ns ns ns ns ns ns ns
2939 tbl 13b
15
____
25
____
0
____
0
____
Write Enable to Output in High-Z Output Active from End-of-Write SEM Flag Write to Read Time SEM Flag Contention Window
15
____ ____ ____
25
____ ____ ____
(1,2,4)
0 5 5
0 5 5
NOTES: 1. Transition is measured 0mV from Low or High-impedance voltage with Output Test Load (Figure 2). 2. This parameter is guaranteed by device characterization, but is not production tested. 3. To access RAM, CE = VIL and SEM = VIH. To access semaphore, CE = VIH and SEM = VIL. Either condition must be valid for the entire tEW time. 4. The specification for tDH must be met by the device supplying write data to the RAM under all operating conditions. Although tDH and tOW values will vary over voltage and temperature, the actual tDH will always be smaller than the actual tOW. 5. 'X' in part numbers indicates power rating (S or L).
6.42 9
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Timing Waveform of Write Cycle No. 1, R/W Controlled Timing(1,5,8)
tWC ADDRESS tHZ (7) OE tAW CE or SEM
(9)
UB or LB
(9)
tAS (6) R/W tWZ (7) DATAOUT
(4)
tWP (2)
tWR
(3)
tOW
(4)
tDW DATAIN
tDH
2939 drw 08
Timing Waveform of Write Cycle No. 2, CE, UB, LB Controlled Timing(1,5)
tWC ADDRESS tAW CE or SEM
(9)
tAS (6) UB or LB
(9)
tEW (2)
tWR (3)
R/W tDW DATAIN
2939 drw 09
tDH
NOTES: 1. R/W or CE or UB and LB = VIH during all address transitions. 2. A write occurs during the overlap (tEW or tWP) of a VIL CE = VIL and R/W = VIL for memory array writing cycle. 3. tWR is measured from the earlier of CE or R/W (or SEM or R/W) going VIH to the end of write cycle. 4. During this period, the I/O pins are in the output state and input signals must not be applied. 5. If the CE or SEM = VIL transition occurs simultaneously with or after the R/W = VIL transition, the outputs remain in the High-impedance state. 6. Timing depends on which enable signal is asserted last, CE or R/W. 7. This parameter is guaranteed by device characterization, but is not production tested. Transition is measured 0mV from steady state with the Output Test Load (Figure 2). 8. If OE = VIL during R/W controlled write cycle, the write pulse width must be the larger of tWP or (tWZ + tDW) to allow the I/O drivers to turn off and data to be placed on the bus for the required tDW. If OE = VIH during an R/W controlled write cycle, this requirement does not apply and the write pulse can be as short as the specified tWP. 9. To access RAM, CE = VIL and SEM = VIH. To access semaphore, CE = VIH and SEM = VIL. tEW must be met for either condition.
6.42 10
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Timing Waveform of Semaphore Read after Write Timing, Either Side(1)
tSAA A0-A2 VALID ADDRESS tAW SEM tDW DATAIN VALID tAS R/W tSWRD OE
Write Cycle Read Cycle
2939 drw 10
tOH
VALID ADDRESS tACE tSOP DATAOUT VALID(2)
tWR tEW
I/O0 tWP
tDH
tAOE
NOTES: 1. CE = VIH or UB and LB = VIH for the duration of the above timing (both write and read cycle). 2. "DATAOUT VALID" represents all I/O's (I/O0-I/O15) equal to the semaphore value.
Timing Waveform of Semaphore Write Contention(1,3,4)
A0"A"-A2"A" MATCH
SIDE
(2)
"A"
R/W"A"
SEM"A" tSPS A0"B"-A2"B" MATCH
SIDE
(2)
"B"
R/W"B"
SEM"B"
2939 drw 11
NOTES: 1. DOR = DOL = VIL, CER = CEL = VIH, or both UB & LB = VIH. 2. All timing is the same for left and right ports. Port "A" may be either left or right port. Port "B" is the opposite from port "A". 3. This parameter is measured from R/W"A" or SEM"A" going HIGH to R/W"B" or SEM"B" going HIGH. 4. If tSPS is not satisfied, there is no guarantee which side will be granted the semaphore flag.
6.42 11
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
AC Electrical Characteristics Over the Operating Temperature and Supply Voltage Range(6,7)
7026X15 Com'l Only Symbol BUSY TIMING (M/S=VIH) tBAA tBDA tBAC tBDC tAPS tBDD tWH BUSY Access Time from Address Match BUSY Disable Time from Address Not Matched BUSY Acce ss Time from Chip Enable Low BUSY Acce ss Time from Chip Enable High Arbitration Priority Set-up Time BUSY Disable to Valid Data Write Hold After BUSY
(5) (2)
____ ____ ____ ____
7026X20 Com'l, Ind & Military Min. Max.
7026X25 Com'l, Ind & Military Min. Max. Unit
Parameter
Min.
Max.
15 15 15 15
____
____ ____ ____ ____
20 20 20 17
____
____ ____ ____ ____
20 20 20 17
____
ns ns ns ns ns ns ns
5
____
5
____
5
____
18
____
30
____
30
____
12
15
17
BUSY TIMING (M/S=VIL) tWB tWH BUSY Input to Write (4) Write Hold After BUSY(5) 0 12
____ ____
0 15
____ ____
0 17
____ ____
ns ns
PORT-TO-PORT DELAY TIMING tWDD tDDD Write Pulse to Data Delay(1) Write Data Valid to Read Data Delay
(1)
____ ____
30 25
____ ____
45 30
____ ____
50 35
ns ns
2939 tbl 14a
7026X35 Com'l, Ind & Military Symbol BUSY TIMING (M/S=VIH) tBAA tBDA tBAC tBDC tAPS tBDD tWH BUSY Access Time from Address Match BUSY Disable Time from Address Not Matched BUSY Acce ss Time from Chip Enable Low BUSY Acce ss Time from Chip Enable High Arbitration Priority Set-up Time BUSY Disable to Valid Data Write Hold After BUSY
(5) (3) (2)
____ ____ ____ ____
7026X55 Com'l, Ind & Military Min. Max. Unit
Parameter
Min.
Max.
20 20 20 20
____
____ ____ ____ ____
45 40 40 35
____
ns ns ns ns ns ns ns
5
____
5
____
35
____
40
____
25
25
BUSY TIMING (M/S=VIL) tWB tWH BUSY Input to Write (4) Write Hold After BUSY
(5)
0 25
____ ____
0 25
____ ____
ns ns
PORT-TO-PORT DELAY TIMING tWDD tDDD Write Pulse to Data Delay(1) Write Data Valid to Read Data Delay
(1)
____ ____
60 45
____ ____
80 65
ns ns
2939 tbl 14b
NOTES: 1. Port-to-port delay through RAM cells from writing port to reading port, refer to "Timing Waveform of Write with Port-to-Port Read and BUSY (M/S = VIH)". 2. To ensure that the earlier of the two ports wins. 3. tBDD is a calculated parameter and is the greater of 0, tWDD - tWP (actual), or tDDD - tDW (actual). 4. To ensure that the write cycle is inhibited on port "B" during contention on port "A". 5. To ensure that a write cycle is completed on port "B" after contention on port "A". 6. 'X' in part numbers indicates power rating (S or L). 7. Industrial temperature: for other speeds, packages and powers contact your sales office.
6.42 12
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Timing Waveform of Write with Port-to-Port Read and BUSY (M/S = VIH)(2,4,5)
tWC ADDR"A" MATCH tWP R/W"A" tDW DATAIN "A" tAPS ADDR"B" tBAA BUSY"B" tWDD DATAOUT "B" tDDD
(3) 2939 drw 12 (1)
tDH VALID
MATCH tBDA tBDD
VALID
NOTES: 1. To ensure that the earlier of the two ports wins. tAPS is ignored for M/S = VIL (slave). 2. CEL = CER = VIL. 3. OE = VIL for the reading port. 4. If M/S = VIL (slave), BUSY is an input. Then for this example BUSY"A" = VIH and BUSY"B" input is shown above. 5. All timing is the same for left and right ports. Port "A" may be either the left or right port. Port "B" is the port opposite from port "A".
Timing Waveform of Write with BUSY (M/S = VIL)
tWP
R/W"A"
tWB(3)
BUSY"B"
tWH
(1)
R/W"B"
(2) 2939 drw 13
,
NOTES: 1. tWH must be met for both BUSY input (SLAVE) and output (MASTER). 2. BUSY is asserted on port "B" blocking R/W"B", until BUSY"B" goes HIGH. 3. tWB is only for the "SLAVE" version.
6.42 13
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Waveform of BUSY Arbitration Controlled by CE Timing (M/S = VIH)(1)
ADDR"A" and "B" CE"A" tAPS (2) CE"B" tBAC BUSY"B"
2939 drw 14
ADDRESSES MATCH
tBDC
Waveform of BUSY Arbitration Cycle Controlled by Address Match Timing (M/S = VIH)(1)
ADDR"A" tAPS ADDR"B" tBAA BUSY"B"
2939 drw 15 (2)
ADDRESS "N"
MATCHING ADDRESS "N" tBDA
NOTES: 1. All timing is the same for left and right ports. Port "A" may be either the left or right port. Port "B" is the port opposite from "A". 2. If tAPS is not satisfied, the BUSY signal will be asserted on one side or another but there is no guarantee on which side BUSY will be asserted.
Truth Table III -- Example of Semaphore Procurement Sequence(1,2,3)
Functions No Action Left Port Writes "0" to Semaphore Right Port Writes "0" to Semaphore Left Port Writes "1" to Semaphore Left Port Writes "0" to Semaphore Right Port Writes "1" to Semaphore Left Port Writes "1" to Semaphore Right Port Writes "0" to Semaphore Right Port Writes "1" to Semaphore Left Port Writes "0" to Semaphore Left Port Writes "1" to Semaphore D0 - D15 Left 1 0 0 1 1 0 1 1 1 0 1 D0 - D15 Right 1 1 1 0 0 1 1 0 1 1 1 Semaphore free Left port has semaphore token No change. Right side has no write access to semaphore Right port obtains semaphore token No change. Left port has no write access to semaphore Left port obtains semaphore token Semaphore free Right port has semaphore token Semaphore free Left port has semaphore token Semaphore free
2939 tbl 15
Status
NOTES: 1. This table denotes a sequence of events for only one of the eight semaphores on the IDT7026. 2. There are eight semaphore flags written to via I/O0 and read from all I/O's (I/O0-I/O15). These eight semaphores are addressed by A0 - A2. 3. CE = VIH, SEM = VIL to access the semaphores. Refer to the semaphore Read/Write Control Truth Table.
6.42 14
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Truth Table IV -- Address BUSY Arbitration
Inputs CEL X H X L CER X X H L AOL-A13L AOR-A13R NO MATCH MATCH MATCH MATCH Outputs BUSYL(1) H H H (2) BUSYR(1) H H H (2) Function Normal Normal Normal Write Inhibit(3)
2939 tbl 16
NOTES: 1. Pins BUSYL and BUSYR are both outputs when the part is configured as a master. Both are inputs when configured as a slave. BUSYX outputs on the IDT7026 are push pull, not open drain outputs. On slaves the BUSYX input internally inhibits writes. 2. LOW if the inputs to the opposite port were stable prior to the address and enable inputs of this port. HIGH if the inputs to the opposite port became stable after the address and enable inputs of this port. If tAPS is not met, either BUSYL or BUSYR = LOW will result. BUSYL and BUSYR outputs cannot be LOW simultaneously. 3. Writes to the left port are internally ignored when BUSYL outputs are driving LOW regardless of actual logic level on the pin. Writes to the right port are internally ignored when BUSYR outputs are driving LOW regardless of actual logic level on the pin.
When expanding an IDT7026 RAM array in width while using BUSY logic, one master part is used to decide which side of the RAM array will receive a BUSY indication, and to output that indication. Any number of slaves to be addressed in the same address range as the master use the BUSY signal as a write inhibit signal. Thus on the IDT7026 RAM the BUSY pin is an output if the part is used as a master (M/S pin = VIH), and the BUSY pin is an input if the part used as a slave (M/S pin = VIL) as shown in Figure 3. If two or more master parts were used when expanding in width, a split decision could result with one master indicating BUSY on one side of the
Width Expansion with BUSY Logic Master/Slave Arrays
MASTER Dual Port RAM BUSYL
CE BUSYR
SLAVE Dual Port RAM BUSYL
CE BUSYR
BUSYL
MASTER Dual Port RAM BUSYL
CE BUSYR
SLAVE Dual Port RAM BUSYL
CE BUSYR BUSYR
2939 drw 16
Functional Description
Figure 3. Busy and chip enable routing for both width and depth expansion with IDT7026 RAMs.
The IDT7026 provides two ports with separate control, address and I/O pins that permit independent access for reads or writes to any location in memory. The IDT7026 has an automatic power down feature controlled by CE. The CE controls on-chip power down circuitry that permits the respective port to go into a standby mode when not selected (CE = VIH). When a port is enabled, access to the entire memory array is permitted.
Busy Logic
Busy Logic provides a hardware indication that both ports of the RAM have accessed the same location at the same time. It also allows one of the two accesses to proceed and signals the other side that the RAM is "Busy". The BUSY pin can then be used to stall the access until the operation on the other side is completed. If a write operation has been attempted from the side that receives a BUSY indication, the write signal is gated internally to prevent the write from proceeding. The use of BUSY logic is not required or desirable for all applications. In some cases it may be useful to logically OR the BUSY outputs together and use any BUSY indication as an interrupt source to flag the event of an illegal or illogical operation. If the write inhibit function of BUSY logic is not desirable, the BUSY logic can be disabled by placing the part in slave mode with the M/S pin. Once in slave mode the BUSY pin operates solely as a write inhibit input pin. Normal operation can be programmed by tying the BUSY pins HIGH. If desired, unintended write operations can be prevented to a port by tying the BUSY pin for that port LOW. The BUSY outputs on the IDT 7026 RAM in master mode, are pushpull type outputs and do not require pull up resistors to operate. If these RAMs are being expanded in depth, then the BUSY indication for the resulting array requires the use of an external AND gate.
array and another master indicating BUSY on one other side of the array. This would inhibit the write operations from one port for part of a word and inhibit the write operations from the other port for the other part of the word. The BUSY arbitration on a master is based on the chip enable and address signals only. It ignores whether an access is a read or write. In a master/slave array, both address and chip enable must be valid long enough for a BUSY flag to be output from the master before the actual write pulse can be initiated with either the R/W signal or the byte enables. Failure to observe this timing can result in a glitched internal write inhibit signal and corrupted data in the slave.
The IDT7026 is an extremely fast Dual-Port 16K x 16 CMOS Static RAM with an additional 8 address locations dedicated to binary semaphore flags. These flags allow either processor on the left or right side of the DualPort RAM to claim a privilege over the other processor for functions defined by the system designer's software. As an example, the semaphore can be used by one processor to inhibit the other from accessing a portion of the Dual-Port RAM or any other shared resource. The Dual-Port RAM features a fast access time, and both ports are completely independent of each other. This means that the activity on the left port in no way slows the access time of the right port. Both ports are identical in function to standard CMOS Static RAM and can be read from, or written to, at the same time with the only possible conflict arising from the simultaneous writing of, or a simultaneous READ/WRITE of, a nonsemaphore location. Semaphores are protected against such ambiguous situations and may be used by the system program to avoid any conflicts
Semaphores
6.42 15
DECODER
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
in the non-semaphore portion of the Dual-Port RAM. These devices have an automatic power-down feature controlled by CE, the Dual-Port RAM enable, and SEM, the semaphore enable. The CE and SEM pins control on-chip power down circuitry that permits the respective port to go into standby mode when not selected. This is the condition which is shown in Truth Table I where CE and SEM = VIH. Systems which can best use the IDT7026 contain multiple processors or controllers and are typically very high-speed systems which are software controlled or software intensive. These systems can benefit from a performance increase offered by the IDT7026's hardware semaphores, which provide a lockout mechanism without requiring complex programming. Software handshaking between processors offers the maximum in system flexibility by permitting shared resources to be allocated in varying configurations. The IDT7026 does not use its semaphore flags to control any resources through hardware, thus allowing the system designer total flexibility in system architecture. An advantage of using semaphores rather than the more common methods of hardware arbitration is that wait states are never incurred in either processor. This can prove to be a major advantage in very highspeed systems.
How the Semaphore Flags Work
The semaphore logic is a set of eight latches which are independent of the Dual-Port RAM. These latches can be used to pass a flag, or token, from one port to the other to indicate that a shared resource is in use. The semaphores provide a hardware assist for a use assignment method called "Token Passing Allocation." In this method, the state of a semaphore latch is used as a token indicating that shared resource is in use. If the left processor wants to use this resource, it requests the token by setting the latch. This processor then verifies its success in setting the latch by reading it. If it was successful, it proceeds to assume control over the shared resource. If it was not successful in setting the latch, it determines that the right side processor has set the latch first, has the token and is using the shared resource. The left processor can then either repeatedly request that semaphore's status or remove its request for that semaphore to perform another task and occasionally attempt again to gain control of the token via the set and test sequence. Once the right side has relinquished the token, the left side should succeed in gaining control. The semaphore flags are active LOW. A token is requested by writing a zero into a semaphore latch and is released when the same side writes a one to that latch. The eight semaphore flags reside within the IDT7026 in a separate memory space from the Dual-Port RAM. This address space is accessed by placing a LOW input on the SEM pin (which acts as a chip select for the semaphore flags) and using the other control pins (Address, OE, and R/W) as they would be used in accessing a standard Static RAM. Each of the flags has a unique address which can be accessed by either side through address pins A0 - A2. When accessing the semaphores, none of the other address pins has any effect. When writing to a semaphore, only data pin D0 is used. If a low level is written into an unused semaphore location, that flag will be set to a zero on that side and a one on the other side (see Table III). That semaphore can now only be modified by the side showing the zero. When a one is written into the same location from the same side, the flag will be set to a
one for both sides (unless a semaphore request from the other side is pending) and then can be written to by both sides. The fact that the side which is able to write a zero into a semaphore subsequently locks out writes from the other side is what makes semaphore flags useful in interprocessor communications. (A thorough discussion on the use of this feature follows shortly.) A zero written into the same location from the other side will be stored in the semaphore request latch for that side until the semaphore is freed by the first side. When a semaphore flag is read, its value is spread into all data bits so that a flag that is a one reads as a one in all data bits and a flag containing a zero reads as all zeros. The read value is latched into one side's output register when that side's semaphore select (SEM) and output enable (OE) signals go active. This serves to disallow the semaphore from changing state in the middle of a read cycle due to a write cycle from the other side. Because of this latch, a repeated read of a semaphore in a test loop must cause either signal (SEM or OE) to go inactive or the output will never change. A sequence WRITE/READ must be used by the semaphore in order to guarantee that no system level contention will occur. A processor requests access to shared resources by attempting to write a zero into a semaphore location. If the semaphore is already in use, the semaphore request latch will contain a zero, yet the semaphore flag will appear as one, a fact which the processor will verify by the subsequent read (see Table III). As an example, assume a processor writes a zero to the left port at a free semaphore location. On a subsequent read, the processor will verify that it has written successfully to that location and will assume control over the resource in question. Meanwhile, if a processor on the right side attempts to write a zero to the same semaphore flag it will fail, as will be verified by the fact that a one will be read from that semaphore on the right side during subsequent read. Had a sequence of READ/WRITE been used instead, system contention problems could have occurred during the gap between the read and write cycles. It is important to note that a failed semaphore request must be followed by either repeated reads or by writing a one into the same location. The reason for this is easily understood by looking at the simple logic diagram of the semaphore flag in Figure 4. Two semaphore request latches feed into a semaphore flag. Whichever latch is first to present a zero to the semaphore flag will force its side of the semaphore flag LOW and the other side HIGH. This condition will continue until a one is written to the same semaphore request latch. Should the other side's semaphore request latch have been written to a zero in the meantime, the semaphore flag will flip over to the other side as soon as a one is written into the first side's request latch. The second side's flag will now stay LOW until its semaphore request latch is written to a one. From this it is easy to understand that, if a semaphore is requested and the processor which requested it no longer needs the resource, the entire system can hang up until a one is written into that semaphore request latch. The critical case of semaphore timing is when both sides request a single token by attempting to write a zero into it at the same time. The semaphore logic is specially designed to resolve this problem. If simultaneous requests are made, the logic guarantees that only one side receives the token. If one side is earlier than the other in making the request, the first side to make the request will receive the token. If both requests arrive at the same time, the assignment will be arbitrarily made to one port or the other. One caution that should be noted when using semaphores is that
6.42 16
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
L PORT SEMAPHORE REQUEST FLIP FLOP D0 WRITE SEMAPHORE READ
D Q
R PORT SEMAPHORE REQUEST FLIP FLOP
Q D
D0 WRITE
SEMAPHORE READ
2939 drw 17
,
Figure 4. IDT7026 Semaphore Logic
semaphores alone do not guarantee that access to a resource is secure. As with any powerful programming technique, if semaphores are misused or misinterpreted, a software error can easily happen. Initialization of the semaphores is not automatic and must be handled via the initialization program at power-up. Since any semaphore request flag which contains a zero must be reset to a one, all semaphores on both sides should have a one written into them at initialization from both sides to assure that they will be free when needed.
Using Semaphores--Some Examples
Perhaps the simplest application of semaphores is their application as resource markers for the IDT7026's Dual-Port RAM. Say the 16K x 16 RAM was to be divided into two 8K x 16 blocks which were to be dedicated at any one time to servicing either the left or right port. Semaphore 0 could be used to indicate the side which would control the lower section of memory, and Semaphore 1 could be defined as the indicator for the upper section of memory. To take a resource, in this example the lower 8K of Dual-Port RAM, the processor on the left port could write and then read a zero in to Semaphore 0. If this task were successfully completed (a zero was read back rather than a one), the left processor would assume control of the lower 8K. Meanwhile the right processor was attempting to gain control of the resource after the left processor, it would read back a one in response to the zero it had attempted to write into Semaphore 0. At this point, the software could choose to try and gain control of the second 8K
section by writing, then reading a zero into Semaphore 1. If it succeeded in gaining control, it would lock out the left side. Once the left side was finished with its task, it would write a one to Semaphore 0 and may then try to gain access to Semaphore 1. If Semaphore 1 was still occupied by the right side, the left side could undo its semaphore request and perform other tasks until it was able to write, then read a zero into Semaphore 1. If the right processor performs a similar task with Semaphore 0, this protocol would allow the two processors to swap 8K blocks of Dual-Port RAM with each other. The blocks do not have to be any particular size and can even be variable, depending upon the complexity of the software using the semaphore flags. All eight semaphores could be used to divide the DualPort RAM or other shared resources into eight parts. Semaphores can even be assigned different meanings on different sides rather than being given a common meaning as was shown in the example above. Semaphores are a useful form of arbitration in systems like disk interfaces where the CPU must be locked out of a section of memory during a transfer and the I/O device cannot tolerate any wait states. With the use of semaphores, once the two devices has determined which memory area was "off-limits" to the CPU, both the CPU and the I/O devices could access their assigned portions of memory continuously without any wait states. Semaphores are also useful in applications where no memory "WAIT" state is available on one or both sides. Once a semaphore handshake has been performed, both processors can access their assigned RAM segments at full speed. Another application is in the area of complex data structures. In this case, block arbitration is very important. For this application one processor may be responsible for building and updating a data structure. The other processor then reads and interprets that data structure. If the interpreting processor reads an incomplete data structure, a major error condition may exist. Therefore, some sort of arbitration must be used between the two different processors. The building processor arbitrates for the block, locks it and then is able to go in and update the data structure. When the update is completed, the data structure block is released. This allows the interpreting processor to come back and read the complete data structure, thereby guaranteeing a consistent data structure.
6.42 17
IDT7026S/L High-Speed 16K x 16 Dual-Port Static RAM
Military, Industrial and Commercial Temperature Ranges
Ordering Information
IDT XXXXX Device Type A Power 999 Speed A Package A Process/ Temperature Range Blank I B G J 15 20 25 35 55 S L 7026 Commercial (0C to +70C) Industrial (-40C to + 85C) Military (-55C to +125C) Compliant to MIL-PRF-38535 QML 84-pin PGA (G84-3) 84-pin PLCC (J84-1) Commercial Only Commercial, Industrial & Military Commercial, Industrial & Military Commercial, Industrial & Military Commercial, Industrial & Military
Speed in nanoseconds
Standard Power Low Power 256K (16K x 16) Dual-Port RAM
, 2939 drw 18
Datasheet Document History
1/14/99: Initiated datasheet document history Converted to new format Cosmetic and typographical corrections Pages 2 and 3 Added additional notes to pin configurations Changed drawing format Page 1 Corrected DSC number Added Industrial Temperature Ranges and removed related notes Replaced IDT logo Page 1 Fixed format in Features Changed 200mV to 0mV in notes Page 3 Clarified TA parameter Page 6 DC Electrical parameters-changed wording from "open" to "disabled" Page 1 & 18 Verified accuracy of Industrial temp information throughout datasheet and updated with registered logo Page 2 & 3 Added date revision for pin configurations
6/3/99: 3/10/00:
5/22/00: 11/20/01:
CORPORATE HEADQUARTERS 2975 Stender Way Santa Clara, CA 95054
for SALES: 800-345-7015 or 408-727-6116 fax: 408-492-8674 www.idt.com
6.42 18
for Tech Support: 831-754-4613 DualPortHelp@idt.com
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