MM74HC688 8-Bit Magnitude Comparator (Equality Detector)
September 1983 Revised February 1999
MM74HC688 8-Bit Magnitude Comparator (Equality Detector)
General Description
The MM74HC688 equality detector utilizes advanced silicon-gate CMOS technology to compare bit for bit two 8-bit words and indicates whether or not they are equal. The P=Q output indicates equality when it is LOW. A single active low enable is provided to facilitate cascading of several packages and enable comparison of words greater than 8 bits. This device is useful in memory block decoding applications, where memory block enable signals must be generated from computer address information. The comparator's output can drive 10 low power Schottky equivalent loads. This comparator is functionally and pin compatible to the 74LS688. All inputs are protected from damage due to static discharge by diodes to VCC and ground.
Features
s Typical propagation delay: 20 ns s Wide power supply range: 2-6V s Low quiescent current: 80 A (74 Series) s Large output current: 4 mA (74 Series) s Same as HC521
Ordering Code:
Order Number MM74HC688WM MM74HC688SJ MM74HC688MTC MM74HC688N Package Number M20B M20D MTC20 N20A Package Description 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide 20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code.
Connection Diagram
Pin Assignments for DIP
Logic Diagram
Top View
Truth Table
Inputs Data P,Q P=Q P>Q P(c) 1999 Fairchild Semiconductor Corporation
DS005018.prf
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MM74HC688
Absolute Maximum Ratings(Note 1)
(Note 2) Supply Voltage (VCC) DC Input Voltage (VIN) DC Output Voltage (VOUT) Clamp Diode Current (IIK, IOK) DC Output Current, per pin (IOUT) DC VCC or GND Current, per pin Power Dissipation (PD) (Note 3) S.O. Package only Lead Temperature (TL) (Soldering 10 seconds) 260C 600 mW 500 mW (ICC) Storage Temperature Range (TSTG) -0.5 to +7.0V
Recommended Operating Conditions
Min 2 0 -40 Max 6 VCC +85 1000 500 400 Units V V C ns ns ns
-1.5 to VCC +1.5V Supply Voltage (V ) CC -0.5 to VCC +0.5V DC Input or Output Voltage 20 mA 25 mA (VIN, VOUT ) Operating Temperature Range (TA)
r f CC
50 mA Input Rise or Fall Times -65C to +150C (t , t ) V = 2.0V VCC = 4.5V VCC = 6.0V
Note 1: Absolute Maximum Ratings are those values beyond which damage to the device may occur. Note 2: Unless otherwise specified all voltages are referenced to ground. Note 3: Power Dissipation temperature derating -- plastic "N" package: - 12 mW/C from 65C to 85C.
DC Electrical Characteristics
Symbol VIH Parameter Minimum HIGH Level Input Voltage VIL Maximum LOW Level Input Voltage VOH Minimum HIGH Level Output Voltage VIN = VIH or VIL |IOUT| 20 A Conditions
(Note 4)
VCC 2.0V 4.5V 6.0V 2.0V 4.5V 6.0V 2.0V 4.5V 6.0V 2.0 4.5 6.0 4.2 5.7 0 0 0 0.2 0.2 TA = 25C Typ 1.5 3.15 4.2 0.5 1.35 1.8 1.9 4.4 5.9 3.98 5.48 0.1 0.1 0.1 0.26 0.26 0.1 8.0 TA = -40 to 85C TA = -55 to 125C Guaranteed Limits 1.5 3.15 4.2 0.5 1.35 1.8 1.9 4.4 5.9 3.84 5.34 0.1 0.1 0.1 0.33 0.33 1.0 80 1.5 3.15 4.2 0.5 1.35 1.8 1.9 4.4 5.9 3.7 5.2 0.1 0.1 0.1 0.4 0.4 1.0 160 Units V V V V V V V V V V V V V V V V A A
VIN = VIH or VIL |IOUT| 4.0 mA |IOUT| 5.2 mA VOL Maximum LOW Level Output Voltage VIN = VIH or VIL |IOUT| 20 A 2.0V 4.5V 6.0V VIN = VIH or VIL |IOUT| 4.0 mA |IOUT| 5.2 mA IIN ICC Maximum Input Current Maximum Quiescent Supply Current VIN = VCC or GND IOUT = 0 A 6.0V VIN = VCC or GND 4.5V 6.0V 6.0V 4.5V 6.0V
Note 4: For a power supply of 5V 10% the worst case output voltages (VOH, and VOL) occur for HC at 4.5V. Thus the 4.5V values should be used when designing with this supply. Worst case VIH and VIL occur at VCC = 5.5V and 4.5V respectively. (The VIH value at 5.5V is 3.85V.) The worst case leakage current (IIN, ICC, and IOZ) occur for CMOS at the higher voltage and so the 6.0V values should be used.
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2
MM74HC688
AC Electrical Characteristics
VCC = 5V, TA = 25C, CL = 15 pF, tr = tf = 6 ns Symbol tPHL, tPLH tPLH, tPHL Parameter Maximum Propagation Delay, any P or Q to Output Maximum Propagation Delay, Enable to any Output 14 20 ns Conditions Typ 21 Guaranteed Limit 30 Units ns
AC Electrical Characteristics
VCC = 2.0V to 6.0V, CL = 50 pF, tr = tf = 6 ns (unless otherwise specified) Symbol tPHL, tPLH Parameter Maximum Propagation Delay, P or Q to Output tPHL, tPLH Maximum Propagation Delay, Enable to Output tTHL, tTLH Maximum Output Rise and Fall Time CPD CIN Power Dissipation Capacitance (Note 5) Maximum Input Capacitance
Note 5: CPD determines the no load dynamic power consumption, PD = CPD VCC2 f + ICC VCC, and the no load dynamic current consumption, IS = CPD VCC f + ICC.
Conditions
VCC 2.0V 4.5V 6.0V 2.0V 4.5V 6.0V 2.0V 4.5V 6.0V
TA= 25C Typ 60 22 19 45 15 13 30 8 7 45 5 10 175 35 30 120 24 20 75 15 13
TA = -40 to 85C TA = -55 to 125C Guaranteed Limits 220 44 38 150 30 25 95 19 16 263 53 45 180 36 30 110 22 19
Units ns ns ns ns ns ns ns ns ns pF
10
10
pF
3
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MM74HC688
Physical Dimensions inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide Package Number M20B
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide Package Number M20D www.fairchildsemi.com 4
MM74HC688
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide Package Number MTC20
5
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MM74HC688 8-Bit Magnitude Comparator (Equality Detector)
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N20A
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