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Combi-Sense
POWER MANAGEMENT Description
The SC2646B controller provides a microprocessor core voltage regulation solution for up to 4 paralleled PWM channels. The solution can be configured in 2, 3, or 4phase form. This multi-phase buck regulator utilizes phase-shift timing control to allow interleaved switching of the power switches. The product's architecture minimizes the core voltage ripple and the input current ripple, which leads to optimized voltage regulator design for power density, transient responses, and thermal performances. To satisfy the highly dynamic nature of the modern microprocessors, the SC2646B adopts peak current mode control topology which ensures wide control loop bandwidth and fast transient responses. The current mode control provides intrinsic phase current matching. The maximum ripple frequency is greater than 2MHz. One of the outstanding features of the SC2646B device is its voltage regulation accuracy. Not only does it provide 0.5% set point accuracy, but also the accuracy to be fully compliant with stringent load line slope specifications mandated by the modern microprocessors. Lossless output current sensing ensures the regulator output voltage is accurately positioned according to the load current condition. Semtech's patented Combi-SenseTM topology is employed by SC2646B controller. The MOSFET Rds(on) and the output inductor winding resistance is used to generate the phase current information. Semtech's SC1211 Combi-SenseTM MOSFET driver works with the SC2646B to enable a complete solution. The cycle-by-cycle current limit plus the intelligent over current shut down provide the maximum versatility of the system without false tripping under all possible changes of VID and load conditions. The differential voltage feedback sense eliminates the error caused by high load current on the ground plane. External offset is easy to achieve for the VID settings. The enable function is also provided to interface with the corresponding system signal for correct start up timing and shut down timing.
TM
2, 3 or 4 Phase PWM Controller
SC2646B
Features
! ! ! ! ! ! ! ! ! ! ! ! ! ! ! VRD/VRM10.X compliant Core Voltage Set Point Accuracy 0.5% Combi-SenseTM Current Mode Control Intrinsic Phase Current Matching Fast Transient Responses Active Droop to Meet Load Line Slope Enable Function for Power Sequencing Cycle-by-Cycle Peak Current Limit Intelligent Over Current Shut Down Over Voltage Protection When Using Semtech Combi-SenseTM Driver SC1211 Under Voltage Protection Built in Externally Programmable Soft-Start Externally Programmable Switching Frequency 2, 3, or 4-Phase Configurations 24-Pin TSSOP Package
Combi-SenseTM is a Trademark of Semtech Corporation
Applications
! Voltage Regulator VRD/VRM10.X ! Voltage Regulation Modules ! High Current, Low Voltage Step Down DC/DC Converters
Revision: Sept. 12, 2005
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SC2646B
VIN ATX12V 1 640nH R1 PN1 AUX1 U1 R2 44.2K 4 3 2 CO BST TG MSENSE C6 R5 TBD AUX3 R6 TBD R7 TBD PN3 R3 44.2K R4 44.2K 1 R8 DRN 9 PGND VR EG VPN V IN BG 1 M2 M3 AUX2 AUX3 D1N4148 1uF PN2 PN3 2R2 M1 D1 C3 2 ATX12V L1
1800uF/16V
VOUT
C1 +
C2 4.7uF/1206
C4
1800uF/6.3V
PN3
L2
C5
1
2
+
1800uF/6.3V
SC1211
C7 6.8nF C10 R14 100 TBD R13 TBD
R9 54.9K C8 6.8nF R10 54.9K C9 6.8nF
R11 54.9K
1nF
R12
820nH
IR0
C11
+
1800uF/6.3V
C12 5 6 7 8
U2 VOUT OS4 OUTSEN OUT4 OUT3 OUT2 OUT1 AGND OSCREF PGOOD VID5 VID3 12 3.3V 4.7uF VID2 VID0 VID1 19 20 21 22 23 VCC 24 1 OS3 OS2 OS1 BGOUT ERROUT GNDSEN FB MSENSE VCC VID4 2 VRM_EN 3 4 300 5 R16 20K C20 1uF VCC MSENSE 8 9 ATX12V R20 11 10 C25 10 7 C22 470pF 6
2.2nF C14 1uF D2 D1N4148 C15 4.7uF VIN C16 1uF M4 4 3 2 18 AUX2 17 16 15 R21 14 100 13 5 6 7 8 R17 320K PN2 1
C13
+
1800uF/6.3V
(Open-Collector) R15
1800uF/16V
C17
+
1800uF/6.3V
C18 +
C21 BST CO TG DRN R18
PN2
1800uF/6.3V
L3
SC1211
C23 1nF
1 PGND VR EG VPN V IN BG 9 1 M5 U3 M6
2
C24 IR0
1800uF/6.3V
C26
2.2nF
C27
+
SC2646
R22 R23 R24 R25 R26 R27 1K 1K 1K 1K 1K 1K D3 VID0 VID1
1800uF/6.3V C28 1uF C29 4.7uF C30 D1N4148 1uF M7 VIN
1800uF/16V
C31
+
1800uF/6.3V
C32 +
C33 4.7uF/1206 4 3 2 PN1 AUX1 1
POWER MANAGEMENT Typical Application Circuit
VID2 VID3 VID4 VID5 VCC R31 2.9K PGOOD (3V3 LOGIC) C39 10nF R33 1.1K
C34 CO BST TG DRN R28
PN1
+
1800uF/6.3V
L4
SC 1211
C35 1nF R30 100
1 PGND VR EG VPN V IN BG 9 1 M8 U4 5 6 7 8 M9
2
820nH
R29
C36
R32 C37 V_COREV_CORE+ C38
2.2nF
PGND
0R0
DIFFERENTIAL PAIR FOR REMOTE SENSE
1uF
4.7uF
2005 Semtech Corp.
IR0
+
2
R19
820nH
HIGH FREQUENCY DECOUPLING NOT SHOWN
C19 4.7uF/1206
+
+
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SC2646B
POWER MANAGEMENT Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied.
Parameter Supply Voltage Combi-Sense/Direct Output Voltage Ambient Temperature Range Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) 10 Sec.
Symbol VCC OS1, OS2, OS3, OS4, OUTSEN TA TJ TSTG TLEAD
Maximum 20 5 0 to 85 0 to 125 -65 to +150 260
Units V V
o
C C C C
o
o
o
Electrical Characteristics
Unless specified: VCC = 12V, FOSC = 600kHz, 4 phase operation, VOUT = 1.28V, TA = 27 C. See Typical Application Circuit. Specifications subject to change without notice.
o
Parameter Chip_Supply IC Supply Voltage IC Supply Current UVLO Ramp Up UVLO Hysteresis Reference Section Bandgap Output Source Current Supply Rejection Temperature Stability (1) Voltage Accuracy Oscillator Section Oscillator Frequency Oscillator Frequency Range Temperature Stability (1) Voltage Error Amplifier Input Bias Current (1) Open Loop Gain (1)
2005 Semtech Corp.
Symbol
Test Conditions
Min
Typ
Max
Units
VCC ICC
7
12 5.4 6.3
14 8.0 7.0
V mA V mV
700
890
VBGOUT
CBGOUT = 4.7nF 55 VCC = 10.0V ~ 14.0V 0oC < TA < 85oC
1.5 70 0.5 0.5 -0.5 +0.5 95
V A mV/V % %
VOUT
Internal offset is -20mV
FOSC FOSC
ROSC = 320K
540 500
600
660 3000
kHz kHz %
0oC < TA < 85oC
+/ - 5
25 1V < VERROUT < 3.4V
3
nA dB
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SC2646B
POWER MANAGEMENT Electrical Characteristics (Cont.)
Unless specified: VCC = 12V, FOSC = 600kHz, 4 phase operation, VOUT = 1.28V, TA = 27 C. See Typical Application Circuit. Specifications subject to change without
o
Parameter Unity Gain Bandwidth (1) Source Current Sink Current Transconductance Gain Current Sense Amplifiers Input Offset Voltage Input Bias Current Gain CMRR (1) Input Common Mode Range Gain Match Bandwidth (1) Droop Amplifier Gain VIDs Logic High Logi c Low Internal Pull-up Impedance (1) Internal Pull-up Voltage (1) 3-Phase Operation Output 4 pull up Threshold Pow er Good Threshold Rising Threshold Falling Power Good Delay (1) Output High Leakage Output Voltage Low Level Current Limit Section Max. Error Amp Voltage for Current Limit Shutdown Voltage
Symbol GBW
Test Conditions CERROUT = 10pF VBG > 1.8V, VFB = 0V, VERROUT = 0.8V VBG > 1V, VFB = 2V, VERROUT = 2V
Min
Typ 5
Max
Units MHz
60 -90 0.62
80 -80 0.82
90 -60 1.03
uA uA mA/V
GM
VIO IM Gca 0 to 3V -0.3
+/-3 50 12.45 80 3 5 6 6
mV nA V/V dB V % MHz
ADRP
VMSENSE-VOUTSEN = 20mV
11.1
11.7
12.3
V/V
[VID0:5] [VID0:5] [VID0:4] [VID0:4]
0.8 0.4 26 1.4
V V Kohm V
3.88
4.0
4.5
V
VID - Power Good Threshold VID - Power Good Threshold From Cross Rising Threshold Pwrgood = VCC Sink Current = 1mA 4.0
100 250 5 60 0.48 0.5 6.5
mV mV mS nA V
VOC V SD VID - Shut Down Threshold
3.45 180
3.63 210
3.81 280
V mV
Note: (1). Guaranteed by design, not tested in production. (2). This device is ESD sensitive. Use of standard ESD handling precautions is required.
2005 Semtech Corp. 4 www.semtech.com
SC2646B
POWER MANAGEMENT Pin Configurations
Top View
OS3 OS2 OS1 BGOUT ERROUT GSENSE FB MSENSE VCC VID4 VID3 VID2 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 OS4 OUTSEN OUT4 OUT3 OUT2 OUT1 AGND OSCREF PGOOD VID5 VID0 VID1
Ordering Information
Part Number SC2646BTSTRT (1) (2) SC2646BEVB Package TSSOP-24 Temp. Range (T J) 0 to 125 OC
Embedded Evaluation Board
Note: (1) Only available in tape and reel packaging. A reel contains 2500 devices for the TSSOP-24 package. (2) Lead free package.Device is fully WEEE and RoHS compliant.
(24-Pin TSSOP)
Pin Descriptions
Pin# 1 2 3 4 5 6 7 8 9 10 15 16 17 18 19 20 21 22 23 24 Pin Name OS3 OS2 OS1 BGOUT ERROUT GSENSE FB MSENSE VC C VID[4:0] VID5 PGOOD OSCREF AGND OUT1 OUT2 OUT3 OUT4 OUTSEN OS4 Current sense input Current sense input. Connect to OUTSEN for 2 phase operation. Current sense input Bandgap reference voltage. Connect soft start cap to AGND. Error-amplifier output. Connect compensation network to AGND. Remote sense for GND. Feedback pin. Route FB and Gsense as differential pair to CPU sense point. Voltage regulator module output current sense. Power supply for chip. VID MSB to LSB. 12.5mV bit. Power good. Open collector output. Oscillator frequency setting. Connect a resistor to AGND. Clean ground for analog signals. PWM output1. PWM output2. PWM output3. PWM output4. Connect to VCC for 3 phase operation. Direct output sense. Current sense input. Connect to OUTSEN for 2 or 3 phase operation.
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Pin Function
2005 Semtech Corp.
SC2646B
POWER MANAGEMENT Block Diagram
C/A1
OS1 3 + OUT +
PWM1
OUT R S Q
DRV1 19 OUT1
C/A2
OS2 2 + OUT -
+
PWM2
OUT R S Q
DRV2 20 OUT2
C/A3
OS3 1 + OUT -
+
PWM3
OUT R S Q
DRV3 21 OUT3
C/A4
OS4 24 + OUT
+
PWM4
OUT R S Q
DRV4
22 OUT4
OUTSEN
OUTSEN 23
-
OSCILLATOR
Ramp OSCREF 17 ROSC OSC
ERROUT CLOCK DIVIDER
CLK SEL3 P1 P2 P3 P4 + OUT
VID0 VID1 VID2 VID3 VID4 VID5
14
DAC
12 11 10 15 VID0 VID1 VID2 VID3 VID4 VID5 Shut Down 13
11111 INHIBIT
3 PHASE SELECT
-
4.2V
I_DAC
PWR_GOOD
+ 16 OUT PWRGD
OUTSEN DROOP
OUT MSENSE FB 8 7 + -
DELAY
0.8*VBG
-
E/A
OUT
ERROUT
5 ERROUT
R
+
BGOUT
BGOUT 4 OUT
OCP & SHUTDOWM
VBG
BUFFER
+
VCC
VCC
9
VCC
+ -
UVLO & LATCH
BGOUT
18
AGND
VREF
GSENSE
6
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SC2646B
POWER MANAGEMENT Applications Information- Output Voltage
VRD10 Output Voltage Unless specified: 0 = GND; 1 = High. TA = 25C, VCC = 12V
VID5 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 VID4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 VID3 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 VID2 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 VID1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 VID0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 Vout (V) 0.8375 0.8500 0.8625 0.8750 0.8875 0.9000 0.9125 0.9250 0.9375 0.9500 0.9625 0.9750 0.9875 1.0000 1.0125 1.0250 1.0375 1.0500 1.0625 1.0750 1.0875 OFF OFF 1.1000 1.1125 1.1250 1.1375 1.1500 1.1625 1.1750 1.1875 1.2000 1.2125 1.2250 1.2375 1.2500 1.2625 1.2750 1.2875 1.3000 1.3125 1.3250 1.3375 1.3500 1.3625 1.3750 1.3875 1.4000 1.4125 1.4250 1.4375 1.4500 1.4625 1.4750 1.4875 1.5000 1.5125 1.5250 1.5375 1.5500 1.5625 1.5750 1.5875 1.6000
2005 Semtech Corp.
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SC2646B
POWER MANAGEMENT Outline Drawing - TSSOP-24
DIMENSIONS MILLIMETERS INCHES DIM MIN NOM MAX MIN NOM MAX
A A1 A2 b c D E1 E e L L1 N 01 aaa bbb ccc .047 .006 .002 .042 .031 .012 .007 .007 .003 .303 .307 .311 .169 .173 .177 .252 BSC .026 BSC .018 .024 .030 (.039) 24 0 8 .004 .004 .008 1.20 0.15 0.05 1.05 0.80 0.19 0.30 0.20 0.09 7.70 7.80 7.90 4.30 4.40 4.50 6.40 BSC 0.65 BSC 0.45 0.60 0.75 (1.0) 24 0 8 0.10 0.10 0.20
A e N 2X E/2 E1 PIN 1 INDICATOR ccc C 2X N/2 TIPS 123 e/2 B E D
aaa C SEATING PLANE
D A2 A
C bxN bbb
A1 C A-B D GAGE PLANE 0.25
H c
L (L1)
01
SIDE VIEW
SEE DETAIL
A
DETAIL
A
NOTES: 1. 2. 3. 4. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). DATUMS -A- AND -B- TO BE DETERMINED AT DATUM PLANE -HDIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. REFERENCE JEDEC STD MO-153, VARIATION AD.
2005 Semtech Corp.
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SC2646B
POWER MANAGEMENT Land Pattern - TSSOP-24
X
DIM
(C) G Z C G P X Y Z
DIMENSIONS INCHES MILLIMETERS
(.222) .161 .026 .016 .061 .283 (5.65) 4.10 0.65 0.40 1.55 7.20
Y P
NOTES: 1.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET.
Contact Information
Semtech Corporation Power Management Products Division 200 Flynn Rd., Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804
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