SC473 SEMTECH [Semtech Corporation], SC473 Datasheet

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SC473

Manufacturer Part Number
SC473
Description
Single-Phase Single Chip Graphics Core Power Supply
Manufacturer
SEMTECH [Semtech Corporation]
Datasheet

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Part Number
Manufacturer
Quantity
Price
Part Number:
SC473AAB
Manufacturer:
IMI
Quantity:
20 000
The SC473 is a single-phase chip, high-performance PWM
controller designed to power advanced graphic cores. On-
chip support is provided that includes slew-rate controlled
VID transitions.
The SC473 implements hysteretic control technology which
provides the fastest possible transient response while
avoiding the stability issues inherent to classical PWM
controllers. Eliminating the sense resistors reduces costs
and PCB area, plus increases system effi ciency. Integrated
SmartDriver™ technology initially turns on the high-side
driver with ‘soft’ drive to reduce ringing, EMI, and capaci-
tive turn-on of the low side MOSFET, while also increasing
overall effi ciency.
Hysteretic operation adaptively reduces the SC473 switch-
ing frequency at light loads. Combined with an automatic
“powersave” mode which prevents negative current fl ow in
the low-side FET, system effi ciency is signifi cantly enhanced
during light loading conditions.
A 5-bit DAC, accurate to 0.85%, sets the output voltage
reference, and implements the voltage range required by
the processor. The DAC slew rate is externally programmed
to minimize transient currents and audible noise. True
differential remote sensing provides accurate point-of-load
regulation at the processor die. Other features include
programmable soft-start, an open-drain PWRGD output,
dual-level over-voltage and programmable over-current pro-
tection. The SC473 is available in a space-saving 4x4mm,
24-pin MLP package.
Updated - Aug 17, 2006
POWER MANAGEMENT
Description
1
Features
Applications
Single-Phase Solution with Integrated Drivers
Hysteretic Control for Fast Transient Response
SmartDriver™ for reduced EMI
True Differential Remote (die) Sensing
VID Programmed Voltage
Delayed Power Good Signal with Blanking
Programmable Soft-Start and DAC Slew Control
Programmable OCP Threshold
Supports all Ceramic Decoupling Solutions
24-Pin MLP (4x4)
Lead-Free Package
RoHS and WEEE compliant
High Performance Graphics
Embedded Applications
Graphics Core Power Supply
Single-Phase Single Chip
www.semtech.com
SC473

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SC473 Summary of contents

Page 1

... Other features include programmable soft-start, an open-drain PWRGD output, dual-level over-voltage and programmable over-current pro- tection. The SC473 is available in a space-saving 4x4mm, 24-pin MLP package. Updated - Aug 17, 2006 Single-Phase Single Chip ...

Page 2

... POWER MANAGEMENT Typical Application Circuit SC473 © 2006 Semtech Corp PMON FB ERROUT 21 DRN AGND 22 TG VREF 23 BST CLSET 24 GND ...

Page 3

... Semtech Corp. Condition Static Transient <100ns Static Transient <100ns θ STG T IRrefl ow < +125°C. J Condition Min 4.5 Rising 4.25 Hysteresis Falling UVLO Operating (Static) 3 SC473 Min Max Units -0.3 6 DRN, -0.3 BST, +0.3 V -0.3 V5, +0 ...

Page 4

... Current Sensing (CS+, CS-) CS+, CS- Input Bias Current Maximum Input Signal Zero-Crosssing Detector Threshold Powersave © 2006 Semtech Corp. Condition <85°C) J 1.15 - 0.85V 0.825V - 0.5V 0.475 - 0.375V 0.3V < DAC < 1.5V Start-up and Operating Discharge (SS = 0.5V) CS+ = CS- = 1.5V 4 SC473 Min Typ Max 0.8 2.0 0.45 0.55 40 -0.85 +0. -14 14 |50| 102 120 138 ...

Page 5

... Semtech Corp. Condition CLSET = 1.2V, TG Low CLSET = 1.2V, TG High HYS = 1V FB Rising Relative DAC FB Falling Relative DAC FB Rising Relative DAC PWRGD High Impedance PWRGD = 0.1V CS+, CS- = 4mV CS+, CS- = 16mV 5 SC473 Min Typ Max 50 80 125 |1| | 1.65 1.7 1.75 +160 +200 ...

Page 6

... G_DN C = 3nF 3nF TG From Hysteretic Comparator Inputs to Driver Output R at 25°C BG_UP BG_UP R at -40° to 125°C BG_UP BG_UP R at 25°C BG_DN BG_DN R at -40° to 125°C BG_DN BG_DN C = 3nF 3nF BG 6 SC473 Min Typ Max 1.75 2.0 2.25 4.1 5.8 7.5 3.48 5.8 9.24 0.9 1.3 1.7 0.76 1.3 1.7 0.42 0.6 0.78 0.34 0.6 1. ...

Page 7

... VID2 PGND PAD 4 VID1 5 VID0 6 HYS SC473 Pin Out Diagram Top View Marking Information yyww = Date Code (Example: 0550) xxxxx = Semtech Lot Number (Example: E9000) xxxxx = (Example: 1–100) © 2006 Semtech Corp. Ordering Information Device SC473MLTRT 18 PWRGD SC473EVB ...

Page 8

... Bootstrap pin - a capacitor is connected between BST and DRN to develop the fl oating 24 BST voltage for the switching MOSFET Thermal Pad Power ground for driver - connect with at least two vias to the system GND plane © 2006 Semtech Corp. Pin Description 8 SC473 www.semtech.com ...

Page 9

... Semtech Corp ERROR AMP - HYSTERETIC COMPARATOR + + - FILTER REFERENCE limit - + VID [4:0] CO DAC START UP DRIVERS CROSS CONDUCTION PROTECTION CO ZERO CS CROSSING SC473 9 SC473 ERROUT I - limit Hys_hi Hys_lo CO + VREF & UVLO - PWRGD LOGIC 3ms PWRGD TIME BST TG DRN V5 BG PGND www.semtech.com ...

Page 10

... The SC473 provides a complete solution to high perfor- mance graphics core requirements. In the SC473, the ripple for the hysteretic switching control is provided by DCR sensing. This provides several advan- tages over plain voltage-mode hysteretic converters, which switch on voltage ripple. • ...

Page 11

... If the FB voltage is 200mV greater than the DAC voltage (i.e., out of the pow- ergood window), the SC473 will latch off and hold the low- side driver on permanently. Either the power or EN must be recycled to clear the latch. The latch is disabled © ...

Page 12

... POWER MANAGEMENT Applications Information (Cont.) DC Sense Voltage RCS LOAD RCS LOAD L1 L-R Rcs R25 R25 100 100 Power Monitor Implementation for SC473 (R Sense) IR33 VDCR (R25 R25 VR33 IR33 R33 PMON_Ideal V R33 Vcc_core © 2006 Semtech Corp. +Vcc_core CS- R33 I V R33 ...

Page 13

... International Rectifi er Fairchild Semiconductor Siliconix Infenion Technologies Various Various Vishay / Panasonic Various IRC, Panasonic Panasonic / NEC-TOKIN SPCAP 13 SC473 Series or Part Number IRF7821, IRF6602, SSC3002S, Si4860DY,Si4410BDY Depends on Application X5R or better Schottky, 200mA or greater 0.2 μH - 0.5μH X5R or better ERJ-M1WTJ 330μF, max ESR 6mΩ ...

Page 14

... SC473 VID0 V OUT 0 1.1500V 1 1.1250V 0 1.1000V 1 1.0750V 0 1.0500V 1 1.0250V 0 1.0000V 1 0.9750V 0 0.9500V 1 0.9250V 0 0.9000V 1 0.8750V 0 0.8500V 1 0.8250V 0 0.8000V 1 0.7750V 0 0.7500V 1 0.7250V 0 0 ...

Page 15

... Figure 2 – Battery Mode Line and Load Regulation Battery Efficiency vs. Output Current V = 0.97500V OUT 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 Output Current (A) 19V 9V Figure 4 – Battery Mode Efficiency v/s Output Current PMON Error vs. Current V = 1.1500V OUT 9.00 14.00 19.00 24.00 29.00 Iout (A) DCR SENSE Figure 6 – Typical PMON Error v/s Output Current www.semtech.com SC473 20.00 22.00 24.00 20.00 22.00 24.00 34.00 ...

Page 16

... Figure 7 – Nominal Operation @ Iout = 30A Figure 9 – Output Voltage with 24A load step *Above performance graphs correspond to Applications Schematic on page 2 © 2006 Semtech Corp. Figure 8 – Voltage Transition 0.95V to 1.15V Figure 10 – Output Voltage with 24A dynamic load release 16 SC473 www.semtech.com ...

Page 17

... POWER MANAGEMENT Outline Drawing - MLP-32 Outline Drawing - MLP 4x4-24 © 2006 Semtech Corp. 17 SC473 www.semtech.com ...

Page 18

... POWER MANAGEMENT Land Pattern - MLP-32 Land Pattern - MLP 4x4-24 Contact Information Phone: (805) 498-2111 Fax: (805) 498-3804 © 2006 Semtech Corp. Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 18 SC473 www.semtech.com ...

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