ST ISA051V1 User Manual

STEVAL-ISA051V1

Complete DDR2/3 memory power supply controller evaluation board based on the PM6670S

Features

■4.5 V to 28 V input voltage range

■0.9 V, ±1% voltage reference

■1.8 V (DDR2) or 1.5 V (DDR3) fixed output voltages

■0.9 V to 2.6 V adjustable output voltage

■1.237 V ±1% reference voltage available

■Very fast load transient response

■Constant on-time loop control

■No RSENSE current sensing using the RDS(on) of the low-side MOSFETs

■Negative current limit

■Latched OVP, UVP and thermal shutdown

■Fixed 3 ms soft-start

■Selectable pulse-skipping at light load

■Selectable no-audible (33 kHz) pulse-skip mode

■All ceramic output capacitors application supported

■Output voltage ripple compensation

Data Brief

STEVAL-ISA051V1

The device is fully compliant with system sleep states S3 and S4/S5, providing LDO output high impedance in suspend-to-RAM and tracking discharge of all outputs in suspend-to-disk.

Description

This evaluation board is based on the PM6670S and represents a complete DDR2/3 power supply regulator for portable applications designed to meet JEDEC specifications. It integrates a constant on-time (COT) buck controller, a 2 Apk sink/source low drop-out regulator and a 15 mA low noise buffered reference. The COT architecture assures fast transient response supporting both polymeric and ceramic output capacitors. An embedded integrator control loop compensates the DC voltage error due to the output ripple. The 2 Apk sink/source linear regulator provides the memory termination voltage with fast load transient response.

February 2008	Rev 1	1/4
For further information contact your local STMicroelectronics sales office.		www.st.com

2/4

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Circuit

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AVCC

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Circuit

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TP6

TP15

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TP16

VTTREF

VCC

AGND

LDOIN

VTT

AGND

JP1

TP18

STRIP 3

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AUX

0603-join

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AUX

VCC

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JP3

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schematic

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Schematic

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AVCC

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C11

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1206-22u

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AUX

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VOUT_1S8

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AVCC

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AVCC

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C28

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R6

JP4

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R3

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C3

TP10

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VOUT_1S5

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TP8

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C6

B Case - 220u

VCC

VTTFB

DSCG VTTREF

LDOIN VTT GNDVTT AVCC

AGND2

PH1SET

AGND3

EN1S8

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R7

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C5

EL SMD C-10u

C15

L2

GND

B Case - 220u

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AGND_1

EN_VTT

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0603-100k

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2839-1u5

SET_SWF

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C8

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VOUT_1S8

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EL SMD C-10u

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CSNS

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U1

32

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JP5

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PM6641_QFPN

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SGND_1S5_1

GND

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28

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VFB_1S5

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COMP_1S5

C30

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26

1

VIN

VFB_1S8

SS_1S5

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25

COMP_1S8

PG_1S5

C34

0603-100p

1S05SGND1 1S05SGND2 1S05VSW1 1S05VSW2

1S8SS

1S05SS

1S05COMP 1S05VFB

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1S05PG

1S8PG

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R11

R32

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THERMAL

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2839-1u

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AUX

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PG_1S5

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STEVAL

R9

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EL SMD C-10u

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R17

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R19

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C13

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EL SMD C-10u

C9

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C14

B Case - 220u

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0603-56k

ISA051V1-

TP12

TP13

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TP7

R10

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JP6

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STRIP 3

VOUT_1S05

GND

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VCC