SMM205

Preliminary Information

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www.summitmicro.com

2069 1.4 6/23/03

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FEATURES & APPLICATIONS

• Extremely accurate (±0.1%) Active

DC Output Control (ADOC)

• ADOC Automatically adjusts supply output

voltage level under all load conditions

• Capable of margining supplies with trim inputs

using either positive or negative trim pin control

• Wide Margin/ADOC range from 0.3V to VDD

• Uses either an internal or external VREF

• Operates from any intermediate bus supply

from 8V to 15V and from 2.7V to 5.5V

• Programmable START and READY pins

• Two programmable general purpose monitor

sensors – UV and OV with FAULT Output Flag

• General Purpose 1k EEPROM with Write Protect

configuration and monitoring status.

• 28 lead QFN package

Applications

• In-system test and control of Point-of-Load

(POL) Power Supplies for Multi-voltage

Processors, DSPs and ASICs

• Enterprise and edge routers, servers, Storage

Area Networks

INTRODUCTION

The SMM205 actively controls the output voltage level

of two DC/DC converters that use a Trim or VADJ/FB

pin to adjust the output. An Active DC Output Control

(ADOC) feature is used during normal operation to

maintain extremely accurate settings of supply

voltages and, during system test, to control margining

of the supplies using I

with a ±0.1% external reference is ±0.2%, and ±0.5%

using the internal reference. The device can margin

supplies with either positive or negative trim pin control

within a range of 0.3V to VDD. The SMM105 supply

can be from 12V, 8V, 5V or 3.3V to as low as 2.7V to

accommodate any intermediate bus supply.

The voltage settings (margin high/low and nominal)

are programmed into nonvolatile memory through the

industry standard I

also used to enable margin high, margin low, ADOC or

normal operation. When margining, the SMM205

checks the voltage output of the converter and make

adjustments to the trim pin via a feedback loop to bring

the voltage to the margin setting. A margining status

register is set to indicate that the system is ready for

test. The SMM205 ADOC continues to monitor and

adjust the channel output at the specified level.

SIMPLIFIED APPLICATIONS DRAWING

START

WP#

VREF_CNTL

TRIM_CAPA

COMP1

TRIMA

COMP2

READY

TRIM_CAPB

TRIMB

VMB

VMA

VDD_CAP

FILT_CAP

SMM205

6V to 15V

2.7V to 5.5V

Intermediate

Bus Voltage

(IBA

BUS

A0

A2

SCL

SDA

A1

DC/DC

V–

Trim

V+

Vin

On/Off

DC/DC

V–

Trim

V+

Vin

On/Off

UV

OV

Processor

V1

V2

GND

External or

Internal

VREF

Figure 1 – Applications Schematic showing the SMM205 ADOC actively control the DC output level of 2

DC/DC Converters as well as provide margin control. The SMM205 can operate over a wide supply range

Note: This is an applications example only. Some pins, components and values are not shown.

Dual Channel Supply Voltage Marginer and Active DC Output Controller