EZ1900

© 1999 SEMTECH CORP.

REGULATOR

BALANCE CONTROLLER

May 27, 1999

652 MITCHELL ROAD NEWBURY PARK CA 91320

1

DESCRIPTION

The EZ1900 is a high performance positive load cur-

rent balancer designed for use in applications utiliz-

ing 2 regulators in parallel to achieve equal current

sharing or identical current for each load. The regula-

tor balance controller allows a flexible motherboard

design to be made to cope with different processor

configurations. The controller reads a logic level up-

grade signal (denoted V

ilar on AMD, Cyrix and PowerPC microprocessors) to

control the output voltage of two linear low dropout

voltage regulators to the CPU core and I/O planes. In

single-voltage plane configurations (V

both regulators are set to the same output voltage

(usually 3.3 - 3.5V) and are configured in master-

slave mode. For split plane processors (V

the outputs of the two regulators are switched - the

core voltage will be set to a nominal 2.5V while the

I/O voltage will remain at 3.3V. The actual output

voltages can be adjusted by means of resistors. The

EZ1900 programmable current balancer is available

in the popular SO-8 surface mount package.

FEATURES

APPLICATIONS

split-plane processors

upgrades

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

ABSOLUTE MAXIMUM RATINGS

Parameter

Symbol

Maximum

Units

Input Voltage Supply

V

IN

7V

Differential

Amplifier

-IN, +IN

S

OUT

7

0 to +V

V

Slave Output Current

(sink only)

I

SLAVE

50

mA

Thermal Resistance

Junction to Ambient

θ

JA

160

°C/W

Operating Junction

Temperature Range

T

J

0 to 70

°C

Storage

Temperature Range

T

STG

-65 to 125

°C

Lead Temperature

(Soldering) 5 Sec

T

LEAD

260

°C

PIN CONFIGURATION

Pin #

Legend

Description

1

Sel

Non-slave mode, voltage select

2

-IN

Negative error amplifier input

3

+IN

Positive error amplifier input

4

-V

Power input, common

5

nc

No Connection

6S

OUT

Sets V

7

+V

Power input, positive

8

nc

No connection

Slave Mode Pin: For non “Computer Select Operation”, the Select

Mode, pin #1, can be left open circuited for continuous slave mode

operation or balance current control. Ground the Select Mode, pin #1,

for non-slave mode operation.

Note:

(1) Add suffix ‘TR’ for tape and reel.

ORDERING INFORMATION

DEVICE

(1)

PACKAGE

EZ1900CS

SO-8