
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
on the Intel P55C; sim-
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
floating),
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
low),
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
Current balance controller for regulators in parallel
Slave and non-slave voltage modes
Slave or non-slave mode computer selected
Compatible with 3 or 5 pin low drop regulators
Remote sense operation
SO-8 package
APPLICATIONS
Flexible upgrade from single voltage plane to
split-plane processors
Intel Pentium Processor P54CS & P55C
upgrades
PowerPC 603 & 604 upgrades
AMD5
K
86 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
7
V
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
6
S
OUT
+V
Sets V
OUT
of slave device
Power input, positive
7
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.
Pentium Processor is a trademark of Intel Corp. PowerPC is a trademark of IBM Corp. AMD5
K
86 is a trademark of Advanced Micro Devices.
Note:
(1) Add suffix ‘TR’ for tape and reel.
ORDERING INFORMATION
DEVICE
(1)
PACKAGE
EZ1900CS
SO-8