REGULATOR
BALANCE CONTROLLER
EZ1900
May 27, 1999
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
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 VCC2DET 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 (VCC2DET 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 (VCC2DET 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.
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•
•
•
•
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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
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•
Flexible upgrade from single voltage plane to
split-plane processors
Intel Pentium® Processor P54CS & P55C
upgrades
PowerPC™ 603 & 604 upgrades
AMD5K86™ upgrades
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ORDERING INFORMATION
DEVICE(1)
PACKAGE
EZ1900CS
SO-8
Note:
(1) Add suffix ‘TR’ for tape and reel.
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol Maximum Units
Input Voltage Supply
VIN
7
V
V
Differential
Amplifier
-IN, +IN
SOUT
7
0 to +V
Slave Output Current
(sink only)
ISLAVE
50
160
mA
°C/W
°C
Pin #
Legend
Sel
-IN
Description
Non-slave mode, voltage select
Negative error amplifier input
Positive error amplifier input
Power input, common
No Connection
1
2
3
4
5
6
7
8
Thermal Resistance
Junction to Ambient
θJA
TJ
Operating Junction
Temperature Range
0 to 70
-65 to 125
260
+IN
-V
Storage
Temperature Range
TSTG
°C
nc
Lead Temperature
(Soldering) 5 Sec
SOUT
+V
Sets VOUT of slave device
Power input, positive
TLEAD
°C
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.
1
Pentium Processor is a trademark of Intel Corp. PowerPC is a trademark of IBM Corp. AMD5K86 is a trademark of Advanced Micro Devices.
© 1999 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
