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Date 5/25/04

SPX1581 5A Ultra Low Dropout Voltage Regulator

©Copyright 2004 Sipex Corporation

The SPX1581 is designed as a high performance

and low cost solution for application requiring a

lower dropout than traditional NPN regulators.

voltage. This allows the 2.5V power for the load

to come from a 3.3V system supply.

As added benefit this will reduce the heat dissi-

pation*, and lower heatsink and cooling fan cost.

supply to provide a nominal 2.5V output. Using

the sense pin allows Kelvin measure the output,

reducing resistance-associated errors.

The SPX1581 can power the 2.5V core voltage

CURRENT

LIMIT

AMPLIFIER

THERMAL OVERLOAD

VOLTAGE

REGULATION

AMPLIFIER

LIMIT

SENSE

SENSE (1)

ADJ (2)

S.O.A

PIN NUMBER

PIN NAME

DESCRIPTION

1

SENSE

voltage of the device).

2

ADJ

Negative side of the reference voltage for the device. Adding a small

bypass capacitor from the ADJ pin to ground will improve the transient

response.

Power output of the device.

Supply pin for the control circuitry of the device. The current flow into this

and 1.3V greater than the output voltage for the

device to regulate.

and 0.8V greater than the output voltage for this device to regulate.

PIN DESCRIPTION

FUNCTIONAL DIAGRAM

APPLICATION NOTES

* The reduction of heat dissipation is a result of the

increase of the regulator efficiency (efficiency = V