SP4438 Datasheet, PDF(3/19 Page) Sipex Corporation – Ultra-Quiet Electroluminescent Lamp Driver For Cellular Phone Applications

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SP4438 Datasheet, PDF (3/19 Pages) Sipex Corporation – Ultra-Quiet Electroluminescent Lamp Driver For Cellular Phone Applications

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PINOUT

VDD 1

ELEN 2

ROSC 3

VSS 4

SP4438

8 EL1

7 EL2

6 CINT

5 COIL

PIN ASSIGNMENTS

Pin 1 â VDD â Positive Battery Power Supply.

Connect such that +2.7V < VDD < +3.3V.

Pin 2 â ELEN â Electroluminescent Lamp

Enable. When driven HIGH, this input pin

enables the EL driver outputs for EL1 and

EL2. This pin has an internal pulldown

resistor.

Pin 3 â R â Oscillator Resistor. Connect-

OSC

ing a resistor to this input pin sets the fre-

quency of the internal clock.

Pin 4 â VSS â Power Supply Common. Con-

nect to the lowest circuit potential, typically

ground.

Pin 5 â COIL â The inductor for the EL lamp

is connected from VDD to this input pin.

Pin 6 â CINT â Integrating Capacitor. An

integrating capacitor (47nF typical) con-

nected from this pin to ground filters out any

coil switching spikes or ripple present in the

output waveform to the EL lamp. Connect-

ing a fast recovery diode from COIL to C

INT

increases the light output of the EL lamp.

Pin 7 â EL2 â Electroluminescent Lamp Out-

put 2. This is a high voltage lamp driver

output pin to connect to the EL lamp.

Pin 8 â EL1 â Electroluminescent Lamp Out-

put 1. This is a high voltage lamp driver

output pin to connect to the EL lamp.

Rev.11/13/00

SP4438 Ultra-Quiet Electroluminescent Lamp Driver

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