MM5450/5451

LED Display Driver

SuperSwitcher and Super ßeta PNP are trademarks of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

February 2006

M9999-021606

(408) 955-1690

General Description

The MM5450 and MM5451 LED display drivers are

monolithic MOS IC’s fabricated in an N-Channel, metal-

gate process. The technology produces low-threshold,

enhancement-mode, and ion-implanted depletion-mode

devices.

A single pin controls the LED display brightness by setting

a reference current through a variable resistor connected

to the supply.

Applications

• Industrial control indicator

• Relay driver

• Digital clock, thermometer, counter, voltmeter

• Instrumentation readouts

Features

• Continuous brightness control

• Serial data input

• No load signal requirement

• Enable (on MM5450)

• Wide power supply operation

• TTL compatibility

• 34 or 35 outputs, 15mA capability

• Alphanumeric capability

Ordering Information

Part Number

Standard

Pb-Free

Junction

Temp. Range

Package

MM5450BN MM5450YN –40°C to+85°C

40-pin PDIP

MM5451BN MM5451YN –40°C to+85°C

40-pin PDIP

MM5450BV

MM5450YV

–40°C to+85°C

44-pin PLCC

MM5451BV

MM5451YV

–40°C to+85°C

44-pin PLCC

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Block Diagram

35 OUTPUT BUFFERS

35 LATCHES

35-BIT SHIFT

REGISTER

LOAD

RESET

RESET

(only available

in die form)

SERIAL DATA

22

CLOCK

21

DATA ENABLE/OUT 35

(See Note 1)

23

19

20

24

OUT 34

18

OUT 1

1

BRIGHTNESS

CONTROL

VDD

Note 1: Pin 23 is Data Enable in MM5450

Pin 23 is Output 35 in MM5451

Figure 1.