LM556

Dual Timer

General Description

The LM556 Dual timing circuit is a highly stable controller ca-

pable of producing accurate time delays or oscillation. The

556 is a dual 555. Timing is provided by an external resistor

and capacitor for each timing function. The two timers oper-

ate independently of each other sharing only V

CC

and

ground. The circuits may be triggered and reset on falling

waveforms. The output structures may sink or source

200mA.

Features

n

Direct replacement for SE556/NE556

n

Timing from microseconds through hours

n

Operates in both astable and monostable modes

n

Replaces two 555 timers

n

Adjustable duty cycle

n

Output can source or sink 200mA

n

Output and supply TTL compatible

n

Temperature stability better than 0.005% per ˚C

n

Normally on and normally off output

Applications

n

Precision timing

n

Pulse generation

n

Sequential timing

n

Time delay generation

n

Pulse width modulation

n

Pulse position modulation

n

Linear ramp generator

Connection Diagram

Ordering Information

Package

Part Number

Package Marking

Media Transport

NSC Drawing

14-Pin SOIC

LM556CM

LM556CM

Rails

M14A

LM556CMX

LM556CM

2.5k Units Tape and Reel

14-Pin MDIP

LM556CN

LM556CN

Rails

N14a

Dual-In-Line, Small Outline Packages

DS007852-1

Top View

March 2000

© 2000 National Semiconductor Corporation

DS007852

www.national.com