7 Detailed Description

7.1 Overview

The LMC555 is a CMOS version of the industry standard 555 series general-purpose timers. In addition to the

standard SOIC, VSSSOP, and PDIP packages, the LMC555 is also available in a chip-sized package (8-bump

DSBGA) using TI’s DSBGA package technology. The LMC555 offers the same capability of generating accurate

time delays and frequencies as the LM555 but with much lower power dissipation and supply current spikes.

When operated as a one-shot, the time delay is precisely controlled by a single external resistor and capacitor. In

the astable mode, the oscillation frequency and duty cycle are accurately set by two external resistors and one

capacitor. The use of TI’s LMCMOS process extends both the frequency range and the low supply capability.

Figure 7-1. Simplified Schematic

7.2 Functional Block Diagram

Resistor

divider

V+

VS

VS

Threshold

Logic

CONTROL

VOLTAGE

THRESHOLD

Trigger

Logic

TRIGGER

Latch

RESET

Output

Drive

Stage

OUTPUT

DISCHARGE

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LMC555

SNAS558N – JANUARY 2000 – REVISED MARCH 2024

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