7.3 Feature Description

7.3.1 Low-Power Dissipation

The LMC555 offers the same capability of generating accurate time delays and frequencies as the LM555

but with much lower power dissipation. A power dissipation of less than 0.2 mW can be achieved with a

1.5-V operating supply voltage and less than 1 mW with a 5-V operating supply voltage. The use of TI’s

LMCMOS process allows this low supply current and voltage capability. Reduced supply current spikes during

output transitions and extremely low reset, trigger and threshold currents also provide low power dissipation

advantages with the LMC555.

7.3.2 Various Packages and Compatibility

There are various packages available for use of the LMC555. In addition to the standard package (8-pin SOIC,

VSSOP, and PDIP, the LMC555 is also available in a chip-sized package (8-bump DSBGA). The PDIP, SOIC,

and VSSOP packages for the LMC555 are pin-for-pin compatible with the 555 series of timers (NE555/SE555/

LM555) allowing flexibility in design and unnecessary modifications to PCB schematics and layouts.

7.3.3 Operates in Both Astable and Monostable Mode

The LMC555 can operate in both astable and monostable mode depending on the application requirements.

• Monostable mode: The LMC555 timer acts as a “one-shot” pulse generator. The pulse begins when the

LMC555 timer receives a signal at the trigger input that falls below a 1/3 of the voltage supply. The width

of the output pulse is determined by the time constant of an RC network. The output pulse ends when

the voltage on the capacitor equals 2/3 of the supply voltage. The output pulse width can be extended or

shortened depending on the application by adjusting the R and C values.

• Astable (free-running) mode: The LMC555 timer can operate as an oscillator and puts out a continuous

stream of rectangular pulses having a specified frequency. The frequency of the pulse stream depends on the

values of RA, RB, and C.

LMC555

SNAS558N – JANUARY 2000 – REVISED MARCH 2024

www.ti.com

8

Submit Document Feedback

Copyright © 2024 Texas Instruments Incorporated

Product Folder Links: LMC555