LMC555: LMC555 design problem

Kai Lai

Part Number: LMC555
Other Parts Discussed in Thread: TLC555, NE555, LM555, NA555, SE555, SA555

Hi Team,

Nice to meet you here!

I have 2 questions for LMC555 design, my customer want use LMC555 be a PWM square wave generator.

1. Can we get 2.73KHz / 50% Duty Square wave output by below value ? Rc=2.61K ohm, C=0.1uF.

2. If Vs = 3.3V, then the VOH & VOL & Io output performance will be?

Thank you !!

Kai Lai

kai.lai@ti.com

0 Tamara M Alani over 3 years ago

Hi Kai,

Thanks for your post. Our engineer responsible for this family of devices is out of office on Holiday, I will help you until she gets back.

Following the equation for frequency, f = 1 / (1.4*2.61k*0.1u) = 2.73kHz
VOH is V+ pin voltage and VOL is GND pin voltage under no or light load. For 3.3V supply. I recommend TLC555 timer. It is a low voltage version of the NE555 and LMC555 timers.

I also would recommend that you read the following FAQ on how to design a stable timer, oscillator, circuits using LMC555, TLC555, LM555, NA555, NE555, SA555, or SE555: https://e2e.ti.com/support/clock-and-timing/f/48/t/879112

0 Kai Lai over 3 years ago in reply to Tamara M Alani

Hi Tamara,

Thanks for your help!

Kai Lai

Clock & timing forum