Hi,
I actually used a TLC556 in a new design. Never thought I'd have the chance again. Go figure. :-)
Because the TRIG input is edge-sensitive I used the one-shot output of the first-half of the dual-timer to generate an RC pulse on the falling edge of the TIMER output. I'm using the 2nd-half of the TLC556 as a latch to enable circuitry.
The issue is when TIMER goes high at the start of the one-shot period. The input to TRIG momentarily goes to +24V. R17 can be adjusted to handle the max allowed current into the TRIG protection diodes ... if they exist.
As you see VDD is +12V for this circuit.
The TLC556 spec says the absolute max input voltage range (Vi) is -0.3V to VDD, with VDD(max) = 18V. I took that to mean there are protection diodes on the TLC556 inputs because of the -0.3V part of the range.
Questions:
1) Is the TRIG input diode protected to VDD and ground?
2) If TRIG is protected by a diode to VDD and a diode from ground, what is the maximum current thru those diodes?
Thanks for your help.