Simulating an astable 555 timer circuit

Hi Everyone,

I am trying to simulate the following astable 555 timer circuit in KiCAD.

I am using the attached (TLC555.zip) TLC555 timer model.

TLC555.zip (731 Bytes)

Rather than the expected square wave output, I am receiving the following, erratic, waveform from the output (pin 3):

The waveform generated by the charge time of the timing capacitor is also wonky:

I’ve also tried simulating this outside of KiCAD (in ngspice) with the same results.

The TLC555 model works for the following monostable configuration:

With the following output (pin 3):

Thank you in advance for any help that you can give me.

Tim