LM324 Output Won't Zero

[CDRIVE]

According to the manufacturer's data sheets the output of a LM324 should be capable of swinging to ground (0V) potential but my simulations show otherwise. The following models were simulated with a single ended supply (10V) and a gain of 10. The none inverting input is held at GND.

Spice Model(LM324/NS): Vout = +64mV.
Schematic Model(LM324/(OA_BIP): Vout = +492mV

Is this a bug?

 

[BeanieBots]

Not really a bug but a "discrepancy" with the SPICE model.
Double check that the model for the op-amp you are using really is that of a 324 and just generic. Also, don't forget that when it comes to driving devices right at the limit (eg single rail to 0v), the model will take a pesimistic value of worst case.

Also, you don't state what is on the op-amp output. That is VERY important when it comes to outputs getting close to either power rail.

Unfortunately, discrepancies close to device limits is where any simulation is likely to be very different to real life. That's just life when it comes to simulators.

 

[CDRIVE]

There are only two active LM324 models in the library and I listed both.
The outputs:
Spice Model (LM324/NS) No load= 64mV, Load= 1K , Vo= 53.4mV.
Schematic Model (LM324/(OA_BIP): No Load, Vo= +492mV, Load= 1K, Vo= 490mV.
So the load is an insignificant factor.

 

[BeanieBots]

"Spice Model (LM324/NS) No load= 64mV, Load= 1K , Vo= 53.4mV.
"
I'd say that's very close to what you can expect in real life. (~500mV is bit high for an LM324)
When compared to many other op-amps, 64mV is close enough to 0v to be regarded as "at rail".
If you want better, you will either need to use a -ve rail or put a series diode in line between output and load (feedback post diode).

 

[CDRIVE]

Yes, I can deal with 64mV, it's the nearly 1/2 Volt from the Schematic Model(LM324/(OA_BIP) that's way off the chart.

Thanks for the suggestions and replies.