PIC16F1503 not running at 2.5v. Normal?

[Emil]

I have a circuit with a 2.5V regulated supply and a PIC16F1503 (QFN package) at 4Mhz.

The chip was detected by the pickit3 and programed and verified. But the program was not running..

Actual voltage was 2.496V (measured at the pads). I don't remember exactly how much ripple there was, but it was <<50mV. After much trouble shooting I removed the regulator and connected it to a variable supply from an LM317. Still not running at the same voltage. After adjusting it up to 2.506 or so volts it started working normally..

According to the datasheet this chip should run at 2.3-5.5V at <16Mhz. There is nothing in the errata to indicate otherwise.

I will switch to an LF version so this won't be a problem for my circuit, but seems strange..

Is this a normal problem? Is it best practice to avoid running PICs close to the lower voltage rating? (200mV didn't seem that close..)

[dannyf]

Anything contradicting the datasheet us not normal. However, the fact that your code didn't work on the chip is no conclusive indication that the chip is at fault.

I would try a simple blinky on the chip to nail down the root cause.

[8086]

Do you have BOD set to 2.5V or something like that?

[Emil]

Do you have BOD set to 2.5V or something like that?

That was it. After disabling Brown-out Reset it runs fine at 2.5V (and much lower). I had not set the brownout fuse and I see now that it defaults on.

Thank you 8086.