The Great Search – Power-on-reset in SOT23-3, a replacement for APX803-26SAG

(Video) Many devices and sensors like it if you give them a fancy reset pulse after power has come up, particularly displays and OLEDs! But sometime for wiring simplicity, we would like to skip using a microcontroller pin, and have the breakout board autoreset on power loss.

In such cases we use a ‘power on reset’ chip such as the APX803-26SAG . It’s worked great but….it’s now discontinued! Let’s find a drop-in replacement. We will need a SOT-23-3 with pin 1 ground, pin 2 open-drain reset and pin 3 VCC. The reset pulse should be about 100ms, VCC should be able to be 3 to 5V, and the reset level about 2.7V, and hold down the reset line for at least 10ms.

The challenge is there’s a lot of options, but they’re not all function/pin compatible! Check it out on Digi-Key!

Note: This is the 9pm pre-recorded video set to “live” / Premiere on YouTube.

See episodes of The Desk of Ladyada in the playlist here and other Great Searches in the playlist here.


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