Interfacing a TTL Logic Gate to a Sparkfun Logic Level Converter - Single Supply

Components & Accessories Power
1

I connected a Sparkfun Logic Level Converter, VCCA 3.3 V Input (GND and A1) to the output pin of my BBC Micro Bit board and found the VCCB Output (GND and D1) responded perfectly with either a 0V or 5V output when I ran a simple program on the BBC Micro Bit that toggles the VCCA 3.3V input.

Using a common GND, I then applied the 5V D1 Converter output directly to a TTL 7404 Inverter gate input expecting its output to inversely follow the input from the Converter, but it quickly overheated the Converter and it no longer functions. How do you interface the Converter 5V output with a TTL Logic Gate?

I was under the impression from the Converter specification that mentions TTL that this would not be a problem.

Grateful for any comments please.

2

This should work without any problems.

Are you sure you’re connection to an input pin on the 7404 and not an output pin, power or ground?

The only thing I can think that might have happened is if you were sending a logic 1 to the B side of the converter while sending a logic 0 to the A side. (or vice-versa)

In that case you’re trying essentially connecting VCC to ground through the converter causing a short circuit.