0
\$\begingroup\$

I'm attempting to use the RESET pin of a TLV809EA26DBZR Push-Pull Active Low Voltage Supervisor IC to assert a high signal when my VDD input voltage exceeds the low voltage threshold of the Supervisor IC, which in this case is ~2.6v. My setup is a TLV809 soldered to an SMD to DIP adapter on a breadboard.

enter image description here

With the low voltage threshold of the TLV809 at 2.6v and the VDD input of the power supply set to 3.3v I expect the RESET pin to be HIGH. Based on page 8 of the data sheet I expect a minimum VOH (voltage output high) to be VDD * .8 or approx 2.6v. Instead I'm only reading ~200mv on the RESET pin instead of the expected 2.6v. When I turn the voltage input down near 2.6v the RESET pin voltage drops to 0v as expected since the supervisor is active and pulling low.

Is there something flawed with my logic? Why isn't the RESET pin voltage closer to 2.6v when my input voltage is 3.3v?

Data sheet for the TLV809

\$\endgroup\$

2 Answers 2

1
\$\begingroup\$

Carefully check the pinout and the part code marked on the chip relative to the datasheet.

You say the part number is TLV809EA26DBZR (reverse pinout option) which means Pin 1 is /RESET, Pin 2 = GND, Pin 3 = VDD

enter image description here

The code number on the chip should be 926A

\$\endgroup\$
2
  • \$\begingroup\$ Chip is definitely marked 926A and I double checked all of my connections. I was using the correct pin outs. I checked VDD, GND and RESET voltages right at the IC pin itself, to eliminate the SMD to DIP adapter as an issue. I also tried 2 other TLV809 ICs and the results were the same so it doesn't appear to be a bad IC. \$\endgroup\$
    – ScottEH
    Commented Jan 24, 2021 at 3:34
  • \$\begingroup\$ I would expect it to read almost exactly the power supply voltage with only the meter as load, assuming it’s higher than 2.7V. \$\endgroup\$ Commented Jan 24, 2021 at 3:41
0
\$\begingroup\$

In double checking my part number against the pin layout I was in fact using the incorrect version. My part number (TLV809EA26DBZR) lacks both the R and V after the threshold voltage (26 in this instance). The trailing "R" after DBZ indicates "Reel". After connecting using pin 1 = GND, pin 2 = RESET, pin 3 = VDD the circuit worked as expected.

enter image description here

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.