TL712: Pull-up Resistor

TI-CSC

Part Number: TL712
Other Parts Discussed in Thread: LMV7219, TLV3201

Hello E2E Experts,

Good day.

1. First, the OE (output enable). To enable I just feed it with 5v. Do I need to use a resistor to limit current or is the internal resistance of the chip enough?

2. What would really help is a reference to a basic "test circuit".

3. Also, is the correct way to get the output by connecting a 1k resistor to Vcc and the other end to the Out pin and reading Vout from there? I just want to make a simple zero crossing circuit that converts sine wave to square wave

4. Also, since the IN + and - can take +/- 25v is it ok if I do not have a Zener diode on the input to protect from negative voltages?

Regards,

CSC

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 284810 points

1. As shown on p. 2, OE is a TTL-compatible logic input. You can connect it directly to V_CC or GND. The input current is specified as I_IH and I_IL.

3. This device has totem-pole outputs. But they output TTL levels; you need pull-up resistors if you want high outputs near 5 V.

4. If you can guarantee that the input voltages stay inside the ±25 V limits, then you do not need additional protection.

The TL712 is very old and uses lots of power. Consider a CMOS comparator like the TLV3201 or LMV7219.

0 Chi Nguyen1 over 1 year ago

TI__Genius 11701 points

Hi CSC,

Clemens's answers are valid and I hope they answer your questions. As mentioned, this is an old device so there isn't much information in general regarding a basic test circuit, but you do have the right idea in terms of set up. I would also refer you to TLV3201 as it has similar speed but less power consumption. But additional protection would be needed with TLV3201 if you expect large voltages beyond the supplies as this part is rail to rail.

0 kai klaas69 over 1 year ago

Guru 140200 points

Hi,

this thread and especially Ron's post may interest you:

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/542133/about-tl712

Kai

0 Chi Nguyen1 over 1 year ago in reply to kai klaas69

TI__Genius 11701 points

Thank you Kai.

CSC,

I will close this post. Let us know if you need any additional help.

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TL712: Pull-up Resistor