Understand the working of OPA2810 as a buffer

Rajat Jhunjhunwala

Part Number: OPA2810IDGKR

Hi TI,

We are looking for an alternate to OPA2863. We came across OPA2810 which has required slew rate and package with pin to pin matching.

What my query is how is it different from OPA2863. Can I use it as a buffer for a window comparator where the latch time is less than 100nS? Will the internal architecture be a hurdle in this?

My input is square wave in the range (+1V to +5V).

over 2 years ago

0 Sean Cashin over 2 years ago

TI__Genius 17756 points

Hi Rajat, the OPA2810 is a JFET amplifier, which gives it high DC input impedance, and it is a 28V device. OPA2863 is a BJT amplifier that has a little more bandwidth, a little less noise, and half of the voltage range. It is also less expensive. OPA2810 will draw 5x the quiescent current of the OPA2863.

From a performance standpoint, OPA2810 will have double the slew rate vs. OPA2863. If that is a critical parameter, another part to look at would be OPA817 (10x slew rate), but it is a different package.

What is your concern about "internal architecture" specifically? These are both crossover type devices, and the THD will be lower if you confine operation to a sub-interval of the full voltage range.

Best regards,

Sean

0 kai klaas69 over 2 years ago

Guru 140200 points

Hi Rajat,

for highest speed it's recommended to not drive the input and output of OPAmp into saturation. I would add a voltage divider at the input to guarantee that the output voltage is always 0.2V away from the supply rails.

Kai

0 Rajat Jhunjhunwala over 2 years ago in reply to kai klaas69

Prodigy 110 points

The input varies from 1.2V to 3.8V.

0 kai klaas69 over 2 years ago in reply to Rajat Jhunjhunwala

Guru 140200 points

Hi Rajat,

Rajat Jhunjhunwala said:
The input varies from 1.2V to 3.8V.

This is good to know. You earlier said:

Rajat Jhunjhunwala said:
My input is square wave in the range (+1V to +5V).

Kai

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Understand the working of OPA2810 as a buffer