LMH7322: LMH7322 as a trigger

The LMH7322 requires a headroom of at least 1.5 V to the positive supply, which can be at most 12 V.

It might be possible to use a voltage divider before the input.

There a 40 V comparators like the TLV1805, with a much lower speed. What propagation delay do you need?

Thank you Clemens for the support.

Venu,

Thanks for reaching out. In addition to Clemens's comments, can you share a little more about your application (supply voltage, input signal freq/speed, reference)? We currently do not have a comparator that can handle 80V with RSPECL outputs but we may be able to divide down your input signal. 

-Chi

Thanks Clemens,

This application is for test & measurement(like scope).I would think ~10ns should be ok..

Please let me know your thoughts.

Regards,

Venu

Thanks Chi,

This application is for test & measurement(like a scope) and we are looking at input voltage swing from -10V to 80V,Analog BW of 500MHz and 125 Msps sampling rate etc.

We are looking at using the comparator to achive the following:

1.Trigger ( High/low/50%/pattern/custom/ 

Hi Venu,

Sorry for the delay. Unfortunately, there are currently some issues with the LMH7322 model, so I am not able to show you the simulation properly. But the idea is similar to Chuck's circuit here in this post (see attached image below as well): (5) TLV7031: Zero crossing detection is not at 50% duty cycle - Amplifiers forum - Amplifiers - TI E2E support forums. Essentially the resistor divider + diode configuration allows you to divide down the voltage when the input swings high and clamps the voltage when the input swings negative. The resistors are chosen so that the voltages seen at the inputs of the comparator are within the input voltage range. As you mentioned, there may be some issues with offset of the comparator as well as variation error of the resistors which may impact the timing and accuracy of your circuit.

What supply voltages do you have? Are you configuring the LMH7322 as LVDS outputs? If so, we also have TLV3604/5 and TLV3801/11 which meets your speed requirements.

Thanks Chi,

Looking at 5V supply voltage..yes,it's mostly going to be configured as LVDS output to FPGA .

I will take a look at TLV36xx & TLV 38xx data sheet..

Regards,

Venu