OPA990: Operational Amplifier

Selvan T

Prodigy 30 points

Part Number: OPA990

Hi Experts,

I want to amplify a TTL signal from 90mV to 3.3V. I want to know, which IC will suit, perfectly.

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 324800 points

"TTL" implies a digital signal, so you should use a comparator. (Use a reference voltage of 45 mV.)

Here is a list of single-channel, 3.3 V comparators: ti.com/amplifier-circuit/comparators/products.html#116=Push-Pull&480=1&358min=0.9;3.3 Your choice makes a balance between propagation delay and power consumptions; a comparator with built-in hysteresis might be helpful.

0 Robert Clifton56 over 2 years ago in reply to Clemens Ladisch

TI__Mastermind 30390 points

Hi Selvan,

Is there a particular reason you believe this application would be better for an op amp rather than a comparator?

Best Regards,

Robert Clifton

0 Selvan T over 2 years ago in reply to Robert Clifton56

Prodigy 30 points

I'm getting 60-100mV LVTTL o/p signal from LVDS TO LVTTL converter IC, but my reference o/p voltage is around 3.3 to 5V. So i have to amplify my o/p and feed into optical converter.

0 Clemens Ladisch over 2 years ago in reply to Selvan T

Guru 324800 points

This is not a typical output level for an LVDS receiver. (In fact, LVDS receivers are comparators.) What converter IC is this? Can you show the schematic? Can you check for a short to ground?

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OPA990: Operational Amplifier