VCA2612: How to input the differential signal to this chip

Liu Hao

Intellectual 320 points

Part Number: VCA2612
Other Parts Discussed in Thread: THS4551

Hi all

When i use the VCA2612 for my IF amplifier , i can not find the details for the differential signal input

But the datasheet write that it support the differential signal input

So could you help me to check the schematic just as below and give me some advise . Thanks a lot

1、My IF signal is 1000ohm internal resistance output

2、The frequency of my IF signal is from 1KHz~20MHz

3、i want to amplify the IF signal may be 40dB and then send it into ADC.

over 3 years ago

0 Michael Steffes over 3 years ago

Guru 48195 points

The easiest way to get differential is with a balun or transformer. You could also use an active device like an FDA. Perhaps a part like the THS4551 would be useful.

0 Liu Hao over 3 years ago in reply to Michael Steffes

Intellectual 320 points

Thanks

i think i need talk about my questions more clearly

1、if my input signal is differential ， the pin "FB" and "SWFB" can be float?

2、if my input signal is differential ,and i want to use "COMP" to create a Low pass filter of LNP

How can i connect the "COMP" pins?

Thanks

0 Liu Hao over 3 years ago

Intellectual 320 points

Coud someone can help me ? Thanks a lot

0 Bellala Kalyan over 3 years ago in reply to Liu Hao

TI__Intellectual 1590 points

Hi Liu,

If your input is differential then you can keep FB and SWFB pins as float. Using differential amp for LPF, you need to be careful with stability issues. Why can't you use the configuration something like below,