Other Parts Discussed in Thread: LMH6401, TIDA-00654
I design an AFE schematic , which use LMH5401 + LMH6401 to test +/- 50mv signal (1.5GHz 50 ohm DC-couple) , the schematic is all the same of TIDA-00654 (http://www.ti.com/lit/df/tidrgy0/tidrgy0.pdf?ts=1590200707928) ,
the Vcom of ADC is +1.8V , the Vdiff is 400mVpp ,
the power of LMH5401 and LMH6401 ，VS+: +3.8V ,VS-: -1.2V.
It's very hard to satisfy the less VICM of LM5401 and the larger Vocm of LMH6401,I use Tina to simulate:
If I set the Vocm of LMH5401 to 0V, the singal out from LMH5401 can't get the VICLR of LMH6401(0.3V) .
So I set the Vocm of LMH5401 to 0.5V , the singal out from LMH5401 get the LMH6401 ,but the sink current from LMH5401 (Vicm) to signal Generation, there is 2mA, It's too lager for a +/-50mv sigal, I need sink current not more than 0.1mA. could you give me same advises to slove this problem.