So I stumbled across this integrated trans-impedance amplifier a while back and want to use it as an AC coupled TIA for a PIN or APD receiver. One thing that I noticed about the datasheet is a lack of a detailed block diagram of the internals. Based on my understanding of a basic op-amp based TIA, the current flow direction determines the output polarity. I intend on applying a positive bias and would expect a falling edge type output but when I look at the simplified pin descriptions I see an NPN common emitter stage on the output. What should I expect in terms of output polarity? Maybe I'm just blind and missing something here but I just want to be certain before I go any further with this.
HMC799 is an inverting transimpedance amplifier, meaning that if current is drawn from the input, positive pulse would appear on the output and visa versa. Simplified output diagram is only to demonstrate the output matching, the output stage has headroom to swing 500mV in both directions.
Thanks for the clarification! I just wasn't sure if the initial stage would invert the diode impulse and if the output stage would invert the signal as well. it wasn't entirely clear to me.