The output stage of the LMH34400 has a 10-Ω series resistor on its output to isolate the amplifier output stage transistors from the package bond-wire inductance and printed circuit board (PCB) capacitance. The net gain of the LMH34400 (TIA + output stage) is 40 kΩ when driving an external 100-Ω resistor. When the external load resistor is increased above 100 Ω, the effective gain from the IN pin to the output pin increases. Consequently, when the external load resistor is decreased to less than 100 Ω, the effective gain from the IN pin to the output pin decreases as a result of the larger voltage drop across the internal 10-Ω resistor. When there is no load resistor connected to the output pin, the effective TIA gain is 44 kΩ. The output voltage of the LMH34400 is set to a fixed value of 1.0 V when there is no current flowing into the amplifier. The output swings above and below 1.0 V when the photodiode sinks and sources current, respectively.