Transimpedance amplifier

https://en.wikipedia.org/wiki/Transimpedance_amplifier For an input current Iin, the output voltage is VREF - Iin * Rfb, where VREF is the value placed on the non inverting input. 1 - 125e-9 * 1e6 = 0.875 1V - 125nA * 1 MOhm = 875mV