A transimpedance amplifier that provides 109 dBOhm within 1% flatness inheriting a cross coupled biquad filtering cell is presented. The nested structure has single-ended input and differential output, which achieves 4 uA max. bidirectional current input level and a bandwidth of 10 kHz. The structure features noise shaping by inserting in-band a zero for the noise transfer function. This results in 56 dB SFDR and 1pA/sqrt(Hz) low frequency noise. The circuit occupies 0.02 mm2 and consumes 160 nW.