Integrated low-noise low-power fast charge-sensitive preamplifier for avalanche photodiodes in JFET-CMOS technology

To take advantage of the compactness of avalanche photodiode (APD) arrays, low-noise power-efficient fast charge-sensitive preamplifier chips with differential current drivers have been developed. A 16-channel and a single-channel version are available. The chips were adapted for low-capacitance 4 x 8 APD arrays produced by Hamamatsu, Japan. A mixed junction field-effect transistor (JFET)-CMOS production process yielded high-quality integrated JFETs for the input stage of the amplifier's folded cascode. Thus. the 1/f-noise corner is kept at 4 kHz. The JFET has a trans conductance of I I mS at a drain current of 3 mA. The serial noise of the input transistor was found to be 0.8 nV/rootHz. The signal rise time of the driver outputs is 20 ns. The rms noise of the preamplifier was found to be 480 e with a 25-e(-)/pF noise slope for a shaping time of 50 ns. The serial input noise of the preamplifler is about 1.4 nV/rootHz from 200 kHz up to 40 MHz, and the 1/f-noise corner is at 70 kHz. The power consumption is 30 mW per preamplifler, including the differential driver. The linearity is better than 1.3% over 48-dB dynamic range. For the 16-channel chip, the channel-to-channel gain variation is less than 3.5%. Performance similar to photomultiplier tubes can be achieved with APDs in combination with this integrated preamplifier chip.