A compact integrated APD device integrates the bias voltage and temperature compensation
functions inside a standard 4-pin PIN package. The active components of the bias
and temperature compensation circuits are integrated into a single ASIC using a
high-voltage CMOS process and operated at frequencies of at least 1 MHz to greatly
reduce the size of the passive components. To mount the relatively large ASIC chip
inside the package with the APD chip, TIA chip and passives, the 4-pin package
may be modified by either recessing the pins inside the can to facilitate surface
mounting the ASIC or adding a spacer inside the can to facilitate three-dimensional
packaging. Communication with the bias and temperature circuits is accomplished
using a unique bi-directional 1-wire serial interface via the power supply pin.
A clock signal is preferably embedded in the control data to synchronize the APD
with an external controller.
