A multi-channel CCD clock driver ASIC for space-based applications

Abstract

A high voltage mixed signal ASIC is described that provides multiple fully programmable clock outputs capable of driving large format CCD capacitive electrodes. The COMET ASIC provides 6 independent clock buffering channels each with individually programmable rising/falling current drive and high/low voltage levels. Output voltage levels are controlled with integrated fast response regulators that operate over a 16.368V range without the need for external decoupling capacitors. Clock drive currents can be adjusted for the load capacitance and voltage swing required over a 409.6mA range, with edge speeds <15ns achievable for small loads. Setup and control of the ASIC is via a simple SPI interface with safety features to ensure correct sequencing of channel operation and prevent driver supply reverse biasing. The ASIC also features an under-voltage lock out circuit to safeguard the chip in the event of power loss. All necessary biases are generated internally and only supply decoupling, a single filtering capacitor, and a resistive divider are required to operate the device. The circuit is manufactured in a commercial 0.35um HV CMOS technology and uses established layout techniques to harden against both Total Ionising Dose (TID) and Single Event Latchup (SEL) radiation effects. The device has been manufactured and test results are shown.