The DDC264 is a 20-bit, 64-channel, current-input analog-to-digital (A/D) converter. It combines both current-to-voltage and A/D conversion so that 64 separate low-level current output devices, such as photodiodes, can be directly connected to its inputs and digitized. For each of the 64 inputs, the DDC264 uses the proven dual switched integrator front-end. This configuration allows for continuous current integration: while one integrator is being digitized by the onboard A/D converter, the other is integrating the input current. This architecture provides both a very stable offset and a loss-less collection of the input current. Adjustable integration times range from 160 µs to 1 s, allowing currents from fAs to µAs to be continuously measured with outstanding precision. The DDC264 has a serial interface designed for daisy-chaining in multi-device systems. Simply connect the output of one device to the input of the next to create the chain. Common clocking feeds all the devices in the chain so that the digital overhead in a multi-DDC264 system is minimal. The DDC264 uses a 5-V analog supply and a 2.7-V to 3.6-V digital supply. Bypass capacitors within the DDC264 package help minimize the external component requirements. Operating over the temperature range of 0°C to 70°C, the DDC264 100-pin NFBGA package is offered in two versions: the DDC264C for low-power applications, and the DDC264CK when higher speeds are required.