Texas Instruments DDC232

32-Channel, Current-Input Analog-to-Digital Converter

The DDC232 is a 20-bit, 32-channel, current-input analog-to-digital (A/D) converter. It combines both current-to-voltage and A/D conversion so that 32 separate low-level current output devices, such as photodiodes, can be directly connected to its inputs and digitized.For each of the 32 inputs, the DDC232 provides a 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. Adjustable integration times range from 166s to 1s, allowing currents from fAs to s to be continuously measured with outstanding precision. The DDC232 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-DDC232 system is minimal. The DDC232 uses a +5V analog supply and a +2.7V to +3.6V digital supply. Operating over the temperature range of 0C to +70C, the DDC232 is offered in a BGA-64 package.