3 Description

The DDC3512 is a 24-bit, 512-channel, current-input analog-to-digital (A/D) converter. The device combines both, current-to-voltage conversion by current integration, and A/D conversion. The device is a stacked-die version of DDC3256, with one die of the latter sitting on top of the other.

Up to 512 individual low-level current output devices, such as photodiodes, can be directly connected to the inputs and digitized in parallel (simultaneously).

For each of the 512 inputs, the device has one low noise and low power integrator designed to capture all the charge from the sensor. The integration time is adjustable from 50μs to 1.6ms, allowing currents in the order of fA to μA to be continuously measured with outstanding precision. The outputs of the integrators are digitized by on-chip low power ADCs and the converted digital codes are transmitted over a single LVDS pair designed to minimize noise coupling in environments with high channel count.

The DDC3512 operates from single 1.85V supply. The device is specified from 0°C to 70°C operating temperature and available in a 13.2 × 17.2mm² 656-ball 0.8mm row-pitch and 0.4mm column-pitch BGA. The on-chip reference buffer and bypass capacitors (on the BGA) help minimize the external component requirements and further reduce board space.