DDC114IRTCR

The DDC114 is a 20-bit, quad channel, current-input analog-to-digital (A/D) converter. It combines both current-to-voltage and A/D conversion so that four low-level current output devices, such as photodiodes, can be directly connected to its inputs and digitized. For each of the four inputs, the DDC114 provides a dual-switched integrator front-end. This design 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 full-scale ranges from 12pC to 350pC and adjustable integration times from 50μs to 1s allow currents from fAs to μAs to be measured with outstanding precision. Low-level linearity is ±0.5 ppm of the full-scale range and noise is 5.2ppm of the full-scale range. Two modes of operation are provided. In Low-Power mode, total power dissipation is only 13.5mW per channel with a maximum data rate of 2.5kSPS. High-Speed mode supports data rates up to 3.125kSPS with a corresponding dissipation of 18mW per channel. The DDC114 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-DDC114 system is minimal. The DDC114 is a single-supply device using a +5V analog supply and supporting a +2.7V to +5.25V digital supply. Operating over the industrial temperature range of -40°C to +85°C, the DDC114 is offered in a QFN-48 package.

Applications

• CT SCANNER DAS
• PHOTODIODE SENSORS
• INFRARED PYROMETERS
• LIQUID/GAS CHROMATOGRAPHY

Key features

• SINGLE-CHIP SOLUTION TO DIRECTLY MEASURE FOUR LOW-LEVEL CURRENTS
• HIGH PRECISION, TRUE INTEGRATING FUNCTION
• INTEGRAL LINEARITY: ±0.01% of Reading ±0.5 ppm of FSR
• VERY LOW NOISE: 5.2ppm of FSR
• LOW POWER: 13.5mW/channel
• ADJUSTABLE DATA RATE: Up to 3.125kSPS
• PROGRAMMABLE FULL SCALE
• DAISY-CHAINABLE SERIAL INTERFACE