Texas Instruments DDC112Y/2K

Overview

DDC112Y/2K from Texas Instruments is a dual-channel, 20-bit monolithic charge-measuring analog-to-digital converter optimized for low-current photodetector and sensor digitization. It features continuous dual-switched integrator architecture, programmable full-scale ranges (up to 1000 pC with external capacitors), ±0.025% integral linearity error (max), and 3.2 ppm rms noise at Range 5 (250 pC). Designed for CT scanner data acquisition systems and precision process control instrumentation.

For engineers reviewing the DDC112Y/2K datasheet, DDC112Y/2K pinout, DDC112Y/2K application, or DDC112Y/2K equivalent, key selection considerations include its TQFP-32 package, –40°C to +85°C industrial temperature grade, cascaded serial interface support, and dual-integrator timing independence from data retrieval clocking.

Technical Context

The DDC112Y/2K implements two independent input channels, each with paired switched integrators (A/B) enabling continuous current integration: while one integrator digitizes, the other integrates. Its delta-sigma modulator and digital filter deliver 20-bit resolution with 3.2 ppm rms noise at 500 µs integration time and 10 MHz system clock.

Full-scale range is selected via RANGE0–RANGE2 pins controlling internal capacitor banks (12.5–87.5 pF) or bypassed for external capacitor use (e.g., up to 1000 pC). The device operates from single +5 V supplies (AVDD/DVDD), uses VREF = +4.096 V for integrator reset and ADC reference, and supports daisy-chained serial output via DCLK/DXMIT/DOUT/DIN.

Key Specifications

Pinout & Package

TQFP-32 package with 0.5 mm pitch; thermally enhanced for stable operation at up to +85°C ambient. Pin 1 is CAP1A (top-left corner, marked dot); exposed thermal pad (pin 33) must be soldered to PCB ground plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar charge-digitizing ADC applications.

Compared with AD7739BRUZ and ADS1258IPWR, the DDC112Y/2K uniquely delivers true dual-channel concurrent charge integration with on-chip programmable full-scale ranges - eliminating external op-amps and enabling direct photodiode interfacing in space-constrained medical and analytical modules.

Availability

DDC112Y/2K is available at Aetrix Electronics and suitable for CT scanner data acquisition systems, infrared pyrometers, liquid/gas chromatography detectors, and blood analysis instrumentation requiring stable component supply across extended industrial temperature ranges.

Supply support for DDC112Y/2K includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision data converters and sensor interface solutions.

The DDC112Y/2K belongs to TI's high-precision charge-digitizing ADC product line, engineered specifically for direct digitization of low-current photodetectors and scientific sensors in medical imaging and analytical instrumentation.

FAQ

What is the maximum full-scale input charge supported by the DDC112Y/2K?

The DDC112Y/2K supports up to 1000 pC full-scale input charge when configured in external capacitor mode (RANGE2–RANGE0 = 000). With internal capacitors only, the maximum is 350 pC (Range 7). This extended range allows direct interfacing with high-capacitance photodiode arrays or long-cable sensor configurations without signal attenuation. The DDC112Y/2K achieves this via dedicated CAP1A/CAP1B and CAP2A/CAP2B pins routed to external precision capacitors.

Does the DDC112Y/2K require separate analog and digital power supplies?

Yes, the DDC112Y/2K requires two independent +5 V supplies: AVDD for the analog section (integrators, reference, modulator) and DVDD for the digital interface (serial logic, shift register). AVDD and DVDD must each be 4.75–5.25 V, and AGND–DGND voltage difference must not exceed ±0.3 V to prevent noise coupling. This separation ensures the DDC112Y/2K maintains its specified 3.2 ppm rms noise and ±0.025% linearity performance in mixed-signal systems.

How does the DDC112Y/2K achieve continuous integration with only one delta-sigma converter?

The DDC112Y/2K achieves continuous integration using a dual-switched integrator architecture per channel: each input has two independent integrators (A and B). While integrator A accumulates charge, integrator B is digitized by the shared delta-sigma converter - and vice versa. The CONV pin controls which integrator is active, and timing is synchronized to CLK. This interleaving eliminates dead time, enabling uninterrupted current measurement - a core capability of the DDC112Y/2K unmatched by standard multiplexed ADCs.

Can multiple DDC112Y/2K devices be synchronized for time-aligned sampling?

Yes, multiple DDC112Y/2K devices can be synchronized using a common CLK and CONV signal distributed across all units. Because integration timing is controlled externally via CONV and CLK edges, and digitization is deterministic relative to those edges, sampling alignment across devices is achievable. The DDC112Y/2K's daisy-chain serial interface (DIN→DOUT) further enables coordinated readout without additional timing lines - critical for multi-slice CT scanner DAS implementations.

What is the role of the TEST pin on the DDC112Y/2K, and how is it used in calibration?

The TEST pin on the DDC112Y/2K initiates an internal self-test mode that injects calibrated 13 pC charge packets into both input channels' integrators. When asserted before a CONV edge, it grounds IN1/IN2 and applies test charge synchronously - enabling verification of gain, linearity, and channel matching without external stimulus. This function is documented in the DDC112Y/2K datasheet (SBAS085B) and supports factory and field calibration of blood analysis and chromatography instruments where traceable charge injection is required.