Texas Instruments DDC316CGXGT

Overview

DDC316CGXGT from Texas Instruments is a 16-bit, 16-channel, current-input analog-to-digital converter with dual-switched integrator front-end, programmable full-scale range (3pC to 12pC), integration time down to 10µs, and serial/parallel data output. It directly digitizes low-level photodiode currents in medical CT scanner detector acquisition systems.

For engineers reviewing the DDC316CGXGT datasheet, DDC316CGXGT pinout, DDC316CGXGT application, or DDC316CGXGT equivalent, key selection factors include its integrated I-to-V conversion architecture, 0°C to +70°C operating range, BGA-64 package, 100kSPS maximum data rate, and compatibility with photodiode sensor arrays requiring high channel density and low-noise charge measurement.

Technical Context

The DDC316CGXGT implements a continuous-time dual-switched integrator per channel: while one side (A or B) integrates input current, the other is digitized by the on-chip 16-bit ADC. Integration time is controlled via the CONV pin and CLK timing, with HI_SPEED bit enabling 10µs minimum integration.

It supports two output modes-TDM (single DOUT1 line, 256 DCLK cycles for 16 channels) or parallel (DOUT1–DOUT4, 64 DCLK cycles)-and uses separate AVDD (+5V) and DVDD (+3.3V) supplies with AGND/DGND isolation and QGND for noise-sensitive analog sections.

Key Specifications

Pinout & Package

BGA-64 package (GXG variant), 9mm × 9mm, 0.8mm pitch, bottom-side solder balls. Thermal pad exposed on underside for PCB heat sinking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-input ADC applications.

Compared with TDC1000 and ADS131M08, the DDC316CGXGT uniquely combines 16-channel current input, dual-integrator architecture, and BGA-64 packaging-enabling compact, low-noise, single-chip photodiode array digitization without external TIAs or multiplexers.

Availability

DDC316CGXGT is available at Aetrix Electronics and suitable for CT scanner detector acquisition systems, photodiode sensor interfaces, and X-ray detection systems requiring stable component supply across extended production lifecycles.

Supply support for DDC316CGXGT 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and high-reliability ICs for industrial, automotive, and medical applications.

The DDC316CGXGT belongs to TI's precision data acquisition product line, designed specifically for low-current, multi-channel photodetector interfacing in diagnostic imaging and scientific instrumentation where leakage, noise, and channel matching are critical.

FAQ

What is the minimum integration time supported by the DDC316CGXGT?

The DDC316CGXGT supports a minimum integration time of 10µs when the HI_SPEED bit is set to 0 and CLK = 40MHz. This is achieved using 400 clock periods (tCLK = 25ns). At HI_SPEED = 1, minimum integration increases to 20µs. The DDC316CGXGT must meet this specification for both side A and side B integrations to ensure valid conversion results.

How does the DDC316CGXGT handle photodiode dark current and input bias errors?

The DDC316CGXGT specifies ±2pA typical input bias current at +25°C and ±10pA maximum over temperature, minimizing offset errors in low-current photodiode applications. Its dual-integrator architecture and programmable full-scale ranges (3pC–12pC) allow users to optimize signal-to-noise ratio while keeping dark current within measurable range. The DDC316CGXGT also provides 1.8% negative headroom in output coding to accommodate small leakage-induced negative inputs without clipping.

Can the DDC316CGXGT operate with an external voltage reference?

Yes, the DDC316CGXGT supports external reference operation via the VREF_IN pin when the BUFDIS bit is set to 1. In this mode, the internal reference buffer is disabled, and an externally supplied stable voltage (e.g., 4.096V) is applied to VREF_IN. This configuration reduces total power dissipation by ~100mW compared to internal buffer mode and improves PSRR for systems with high-precision external references. The DDC316CGXGT maintains full specification compliance in both internal and external reference configurations.

What are the power supply requirements for the DDC316CGXGT?

The DDC316CGXGT requires two independent supplies: AVDD = +5V (4.75–5.25V) for analog circuitry including integrators and reference buffer, and DVDD = +3.3V (3.0–3.6V) for digital logic and I/O. Total power dissipation is 540mW with internal reference buffer enabled and 440mW with it disabled. AGND and DGND must be separated on PCB with single-point connection; QGND provides additional isolation for the most noise-sensitive analog nodes. The DDC316CGXGT specifies ±0.2V maximum offset between AGND and DGND.

How does the DDC316CGXGT manage noise in high-capacitance photodiode applications?

Noise performance of the DDC316CGXGT degrades with increasing sensor capacitance (CSENSOR): at 10pF, rms noise is 3.5–6.0 LSB (16-bit FSR); at 100pF, it rises to 9.4–17.8 LSB. The device mitigates this via selectable integration capacitors (0.75pF/1.5pF/3pF) and HI_SPEED bit control-shorter integration times reduce integration noise but increase sensitivity to clock jitter. For high-CSENSOR applications, using Range 1 (3pC FSR) with longer tINT and external low-noise reference yields optimal SNR. The DDC316CGXGT's QGND and separate AVDD/DVDD domains further suppress supply-coupled noise.