Texas Instruments DDC118 Data Sheet
Summary
This comprehensive manual details the DDC118, a high-precision 20-bit octal current input Analog-to-Digital Converter (ADC). Designed to measure ultra-low levels of current from sensors like photodiodes and pyrometers in applications such as CT scanners and chromatography systems. The guide covers critical features including dual $\Delta\Sigma$ integration, programmable full-scale ranges ($\pm 0.5 \text{ppm}$ linearity), and flexible operation in both low-power and high-speed modes, making it ideal for engineers developing complex, multi-device measurement and monitoring systems that require outstanding accuracy over an industrial temperature range.
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DDC118
SBAS325A − JUNE 2004 − REVISED JUNE 2005
Octal Current Input 20-Bit Analog-To-Digital Converter
FEATURES APPLICATIONS SINGLE-CHIP SOLUTION TO DIRECTLY CT SCANNER DAS MEASURE EIGHT LOW-LEVEL CURRENTS PHOTODIODE SENSORS HIGH PRECISION, TRUE INTEGRATING INFRARED PYROMETER FUNCTION
LIQUID/GAS CHROMATOGRAPHY
INTEGRAL LINEARITY: Protected by US Patent #5841310 ±0.01% of Reading ±0.5ppm of FSR VERY LOW NOISE: 5.2ppm of FSR
LOW POWER: 13.5m W/channel DESCRIPTION
ADJUSTABLE DATA RATE: Up to 3.125k SPS The DDC118 is a 20-bit octal channel, current-input
PROGRAMMABLE FULL SCALE analog-to-digital (A/D) converter. It combines both DAISY-CHAINABLE SERIAL INTERFACE current-to-voltage and A/D conversion so that eight low-level current output devices, such as photodiodes, can
VREF DVDDAVDD be directly connected to its inputs and digitized.
CLK For each of the eight inputs, the DDC118 provides a CONV
IN1 dual-switched integrator front-end. This design allows for
RANGE0
Dual RANGE1
Switched ∆Σ Digital continuous current integration: while one integrator is
Integrator Modulator Filter Control RANGE2
TEST being digitized by the onboard A/D converter, the other is
IN3 CLK_4X
integrating the input current. Adjustable full-scale ranges
HISPD/LOPWR
Switched RESET from 12p C to 350p C and adjustable integration times from
Integrator
50µs to 1s allow currents from f As to µAs to be measured
with outstanding precision. Low-level linearity is ±0.5ppm
Switched ∆Σ Digital of the full-scale range and noise is 5.2ppm of the full-scale Integrator Modulator Filter
FORMAT
range.
DCLK Two modes of operation are provided. In Low-Power
Dual Switched
Integrator mode, total power dissipation is only 13.5m W per channel
with a maximum data rate of 2.5k SPS. High-Speed mode
IN5 supports data rates up to 3.125k SPS with a corresponding
DVALID
Dual Digital
∆Σ Digital dissipation of 18m W per channel.
Switched Input/Output
Integrator Modulator Filter
The DDC118 has a serial interface designed for
DOUT daisy-chaining in multi-device systems. Simply connect
Dual Switched the output of one device to the input of the next to create Integrator
the chain. Common clocking feeds all the devices in the
chain so that the digital overhead in a multi-DDC118
Dual DIN
Switched ∆Σ Digital
Modulator system is minimal.
Integrator Filter
IN8 The DDC118 is a single-supply device using a +5V analog
Dual supply and supporting a +2.7V to +5.25V digital supply. Switched Integrator Operating over the industrial temperature range of −40°C
DGNDAGND to 85°C, the DDC118 is offered in a QFN-48 package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners.
Copyright 2002−2005, Texas Instruments Incorporated
www.ti.com
Page Summary Contents For Texas Instruments DDC118 Data Sheet
Manual Details
| Brand | Texas Instruments |
|---|---|
| Pages | 30 |
| File Size | 379.44 KB |
| Published | July 12, 2026 |
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Frequently Asked Questions
How can I connect multiple DDC118 units?
They support daisy-chaining; simply connect the DOUT of one device to the DIN of the next unit in the chain.
What are the operating voltage ranges required for the DDC118?
It is a single-supply device using +5V analog and supporting digital supplies from +2.7V to +5.25V.
What is the difference between Low-Power and High-Speed modes?
Low-Power mode operates up to 2.5kSPS with 13.5mW per channel, while High-Speed mode reaches 3.125kSPS at 18mW per channel.
What are the temperature limits for the DDC118?
The package operating temperature range is from -40°C to +85°C.