Texas Instruments TLC0838CDWG4

Overview

TLC0838CDWG4 from Texas Instruments is an 8-bit successive-approximation analog-to-digital converter (ADC) with integrated 8-channel analog multiplexer, serial control interface, and ratiometric operation capability. It supports single-ended, differential, and pseudodifferential input configurations, operates from a single 5-V supply with 0–5-V input range, and delivers ±1 LSB total unadjusted error at 250 kHz clock frequency for industrial data acquisition systems.

For engineers reviewing the TLC0838CDWG4 datasheet, TLC0838CDWG4 pinout, TLC0838CDWG4 application, or TLC0838CDWG4 equivalent, key selection criteria include its 20-pin SOIC (DW) package, software-configurable channel addressing, MSB/LSB-first serial output mode controlled by SE pin, 32 µs conversion time, and compatibility with TTL/MOS logic levels in microprocessor-interfaced sensor front-ends.

Technical Context

The TLC0838CDWG4 implements a sample-data-comparator architecture with internal resistive ladder and SAR logic, enabling precise 8-bit quantization of analog inputs selected via 5-bit serial address word. Its multiplexer supports eight independent analog channels (CH0–CH7) plus COM terminal for pseudodifferential mode, with polarity assignment per channel pair under software control.

Serial communication uses a 3–4-bit assignment word preceded by a start bit on DI; conversion initiates when the start bit reaches the SARS register, triggering 8-clock-cycle conversion with MSB-first output on DO. The SE pin determines LSB-first or MSB-first data format, and CS must remain low throughout conversion to maintain internal logic enablement.

Key Specifications

Pinout & Package

Package: 20-pin SOIC (DW), 7.5 mm × 12.8 mm body, 1.27 mm pitch, RoHS-compliant NIPDAU lead finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit serial ADC applications.

Compared with ADC0838CCN, TLC0838CDWG4 eliminates Zener-related power loss and thermal drift, improving system efficiency and long-term accuracy; versus TLC0838CPW, it trades smaller size for easier hand-soldering and broader thermal mass in industrial environments.

Availability

TLC0838CDWG4 is available at Aetrix Electronics and suitable for industrial sensor interfaces, embedded data loggers, motor control feedback systems, and medical instrumentation requiring stable component supply and long-term production continuity.

Supply support for TLC0838CDWG4 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, embedded processing, and connectivity technologies with over 90 years of innovation in precision data conversion.

The TLC0838 product line was designed for cost-sensitive, microprocessor-based data acquisition systems requiring flexible analog input routing, low-power serial interfacing, and robust performance across commercial temperature ranges.

FAQ

What is the maximum clock frequency supported by the TLC0838CDWG4?

The TLC0838CDWG4 supports a clock frequency range of 10 kHz to 600 kHz, with recommended operation at 250 kHz for optimal timing margins and ±1 LSB accuracy. At 600 kHz, conversion time reduces to ~12.8 µs, but linearity error increases slightly per Figure 7 in the datasheet; full specification compliance requires adherence to the 40–60% duty cycle constraint.

Does the TLC0838CDWG4 require an external voltage reference?

Yes, the TLC0838CDWG4 requires an external voltage applied to the REF pin to define its full-scale range; it does not contain an internal reference. The device operates ratiometrically when REF is tied to VCC, or accepts any stable 0–5 V reference for scaled full-scale encoding - enabling precise measurement of sub-5-V analog spans.

How does the SE pin affect data output format on the TLC0838CDWG4?

The SE pin on the TLC0838CDWG4 controls serial output order: when SE is high, DO outputs MSB-first; when SE is pulled low before conversion, the device outputs LSB-first after the initial MSB-first sequence. This dual-mode capability allows seamless integration with microcontrollers that expect either bit-order convention without additional software bit-reversal.

Can the TLC0838CDWG4 perform true differential measurements between non-adjacent channels?

No, the TLC0838CDWG4 only supports true differential measurements between adjacent channel pairs (e.g., CH0/CH1, CH2/CH3, CH4/CH5, CH6/CH7). Non-adjacent combinations like CH0/CH3 are not supported by the internal multiplexer architecture; such configurations would require external signal conditioning or use of pseudodifferential mode with the COM terminal.

What is the purpose of the COM pin on the TLC0838CDWG4?

The COM pin on the TLC0838CDWG4 serves as the common analog reference for pseudodifferential input mode, where it acts as the shared negative input for all eight channels. This allows all channels to be referenced to an arbitrary bias voltage (e.g., 2.5 V) instead of ground, simplifying designs where sensors are biased above ground potential for noise immunity or signal swing optimization.