Texas Instruments TLC2558CDWG4

Overview

TLC2558CDWG4 from Texas Instruments is a 12-bit, 400 kSPS serial analog-to-digital converter (ADC) with 8-channel analog multiplexer, built-in 4-V reference, and 8× FIFO buffer. It operates from a single 5-V supply, supports SPI/DSP-compatible serial interface up to 20 MHz SCLK, and features hardware/software/auto power-down modes (1 µA max in power-down). It is used in industrial data acquisition systems requiring low-power, multi-channel sampling with programmable sweep sequencing.

For engineers reviewing the TLC2558CDWG4 datasheet, TLC2558CDWG4 pinout, TLC2558CDWG4 application, or TLC2558CDWG4 equivalent, key selection considerations include its 8-channel pseudo-differential/single-ended input capability, configurable sampling period (12/24 SCLKs), EOC/INT dual-function pin, FIFO-triggered interrupt levels, and compatibility with TMS320 DSP frame sync protocols.

Technical Context

The TLC2558CDWG4 implements a 12-bit successive-approximation register (SAR) ADC with 2-bit resistor-string DAC and charge-redistribution capacitor array. Its analog multiplexer selects among eight external inputs or three internal test voltages, with break-before-make switching to minimize inter-channel crosstalk.

Conversion timing is derived directly from the external SCLK (up to 20 MHz), enabling 1.6 µs conversion time. Sampling is configurable as normal (CS- or FS-triggered, 12/24 SCLK duration) or extended (CSTART edge-controlled), supporting high-impedance sources and precise timing alignment in real-time control loops.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (DW) - RoHS-compliant, surface-mount, 6.5 mm × 4.4 mm footprint, 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, multi-channel, serial ADC applications.

Compared with ADS7822U and MCP3208-CI/P, the TLC2558CDWG4 delivers higher resolution (12-bit vs 8-bit), faster throughput (400 kSPS vs ≤100 kSPS), integrated FIFO and reference, and DSP-compatible frame sync-making it uniquely suited for real-time, multi-sensor industrial control where timing determinism and reduced host load are critical.

Availability

TLC2558CDWG4 is available at Aetrix Electronics and suitable for industrial process monitoring, motor control feedback, portable data loggers, and DSP-based signal analysis requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TLC2558CDWG4 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 power management technologies, with decades of heritage in precision data converters and industrial-grade ICs.

The TLC2558CDWG4 belongs to TI's legacy precision SAR ADC product line, designed specifically for low-power, multi-channel industrial data acquisition systems requiring robust serial interfacing, flexible power management, and deterministic timing in harsh environments.

FAQ

What is the maximum SCLK frequency supported by the TLC2558CDWG4?

The TLC2558CDWG4 supports SCLK frequencies up to 20 MHz. This clock serves dual roles: as the serial interface clock for SDI/SDO data transfer and as the source for the internal conversion clock, enabling a minimum conversion time of 1.6 µs. Operation above 20 MHz is not guaranteed and may violate setup/hold timing margins for reliable command decoding and data capture in the TLC2558CDWG4.

Does the TLC2558CDWG4 require an external reference voltage?

No, the TLC2558CDWG4 includes an internal 4-V reference that can be selected via CFR bit D11. When internal reference is enabled, REFP and REFM pins serve as decoupling points for the internal reference circuitry and must be bypassed with 10 µF and 0.1 µF capacitors. An external reference may be used for higher accuracy or different voltage scaling, but it is not required for basic operation of the TLC2558CDWG4.

How does the CSTART pin function in extended sampling mode on the TLC2558CDWG4?

In extended sampling mode, the CSTART pin provides asynchronous control of sampling timing: a high-to-low transition initiates sampling, and a low-to-high transition ends sampling and starts conversion. This allows precise control over sampling duration independent of SCLK frequency or count, which is essential for high-impedance analog sources (>1 kΩ) or applications requiring fixed aperture time. The TLC2558CDWG4 retains this behavior across all conversion modes when CSTART is active.

Can the TLC2558CDWG4 operate in pseudo-differential mode, and how is it configured?

Yes, the TLC2558CDWG4 supports pseudo-differential mode by setting CFR bit D7 = 1. In this mode, A2 becomes the dedicated MINUS input, and seven channels (A0, A1, A3–A7) serve as PLUS inputs. The MINUS input accepts up to ±0.2 V ripple, enabling effective ground noise rejection. Configuration is performed via a 16-bit write CFR command (e.g., 0xA000 + 12-bit data), and the setting persists through hardware/software power-down cycles in the TLC2558CDWG4.

What are the FIFO interrupt trigger levels available on the TLC2558CDWG4?

The TLC2558CDWG4 offers four programmable FIFO interrupt trigger levels via CFR bits D1:D0: 00 = full (7 entries), 01 = 3/4 full (5 entries), 10 = 1/2 full (3 entries), and 11 = 1/4 full (1 entry). When the FIFO reaches the selected level, the EOC/(INT) pin asserts a falling-edge interrupt. This allows the host processor to optimize data read timing - e.g., triggering a FIFO read before overflow - without continuous polling, improving efficiency in the TLC2558CDWG4's multi-channel acquisition workflow.