Texas Instruments TLC2558CPW

Overview

TLC2558CPW 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 delivers ±1 LSB differential/integral nonlinearity for precision data acquisition in industrial sensor interfaces.

For engineers reviewing the TLC2558CPW datasheet, TLC2558CPW pinout, TLC2558CPW application, or TLC2558CPW equivalent, key selection criteria include its 8-channel pseudo-differential input capability, programmable sampling period (12/24 SCLK), auto power-down mode (1 µA max), hardware-controlled CSTART trigger, and compatibility with TMS320 DSP frame sync protocols.

Technical Context

The TLC2558CPW 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 single-ended or pseudo-differential inputs (A0–A7), with A2 serving as the dedicated MINUS input in pseudo-differential mode.

Conversion timing is synchronized to the external SCLK (up to 20 MHz), supporting both normal sampling (12 or 24 SCLK cycles) and extended asynchronous sampling via the CSTART pin. The device uses internal logic to decode 4-bit command words (e.g., 0000h–7000h for channel selection) and stores configuration in a 12-bit CFR register controlling reference source, output format, sweep sequence, and FIFO interrupt thresholds.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (PW), RoHS-compliant, 0°C to 70°C operating temperature range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and TLC2543CN, the TLC2558CPW provides higher resolution and throughput, integrated reference, and hardware-triggered sampling-making it optimal for precision, multi-channel, low-power, and DSP-coupled designs where timing control and noise immunity are critical.

Availability

TLC2558CPW is available at Aetrix Electronics and suitable for industrial process monitoring, automotive sensor interface, medical instrumentation, and test & measurement equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TLC2558CPW 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 digital signal technologies with over 50 years of innovation in precision data converters.

The TLC2558CPW belongs to TI's legacy precision SAR ADC product line, designed specifically for low-power, multi-channel, serial-interface data acquisition in industrial and instrumentation applications where reliability, internal reference integration, and flexible timing control are essential.

FAQ

What is the maximum SCLK frequency supported by the TLC2558CPW?

The TLC2558CPW supports SCLK frequencies up to 20 MHz, enabling its maximum 400 kSPS throughput. At this rate, conversion time remains fixed at 1.6 µs. The device uses SCLK directly as the conversion clock source unless CFR.D8 is set to 1, in which case it divides SCLK by 2-reducing maximum throughput to 200 kSPS but improving noise immunity in electrically noisy environments. This setting is confirmed in the SLAS220A datasheet timing specifications.

Does the TLC2558CPW support pseudo-differential input mode, and how is it configured?

Yes, the TLC2558CPW supports pseudo-differential input mode by setting CFR.D7 = 1. In this mode, A2 becomes the dedicated MINUS input, while A0–A1 and A3–A7 serve as selectable PLUS inputs. The MINUS input tolerates up to ±0.2 V ripple, enabling effective ground noise rejection. Configuration requires writing to the 12-bit Configuration Register (CFR) using command 0xA000h followed by the 12-bit data word, as defined in Table 2 of the SLAS220A datasheet.

How does the CSTART pin function in the TLC2558CPW, and what is its timing requirement?

The CSTART pin provides hardware-controlled extended sampling: a high-to-low transition starts sampling, and a low-to-high transition ends sampling and initiates conversion. Its minimum low time is 800 ns. Unlike SCLK-synchronized sampling, CSTART operates asynchronously-enabling precise control over sampling duration independent of serial clock speed. This is critical for high-impedance sources (>1 kΩ) where longer acquisition times ensure 0.5 LSB accuracy, as documented in the "Extended Sampling" section of SLAS220A.

What are the FIFO interrupt threshold options in the TLC2558CPW, and how are they selected?

The TLC2558CPW offers four FIFO interrupt thresholds: Full (level 7), 3/4 full (level 5), 1/2 full (level 3), and 1/4 full (level 1). These are selected via CFR.D1:D0 bits (00–11). When the FIFO reaches the programmed level, the EOC/(INT) pin asserts a falling-edge interrupt. This allows the host processor to batch-read data efficiently-reducing interrupt overhead in continuous acquisition systems. Threshold selection is retained across power-down states, as specified in Table 2 of the SLAS220A datasheet.

Can the TLC2558CPW operate with an external reference, and what are the voltage requirements?

Yes, the TLC2558CPW supports external reference operation via REFP and REFM pins. The reference voltage difference (VREFP – VREFM) sets the full-scale input range, which must be ≤ VCC (5 V). For optimal performance, TI recommends 10 µF and 0.1 µF capacitors between REFP and REFM. External reference mode is enabled by setting CFR.D11 = 0. This configuration allows custom full-scale ranges (e.g., 2.5 V or 3.3 V) and improves accuracy when paired with precision external references, as detailed in the "Reference" section of SLAS220A.