Texas Instruments TLC1542IN

Overview

TLC1542IN from Texas Instruments is a 10-bit CMOS successive-approximation analog-to-digital converter with 11 analog input channels, on-chip 14-channel multiplexer, and serial 4-wire interface (CS, I/O CLOCK, ADDRESS, DATA OUT). It features inherent sample-and-hold, differential high-impedance reference inputs (REF+/REF−), end-of-conversion (EOC) output, and total unadjusted error of ±1 LSB max. Used in industrial sensor data acquisition systems requiring ratiometric conversion and noise-isolated analog front-ends.

For engineers reviewing the TLC1542IN datasheet, TLC1542IN pinout, TLC1542IN application, or TLC1542IN equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior across six serial interface modes, confirmed self-test voltage selection logic, and validated alternative parts for embedded measurement systems operating from −40°C to +85°C.

Technical Context

The TLC1542IN implements a switched-capacitor successive-approximation architecture with binary-weighted capacitor array, where sampling begins on the fourth I/O CLOCK falling edge and holds on the tenth. Its internal system clock drives conversion without external timing components, and the 4-bit serial address selects one of 11 analog inputs (A0–A10) or three internal self-test voltages (VREF−, VREF+, mid-scale).

It supports six configurable serial interface timing modes-three fast (10- or 16-clock transfers) and three slow (11–16-clock)-determined by CS state and I/O CLOCK count. The device outputs 10-bit results MSB-first on DATA OUT, with EOC asserting low on the tenth I/O CLOCK falling edge and returning high when conversion completes (21 µs typical).

Key Specifications

Pinout & Package

Package: 20-pin plastic DIP (N package), through-hole mounting, 0.3-inch width, JEDEC MS-001AC compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit serial ADC applications.

Compared with TLC1542IN, TLC1543IN extends functionality with an internal reference and configurable channel count, while ADS7822U trades integrated multiplexing and self-test for higher resolution and speed-making TLC1542IN optimal for cost-sensitive, 11-channel industrial monitoring where guaranteed ±1 LSB error and proven reliability are critical.

Availability

TLC1542IN is available at Aetrix Electronics and suitable for industrial process monitoring, automotive sensor interface, medical instrumentation, and energy metering front-end designs requiring stable component supply across extended temperature ranges.

Supply support for TLC1542IN 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 decades of heritage in precision data converters and industrial-grade ICs.

The TLC1542IN belongs to TI's legacy precision ADC product line designed specifically for cost-effective, noise-resilient industrial data acquisition-emphasizing ease of integration, ratiometric accuracy, and robust serial control in resource-constrained microcontroller systems.

FAQ

What is the maximum recommended I/O CLOCK frequency for reliable operation of the TLC1542IN?

The TLC1542IN supports up to 2.1 MHz I/O CLOCK frequency across its full operating temperature range (−40°C to +85°C). At this rate, the minimum I/O CLOCK pulse width is 190 ns high and 190 ns low. Exceeding 2.1 MHz may cause timing violations in address capture, sampling, or data output validity windows-particularly under worst-case temperature and voltage conditions. Always verify setup/hold times (e.g., tsu(CS) = 1.425 µs) in your host controller's timing budget when using the TLC1542IN.

Does the TLC1542IN require an external sample-and-hold circuit?

No, the TLC1542IN incorporates an inherent sample-and-hold function. Sampling begins automatically on the fourth falling edge of I/O CLOCK and holds on the tenth falling edge-fully managed by internal switched-capacitor circuitry. This eliminates the need for external sample-and-hold components, reducing board space and design complexity. The analog input source impedance must remain ≤1 kΩ to ensure proper capacitor charging within the 6-clock sampling window.

How does the TLC1542IN handle analog inputs outside the REF+ to REF− range?

The TLC1542IN clamps out-of-range inputs digitally: voltages ≥ REF+ convert to 0x3FF (1023), and voltages ≤ REF− convert to 0x000 (0). No damage occurs within absolute maximum ratings, but valid linear conversion only occurs between REF− and REF+. For example, with REF+ = 5 V and REF− = 0 V, an input of 5.2 V yields 0x3FF, while −0.3 V yields 0x000. This behavior is intrinsic to the TLC1542IN's architecture and requires no external clamping diodes.

Can the TLC1542IN be used with a 3.3 V microcontroller SPI interface?

Yes, but level translation is required for control signals (CS, I/O CLOCK, ADDRESS) and DATA OUT. The TLC1542IN operates from 4.5 V to 5.5 V (VCC), so its logic thresholds are TTL-compatible (VIH ≥ 2 V, VIL ≤ 0.8 V), but its output high voltage (VOH ≈ VCC − 0.1 V) exceeds 3.3 V logic high. Use bidirectional level shifters or resistor-divider networks on DATA OUT, and ensure 3.3 V signals meet VIH/VIL specs when driving CS/I/O CLOCK/ADDRESS. The TLC1542IN itself must be powered at 5 V.

What self-test voltages are available on the TLC1542IN and how are they selected?

The TLC1542IN provides three internal self-test voltages: VREF− (output code 0x200), VREF+ (0x000), and mid-scale (0x3FF), selected by writing address values B1011, B1100, and B1101 to the ADDRESS pin during the serial interface cycle. These codes are ideal values; actual outputs vary slightly with reference stability and internal offsets. Self-test mode enables in-system verification of ADC functionality without external test equipment-critical for safety-critical or field-deployed TLC1542IN applications.