Texas Instruments TLC1542QFN

Overview

TLC1542QFN from Texas Instruments is a 10-bit CMOS switched-capacitor successive-approximation analog-to-digital converter with 11 analog input channels, on-chip 14-channel multiplexer, inherent sample-and-hold, and serial 4-wire interface (CS, I/O CLOCK, ADDRESS, DATA OUT). It operates over –40°C to +125°C and delivers ±1 LSB total unadjusted error at up to 2.1 MHz I/O clock frequency, used in industrial sensor signal conditioning and embedded data acquisition systems.

For engineers reviewing the TLC1542QFN datasheet, TLC1542QFN pinout, TLC1542QFN application, or TLC1542QFN equivalent, this page provides verified technical context, validated pin functions, confirmed operating specifications including conversion time (21 µs), reference input flexibility (differential high-impedance REF+/REF−), and real-world application mappings for automotive engine control, motor drive feedback, battery monitoring, and industrial PLC analog front-ends.

Technical Context

The TLC1542QFN implements a charge-redistribution 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.

It supports six serial interface timing modes-three fast (10–16 clocks) and three slow (11–16 clocks)-with CS-active or CS-inactive sequencing, enabling flexible host processor synchronization. The 4-bit ADDRESS input selects one of 11 analog inputs (A0–A10) or three internal self-test voltages (VREF−, VREF+, mid-scale).

Key Specifications

Pinout & Package

Package: 20-pin QFN (quad flat no-lead), 4 mm × 4 mm, 0.5 mm pitch, exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC1543QFN, TLC1542QFN provides identical channel count, timing, and temperature rating but omits auto-increment addressing-reducing firmware overhead in fixed-sequence applications. Versus ADS7822U, TLC1542QFN trades 2-bit resolution for robustness, on-chip diagnostics, and guaranteed operation to +125°C with minimal external components.

Availability

TLC1542QFN is available at Aetrix Electronics and suitable for automotive engine control units, industrial motor drives, battery management systems, and programmable logic controller analog input modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TLC1542QFN 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 experience in high-reliability data conversion solutions.

The TLC1542QFN belongs to TI's legacy precision ADC product line designed for cost-sensitive, high-volume industrial and automotive applications requiring robust serial interface, integrated multiplexing, and extended temperature operation without external support components.

FAQ

What is the maximum I/O CLOCK frequency supported by the TLC1542QFN?

The TLC1542QFN supports an I/O CLOCK frequency up to 2.1 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = –40°C to +125°C). At this rate, the minimum I/O CLOCK period is 476 ns, and timing parameters such as tsu(A), td(I/O-DATA), and tconv remain within specification. Exceeding 2.1 MHz may cause setup/hold violations or incomplete conversions, especially at temperature extremes.

Does the TLC1542QFN require an external clock source for its A/D conversion?

No, the TLC1542QFN does not require an external clock source for A/D conversion. It incorporates an on-chip system clock that drives the successive-approximation process. The I/O CLOCK signal provided by the host processor controls serial interface timing (address loading and data shifting) and initiates sampling-but the internal conversion timing is fully autonomous and synchronized to the internal oscillator.

How many analog input channels does the TLC1542QFN support, and how are they selected?

The TLC1542QFN supports 11 analog input channels labeled A0 through A10. Channel selection is performed via a 4-bit serial address presented to the ADDRESS pin, MSB first, on the first four rising edges of I/O CLOCK. Valid binary addresses 0000 (0x0) through 1010 (0xA) correspond directly to A0–A10 as defined in Table 2 of the datasheet. The TLC1542QFN does not support automatic channel incrementing-each conversion requires explicit address transmission.

What is the purpose of the EOC pin on the TLC1542QFN, and how is it used in system design?

The EOC (End-of-Conversion) pin on the TLC1542QFN is an active-low, open-drain output that transitions low on the trailing edge of the tenth I/O CLOCK pulse and remains low until conversion completion. It serves as a hardware-ready signal for interrupt-driven data capture-allowing the host microcontroller to read the 10-bit result from DATA OUT immediately after EOC rises. This eliminates polling delays and ensures deterministic timing in real-time control loops using the TLC1542QFN.

Can the TLC1542QFN operate with a 3.3 V supply voltage?

No, the TLC1542QFN is not specified for 3.3 V operation. Its recommended operating supply voltage is 4.5 V to 5.5 V, and absolute maximum ratings limit VCC to –0.5 V to +6.5 V. Operating below 4.5 V violates the recommended conditions and risks degraded performance-including increased total unadjusted error, reduced noise immunity, and potential failure to meet timing specifications such as tconv (21 µs) or td(I/O-EOC) (70–240 ns). For 3.3 V systems, consider TI's ADS7822 or similar 3.3 V–compatible ADCs instead of the TLC1542QFN.