Texas Instruments TLC1549CD

Overview

TLC1549CD from Texas Instruments is a 10-bit switched-capacitor successive-approximation analog-to-digital converter with integrated sample-and-hold, serial three-wire interface (CS, I/O CLOCK, DATA OUT), ±1 LSB total unadjusted error, on-chip system clock, and operation over 0°C to 70°C. It interfaces directly with microcontrollers in embedded data acquisition systems requiring ratiometric conversion via differential reference inputs (REF+, REF–).

For engineers reviewing the TLC1549CD datasheet, TLC1549CD pinout, TLC1549CD application, or TLC1549CD equivalent, this device supports fast (≤21 µs) and slow serial transfer modes, offers 2.1 MHz max I/O CLOCK frequency, provides high-impedance analog input with 60 pF typical capacitance, and enables low-noise signal digitization in cost-sensitive industrial and instrumentation designs.

Technical Context

The TLC1549CD implements a CMOS switched-capacitor SAR architecture with automatic sample-and-hold triggered on the third falling edge of I/O CLOCK and held on the tenth. Its differential reference inputs (REF+, REF–) support ratiometric scaling and isolation from supply noise, while the internal system clock eliminates external timing components.

It uses a 10-bit binary-weighted capacitor array for charge redistribution-based bit determination, with MSB-first serial output driven on DATA OUT under CS control. The device supports six defined serial interface timing modes-three fast (≤21 µs post-tenth clock) and three slow-determined by CS state and I/O CLOCK count (10–16 clocks).

Key Specifications

Pinout & Package

Package: SOIC-8 (D package), 8-pin small outline integrated circuit with gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC1549CP, the TLC1549CD offers superior thermal performance and smaller PCB area in SOIC-8; compared with TLV1549CD, it trades lower supply flexibility for higher noise immunity and guaranteed 5-V timing margins in industrial 5-V systems.

Availability

TLC1549CD is available at Aetrix Electronics and suitable for industrial sensor interface, embedded data logging, motor control feedback, and power supply monitoring requiring stable component supply across commercial temperature range and long-term production continuity.

Supply support for TLC1549CD 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 company founded in 1930, specializing in analog, embedded processing, and silicon technologies for industrial, automotive, and communications markets.

The TLC1549 series belongs to TI's legacy precision data acquisition product line, designed specifically for cost-effective, low-pin-count serial ADC applications in resource-constrained microcontroller systems.

FAQ

What is the maximum I/O CLOCK frequency supported by the TLC1549CD?

The TLC1549CD supports an I/O CLOCK frequency up to 2.1 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V). This corresponds to a minimum clock period of 476 ns. Exceeding this frequency may cause timing violations, incomplete sampling, or invalid data output. The device's internal logic and capacitor settling behavior are characterized and guaranteed only within this limit.

Does the TLC1549CD require an external clock source?

No, the TLC1549CD does not require an external clock source for core conversion timing. It integrates an on-chip system clock that drives the successive-approximation process. The I/O CLOCK signal provided by the host processor controls serial data transfer timing and sampling window synchronization-not the internal conversion engine-making the TLC1549CD self-timed for analog-to-digital conversion.

Can the TLC1549CD operate with a 3.3-V supply?

No, the TLC1549CD is not specified for 3.3-V operation. Its recommended supply voltage range is 4.5 V to 5.5 V, and absolute maximum VCC is 6.5 V for the C-grade version. Operating below 4.5 V risks violating timing specifications, increasing total unadjusted error beyond ±1 LSB, and causing unreliable DATA OUT drive strength. For 3.3-V systems, consider the pin-compatible TLV1549CD instead.

How does the TLC1549CD handle analog input voltages outside the REF+ to REF– range?

The TLC1549CD clamps out-of-range inputs digitally: voltages ≥ REF+ convert to all ones (1111111111), and voltages ≤ REF– convert to all zeros (0000000000). This behavior is deterministic and repeatable, but no linear conversion occurs beyond those bounds. The device remains functional with reference spans as low as 1 V, though electrical specifications (e.g., ±1 LSB error) apply only within the 2.5 V to VCC+0.2 V differential range.

Is the TLC1549CD pin-compatible with the TLC549?

Yes, the TLC1549CD is terminal-compatible with the TLC549 in the same SOIC-8 (D) package. Pin functions (REF+, ANALOG IN, REF–, GND, CS, DATA OUT, I/O CLOCK, VCC) and electrical timing behavior-including CS setup/hold, DATA OUT enable/disable delays, and I/O CLOCK edge sensitivity-are functionally identical. This allows direct substitution in existing TLC549 designs without layout changes.