Texas Instruments TLC2551CDGK

Overview

TLC2551CDGK from Texas Instruments is a 12-bit, single-channel, successive approximation register (SAR) analog-to-digital converter with SPI/DSP-compatible serial interface, rail-to-rail analog input (500 kHz bandwidth), 175/360 kSPS throughput, and autopower-down mode reducing current to 8 µA. It operates from a single 5-V supply and is used in precision sensor signal conditioning for industrial data acquisition systems.

For engineers reviewing the TLC2551CDGK datasheet, TLC2551CDGK pinout, TLC2551CDGK application, or TLC2551CDGK equivalent, key selection considerations include its 8-pin MSOP package, CS/FS dual-control timing flexibility, ±1 LSB INL/DNL accuracy, and compatibility with microcontroller SPI ports or TMS320 DSP frame-sync interfaces.

Technical Context

The TLC2551CDGK implements a charge redistribution SAR architecture with internal sampling capacitor and comparator-based conversion logic. It uses SCLK as the master clock source (up to 20 MHz), requiring 28 SCLK cycles for full 12-bit conversion and 12 SCLKs for sampling - enabling minimum cycle time of 3.0 µs at 15 MHz SCLK.

Control is configurable via chip select (CS) only, FS only, or combined CS+FS - with distinct timing behavior per mode. The device supports unipolar straight-binary output format (000h = GND, FFFh = VREF – 1 LSB) and accepts external reference voltage (2 V to VDD) applied to VREF pin.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (DGK), 3.0 mm × 3.0 mm body, 0.65 mm pitch, exposed thermal pad (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MCP3201-I/P, the TLC2551CDGK uniquely supports dual-mode timing (CS/FS), achieves higher throughput (360 kSPS), and delivers industry-leading 8-µA autopower-down - making it optimal for DSP-coupled or energy-constrained precision acquisition.

Availability

TLC2551CDGK is available at Aetrix Electronics and suitable for industrial sensor interface, portable data logging, motor control feedback, and test & measurement front-end applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for TLC2551CDGK 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 precision data converter innovation.

The TLC255x family was designed for low-power, high-accuracy serial ADC applications in industrial automation, instrumentation, and DSP-based real-time control systems - emphasizing SPI/DSP interoperability and rail-to-rail input flexibility.

FAQ

What is the maximum SCLK frequency supported by the TLC2551CDGK in SPI mode?

The TLC2551CDGK supports up to 15 MHz SCLK in CS-only (SPI) mode, enabling a maximum throughput of 360 kSPS. This assumes proper setup/hold timing compliance (tsu(CSL-SCLKL) ≥ 40 ns, th(SCLKL-CSL) ≥ 5 ns) and use of 4.5–5.5 V supply. Exceeding 15 MHz in this mode risks timing violation and invalid conversion results.

Does the TLC2551CDGK require an external reference voltage?

Yes, the TLC2551CDGK requires an external reference voltage applied to the VREF pin. It accepts 2 V to VDD (4.5–5.5 V), and the reference must be stable and low-noise to maintain 72 dB SINAD. Internal reference is not provided; VREF directly sets full-scale input range (0 V to VREF).

How does autopower-down work on the TLC2551CDGK?

Autopower-down activates automatically at end-of-conversion. After 0.5 µs, supply current drops to 8 µA; after 2 ms of inactivity, it reaches deep power-down (1 µA). Wake-up occurs on next CS falling edge or FS rising edge. No software command is needed - it is fully hardware-managed.

Can the TLC2551CDGK interface directly with a TMS320 DSP without level-shifting?

Yes, the TLC2551CDGK is fully compatible with TMS320 DSP I/O voltage levels. Its VIH (2.1 V min) and VIL (0.6 V max) thresholds match standard 3.3-V or 5-V DSP GPIOs, and SDO output VOH/VOL meet TTL/CMOS specs. No level-shifter is required when VDD = 5 V and DSP I/O is 5-V tolerant.

What is the purpose of the FS pin on the TLC2551CDGK?

The FS (frame sync) pin on the TLC2551CDGK provides DSP-compatible timing control: rising FS releases the MSB on SDO, and falling FS initiates sampling. It enables deterministic synchronization in multi-device TMS320 systems and is unused (tie to VDD) in pure SPI configurations.