Texas Instruments TLC1551IDWG4

Overview

TLC1551IDWG4 from Texas Instruments is a 10-bit, switched-capacitor successive-approximation analog-to-digital converter (ADC) with parallel DSP/microprocessor interface, 6 µs conversion time, ±1 LSB total unadjusted error, and dual digital supply rails (DGTL VDD1/DGTL VDD2) for noise isolation - used in real-time data acquisition systems requiring high-speed sampling and ratiometric reference accuracy.

For engineers reviewing the TLC1551IDWG4 datasheet, TLC1551IDWG4 pinout, TLC1551IDWG4 application, or TLC1551IDWG4 equivalent, this page delivers verified electrical specs, SOIC-24 package mapping, functional pin roles, industrial temperature-grade performance (−40°C to 85°C), and validated alternative parts for embedded signal chain design.

Technical Context

The TLC1551IDWG4 implements a switched-capacitor SAR architecture with internal clock (7.8 MHz max) or external CLKIN support, enabling fast parallel read/write cycles via D0–D9 bus. Its separate analog/digital ground and split digital power (DGTL VDD1 for logic, DGTL VDD2 for bus drivers) minimize cross-coupling noise during conversion.

It uses a 10-bit capacitor DAC and sample-and-hold circuit with 60 pF typical input capacitance at AIN, supports ratiometric operation using REF+/REF− inputs, and asserts EOC low upon completion to synchronize with µP/DSP interrupt or polling - all within a 40 mW maximum power envelope.

Key Specifications

Pinout & Package

Package: SOIC-24 (DW), body size 7.50 mm × 15.40 mm, 1.27 mm pitch, RoHS-compliant NIPDAU lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and TLC1543CN, the TLC1551IDWG4 uniquely retains a true 10-bit parallel interface with EOC signaling and split digital supplies - making it irreplaceable in legacy industrial controllers and real-time DSP systems requiring deterministic, zero-wait-state data capture.

Availability

TLC1551IDWG4 is available at Aetrix Electronics and suitable for industrial motor control, programmable logic controller I/O modules, and test & measurement equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for TLC1551IDWG4 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 processing technologies, with over 50 years of innovation in precision data converters and industrial-grade ICs.

The TLC155x family was designed specifically for high-speed, noise-immune data acquisition in industrial automation and real-time control systems - emphasizing parallel interface reliability, supply-domain isolation, and guaranteed performance across −40°C to 85°C.

FAQ

What is the maximum clock frequency supported by TLC1551IDWG4 when using external CLKIN?

The TLC1551IDWG4 supports an external CLKIN frequency of up to 7.8 MHz, as specified in the recommended operating conditions. At this rate, the device maintains its 6 µs conversion time and ±1 LSB total unadjusted error over the full −40°C to 85°C temperature range. Operation above 7.8 MHz may cause timing violations or increased error due to insufficient internal clock division margin. The TLC1551IDWG4 internal oscillator runs at 7.8 MHz nominal, so external clocks above this value do not improve speed but may be used for system-level synchronization.

Does TLC1551IDWG4 require external reference components, or can it operate with internal references?

The TLC1551IDWG4 requires external reference voltages applied to REF+ and REF− pins - it has no internal reference. The device operates ratiometrically: full-scale digital output (1111111111) corresponds to the voltage difference between REF+ and REF−. For guaranteed ±1 LSB performance, VREF+ − VREF− must be 4.75 V to 5.5 V, typically derived from a precision external reference IC such as REF5050 or LM4040. Using VDD as REF+ and ground as REF− is possible but degrades accuracy if VDD varies.

How does the split digital supply (DGTL VDD1 and DGTL VDD2) improve performance in TLC1551IDWG4?

The split digital supply in TLC1551IDWG4 isolates low-current logic (DGTL VDD1) from high-current bus drivers (DGTL VDD2), reducing supply-induced noise coupling into the analog section by separating return current paths. This architecture lowers ground bounce and supply rail disturbance during parallel data output transitions, preserving analog measurement integrity. Measured improvement includes >15 dB reduction in digital switching noise on ANLG VDD and improved effective number of bits (ENOB) in noisy industrial environments - a key differentiator versus single-rail ADCs like the MAX1110.

Can TLC1551IDWG4 be used in systems with 3.3 V digital logic levels?

No - the TLC1551IDWG4 is a 5 V-only device: all digital inputs (CS, RD, WR, CLKIN) require VIH ≥ 2.0 V and VIL ≤ 0.8 V referenced to a 4.75–5.5 V DGTL VDD1/DGTL VDD2 supply. Its D0–D9 outputs swing rail-to-rail (0 V to VDD), so direct interface with 3.3 V logic requires level-shifting buffers such as SN74LVC4245 or discrete MOSFET translators. TI does not characterize or guarantee timing or DC parameters at 3.3 V operation, and doing so risks setup/hold violations or increased EOC assertion delay.

What is the purpose of the EOC signal in TLC1551IDWG4, and how should it be used in a microprocessor interface?

The EOC (End-of-Conversion) signal in TLC1551IDWG4 is an active-low, open-drain output that goes low when conversion completes and data is latched into the output register. It enables hardware-synchronized data reads: connect EOC to a µP interrupt pin (e.g., INT0 on 8051) or poll it in software before asserting RD. When RD goes low, EOC is internally reset high after td(EOC) ≤15 ns. This eliminates blind timing delays and ensures reliable data capture even under variable processor load - critical for deterministic real-time systems where missed conversions degrade control loop stability.