Texas Instruments TLC1551IDWR

Overview

TLC1551IDWR from Texas Instruments is a 10-bit, switched-capacitor, successive-approximation analog-to-digital converter (ADC) with parallel 3-state digital interface, 6 µs conversion time, ±1 LSB total unadjusted error, and dual digital supply rails (DGTL VDD1/DGTL VDD2) for noise isolation-designed for high-speed data acquisition in DSP and microprocessor systems.

For engineers reviewing the TLC1551IDWR datasheet, TLC1551IDWR pinout, TLC1551IDWR application, or TLC1551IDWR equivalent, key selection considerations include its SOIC-24 package, internal/external clock flexibility, separate analog/digital ground and supply domains, ratiometric reference architecture, and guaranteed operation from −40°C to 85°C.

Technical Context

The TLC1551IDWR implements a switched-capacitor SAR architecture with an integrated 10-bit capacitor DAC and sample-and-hold, enabling precise ratiometric conversion against REF+ and REF− inputs. Its control logic synchronizes sampling, hold, and conversion phases using either the internal divided-by-2 clock or an external CLKIN signal up to 7.8 MHz.

Dual digital power domains isolate low-current logic (DGTL VDD1) from high-current bus drivers (DGTL VDD2), while separate analog ground (ANLG GND) and dedicated reference inputs (REF+, REF−) minimize noise coupling. The EOC signal provides synchronous end-of-conversion indication for interrupt-driven or polled read operations.

Key Specifications

Pinout & Package

Package: SOIC-24 (DW), 15.4 mm × 7.5 mm body, 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-output ADC applications.

Compared with ADS7822U and TLC1543CN, the TLC1551IDWR uniquely delivers µP/DSP-optimized parallel timing, dual digital supply isolation, and guaranteed ±1 LSB error in an industrial-temperature SOIC package-making it irreplaceable for legacy or high-throughput bus-coupled data acquisition.

Availability

TLC1551IDWR is available at Aetrix Electronics and suitable for industrial data logging, motor control feedback, medical instrumentation, and test & measurement equipment requiring stable component supply and long-term production continuity.

Supply support for TLC1551IDWR 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 technologies, with decades of expertise in precision data converters and industrial-grade IC design.

The TLC155x family was engineered specifically for high-speed, noise-resilient data acquisition in µP- and DSP-based systems-emphasizing parallel bus compatibility, supply domain separation, and guaranteed AC/DC performance across extended temperature ranges.

FAQ

What is the maximum clock frequency supported by the TLC1551IDWR when using external CLKIN?

The TLC1551IDWR accepts an external clock input (CLKIN) up to 7.8 MHz, as specified in the recommended operating conditions. This allows synchronization with system clocks or reduction of jitter compared to the internal divided-by-2 clock. Operation above this frequency risks timing violations and conversion errors. The internal clock derives from CLKIN/2, so a 7.8 MHz external clock yields a 3.9 MHz internal rate-still sufficient for the guaranteed 6 µs conversion time. Always verify setup/hold times for CS, WR, and RD relative to CLKIN edges per Figure 3 timing diagram in the SLAS043G datasheet.

Does the TLC1551IDWR require external passive components for stable operation?

Yes-the TLC1551IDWR requires local bypass capacitors: at least one 0.1 µF ceramic capacitor between each DGTL VDD1/DGTL VDD2 and its respective ground (DGTL GND1/DGTL GND2), and another 0.1 µF between ANLG VDD and ANLG GND. These minimize supply noise and ensure accurate sampling. No external RC network is needed at AIN for basic operation, but driving sources with Rs > 1 kΩ require external buffering to meet the 60 pF input capacitance and 1/2-LSB settling requirement per Equation 5 in the datasheet. Reference decoupling (REF+/REF−) is not required if using clean, low-impedance references.

Can the TLC1551IDWR operate with a single 5-V supply across all rails?

Yes-the TLC1551IDWR supports a single 5-V supply applied to ANLG VDD, DGTL VDD1, and DGTL VDD2 simultaneously, as confirmed by the "Supply voltage, VDD1, VDD2, VDD3" specification (4.75–5.5 V) and Note 1 in the datasheet. However, separating DGTL VDD1 and DGTL VDD2-even at the same voltage-maintains internal noise isolation between logic and bus drivers. If using a shared rail, ensure low-impedance routing and dedicated 0.1 µF bypassing per supply pin. Performance remains within spec, but noise rejection degrades slightly versus split-rail implementation.

How does the TLC1551IDWR handle analog input voltages outside the REF+ to REF− range?

The TLC1551IDWR performs ratiometric conversion: input voltages ≤ REF− produce all zeros (0000000000), and voltages ≥ REF+ produce all ones (1111111111). Inputs between REF− and REF+ scale linearly across the 10-bit range. This behavior is inherent to its switched-capacitor SAR architecture and is explicitly documented in Notes 2 and 4 of the SLAS043G datasheet. Total unadjusted error remains ±1 LSB only when the differential reference voltage (REF+ − REF−) is ≥4.75 V; lower differentials increase error beyond specification.

Is the TLC1551IDWR pin-compatible with the TLC1550IDWR?

Yes-the TLC1551IDWR and TLC1550IDWR share identical SOIC-24 (DW) packaging, pinout, and terminal functions per the J/DW package diagrams in SLAS043G. Both devices have identical pin numbering (e.g., AIN = Pin 5, D0 = Pin 13, EOC = Pin 12). The primary difference is total unadjusted error: TLC1550I is specified at ±0.5 LSB (full range), while TLC1551I is ±1 LSB (full range). Functionally, they are drop-in replacements where ±1 LSB accuracy suffices, but system-level validation is recommended before substitution in precision-critical designs.