Texas Instruments TLC1550IDW

Overview

TLC1550IDW 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-used in real-time DSP data acquisition systems requiring fast, accurate sampling of analog sensor or signal sources.

For engineers reviewing the TLC1550IDW datasheet, TLC1550IDW pinout, TLC1550IDW application, or TLC1550IDW equivalent, this page delivers verified electrical specs, SOIC-24 package terminal mapping, functional role per pin, confirmed industrial temperature range (−40°C to 85°C), and two validated alternative ADCs with documented parameter and interface differences.

Technical Context

The TLC1550IDW implements a switched-capacitor SAR architecture with internal clock (7.8 MHz max) or external CLKIN-driven operation, enabling precise ratiometric conversion referenced to REF+ and REF−. Its separate analog (ANLG VDD/ANLG GND) and split digital (DGTL VDD1/DGTL VDD2 + DGTL GND1/DGTL GND2) power domains suppress coupling noise during high-speed parallel read/write cycles.

Conversion is initiated by a rising edge on WR while CS is low; EOC asserts low upon completion, allowing interrupt-driven or polled data retrieval via RD. Input sampling impedance is 5 MΩ (hold mode) and 1 kΩ (sampling mode), with 60 pF typical input capacitance at AIN-requiring careful driver source resistance (≤1 kΩ) and settling time design per 1/2-LSB accuracy.

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 TLC1550IDW uniquely provides 10-bit parallel output with sub-6-µs latency and split digital supplies-making it irreplaceable in legacy µP/DSP systems requiring minimal interface overhead and strict analog noise isolation.

Availability

TLC1550IDW is available at Aetrix Electronics and suitable for industrial automation, motor control, and test equipment applications requiring stable component supply, long-lifecycle support, and guaranteed SOIC-24 packaging consistency.

Supply support for TLC1550IDW 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 expertise in precision data converters and industrial-grade ICs.

The TLC1550x series was designed for high-fidelity, real-time analog data acquisition in noise-sensitive embedded systems-emphasizing parallel interface speed, supply-domain isolation, and robust industrial temperature operation.

FAQ

What is the maximum clock frequency supported by the TLC1550IDW when using an external CLKIN?

The TLC1550IDW accepts an external clock input (CLKIN) up to 7.8 MHz, as specified in the recommended operating conditions. At this frequency, the device achieves its rated 6 µs conversion time. Operation above 7.8 MHz is not guaranteed and may result in timing violations or increased total unadjusted error. The internal clock runs at 7.8 MHz nominal, so external CLKIN is typically used for synchronization-not speed increase.

Does the TLC1550IDW require external reference components, or does it have an internal voltage reference?

The TLC1550IDW has no internal voltage reference and requires external REF+ and REF− connections. It operates ratiometrically: output code depends on the ratio of AIN to (REF+ − REF−). Standard configuration ties REF+ to ANLG VDD and REF− to ANLG GND, making the full-scale range equal to the analog supply voltage. Using precision external references (e.g., REF5025) enables improved absolute accuracy beyond the ±1 LSB specification.

Can the TLC1550IDW operate with a single 5 V supply, or must ANLG VDD and DGTL VDD1/VDD2 be independently regulated?

The TLC1550IDW can operate with a single 5 V supply if all three supply pins (ANLG VDD, DGTL VDD1, DGTL VDD2) are tied together-but doing so forfeits the primary noise-reduction benefit of the split digital supply architecture. For optimal performance, TI recommends separate low-noise regulation: one clean 5 V for ANLG VDD, and two well-decoupled 5 V rails for DGTL VDD1 (logic) and DGTL VDD2 (bus drivers), each with dedicated 0.1 µF ceramic capacitors near their respective pins.

How is the end-of-conversion (EOC) signal used in a typical µP interface with the TLC1550IDW?

In a typical µP interface, EOC is connected to an interrupt input (e.g., INT0 on an 8051 or GPIO interrupt on ARM Cortex-M). When WR initiates conversion, EOC remains high; upon completion, EOC goes low, triggering the ISR. Within the ISR, software asserts CS and RD low to read D0–D9. The falling edge of RD automatically resets EOC high, confirming data latch readiness for the next conversion. Polling EOC is also supported but consumes more CPU cycles.

Is the TLC1550IDW pin-compatible with the TLC1551IDW, and what is the key functional difference between them?

Yes, the TLC1550IDW and TLC1551IDW share identical SOIC-24 pinouts, electrical specifications, and timing behavior. The sole functional difference is in linearity performance: the TLC1550IDW guarantees ±0.5 LSB linearity error at 25°C (±1 LSB over full temperature range), while the TLC1551IDW specifies ±1 LSB linearity over full temperature range-making the TLC1550IDW preferred for higher-accuracy applications where tighter INL is required at room temperature.