Texas Instruments TLC1550IFN

Overview

TLC1550IFN 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 operation over −40°C to 85°C. It supports external or internal clocking and is used in DSP- and microprocessor-based data acquisition systems requiring fast, accurate digitization of analog sensor or signal chain outputs.

For engineers reviewing the TLC1550IFN datasheet, TLC1550IFN pinout, TLC1550IFN application, or TLC1550IFN equivalent, key selection considerations include its dual-supply isolation (ANLG VDD/DGTL VDD1/DGTL VDD2), separate analog/digital ground pins, EOC-driven interrupt capability, and PLCC-28 package compatibility with industrial embedded control and test equipment designs.

Technical Context

The TLC1550IFN implements a successive-approximation register (SAR) architecture with a 10-bit capacitor DAC and sample-and-hold circuit. Its internal clock operates at ~7.8 MHz (divided-by-2 output), while CLKIN accepts external frequencies up to 7.8 MHz for synchronous system timing control.

Dual digital power domains isolate logic (DGTL VDD1) from high-current bus drivers (DGTL VDD2), and dedicated analog ground (ANLG GND) minimizes noise coupling. The device uses Advanced LinEPIC™ single-poly CMOS process to achieve close capacitor matching for improved linearity and accuracy.

Key Specifications

Pinout & Package

Package: PLCC-28 (FN), 11.43 mm × 11.43 mm body, 4.57 mm max height, lead finish NIPDAU, 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 TLC1550IFN provides deterministic 6 µs latency, direct µP/DSP bus integration, and thermal ruggedness for industrial use-but requires more PCB area and three independent supply rails.

Availability

TLC1550IFN is available at Aetrix Electronics and suitable for motor control feedback, industrial sensor interface, test equipment signal capture, and DSP-based audio processing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TLC1550IFN 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 headquartered in Dallas, Texas, delivering analog, embedded processing, and connectivity solutions since 1930.

The TLC1550IFN belongs to TI's precision data acquisition ADC family, designed specifically for industrial and instrumentation applications demanding high accuracy, noise immunity, and direct microprocessor interfacing without external interface logic.

FAQ

What is the maximum clock frequency supported by the TLC1550IFN CLKIN pin?

The TLC1550IFN CLKIN pin accepts an external clock frequency up to 7.8 MHz, as specified in the recommended operating conditions. At this rate, the device achieves its rated 6 µs conversion time. Driving CLKIN above 7.8 MHz may cause timing violations or undefined behavior, and is not guaranteed by the datasheet. The internal clock operates at approximately half the CLKIN frequency, so the internal oscillator runs at ~3.9 MHz when CLKIN is at 7.8 MHz. The TLC1550IFN must be operated within these limits to maintain ±1 LSB total unadjusted error performance.

Does the TLC1550IFN require external reference components?

Yes, the TLC1550IFN requires externally applied reference voltages on REF+ and REF− pins. It does not include an internal reference. The datasheet specifies that VREF+ should equal ANLG VDD (4.75–5.5 V) and VREF− should be 0 V for standard operation, establishing a ratiometric full-scale range. Using precision external references (e.g., REF5025 or REF5050) allows improved absolute accuracy beyond the ±1 LSB total unadjusted error spec. The TLC1550IFN reference inputs are high-impedance, so low-noise, low-output-impedance reference buffers are recommended for optimal performance.

Can the TLC1550IFN operate with a single 5-V supply?

No, the TLC1550IFN requires three independent supply connections: ANLG VDD (analog), DGTL VDD1 (logic), and DGTL VDD2 (bus drivers), each rated 4.75–5.5 V. While all three may be tied to the same 5-V rail, the datasheet mandates physical separation of their bypass capacitors and recommends individual 0.1 µF ceramic capacitors placed near each VDD pin. This separation is essential to prevent digital switching noise on DGTL VDD2 from modulating the analog reference or sampling circuitry. Operating with only one supply connection violates the pinout and functional design, and will result in degraded accuracy or failure to convert.

How is end-of-conversion signaled on the TLC1550IFN?

The TLC1550IFN signals end-of-conversion using the active-low EOC (End-of-Conversion) pin. EOC goes low immediately after conversion completes and the result is latched into the output register. It remains low until RD is asserted (pulled low), at which point EOC returns high within 15 ns (td(EOC)). This allows the host processor to either poll EOC or connect it directly to an interrupt input. Unlike some ADCs, EOC is not edge-triggered-it is level-sensitive and provides a clear, synchronous indication that valid data is present on D0–D9. The TLC1550IFN EOC timing is fully characterized across temperature and supply voltage.

Is the TLC1550IFN pin-compatible with the TLC1551IFN?

Yes, the TLC1550IFN and TLC1551IFN share identical PLCC-28 pinouts, electrical specifications, and timing characteristics, differing only in linearity performance: the TLC1550IFN guarantees ±0.5 LSB linearity error (typical), while the TLC1551IFN specifies ±1 LSB linearity error (max). Both devices have identical pin functions, supply requirements, and interface protocols. Therefore, the TLC1551IFN is a functional drop-in alternative where ±1 LSB linearity is acceptable, and the TLC1550IFN can replace the TLC1551IFN in applications requiring tighter linearity-without any PCB layout changes.