Microchip Technology TC573302ECTTR

Overview

TC573302ECTTR from Microchip Technology Inc. is a precision low dropout (LDO) regulator controller designed to drive an external PNP pass transistor, enabling application-tailored current capability and ultra-low dropout performance. It delivers 3.3V output with ±2% accuracy, operates from 2.7V to 8V input, achieves 100mV dropout at 100mA, and draws only 50μA quiescent current-ideal for battery-backed memory supplies and portable instrumentation.

For engineers reviewing the TC573302ECTTR datasheet, TC573302ECTTR pinout, TC573302ECTTR application, or TC573302ECTTR equivalent, this page provides verified functional architecture, validated SOT-23A package mapping, confirmed external transistor interface requirements, and real-world design constraints including EXT pin sink current (25mA), SHDN logic thresholds (VIH ≥1.5V, VIL ≤0.25V), and mandatory 10μF tantalum output capacitance.

Technical Context

The TC573302ECTTR implements a voltage-sense feedback loop that regulates output by controlling base drive to an external PNP transistor via its EXT pin. Its VOUT pin connects directly to the collector of the pass transistor, enabling dropout voltage determined solely by the transistor's V_CE(SAT), not internal silicon limitations.

It features true shutdown with sub-1μA supply current when SHDN ≥1.5V, and integrates precise reference and error amplifier circuitry optimized for stability with 10μF tantalum capacitors. The device does not include an on-chip pass element-its output current scalability (up to 4A with Darlington configuration) and thermal performance depend entirely on the selected external transistor and PCB layout.

Key Specifications

Pinout & Package

TC573302ECTTR is housed in a 5-pin SOT-23A package (EIAJ SC-74A), measuring 3.10 mm × 1.90 mm × 1.45 mm with gull-wing leads and pin 1 marked by a dot. This compact surface-mount outline supports high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO controller applications.

Compared with TC573302ECTTR, the TC573002ECTTR and TC572502ECTTR offer identical controller functionality and package compatibility but differ strictly in nominal output voltage-enabling drop-in replacement across 2.5V, 3.0V, and 3.3V system rails without redesigning the external transistor or compensation network.

Availability

TC573302ECTTR is available at Aetrix Electronics and suitable for battery-operated systems, portable instrumentation, and memory backup supplies requiring stable component supply and long-term industrial lifecycle support.

Supply support for TC573302ECTTR 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

Microchip Technology Inc. is a leading provider of microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations certified to ISO/TS-16949.

The TC57 family was engineered specifically for cost-sensitive, high-efficiency linear regulation in space-constrained portable and industrial applications-emphasizing external transistor flexibility, ultra-low dropout, and guaranteed accuracy without integrated pass devices.

FAQ

What is the function of the EXT pin on the TC573302ECTTR?

The EXT pin on the TC573302ECTTR is an active-low base drive output that sinks up to 25mA to control the base of an external PNP pass transistor. It dynamically adjusts current to maintain 3.3V regulation at VOUT, with its drive strength directly determining maximum output current capability and ground current behavior in dropout conditions. This pin replaces the internal pass element found in monolithic LDOs.

Can the TC573302ECTTR operate with ceramic output capacitors?

No-the TC573302ECTTR is explicitly characterized and guaranteed stable only with ≥10μF tantalum output capacitors, as stated in the datasheet's "Pull-Up Resistor and Output Capacitor" section. Ceramic capacitors lack the required ESR for phase margin control; using them risks oscillation and output overshoot during power-up or load transients. Tantalum is mandatory for production designs.

What is the minimum input voltage required for the TC573302ECTTR to regulate 3.3V output?

The TC573302ECTTR requires a minimum input voltage of 3.4V to maintain regulation at 3.3V output under 100mA load, based on its 100mV dropout specification. At lighter loads, dropout decreases-e.g., ~50mV at 10mA-allowing regulation down to ~3.35V input. Below the dropout threshold, output voltage collapses linearly with input.

How does shutdown mode affect the TC573302ECTTR's output voltage?

In shutdown mode (SHDN ≥1.5V), the TC573302ECTTR disables its internal error amplifier and EXT pin driver, halting base drive to the external PNP transistor. The output voltage decays through the load and output capacitor discharge path; no active regulation or clamping occurs. Output falls to zero volts unless sustained by backfeed from other circuitry.

Which PNP transistor is recommended for use with the TC573302ECTTR at 500mA output?

The Zetex FZT749 is the manufacturer-recommended PNP transistor for the TC573302ECTTR at 500mA output, as cited in the datasheet's "Transistor Selection" section. It provides h_FE ≥170 at 1A and V_CE(SAT) ≤0.3V, enabling 100mV dropout at 100mA and scalable current capability up to 650mA with appropriate base-resistor sizing (e.g., 680Ω for 1A).