STMicroelectronics LD2980CM33TR

Overview

LD2980CM33TR from STMicroelectronics is a 3.3 V ultra-low-dropout linear voltage regulator in SOT23-5L package, delivering up to 50 mA output current with 120 mV typical dropout at 50 mA, 80 µA quiescent current in active mode, and <1 µA shutdown current. It features logic-controlled inhibit (TTL-compatible), ±0.5% output voltage tolerance over temperature, and 160 µV_RMS output noise - designed for low-power, battery-operated portable electronics requiring stable local regulation.

For engineers reviewing the LD2980CM33TR datasheet, LD2980CM33TR pinout, LD2980CM33TR application, or LD2980CM33TR equivalent, key selection criteria include dropout performance at light-to-moderate load, shutdown leakage, ceramic capacitor compatibility, thermal shutdown threshold (170 °C), and SOT23-5L board space constraints in space-constrained embedded systems.

Technical Context

The LD2980CM33TR uses a PNP pass transistor architecture enabling ultra-low dropout (7 mV typ. at 1 mA) and minimal quiescent current. Its internal feedback network sets nominal 3.3 V output with ±0.5% initial tolerance and maintains regulation across –40 to +125 °C junction temperature.

It integrates logic-level inhibit control on Pin 3 (INHIBIT), requiring external pull-up to VIN for enablement; floating is prohibited. The device lacks internal ESD diodes between IN and OUT, eliminating reverse current conduction when V_OUT > V_IN, with measured reverse current of 160 µA via internal feedback resistors.

Key Specifications

Pinout & Package

SOT23-5L is a 5-pin, surface-mount plastic package measuring 2.95 mm × 1.60 mm × 1.45 mm (max height), optimized for high-density PCB layouts and automated assembly. Its exposed pad variant is not specified; standard version uses non-thermal-enhanced leadframe.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2210K-3.3TRG1 and MCP1700T-3302E/TT, LD2980CM33TR uniquely combines sub-µA shutdown, ultra-low dropout at light load, and integrated inhibit control in SOT23-5L - making it optimal for ultra-low-power, intermittently active systems where every nanoamp and millivolt matters.

Availability

LD2980CM33TR is available at Aetrix Electronics and suitable for wearable electronics, industrial IoT edge nodes, medical monitoring devices, and automotive cabin modules requiring stable component supply, long-lifecycle support, and AEC-Q200-aligned reliability.

Supply support for LD2980CM33TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.

The LD2980 series belongs to ST's ultra-low-power LDO portfolio, engineered specifically for battery-constrained and noise-sensitive applications where minimal dropout, nanoscale quiescent current, and ceramic-capacitor compatibility are mandatory design requirements.

FAQ

What is the minimum input voltage required for regulation at full 50 mA load?

The LD2980CM33TR requires input voltage ≥3.42 V to maintain 3.3 V output at 50 mA, based on its 120 mV typical dropout voltage. At lower loads (e.g., 1 mA), input can be as low as 3.307 V due to 7 mV dropout. Operation below 2.5 V input is not supported per absolute maximum ratings.

Can the INHIBIT pin be left unconnected?

No - the INHIBIT pin has no internal pull-up or pull-down and must never be left floating. If shutdown control is unused, it must be hard-wired to VIN to ensure continuous regulation. Floating INHIBIT may cause erratic enable/disable behavior or increased leakage due to undefined logic state.

Which output capacitor types and values are validated for stability?

ST validates 2.2 µF X7R ceramic capacitors (with ESR ≤1 Ω) for 3.3 V versions. Tantalum capacitors may work but are discouraged due to size, cost, and aging effects. Capacitor must be placed ≤12.7 mm from VOUT pin and grounded to clean analog ground; lower values require series ESR tuning per Figures 18–19 in the datasheet.

Does the LD2980CM33TR support reverse current protection?

Yes - the internal PNP pass transistor lacks a body diode, preventing reverse current flow from VOUT to VIN when output voltage exceeds input. Reverse current is limited to ~160 µA through internal feedback resistors (R1 = 42.6 kΩ, R2 = 51.15 kΩ), eliminating need for external blocking diodes in back-powered scenarios.