STMicroelectronics LD2980ABM33TR

Overview

LD2980ABM33TR 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 typical quiescent current in active mode, and <1 µA shutdown current. It features logic-controlled inhibit (TTL-compatible), ±0.5% output voltage tolerance, and 160 µVRMS output noise-designed for local regulation in battery-powered portable electronics.

For engineers reviewing the LD2980ABM33TR datasheet, LD2980ABM33TR pinout, LD2980ABM33TR application, or LD2980ABM33TR equivalent, key selection criteria include dropout performance at light-to-moderate load, shutdown leakage, ceramic capacitor compatibility, thermal stability over –40°C to +125°C, and SOT23-5L board space constraints in space-constrained embedded systems.

Technical Context

The LD2980ABM33TR employs a PNP pass transistor architecture enabling ultra-low dropout (7 mV typ. at 1 mA) and stable operation with low-ESR ceramic capacitors ≥2.2 µF. Its internal feedback network uses implanted resistors (R1 = 42.6 kΩ, R2 = 51.15 kΩ) to set the 3.3 V output with ±0.5% initial accuracy.

Shutdown is implemented via an active-low INHIBIT pin (pin 3) with logic thresholds of VINH ≤ 0.18 V (OFF) and VINL ≥ 1.3 V (ON); no internal pull-up requires external biasing. Thermal shutdown activates at 170°C, and reverse-current protection limits flow from VOUT to VIN when VOUT > VIN.

Key Specifications

Pinout & Package

SOT23-5L is a 5-pin, surface-mount plastic package (2.95 × 1.60 mm footprint, 1.30 mm height) with exposed pad for thermal enhancement. Pin 4 is NC (not connected); all pins are lead-free and RoHS-compliant per ECOPACK2 specification.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout, low-quiescent-current regulator applications.

Compared with TPS78033DRVR and MCP1700-3302E/TO, the LD2980ABM33TR offers the best balance of ultra-low dropout, precise 3.3 V output, SOT23-5L compatibility, and integrated inhibit control-making it optimal for compact, battery-aware designs where input voltage margin is constrained.

Availability

LD2980ABM33TR is available at Aetrix Electronics and suitable for wearable electronics, industrial edge controllers, medical diagnostics, and automotive cabin modules requiring stable component supply with full production lifecycle support.

Supply support for LD2980ABM33TR 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-I_Q LDO portfolio, engineered specifically for energy-constrained portable and embedded systems needing high accuracy, ceramic-capacitor compatibility, and robust thermal behavior across extended temperature ranges.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 50 mA load?

The LD2980ABM33TR requires a minimum input voltage of 3.42 V (3.3 V + 120 mV typical dropout) at 50 mA and 25°C. At maximum junction temperature (125°C), dropout rises to 225 mV, so minimum input becomes 3.525 V. Input must stay within 2.5–16 V absolute rating.

Can the INHIBIT pin be left floating?

No. The INHIBIT pin has no internal pull-up or pull-down and must never be left floating. To enable continuous operation, tie it directly to VIN. To disable, drive it to ≤0.18 V (e.g., via microcontroller GPIO). Floating may cause erratic ON/OFF behavior or increased leakage.

Which output capacitor types and values are validated for stability?

ST validates stability with ≥2.2 µF X7R or C0G ceramic capacitors (100 kHz ESR ≤ 300 mΩ). Tantalum is possible but not recommended due to size/cost. For 3.3 V versions, 2.2 µF is the minimum; lower values require series ESR tuning per Figures 18–19 in the datasheet.

Does the LD2980ABM33TR support reverse current protection?

Yes. The internal PNP pass transistor lacks a body diode, preventing forward conduction from VOUT to VIN. When VOUT exceeds VIN, reverse current flows only through internal feedback resistors (R1/R2), measured at ~160 µA - eliminating need for external blocking diodes in back-powering scenarios.