STMicroelectronics LD2980CM50TR

Overview

LD2980CM50TR from STMicroelectronics is a 5.0 V fixed-output ultra-low-dropout linear voltage regulator in SOT23-5L package, delivering up to 50 mA with 120 mV typical dropout at full load, 80 µA typical quiescent current in active mode, and <1 µA shutdown current - designed for battery-powered portable electronics requiring stable low-noise power.

For engineers reviewing the LD2980CM50TR datasheet, LD2980CM50TR pinout, LD2980CM50TR application, or LD2980CM50TR equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in portable systems, and validated alternative options with documented functional trade-offs.

Technical Context

The LD2980CM50TR employs a PNP pass transistor architecture enabling ultra-low dropout (7 mV typ. at 1 mA, 120 mV typ. at 50 mA) and stable operation with low-ESR ceramic capacitors ≥2.2 µF. Its inhibit-controlled shutdown logic (TTL-compatible INHIBIT pin) enables system-level power gating.

It integrates internal current limiting, thermal shutdown at 170 °C, and delivers 160 µVRMS output noise (300 Hz–50 kHz) with 63 dB supply voltage rejection at 1 kHz - optimized for noise-sensitive analog and RF subsystems in compact portable devices.

Key Specifications

Pinout & Package

SOT23-5L: 5-pin surface-mount package (2.95 × 1.60 mm footprint), thermally enhanced for high ambient operation; R_thJA = 255 °C/W, R_thJC = 81 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2112K-5.0 and MCP1700T-5002E/TT, the LD2980CM50TR uniquely combines sub-µA shutdown, ultra-low dropout, and integrated inhibit logic in SOT23-5L - making it optimal for space-constrained, battery-sensitive designs requiring precise power gating.

Availability

LD2980CM50TR is available at Aetrix Electronics and suitable for portable audio devices, digital camera modules, wireless sensor nodes, and industrial HMI displays requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LD2980CM50TR 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-dropout LDO portfolio, engineered specifically for battery-powered portable electronics where minimal voltage overhead, low quiescent current, and ceramic-capacitor stability are mandatory.

FAQ

What is the minimum output capacitance required for stable operation of LD2980CM50TR?

The LD2980CM50TR requires a minimum 2.2 µF ceramic output capacitor (X7R or X5R dielectric) with ESR between 10 mΩ and 300 mΩ for stable operation across -40 to 125 °C. Using a lower-value capacitor risks oscillation unless a series resistor is added to emulate required ESR per Figures 18–19 in the datasheet.

Can the INHIBIT pin be left unconnected?

No - the INHIBIT pin is not internally pulled up or down and must never be left floating. If shutdown control is unused, it must be tied directly to VIN to ensure continuous regulator operation. Leaving it open may cause unpredictable ON/OFF behavior due to noise coupling.

Does LD2980CM50TR support reverse current protection?

The LD2980CM50TR has no body diode between VIN and VOUT, so it inherently blocks reverse current flow from output to input. However, when VOUT exceeds VIN, a small reverse current (~160 µA) flows through internal feedback resistors to GND - not through the pass element - preserving system integrity during back-driving events.

How does thermal performance compare between SOT23-5L and larger packages?

In SOT23-5L, the LD2980CM50TR has R_thJA = 255 °C/W on standard 2-layer FR-4. With 50 mA load and 120 mV dropout, power dissipation is 6 mW - resulting in ~1.5 °C junction rise above ambient. Adding copper pour or thermal vias reduces R_thJA significantly, but the package is rated for continuous operation up to 125 °C junction temperature.