STMicroelectronics LD2980CM18TR

Overview

LD2980CM18TR from STMicroelectronics is a 1.8 V fixed-output ultra-low-dropout linear voltage regulator in SOT23-5L package, designed for local regulation in space-constrained battery-powered systems. It delivers up to 50 mA output current with 7 mV typical dropout at 1 mA load, 80 µA typical quiescent current in active mode, and <1 µA shutdown current-enabling multi-day operation in portable medical sensors and Bluetooth LE peripherals.

For engineers reviewing the LD2980CM18TR datasheet, LD2980CM18TR pinout, LD2980CM18TR application, or LD2980CM18TR equivalent, key selection criteria include its low-noise (160 µVRMS) output, logic-controlled inhibit function (TTL-compatible), stability with low-ESR ceramic capacitors down to 1 µF, and guaranteed operation across –40 °C to +125 °C junction temperature.

Technical Context

The LD2980CM18TR uses a PNP pass transistor architecture enabling ultra-low dropout voltage and minimal quiescent current across load and temperature. Its internal feedback loop is optimized for stability with ceramic output capacitors as low as 1 µF (for ≥3.8 V versions) or 3.3 µF (for 1.8 V version), eliminating need for tantalum or electrolytic alternatives.

It integrates logic-level inhibit control (pin 3), thermal shutdown at 170 °C, and internal current limiting. The INHIBIT pin requires external pull-up to VIN when unused; it draws only –1 µA at 0 V and 15 µA at 5 V, supporting direct interface with microcontroller GPIOs without level-shifting.

Key Specifications

Pinout & Package

SOT23-5L is a 5-pin surface-mount 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 used in this part; standard SOT23-5L footprint applies per Figure 24 in ST DocID6280 Rev 21.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-1802E/TT and XC6206P182MR-G, LD2980CM18TR uniquely combines sub-10 mV dropout, <1 µA shutdown current, integrated thermal shutdown, and TTL-compatible inhibit-all in SOT23-5L-making it optimal for battery-sensitive, safety-critical embedded systems.

Availability

LD2980CM18TR is available at Aetrix Electronics and suitable for wearable health sensors, BLE modules, industrial transmitters, and automotive cabin controllers requiring stable component supply with full lifecycle support.

Supply support for LD2980CM18TR 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 microcontrollers, power management ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The LD2980 series belongs to ST's ultra-low-dropout linear regulator product line, engineered specifically for battery-powered and noise-sensitive applications where minimal voltage overhead and microamp-level quiescent current are mandatory.

FAQ

What is the minimum output capacitance required for stable operation of LD2980CM18TR?

The LD2980CM18TR requires a minimum 3.3 µF ceramic output capacitor (X7R or better) due to its 1.8 V output voltage-per ST's Figure 19 in DocID6280 Rev 21. Using less capacitance risks instability; adding a series resistor (per Figure 18) may restore stability but degrades transient response and increases output impedance.

Can the INHIBIT pin be left unconnected?

No-the INHIBIT pin (pin 3) is not internally pulled up and must never be left floating. If shutdown control is unused, it must be hard-wired to VIN to ensure continuous operation. Leaving it open may cause erratic enable/disable behavior and increased system current consumption.

Does LD2980CM18TR support reverse current protection?

Yes-the internal PNP pass transistor lacks an inherent body diode, preventing reverse current flow 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 backup-supply configurations.

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

The SOT23-5L package has RthJA = 255 °C/W and RthJC = 81 °C/W (per Table 3). At 50 mA load and 125 °C ambient, junction temperature rises ~12.8 °C above ambient-well within the 170 °C thermal shutdown threshold. For sustained high-current operation (>30 mA) in enclosed environments, consider PCB copper pour under pin 2 (GND) to improve heat dissipation.