STMicroelectronics LD59015C25R

Overview

LD59015C25R from STMicroelectronics is a 150 mA low-noise, high-PSRR linear voltage regulator delivering a fixed 2.5 V output with ±1.8% accuracy at 25 °C, 150 mV typical dropout at 150 mA, 20 µV_RMS output noise (10 Hz–100 kHz), and 80 dB PSRR at 100 Hz - designed for power-sensitive RF and analog circuitry in portable battery-powered systems.

For engineers reviewing the LD59015C25R datasheet, LD59015C25R pinout, LD59015C25R application, or LD59015C25R equivalent, key selection criteria include quiescent current (31 µA typ. at no load), enable logic control thresholds (0.4 V low / 0.9 V high), ceramic capacitor compatibility (1 µF min.), thermal shutdown (160 °C), and SOT323-5L package constraints for space-constrained PCB layouts.

Technical Context

The LD59015C25R employs a bandgap reference with internal trimming to maintain 2.5 V output across -40 °C to 125 °C junction temperature, using a 0.8 V internal reference and resistor divider feedback. Its enable input controls a MOSFET pass element via logic-level compatible thresholds, supporting fast turn-on (200 µs) and sub-1 µA shutdown current.

PSRR performance is architecture-dependent: 80 dB at 100 Hz drops to 76 dB at 10 kHz and 54 dB at 100 kHz due to internal compensation and pass device transconductance roll-off. Internal thermal and short-circuit protection operate independently of external components, with 20 °C hysteresis on thermal shutdown.

Key Specifications

Pinout & Package

LD59015C25R is housed in a compact SOT323-5L surface-mount package (2.0 × 2.1 mm footprint, 0.9 mm height), optimized for high-density portable PCBs and thermally constrained layouts. The package features an exposed pad for enhanced thermal dissipation (R_thJA = 645.69 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B252MR-G and ADP125ARHZ-2.5-R7, the LD59015C25R uniquely balances ultra-low noise (20 µV_RMS), high PSRR (80 dB @ 100 Hz), logic-enable control, and minimal quiescent current - making it optimal for space- and noise-constrained battery-powered analog/RF systems where all three attributes are simultaneously required.

Availability

LD59015C25R is available at Aetrix Electronics and suitable for mobile communications, wearable health monitoring, industrial sensor nodes, and medical handheld devices requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LD59015C25R 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 products for automotive, industrial, and consumer markets.

The LD59015 belongs to ST's high-performance LDO regulator product line, engineered specifically for ultra-low-noise, low-quiescent-current power delivery in battery-operated portable and medical electronics where signal integrity and energy efficiency are critical.

FAQ

What is the minimum input voltage required for LD59015C25R to regulate 2.5 V at full 150 mA load?

The LD59015C25R requires a minimum input voltage of 2.65 V under full load, based on its 150 mV typical dropout voltage specification. At 150 mA and 25 °C, VIN must exceed VOUT + VDROP = 2.5 V + 0.15 V = 2.65 V. Derating applies at elevated temperatures, where dropout increases to 210 mV maximum, requiring VIN ≥ 2.71 V for guaranteed regulation.

Can LD59015C25R operate with a 0.47 µF ceramic output capacitor?

No - the LD59015C25R requires a minimum 1 µF ceramic output capacitor (X5R/X7R) for stability, as specified in Section 3 (Typical Application) and Table 5 of the datasheet. Using 0.47 µF risks oscillation or poor transient response due to insufficient phase margin; the recommended range is 1–4.7 µF with ESR ≤1 Ω at 100 kHz.

Does the NC pin (Pin 4) require any PCB layout treatment?

Pin 4 is internally unconnected and must remain electrically floating. ST recommends leaving it unconnected on the PCB; grounding or routing signals to this pin may cause unpredictable behavior or violate internal isolation. No copper pour or thermal relief should be attached to this pad in the SOT323-5L footprint.

How does the LD59015C25R behave during thermal shutdown?

When junction temperature reaches 160 °C, the LD59015C25R disables its pass transistor and forces output to 0 V while maintaining EN pin responsiveness. It remains latched off until temperature falls by 20 °C (to ~140 °C), then automatically resumes regulation. This hysteresis prevents thermal cycling and ensures safe cooldown before restart.