STMicroelectronics LD49100PU25RY

Overview

LD49100PU25RY from STMicroelectronics is an AEC-Q100 Grade 1 qualified ultra-low-dropout linear regulator delivering 1 A output current with 200 mV typical dropout at full load, 20 µA quiescent current at no load, and 30 µV_RMS output noise (at 0.8 V output, 10 Hz–100 kHz) without bypass capacitor-designed for automotive infotainment, ADAS, and telematics power rails.

For engineers reviewing the LD49100PU25RY datasheet, LD49100PU25RY pinout, LD49100PU25RY application, or LD49100PU25RY equivalent, this page provides verified package mapping (DFN6 3×3 mm wettable flanks), confirmed fixed 2.5 V output version, Power Good and enable logic interface behavior, thermal shutdown threshold (160 °C), and ceramic-capacitor stability (C_OUT = 1 µF).

Technical Context

The LD49100PU25RY implements a precision bandgap-referenced error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and high PSRR (70 dB @ 1 kHz). Its internal 1 ms soft-start circuit limits inrush current during enable transitions, while the open-drain Power Good output monitors regulated output voltage against ±7% thresholds (V_{PG_ON} = 93–99% V_OUT, V_{PG_OFF} = 91–95% V_OUT).

It integrates short-circuit constant-current limiting (2.5 A typ.), thermal shutdown with 20 °C hysteresis, and logic-controlled shutdown consuming ≤1 µA. The fixed 2.5 V version uses pin 5 as VSENSE-requiring connection to VOUT for local regulation or to remote load for sensing-ensuring ±2.0% output accuracy over temperature (−40 °C to 125 °C).

Key Specifications

Pinout & Package

LD49100PU25RY is housed in a DFN6 (3 × 3 mm) package with wettable flanks for automated optical inspection (AOI) of solder joints in automotive PCB assembly. The exposed thermal pad must be connected to GND for optimal thermal performance (R_thJC = 10 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B252MR-G, LD49100PU25RY adds automotive-grade reliability and sequencing capability; versus ADM7172ACPZ-2.5-R7, it trades 0.25 A current headroom for guaranteed AEC-Q100 Grade 1 operation and lower quiescent current in standby.

Availability

LD49100PU25RY is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and telematics control units requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.

Supply support for LD49100PU25RY 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 specializing in automotive, industrial, and power management solutions, with over 40 years of analog IC innovation and manufacturing excellence.

The LD49100 belongs to ST's automotive-grade LDO portfolio, engineered specifically for low-noise, low-quiescent-current power delivery in safety-critical vehicle subsystems operating across extended temperature ranges.

FAQ

What is the minimum input voltage required for LD49100PU25RY to regulate 2.5 V output?

The LD49100PU25RY requires a minimum input voltage of 2.7 V to maintain regulation at 2.5 V output under 1 A load, based on its 200 mV typical dropout voltage. At light loads (<100 mA), regulation is maintained down to 2.55 V input. Input below 1.5 V is prohibited per absolute maximum ratings.

Can LD49100PU25RY operate with a 1 µF ceramic output capacitor only, or is additional capacitance needed?

Yes-LD49100PU25RY is fully stable with a single 1 µF X5R or X7R ceramic capacitor (ESR 0–150 mΩ) on the output, as confirmed in Section 6.1.2 of DS13115. Larger values improve transient response but are not required for stability. Avoid high-ESR or aging-prone capacitors like Y5V.

How should the PG (Power Good) pin be interfaced in a microcontroller-based system?

Connect a 470 kΩ pull-up resistor from PG to VIN (or VOUT), then route the PG node to a GPIO interrupt pin. The open-drain PG asserts low (≤0.4 V) when VOUT falls below 91% of nominal; it floats high when valid. No external level-shifting is needed for 3.3 V or 5 V MCUs.

Is the exposed thermal pad on the DFN6 package electrically connected, and how must it be handled in PCB layout?

Yes-the exposed pad is internally connected to GND and must be soldered to a dedicated PCB ground plane using ≥4 thermal vias (0.3 mm diameter) spaced evenly beneath the pad. This achieves the specified R_thJA = 55 °C/W and prevents thermal shutdown during 1 A continuous operation.