STMicroelectronics LD49100PU33RY

Overview

LD49100PU33RY 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, 3.3 V fixed output voltage, and operation across 1.5–5.5 V input range. It features logic-controlled enable, Power Good flag, 1 ms internal soft-start, and stability with 1 µF ceramic output capacitors - deployed in automotive infotainment power rails and ADAS domain controllers.

For engineers reviewing the LD49100PU33RY datasheet, LD49100PU33RY pinout, LD49100PU33RY application, or LD49100PU33RY equivalent, key selection criteria include its ±2.0% output tolerance at 25 °C, 20 µA no-load quiescent current, 30 µVRMS noise (at 0.8 V), 70 dB low-frequency PSRR, and DFN6 (3×3 mm) wettable flanks package for automated optical inspection.

Technical Context

The LD49100PU33RY implements a precision bandgap reference and error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and high PSRR up to 70 dB at 1 kHz. Its internal 1 ms soft-start circuit limits inrush current during enable transitions, while thermal shutdown (160 °C) and constant-current short-circuit protection ensure robustness under fault conditions.

Power Good monitoring uses a comparator referenced to 93–99% of actual VOUT (not nominal), with open-drain output requiring external pull-up. The EN pin accepts TTL/CMOS-compatible logic levels (VIH ≥ 0.9 V, VIL ≤ 0.4 V), and shutdown draws <1 µA - critical for always-on automotive subsystems.

Key Specifications

Pinout & Package

LD49100PU33RY is housed in a 6-pin DFN6 (3×3 mm) package with wettable flanks for solder joint inspection. The exposed thermal pad must be connected to GND for optimal thermal performance (R_thJA = 55 °C/W on 4-layer JEDEC board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-dropout automotive LDO applications.

Compared with TLE42754G and NCP114AMX33TBG, LD49100PU33RY uniquely combines AEC-Q100 Grade 1 qualification, 3.3 V fixed output, Power Good flag, wettable flanks, and 200 mV dropout - making it the only viable choice for safety-critical automotive subsystems requiring rail monitoring and AOI-capable packaging.

Availability

LD49100PU33RY is available at Aetrix Electronics and suitable for infotainment, ADAS, and telematics applications requiring stable component supply, automotive-grade lifecycle assurance, and traceable sourcing through STMicroelectronics' authorized channel.

Supply support for LD49100PU33RY 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 power management markets since 1987.

The LD49100 belongs to ST's automotive-grade LDO portfolio, engineered specifically for demanding power integrity requirements in modern vehicle ECUs - emphasizing low noise, ultra-low dropout, and functional safety-aware features like Power Good and thermal protection.

FAQ

What is the minimum input voltage required for LD49100PU33RY to regulate at 3.3 V?

The LD49100PU33RY requires a minimum input voltage of 3.5 V to maintain regulation at 3.3 V output under 1 A load, based on its 200 mV typical dropout voltage. At lighter loads, regulation is possible down to 3.35 V input. Input below 1.5 V is prohibited per absolute maximum ratings.

Can LD49100PU33RY operate without an external pull-up resistor on the PG pin?

No - the PG pin is an open-drain output and requires an external pull-up resistor (100 kΩ to 1 MΩ) to either VIN or VOUT to generate a valid logic-high signal. Leaving PG floating results in undefined behavior; if unused, the pin must remain unconnected per datasheet guidance.

Is the DFN6 (3x3 mm) package of LD49100PU33RY compatible with standard reflow profiles?

Yes - the LD49100PU33RY's DFN6 package is rated for standard lead-free reflow profiles (J-STD-020), including peak temperatures up to 260 °C. Its wettable flanks are designed for compatibility with automated optical inspection after reflow, provided stencil design and solder paste volume meet ST's recommended footprint guidelines.

Does LD49100PU33RY require a bypass capacitor for low-noise operation?

No - the LD49100PU33RY achieves 30 µVRMS output noise (10 Hz–100 kHz) without any external bypass capacitor, as confirmed in the datasheet for the 0.8 V version and validated across output voltages. This eliminates BOM cost and board space for noise filtering in space-constrained automotive modules.