STMicroelectronics LD56100DPU33R

Overview

LD56100DPU33R from STMicroelectronics is a 1 A ultra-low-dropout linear voltage regulator delivering 3.3 V output with ±1% accuracy across –40 °C to +85 °C, 120 mV typical dropout at 1 A, 13 µV_RMS noise (10 Hz–100 kHz), and 70 dB PSRR at 1 kHz. It operates from 1.8–5.5 V input and targets precision power rails in mobile camera modules and battery-powered imaging subsystems.

For engineers reviewing the LD56100DPU33R datasheet, LD56100DPU33R pinout, LD56100DPU33R application, or LD56100DPU33R equivalent, key selection criteria include dropout performance at full load, ultra-low-noise operation for analog sensor supply, thermal foldback behavior under short-circuit, and compatibility with 1 µF ceramic output capacitors in space-constrained DFN8 layouts.

Technical Context

The LD56100DPU33R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and fast transient response without external compensation. Its internal soft-start limits inrush current to <100 µs rise time, while logic-controlled EN pin enables sub-0.1 µA shutdown current.

Current limiting is configurable via LCON pin: high selects 1.1–1.6 A foldback limit, low reduces it to 0.6–0.8 A. The optional output discharge MOSFET (enabled in this DPU33R variant) actively sinks C_OUT when EN is deasserted, eliminating hold-up voltage in sequenced power-down systems.

Key Specifications

Pinout & Package

LD56100DPU33R is housed in a thermally enhanced DFN8 package (1.2 × 1.6 mm, 0.4 mm pitch) with exposed thermal pad connected to GND for efficient heat dissipation in compact layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G and ADP125ARHZ-3.3-R7, LD56100DPU33R uniquely combines ultra-low dropout, ultra-low noise, programmable current limiting, and integrated discharge - making it the only option meeting simultaneous requirements for compact camera modules, wearable PPG, and battery-powered imaging with strict power sequencing.

Availability

LD56100DPU33R is available at Aetrix Electronics and suitable for mobile camera modules, wearable health sensors, and industrial barcode scanners requiring stable component supply with guaranteed long-term availability and full traceability.

Supply support for LD56100DPU33R 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 power management, analog, and microcontroller solutions for automotive, industrial, and consumer markets.

The LD56100 series is designed specifically for ultra-low-noise, high-accuracy power delivery in battery-operated imaging and sensing applications where space, efficiency, and signal integrity are critical.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 1 A?

The LD56100DPU33R requires VIN ≥ VOUT + VDROP = 3.3 V + 0.12 V = 3.42 V for full 1 A regulation. At lower inputs, output current is reduced per the dropout curve - e.g., at 3.35 V input, maximum load is ~800 mA. Input must remain ≥1.8 V for circuit biasing, but regulation ceases below 3.42 V under full load.

How does the LCON pin affect short-circuit protection behavior?

When LCON is tied to VIN, short-circuit current folds back to ~400 mA at VOUT = 0 V. When LCON is grounded, foldback reduces to ~180 mA. This dual-threshold design allows designers to match protection level to load fault energy - higher limit for brief surges, lower for sustained shorts in sensitive sensor interfaces.

Can the LD56100DPU33R operate without an output capacitor?

No. The control loop requires a minimum 1 µF ceramic output capacitor (X5R/X7R) for stability. Omitting COUT causes oscillation and unregulated output. The device is optimized for 1–22 µF range; values outside this may degrade transient response or phase margin, especially at temperature extremes.

Is the thermal pad (pin 8) electrically isolated or connected internally?

Pin 8 is the exposed thermal pad and is internally connected to GND. It must be soldered to a dedicated GND copper pour on the PCB to achieve the specified R_thJA = 80 °C/W. Leaving it floating or connecting to another net violates absolute maximum ratings and risks thermal runaway under 1 A load.