STMicroelectronics LDK220PU40R

Overview

LDK220PU40R from STMicroelectronics is a 4.0 V fixed-output, 200 mA low-dropout linear regulator in DFN6-1.2×1.3 package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and logic-controlled shutdown with <1 µA off-mode current. It powers core rails in portable set-top boxes and industrial sensors where low noise (20 µV_RMS) and ceramic-capacitor stability (1 µF C_OUT) are critical.

For engineers reviewing the LDK220PU40R datasheet, LDK220PU40R pinout, LDK220PU40R application, or LDK220PU40R equivalent, this page delivers verified pin functions, thermal derating guidance, load/line regulation performance, and validated alternatives for battery-powered and thermally constrained designs.

Technical Context

The LDK220PU40R implements a bandgap-referenced op-amp control loop with internal current limiting and thermal shutdown at 160 °C (20 °C hysteresis). Its enable input accepts logic-level signals (V_IL ≤ 0.4 V, V_IH ≥ 1.2 V) and activates an internal discharge resistor (18 Ω) when pulled low, preventing floating output during shutdown.

It operates across 2.5–13.2 V input range with guaranteed 200 mA output, supports 1 µF ceramic output capacitors, and maintains 55 dB PSRR at 120 Hz–1 kHz while delivering 20 µV_RMS integrated noise (10 Hz–100 kHz) - enabling clean power for ADCs and RF front-ends.

Key Specifications

Pinout & Package

LDK220PU40R uses the DFN6-1.2×1.3 package (1.2 mm × 1.3 mm × 0.5 mm), optimized for high-density PCB layouts and thermal performance (R_thJA = 237 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, 4 V LDO applications.

Compared with LDK220PU40R, XC6219B402MR-G lacks enable control and output discharge-limiting use in power-managed systems-while AP7361-40SG-7 trades lower dropout and noise for higher output current, making it less optimal for battery-constrained, noise-sensitive applications.

Availability

LDK220PU40R is available at Aetrix Electronics and suitable for industrial sensor nodes, set-top box power rails, and automotive display modules requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LDK220PU40R 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 consumer markets since 1987.

The LDK220 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for battery-powered and thermally constrained applications demanding sub-100 mV dropout and µA-level quiescent current.

FAQ

What is the minimum input voltage required for LDK220PU40R to maintain regulation at 200 mA load?

The minimum input voltage is calculated as V_OUT + V_DROP = 4.0 V + 350 mV = 4.35 V (max dropout at 200 mA, 40–125 °C). At room temperature, 4.1 V input sustains regulation due to 100 mV typical dropout. Input below 4.35 V risks output collapse under full load and high temperature.

Can LDK220PU40R be used with aluminum polymer capacitors instead of ceramic?

No-aluminum polymer capacitors typically exhibit ESR > 10 mΩ and capacitance drift over temperature/frequency, violating the LDK220PU40R's stability requirement (1–22 µF, ESR < 100 mΩ). Ceramic capacitors are mandatory; X5R/X7R dielectrics with 1 µF nominal value and 10% tolerance are validated per Figure 22.

Is the ADJ pin on LDK220PU40R required to be terminated?

No-the ADJ pin is internally disconnected on fixed-output variants like LDK220PU40R (Table 2, DFN6 pin description). It must remain unconnected (no pull-up, pull-down, or capacitor); connecting it risks undefined behavior or damage per datasheet note on page 3.

How does the output discharge function behave during EN deactivation?

When EN is driven low, the internal 18 Ω discharge resistor connects V_OUT to GND, discharging a 1 µF output capacitor from 4.0 V to <0.5 V in ~13 ms (τ = R × C = 18 Ω × 1 µF). This prevents back-driving of upstream circuitry and ensures safe reset sequencing-critical for FPGAs and microcontrollers.