STMicroelectronics LDK220C40R

Overview

LDK220C40R from STMicroelectronics is a fixed-output 4.0 V, 200 mA low-dropout linear regulator in SOT23-5L 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 supports ceramic output capacitors as low as 1 µF and operates across -40 °C to 125 °C for battery-powered and industrial power rails.

For engineers reviewing the LDK220C40R datasheet, LDK220C40R pinout, LDK220C40R application, or LDK220C40R equivalent, key selection criteria include ultra-low quiescent current (55 µA typ.), low-noise operation (20 µVRMS/V), thermal/short-circuit protection, and compatibility with compact ceramic capacitors in space-constrained portable designs.

Technical Context

The LDK220C40R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling stable regulation with minimal dropout and high PSRR (55 dB @ 120 Hz–1 kHz). Its internal bias generator and thermal shutdown circuit (160 °C trigger, 20 °C hysteresis) ensure robust operation under load transients and overtemperature conditions.

Logic-controlled enable input (EN) provides precise on/off sequencing with defined thresholds (V_IL ≤ 0.4 V, V_IH ≥ 1.2 V), while integrated output discharge (R_dis = 18 Ω) actively pulls VOUT to GND during shutdown-critical for preventing back-powering in multi-rail systems.

Key Specifications

Pinout & Package

LDK220C40R is packaged in SOT23-5L (JEDEC TO-236AB), a 5-pin surface-mount package with 1.3 mm × 2.9 mm footprint and 1.45 mm height. Thermal resistance is R_thJA = 160 °C/W, supporting up to 500 mW power dissipation in standard PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73340PDBVR and AP2204K-4.0TRG1, LDK220C40R delivers superior low-load efficiency (55 µA vs. ≥65 µA), lower noise (20 vs. ≥40 µVRMS/V), and tighter dropout (100 mV vs. ≥170 mV), making it optimal for battery longevity and analog signal fidelity in constrained-input systems.

Availability

LDK220C40R is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC I/O modules, smart TV power management, and automotive infotainment displays requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LDK220C40R 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The LDK220 series belongs to ST's high-efficiency, low-noise LDO portfolio engineered specifically for battery-powered and thermally demanding applications where ultra-low IQ, fast transient response, and ceramic-capacitor compatibility are mandatory.

FAQ

What is the minimum input voltage required for LDK220C40R to maintain regulation at full 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 suffices due to 200 mV typical dropout. Input below 4.35 V risks output collapse under worst-case thermal/load conditions.

Can LDK220C40R be used with a 0.47 µF output capacitor?

No-ST specifies 1 µF minimum ceramic COUT for stability across all operating conditions. Using 0.47 µF violates the stability boundary shown in Figure 22 and may cause oscillation or poor load transient response, especially with ESR <0.5 Ω.

Is the ADJ pin on LDK220C40R internally connected or should it be left floating?

The ADJ pin is Not Connected (NC) in the fixed-output LDK220C40R variant. Per Table 1, it must remain unconnected-no pull-up, pull-down, or capacitor. Connecting it risks undefined behavior or damage, as the pin is not bonded in this version.

Does LDK220C40R support reverse current blocking when EN is low?

Yes-the integrated output discharge function (R_dis = 18 Ω) actively sinks current from VOUT to GND when EN is low, preventing reverse current flow into the LDO. This protects upstream sources and ensures clean rail sequencing in multi-supply systems.