STMicroelectronics LDK220M32R

Overview

LDK220M32R from STMicroelectronics is a fixed-output 3.2 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 consumer and industrial power rails.

For engineers reviewing the LDK220M32R datasheet, LDK220M32R pinout, LDK220M32R application, or LDK220M32R equivalent, key selection criteria include dropout performance at 200 mA load, enable threshold compatibility with 1.8 V/3.3 V logic, thermal derating in SOT23-5L (R_thJA = 160 °C/W), and noise-sensitive use in set-top box AV subsystems.

Technical Context

The LDK220M32R integrates a bandgap reference, error amplifier, and PMOS pass transistor with internal current and thermal limiting. Its enable input drives an internal bias generator that disables the regulator core and activates an 18 Ω output discharge path when pulled low.

It achieves low-noise regulation (20 µV_RMS over 10 Hz–100 kHz) via internal compensation compatible with 1 µF ceramic C_OUT, and maintains 55 dB supply rejection at 120 Hz–1 kHz while drawing only 55 µA quiescent current across -40 °C to 125 °C.

Key Specifications

Pinout & Package

LDK220M32R is supplied in SOT23-5L package (2.95 mm × 1.60 mm × 1.45 mm), optimized for space-constrained PCB layouts and reflow-compatible assembly. Thermal resistance is R_thJA = 160 °C/W (JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV70232DBVR and MCP1700T-3202E/TT, LDK220M32R uniquely combines sub-100 mV dropout, integrated discharge, and 20 µV_RMS noise in a 5-pin SOT23 - making it optimal for compact, battery-aware systems demanding fast power cycling and ultra-clean analog bias.

Availability

LDK220M32R is available at Aetrix Electronics and suitable for battery-powered equipment, set-top boxes, and industrial sensor nodes requiring stable component supply with guaranteed 200 mA output and -40 °C to 125 °C operation.

Supply support for LDK220M32R 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 designing and manufacturing silicon solutions for automotive, industrial, and consumer markets, with strong IP in analog, power management, and microcontrollers.

The LDK220 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for space-constrained, battery-sensitive applications where ultra-low quiescent current, fast enable response, and ceramic-capacitor stability are mandatory.

FAQ

What is the minimum input voltage required for LDK220M32R to maintain regulation at 200 mA load?

The minimum input voltage is determined by dropout: at 200 mA, max dropout is 350 mV (per Table 6). Thus, VIN must be ≥ 3.2 V + 0.35 V = 3.55 V to sustain 3.2 V output. Below this, output collapses linearly with VIN.

Can LDK220M32R be used with a 10 µF aluminum electrolytic output capacitor instead of ceramic?

No - the device is compensated for 1–22 µF ceramic capacitors (ESR < 10 mΩ). Aluminum electrolytics have ESR > 100 mΩ and phase shift that risks instability, per Figure 22 stability boundary. Ceramic or polymer capacitors only.

Is the ADJ pin on LDK220M32R functional, and what happens if it's left floating?

The ADJ pin is not connected (NC) in the fixed-output LDK220M32R variant. Per Table 1, it is "ADJ/NC" - tied internally to GND or open. Leaving it unconnected is safe; tying to GND adds no benefit but avoids potential noise coupling.

How does the output discharge function behave during EN deactivation, and what is its time constant?

When EN is pulled low, an internal 18 Ω resistor connects OUT to GND. With 1 µF C_OUT, discharge time to 10% residual voltage is ~42 µs (τ = R×C = 18 Ω × 1 µF). Larger C_OUT increases discharge time linearly - e.g., 10 µF yields ~420 µs.