STMicroelectronics LDK320ADU120R

Overview

LDK320ADU120R from STMicroelectronics is a 12 V fixed-output, high-accuracy (±0.5% at 25 °C), low-dropout linear regulator delivering up to 200 mA with 100 mV typical dropout at 100 mA, 88 dB PSRR at 120 Hz, and 60 μA quiescent current - designed for stable power in space-constrained industrial and consumer applications including DVD/BD players and PC peripherals.

For engineers reviewing the LDK320ADU120R datasheet, LDK320ADU120R pinout, LDK320ADU120R application, or LDK320ADU120R equivalent, this page delivers verified electrical specs, SOT-23-5L package details, thermal protection behavior, enable-controlled shutdown (<1 μA off-mode current), and real-world load/line regulation performance across -40 °C to 125 °C.

Technical Context

The LDK320ADU120R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and high PSRR via internal compensation optimized for 1 μF ceramic output capacitors. Its logic-controlled EN pin directly interfaces with microcontroller GPIOs without level-shifting.

Thermal shutdown (160 °C) and foldback current limiting protect against sustained overloads; SOA protection prevents damage during transient short circuits. The device operates stably with output capacitance as low as 1 μF and ESR down to 0.01 Ω, eliminating need for tantalum or electrolytic capacitors.

Key Specifications

Pinout & Package

SOT-23-5L (5-pin small-outline transistor) package with exposed pad for thermal enhancement; footprint compatible with JEDEC MO-178AC standard. Pin 1 = IN, Pin 2 = GND, Pin 3 = EN, Pin 4 = NC (not connected - fixed-output version), Pin 5 = OUT.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout, fixed-output voltage regulator applications.

Compared with XC6206P122MR and AP2204K-12W5, the LDK320ADU120R provides superior accuracy (±0.5% vs. ±2%), lower dropout (100 mV vs. ≥150 mV), and higher PSRR (88 dB), making it optimal for noise-sensitive, thermally constrained, or battery-life-critical designs requiring guaranteed 12 V regulation.

Availability

LDK320ADU120R is available at Aetrix Electronics and suitable for DVD/Blu-ray players, industrial sensor nodes, PC peripheral interface cards, and automotive infotainment display modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LDK320ADU120R 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The LDK320 series belongs to ST's high-PSRR, low-quiescent-current LDO portfolio, engineered specifically for battery-powered and noise-sensitive applications where precision regulation, thermal robustness, and ceramic capacitor compatibility are mandatory.

FAQ

What is the minimum input voltage required for 12 V output regulation?

The LDK320ADU120R requires VIN ≥ VOUT + VDROP. With 100 mV typical dropout at 100 mA, the minimum functional input is 12.1 V. At full 200 mA load, worst-case dropout reaches 350 mV (per Table 6), so VIN must be ≥12.35 V to guarantee regulation across temperature and process variation.

Can the LDK320ADU120R be used with a 22 μF ceramic output capacitor?

Yes - the datasheet explicitly specifies COUT = 1–22 μF ceramic (Table 5 and Figure 25). A 22 μF X7R 0805 ceramic capacitor with ESR ≤ 0.1 Ω ensures stable operation and improves load-transient response, especially for pulsed 200 mA loads like motor drivers or RF transceivers.

Is the EN pin internally pulled down?

No - the EN pin has no internal pull-down. It presents ≤100 nA leakage (Table 6) and requires an external pull-down resistor (typically 100 kΩ) to ensure reliable shutdown during power-up or MCU reset. Leaving EN floating may cause undefined startup behavior.

Does the LDK320ADU120R support reverse-voltage protection?

No - the device lacks integrated reverse-polarity protection. If reverse input voltage (>0.3 V below GND) is possible in the system, an external series Schottky diode (e.g., 1N5819) or ideal diode controller must be added to prevent damage, as specified in Absolute Maximum Ratings (Table 4).