STMicroelectronics LDK320AM120R

Overview

LDK320AM120R from STMicroelectronics is a high-accuracy, low-dropout linear voltage regulator delivering 200 mA output current with ±0.5% initial output voltage tolerance at 25 °C and 12 V fixed output. It operates from 2.5 V to 18 V input, achieves 100 mV typical dropout at 100 mA, and features logic-controlled shutdown (EN pin), 88 dB PSRR at 120 Hz, and compatibility with 1 μF ceramic output capacitors. It is used in DSC, TV, and industrial power rails requiring stable low-noise bias.

For engineers reviewing the LDK320AM120R datasheet, LDK320AM120R pinout, LDK320AM120R application, or LDK320AM120R equivalent, key selection criteria include its 12 V fixed output accuracy, SOT23-5L package footprint, EN-controlled ultra-low-off-current mode (<1 μA), and thermal/SOA protection for robust operation in battery-powered and space-constrained systems.

Technical Context

The LDK320AM120R implements a bandgap-referenced op-amp control loop with internal bias generator and thermal shutdown circuitry. Its architecture supports fast transient response and high PSRR via optimized internal compensation, enabling stable regulation even with minimal 1 μF ceramic COUT.

It integrates logic-level enable functionality (EN pin active-high), short-circuit current limiting, and thermal foldback protection. The device is specified across –40 °C to +125 °C junction temperature and supports both fixed-output (12 V) and adjustable versions - though LDK320AM120R is fixed-output only and available exclusively in SOT23-5L.

Key Specifications

Pinout & Package

LDK320AM120R is packaged in SOT23-5L - a 5-pin, surface-mount, thermally enhanced plastic package with exposed pad (pin 5 is OUT, pin 3 is EN, pin 2 is GND). The package measures 2.92 mm × 2.80 mm × 1.25 mm (max height) and supports reflow soldering per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO applications.

Compared with TSM1012-12 and MCP1703T-1202E/MB, LDK320AM120R offers superior accuracy (±0.5% vs. ±1–2%), lowest dropout (100 mV), and highest PSRR (88 dB), making it optimal for noise-sensitive, battery-constrained, or thermally demanding 12 V regulation tasks.

Availability

LDK320AM120R is available at Aetrix Electronics and suitable for DSC, industrial sensor nodes, and BD/DVD optical drive designs requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for LDK320AM120R 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 industrial, automotive, and consumer markets.

The LDK320 series is designed for high-accuracy, low-noise, low-power linear regulation in space-constrained and thermally challenging applications - emphasizing precision, protection, and ceramic-capacitor simplicity.

FAQ

What is the minimum input voltage required for LDK320AM120R to maintain 12 V output at full 200 mA load?

The dropout voltage is 350 mV maximum at 200 mA and full temperature range. Therefore, minimum input voltage is 12 V + 0.35 V = 12.35 V. At room temperature, typical dropout is 200 mV, so 12.2 V suffices. Input below this causes output collapse or regulation loss.

Can LDK320AM120R be used with tantalum or aluminum electrolytic output capacitors?

Yes, but not recommended. The device is optimized for 1 μF ceramic capacitors (X7R/X5R) with ESR < 100 mΩ. Tantalum or electrolytic caps may cause instability due to higher ESR and aging effects; ceramic ensures guaranteed stability and best transient response per datasheet Figure 25.

Is the ADJ pin functional on LDK320AM120R?

No. LDK320AM120R is the fixed 12 V version; pin 4 is labeled ADJ/NC and is internally disconnected. It must be left floating or grounded - no external resistor divider is used or supported. Only adjustable versions (e.g., LDK320ADU120R) utilize the ADJ pin.

Does LDK320AM120R require an input capacitor, and if so, what value?

Yes - a 1 μF ceramic capacitor (X7R/X5R) is required at the IN pin, placed as close as possible to pins 1 and 2. This minimizes input impedance, suppresses high-frequency noise, and prevents oscillation during load transients, as validated in the typical application circuit (Figure 4, DS11321 page 4).