STMicroelectronics LDK320AM-R

Overview

LDK320AM-R from STMicroelectronics is a 200 mA low-dropout linear regulator with fixed 3.3 V output, ±0.5% accuracy at 25 °C, 100 mV typical dropout at 100 mA, and 88 dB PSRR at 120 Hz. It operates from 2.5 V to 18 V input, supports logic-controlled shutdown (≤1 μA off-mode current), and is stabilized with 1 μF ceramic output capacitor. Used in DSC, BD/DVD players, and industrial power rails requiring high-accuracy, low-noise bias.

For engineers reviewing the LDK320AM-R datasheet, LDK320AM-R pinout, LDK320AM-R application, or LDK320AM-R equivalent, this page delivers verified electrical specs, SOT23-5L/SOT-89 package mapping, thermal protection behavior, enable logic thresholds, and real-world load/line transient performance - all confirmed from STMicroelectronics DS11321 Rev 13.

Technical Context

The LDK320AM-R implements a bandgap-referenced op-amp control loop with internal current limiting, thermal shutdown (160 °C, 20 °C hysteresis), and SOA protection. Its architecture enables stable regulation with 1 μF ceramic COUT across the full -40 °C to 125 °C junction temperature range.

It features dual-package support: SOT23-5L includes dedicated EN and ADJ/NC pins, while SOT-89 (D configuration) integrates IN to the tab for enhanced thermal dissipation but omits EN and ADJ functionality. Both packages are ECOPACK-compliant.

Key Specifications

Pinout & Package

LDK320AM-R is available in two RoHS-compliant packages: SOT23-5L (compact, 5-pin surface-mount) and SOT-89 (power-optimized, 3-pin + tab). The SOT23-5L variant supports enable control and adjustable versions; SOT-89 (D configuration) uses the tab as IN for improved thermal resistance (R_thJC = 15 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDK320M33R, the LDK320AM-R delivers tighter voltage accuracy critical for ADC references; versus TSM1052-3.3, it provides superior dynamic rejection and integrated shutdown control essential for battery-aware designs.

Availability

LDK320AM-R is available at Aetrix Electronics and suitable for DSC, BD/DVD player, and industrial PLC applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing from STMicroelectronics' qualified production line.

Supply support for LDK320AM-R 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, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The LDK320 series belongs to ST's high-accuracy, high-PSRR LDO product line, engineered specifically for noise-sensitive, battery-constrained applications where precision regulation and ultra-low quiescent current are mandatory.

FAQ

What is the minimum input voltage required for 3.3 V output regulation?

The LDK320AM-R maintains regulation as long as VIN ≥ VOUT + VDROP. With a typical dropout of 100 mV at 100 mA and 200 mV maximum at 200 mA over temperature, the absolute minimum input is 3.4 V at light loads and 3.5 V under full 200 mA load at 125 °C. Below this, output voltage collapses linearly.

Can the LDK320AM-R be used with a 10 μF aluminum electrolytic output capacitor?

No - the LDK320AM-R requires an output capacitor with ESR between 0.01 Ω and 1 Ω for stability. Standard aluminum electrolytics exceed 1 Ω ESR and will cause oscillation. Only X5R/X7R ceramic capacitors (1–22 μF) or specialty low-ESR polymer types meeting the datasheet's stability plan (Figure 25) are approved.

Does the EN pin require a pull-up resistor when driven by an open-drain microcontroller GPIO?

Yes - the EN pin has no internal pull-up. When driven by an open-drain GPIO, a 10–100 kΩ external pull-up to VIN is required to ensure reliable activation (>1.2 V threshold). Without it, the EN pin floats near 0.4 V, risking undefined state and intermittent regulation.

How does thermal shutdown behave during continuous overload?

When junction temperature reaches 160 °C, the LDK320AM-R shuts down output and enters thermal hysteresis mode. It remains off until temperature falls to ~140 °C (20 °C hysteresis), then re-enables. This cycle repeats autonomously - no external reset is needed, but repeated cycling indicates insufficient PCB copper area or excessive ambient temperature.