STMicroelectronics LDK320AM33R

Overview

LDK320AM33R from STMicroelectronics is a 3.3 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 power-sensitive applications in digital consumer electronics requiring stable low-noise bias.

For engineers reviewing the LDK320AM33R datasheet, LDK320AM33R pinout, LDK320AM33R application, or LDK320AM33R equivalent, this page delivers verified electrical specs, SOT23-5L package details, thermal protection behavior, ceramic-capacitor stability validation, and real-world use context for battery-powered DSC, BD/DVD, and industrial control subsystems.

Technical Context

The LDK320AM33R implements a bandgap-referenced op-amp control loop with internal bias generator and thermal shutdown (160 °C, 20 °C hysteresis), enabling precise output regulation across -40 °C to 125 °C junction temperature. Its logic-controlled enable input (VENL = 0.4 V max, VENH = 1.2 V min) supports ultra-low-off-state current (<1 μA).

It features integrated short-circuit current limiting (330 mA typ.), SOA protection, and compatibility with 1 μF ceramic output capacitors - validated for stability across 1–22 μF COUT with ESR ≤1 Ω - eliminating need for electrolytic or tantalum alternatives in space-constrained designs.

Key Specifications

Pinout & Package

LDK320AM33R is supplied in the SOT23-5L package (3.02 mm × 2.80 mm × 1.25 mm), optimized for compact PCB layouts and automated assembly. Thermal resistance is R_thJA = 160 °C/W, supporting up to ~200 mW dissipation in standard FR-4 with minimal copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6206P332MR and AP2204K-3.3TRG1, LDK320AM33R uniquely combines ±0.5% accuracy, 100 mV dropout, integrated thermal shutdown, and enable functionality in SOT23-5L - making it the only choice for thermally constrained, precision-biased, battery-aware systems.

Availability

LDK320AM33R is available at Aetrix Electronics and suitable for digital still cameras, Blu-ray/DVD players, industrial PLC I/O modules, and PC embedded controller supplies requiring stable component supply, long-term lifecycle support, and automotive-grade reliability screening.

Supply support for LDK320AM33R 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-accuracy, low-noise LDO product line, engineered specifically for power-sensitive portable and industrial electronics demanding tight regulation, ultra-low quiescent current, and robust fault protection.

FAQ

What is the minimum input voltage required for LDK320AM33R to maintain regulation at full 200 mA load?

The minimum input voltage is determined by dropout voltage plus nominal output: V_IN(min) = V_OUT + V_DROP. At 200 mA and -40 °C to 125 °C, V_DROP ≤ 350 mV per datasheet Table 6, so V_IN(min) = 3.3 V + 0.35 V = 3.65 V. At 25 °C, typical dropout is 200 mV, allowing operation down to 3.5 V.

Can LDK320AM33R be used with a 10 μF X5R ceramic capacitor on the output?

Yes - the device is explicitly characterized for stability with 1–22 μF ceramic capacitors (Table 5, Section 6). A 10 μF X5R capacitor with ESR ≤1 Ω at 100 kHz satisfies the stability criteria shown in Figure 25 and requires no series resistor or additional compensation.

Does LDK320AM33R require an input capacitor, and if so, what value and type?

Yes - a minimum 1 μF ceramic capacitor is required on the IN pin per Section 3 (Typical Application) and Figure 4. This improves line transient response and prevents oscillation under fast input voltage changes; X5R or X7R dielectrics are recommended for stable capacitance across temperature and bias.

How does the enable pin behave during power-up, and is an external pull-up required?

The EN pin is not internally biased; it must be actively driven high (≥1.2 V) to enable regulation or pulled low (≤0.4 V) to enter shutdown. No internal pull-up exists - an external resistor to VIN or host GPIO is required for controlled startup sequencing in systems with multiple power domains.