STMicroelectronics LDK320ADU30R

Overview

LDK320ADU30R from STMicroelectronics is a high-accuracy, low-dropout linear voltage regulator delivering 3.0 V fixed output at up to 200 mA, with ±0.5% output tolerance 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 and features logic-controlled shutdown (EN pin), thermal/short-circuit protection, and ceramic capacitor compatibility (1 μF C_OUT). Used in DSC, TV, BD/DVD, and PC power rails.

For engineers reviewing the LDK320ADU30R datasheet, LDK320ADU30R pinout, LDK320ADU30R application, or LDK320ADU30R equivalent, key selection criteria include output accuracy under load/temperature variation, EN pin logic thresholds, dropout behavior at full load, and SOT23-5L thermal resistance (160 °C/W) for compact battery-powered designs.

Technical Context

The LDK320ADU30R implements a bandgap-referenced op-amp control loop with internal bias generator and thermal shutdown circuitry. Its EN pin directly controls the pass transistor gate via logic-level input (V_ENL ≤ 0.4 V, V_ENH ≥ 1.2 V), enabling sub-1 μA off-state current.

It supports two package variants: SOT23-5L (5-pin, with IN/GND/EN/ADJ/OUT) and SOT-89 (3-pin, with OUT/GND/IN). The ADJ pin is NC on fixed-output versions like LDK320ADU30R, confirming its role as a dedicated 3.0 V regulator-not adjustable-designed for stable point-of-load regulation in space-constrained consumer electronics.

Key Specifications

Pinout & Package

LDK320ADU30R is packaged in SOT23-5L (5-pin, 2.92 mm × 2.80 mm × 1.25 mm), optimized for PCB area efficiency and thermal performance (R_thJA = 160 °C/W). The pinout is validated per DS11321 Rev 13, Table 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSM1083-3.0 and AP2210K-3.0TRG1, LDK320ADU30R delivers tighter regulation (±0.5%), lower dropout (100 mV vs. ≥300 mV), and superior noise rejection (88 dB vs. ≤75 dB), making it optimal for precision, low-power, and noise-critical embedded applications.

Availability

LDK320ADU30R is available at Aetrix Electronics and suitable for DSC, Blu-ray player, industrial HMI, and PC peripheral designs requiring stable component supply, long-term manufacturability, and guaranteed parametric compliance across temperature.

Supply support for LDK320ADU30R 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, microcontrollers, and analog ICs, with manufacturing aligned to ISO 9001 and AEC-Q200 standards.

The LDK320 series belongs to ST's high-accuracy, low-quiescent-current LDO family, designed specifically for battery-powered consumer electronics and industrial equipment demanding tight regulation and robust fault protection.

FAQ

What is the minimum input voltage required for LDK320ADU30R to maintain 3.0 V output at 200 mA?

The dropout voltage is 200–350 mV over temperature at 200 mA (Table 6). At 25 °C, typical dropout is ~150 mV. Thus, minimum input is 3.0 V + 0.15 V = 3.15 V for nominal operation; design margin requires ≥3.3 V to ensure regulation across –40 °C to +125 °C.

Can LDK320ADU30R be used with tantalum or aluminum electrolytic capacitors instead of ceramic?

No. The datasheet specifies stability with 1–22 μF ceramic capacitors having ESR ≤1 Ω (Figures 25–26). Tantalum and aluminum electrolytics exhibit higher ESR and capacitance drift, risking oscillation or poor transient response. Ceramic is mandatory for guaranteed performance.

Does the EN pin require a pull-up resistor when interfaced with a 1.8 V GPIO?

Yes. The EN pin logic-high threshold is ≥1.2 V (Table 6), so a 1.8 V GPIO meets this. However, a 100 kΩ pull-up to VIN is recommended to ensure reliable activation during power ramp-up and prevent floating states that could cause erratic startup behavior.

How does thermal performance differ between SOT23-5L and SOT-89 packages for LDK320ADU30R?

SOT-89 has lower thermal resistance: R_thJA = 110 °C/W vs. 160 °C/W for SOT23-5L (Table 5). At 200 mA and 100 mV dropout (20 mW dissipation), SOT-89 junction rise is ~2.2 °C above ambient, while SOT23-5L rises ~3.2 °C-both well within limits, but SOT-89 enables higher ambient or longer duty cycles.