STMicroelectronics LD39020TPU33R

Overview

LD39020TPU33R from STMicroelectronics is a 3.3 V, 200 mA ultra-low-dropout linear voltage regulator in DFN4 1×1 package, featuring 200 mV typical dropout at 200 mA, ±0.5 % output accuracy (A-version), and 20 µA typical quiescent current at no load. It delivers stable power to noise-sensitive RF and digital baseband circuits in space-constrained portable devices.

For engineers reviewing the LD39020TPU33R datasheet, LD39020TPU33R pinout, LD39020TPU33R application, or LD39020TPU33R equivalent, key selection criteria include dropout performance under 200 mA load, enable-controlled shutdown current <0.1 µA, ceramic capacitor compatibility (≥0.47 µF), thermal protection behavior, and dual-package availability (DFN4 1×1 vs. SOT23-5L).

Technical Context

The LD39020TPU33R employs a PMOS pass transistor architecture enabling ultra-low dropout and near-zero reverse current during shutdown. Its bandgap-referenced error amplifier drives an internal soft-start circuit that limits inrush current by controlling output ramp-up over ~100 µs without external components.

It integrates logic-controlled enable (EN) with TTL-compatible thresholds (V_IL ≤ 0.4 V, V_IH ≥ 1 V), thermal shutdown at 160 °C with 20 °C hysteresis, and internal current limiting (~300 mA). The A-version (denoted by 'A' in part number) guarantees ±0.5 % initial output tolerance at 25 °C - critical for precision biasing of ADC references and RF synthesizers.

Key Specifications

Pinout & Package

LD39020TPU33R is supplied in the DFN4 1×1 mm package (0.4 mm height), optimized for ultra-dense portable designs. The exposed thermal pad must be soldered to a PCB ground plane for effective heat dissipation (R_thJA = 250 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G and BD39020MUV-E2, LD39020TPU33R provides superior initial accuracy (±0.5 %), lower quiescent current (20 µA), integrated soft-start, and full thermal protection - making it the preferred choice for precision, safety-critical, and battery-sensitive designs.

Availability

LD39020TPU33R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and industrial handhelds requiring stable component supply with long-term manufacturability and RoHS-compliant packaging.

Supply support for LD39020TPU33R 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

LD39020TPU33R belongs to ST's high-accuracy, ultra-low-I_Q LDO family targeting battery-powered portable electronics - engineered to maximize runtime while maintaining tight voltage regulation and noise immunity.

FAQ

What is the minimum input voltage required for LD39020TPU33R to regulate 3.3 V at 200 mA?

The minimum input voltage is determined by dropout: VIN(min) = VOUT + VDROP = 3.3 V + 0.2 V = 3.5 V (typical). At worst-case 350 mV dropout (−40 °C to +125 °C), VIN must be ≥3.65 V to sustain 200 mA output. Below this, regulation fails and VOUT drops linearly with VIN.

Can LD39020TPU33R be used with a 0.22 µF output capacitor?

No - the datasheet specifies a minimum stable output capacitance of 0.47 µF for guaranteed loop stability across temperature, input voltage, and load variations. Using 0.22 µF risks oscillation or poor transient response, especially at high temperatures or light loads.

Does LD39020TPU33R include output discharge functionality?

No - LD39020TPU33R is the standard version without auto-discharge MOSFET. Only variants with "AD" or "D" in the order code (e.g., LD39020ADTPU33R) integrate the optional output discharge transistor. This part relies on external bleed resistors if fast VOUT decay is required.

How does the EN pin behave during power-up when VIN ramps slowly?

The EN pin has no internal pull-up or pull-down; it must be actively driven. If left floating during slow VIN ramp, undefined logic state may cause erratic turn-on or latch-up. Designers must ensure EN is held low until VIN exceeds 1.5 V, then driven high with a clean edge - often using a resistor-divider from VIN or dedicated reset IC.