STMicroelectronics LD39020TPU185R

Overview

LD39020TPU185R from STMicroelectronics is a 200 mA ultra-low-dropout linear regulator with 1.85 V fixed output, 200 mV typical dropout at 200 mA, ±2.0 % output tolerance at 25 °C, 20 µA typical quiescent current at no load, and logic-controlled enable (EN) pin for shutdown. It operates from 1.5 V to 5.5 V input and targets space-constrained, battery-powered systems requiring stable low-noise bias.

For engineers reviewing the LD39020TPU185R datasheet, LD39020TPU185R pinout, LD39020TPU185R application, or LD39020TPU185R equivalent, key selection criteria include dropout voltage under 200 mA load, standby current below 0.1 µA in off mode, ceramic capacitor compatibility (≥0.47 µF), thermal protection behavior, and EN logic thresholds across –40 °C to 125 °C.

Technical Context

The LD39020TPU185R implements a bandgap-referenced error amplifier with internal soft-start (100 µs turn-on time) and thermal shutdown (160 °C trip with 20 °C hysteresis). Its control loop is optimized for stability with ceramic output capacitors as low as 0.47 µF and ESR <15 Ω.

It features a dedicated EN pin (logic-high active, V_IL ≤ 0.4 V, V_IH ≥ 1 V) enabling system-level power sequencing, and includes internal current limiting (250–350 mA short-circuit current) and junction-temperature monitoring. The device lacks integrated output discharge (confirmed by order code "TPU" - no "D" suffix).

Key Specifications

Pinout & Package

LD39020TPU185R is available in SOT23-5L package (5-pin, 2.95 mm × 1.60 mm × 1.45 mm height), with exposed pad not connected internally. Pin assignment is identical across both DFN4 and SOT23-5L variants per datasheet Figure 2 and Table 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD39020TPU185R, the LD39020ATPU185R improves initial accuracy without trade-offs in size or power, while the XC6210B185MR-G reduces output capability and protection robustness to meet cost-sensitive, lower-power designs.

Availability

LD39020TPU185R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and cordless phone systems requiring stable component supply with guaranteed 200 mA output and ultra-low quiescent current.

Supply support for LD39020TPU185R 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.

LD39020TPU185R belongs to ST's high-accuracy, ultra-low-I_Q LDO family targeting battery-powered portable electronics, emphasizing minimal dropout, ceramic capacitor compatibility, and robust thermal protection in miniature packages.

FAQ

What is the minimum input voltage required for regulation at 200 mA load?

The LD39020TPU185R maintains regulation as long as input voltage exceeds output voltage plus dropout. With 1.85 V output and 200 mV typical dropout at 200 mA, VIN must be ≥2.05 V. Absolute minimum VIN is 1.5 V per datasheet, but regulation fails below 2.05 V under full load.

Does LD39020TPU185R include output discharge functionality?

No. The "T" in LD39020TPU185R indicates standard version without integrated output discharge MOSFET. Only part numbers with "D" suffix (e.g., LD39020DTPU185R) include this feature. This version relies on external discharge paths or natural capacitor leakage.

Can LD39020TPU185R be used with a 0.22 µF output capacitor?

No. The datasheet specifies a minimum stable output capacitance of 0.47 µF (X5R/X7R ceramic). Using 0.22 µF risks instability, especially under temperature or load variation, as confirmed by Figure 17's stability boundary requiring ≥0.47 µF for ESR <15 Ω.

What is the thermal resistance of the SOT23-5L package?

The SOT23-5L package has R_thJA = 255 °C/W (junction-to-ambient, free-air) and R_thJC = 81 °C/W (junction-to-case), per Table 3. Effective thermal performance depends on PCB copper area: adding ≥100 mm² thermal pad under the exposed leadframe significantly lowers operating temperature.