STMicroelectronics LDL212D33R

Overview

LDL212D33R from STMicroelectronics is a fixed-output 3.3 V, 1.2 A low-dropout linear regulator IC with 350 mV typical dropout at full load, 87 dB PSRR at 120 Hz, and operation from 2.5 V to 18 V input. It integrates enable control, thermal shutdown, current limiting, and undervoltage lockout-designed for post-regulation in DC-DC converters and noise-sensitive analog rails in industrial power supplies.

For engineers reviewing the LDL212D33R datasheet, LDL212D33R pinout, LDL212D33R application, or LDL212D33R equivalent, this device supports precise point-of-load regulation where high PSRR, stable output accuracy (±2% at 25°C), fast enable response (120 µs turn-on), and robust thermal protection are required in compact SO-8 or DFN6 packages.

Technical Context

The LDL212D33R employs a bandgap-referenced op-amp control loop with internal bias generation and RC-filtered feedback sensing. Its architecture enables high PSRR across frequency (87 dB @ 120 Hz, 75 dB @ 1 kHz, 50 dB @ 100 kHz) and tight line/load regulation (0.002%/V and 0.0001%/mA typical).

Thermal protection triggers at 175°C with 25°C hysteresis; UVLO activates below 2.3 V with 200 mV hysteresis. The device operates over –40°C to +125°C junction temperature and supports both fixed (3.3 V) and adjustable versions via external resistor divider on the ADJ/SENSE pin.

Key Specifications

Pinout & Package

LDL212D33R is available in SO-8 batwing plastic micropackage and DFN6 (3×3 mm and 2×2 mm) packages. All variants share identical pin functions but differ in thermal resistance and footprint size.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSM10833DCQ and MCP1703T-3302E/MB, LDL212D33R delivers higher current, wider input range, superior PSRR, and comprehensive protection - making it the only choice for demanding 1.2 A point-of-load applications requiring long-term thermal stability and ripple rejection.

Availability

LDL212D33R is available at Aetrix Electronics and suitable for industrial PLCs, automotive infotainment systems, medical sensor modules, and networking PHY interfaces requiring stable component supply with full traceability and lifecycle support.

Supply support for LDL212D33R 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 LDL212 belongs to ST's high-PSRR, low-dropout LDO family targeting noise-sensitive post-regulation in switched-mode power systems - engineered for reliability in extended temperature and high-ripple environments.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 1.2 A?

The LDL212D33R requires VIN ≥ VOUT + VDROP(MAX). With 350 mV typical dropout and up to 600 mV maximum at full temperature range, a minimum input of 3.9 V ensures stable 3.3 V output at 1.2 A. At cold temperatures or light loads, 3.65 V may suffice per datasheet Figure 16.

Can the SENSE pin be left floating on the fixed-version LDL212D33R?

No. Per datasheet Table 1 note 1, the SENSE pin on fixed versions must be connected directly to VOUT. Floating or misrouting causes output regulation failure and potential instability due to broken feedback path in the internal error amplifier.

Which package offers the best thermal performance for continuous 1.2 A operation?

The DFN6 (3×3 mm) package provides the lowest thermal resistance: 10 °C/W junction-to-case and 55 °C/W junction-to-ambient (Table 3). This enables higher sustained power dissipation versus SO-8 (20 °C/W J-C) or DFN6 (2×2 mm) (15 °C/W J-C) under identical PCB copper area.

Does the LDL212D33R support reverse-voltage protection?

No. The device lacks intrinsic reverse-polarity protection. Applying reverse voltage on VIN or VOUT may damage internal structures. External protection - such as a series Schottky diode on VIN or back-to-back MOSFETs - is required in systems prone to battery reversal or hot-swap events.