STMicroelectronics LDL40PUR

Overview

LDL40PUR from STMicroelectronics is an automotive-grade adjustable low-dropout linear voltage regulator designed for direct battery connection in EV powertrain and always-on systems. It delivers 200 mA output with 700 mV typical dropout at full load, ±2.5% output accuracy over -40 °C to 150 °C, ultra-low 2 µA quiescent current at no load, and integrated Power Good and active output discharge functions.

For engineers reviewing the LDL40PUR datasheet, LDL40PUR pinout, LDL40PUR application, or LDL40PUR equivalent, this page provides verified pin-level circuit roles, thermal shutdown behavior at 170 °C, wettable-flank DFN6 (2 × 2) package layout guidance, and real-world ADAS infotainment supply design constraints.

Technical Context

The LDL40PUR uses a P-channel MOSFET pass element enabling operation down to 3.3 V input while supporting up to 40 V - sufficient to withstand automotive load dump transients. Its bandgap reference and error amplifier deliver 1.2 V to 12 V adjustable output via external resistor divider on the ADJ/VSENSE pin.

Internal protection includes thermal shutdown (170 °C trip, 20 °C hysteresis), current limiting (350–800 mA depending on temperature), and logic-controlled shutdown with sub-0.3 µA standby current. The open-drain Power Good output monitors VOUT against 93–98% rising and 86–95% falling thresholds.

Key Specifications

Pinout & Package

LDL40PUR is housed in a DFN6 (2 mm × 2 mm) wettable flanks package with exposed thermal pad. This compact automotive-qualified outline enables AOI-compatible solder joint inspection and efficient heat transfer to PCB ground planes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable LDO applications.

Compared with TLD6512-2ES and TPS7B8250QDGNRQ1, LDL40PUR uniquely combines 40 V input tolerance, adjustable output, active discharge, and wettable-flank packaging - making it the only option qualified for high-density, load-dump-resilient ADAS domain controllers.

Availability

LDL40PUR is available at Aetrix Electronics and suitable for EV powertrain control units, ADAS camera modules, and automotive instrument clusters requiring stable component supply across extended temperature and transient stress conditions.

Supply support for LDL40PUR 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, with design and manufacturing facilities across Europe, Asia, and the Americas.

LDL40PUR belongs to ST's automotive-qualified LDO portfolio targeting battery-connected systems, engineered specifically for functional safety compliance and thermal resilience in engine bay and ADAS applications.

FAQ

What is the minimum input voltage required for LDL40PUR to regulate?

The LDL40PUR begins regulation when VIN reaches VOUT(NOM) + VDROP, with minimum operational input specified as 3.3 V. For example, with a 1.2 V output set by external resistors, regulation starts at ~1.9 V input (1.2 V + 700 mV dropout). However, the device's undervoltage lockout activates below 2.8 V, ensuring controlled startup only above safe margin.

Can LDL40PUR be used with ceramic output capacitors smaller than 1 µF?

No - the datasheet mandates a minimum 1.0 µF ceramic output capacitor (X5R/X7R) for loop stability. Using smaller values risks oscillation or poor transient response, especially under load steps. Capacitor ESR must remain between 5 mΩ and 10 Ω across -40 °C to 150 °C to maintain phase margin.

How does the Power Good (PG) pin behave during enable/disable transitions?

PG is high-impedance when EN = LOW (device disabled) or when VOUT is within valid regulation range. It pulls low only when VOUT drops below the falling threshold (86–95% of nominal). During startup, PG asserts high after VOUT reaches 93–98% of target and remains asserted until regulation fails.

Is the exposed pad of the DFN6 package electrically connected internally?

Yes - the exposed pad is internally connected to GND and must be soldered to a PCB ground plane for both thermal performance and electrical integrity. Thermal resistance drops from 62 °C/W (with pad) to 180 °C/W (without pad), and floating the pad risks instability and premature thermal shutdown.