STMicroelectronics L4940D2T10-TR

Overview

L4940D2T10-TR from STMicroelectronics is a fixed-output 10 V, 1.5 A low-dropout linear voltage regulator in D2PAK package, featuring 450 mV typical dropout at 1 A, ±2% output voltage accuracy over load/temperature, and integrated thermal shutdown, short-circuit, and reverse-polarity protection. It serves as a post-regulator in battery-powered industrial controllers and portable instrumentation where input-to-output headroom is constrained.

For engineers reviewing the L4940D2T10-TR datasheet, L4940D2T10-TR pinout, L4940D2T10-TR application, or L4940D2T10-TR equivalent, key selection criteria include dropout voltage at full load, quiescent current under light-load conditions, output voltage drift versus temperature, and thermal resistance in the D2PAK package for board-level power dissipation management.

Technical Context

The L4940D2T10-TR implements a three-terminal monolithic linear regulator architecture with internal current limiting, antisaturation circuitry, and safe-area protection. Its feedback loop maintains regulation across 5 mA–1.5 A output current and 11.7 V–15 V input range while delivering 10 V ±2% output stability.

Thermal shutdown activates at junction temperatures exceeding +150 °C, and reverse polarity protection blocks conduction when input voltage falls below −15 V (with 200 Ω load). The device achieves 56–62 dB supply voltage rejection at 120 Hz and 1 mV/°C output voltage drift over operating temperature.

Key Specifications

Pinout & Package

D2PAK (TO-263) surface-mount package with exposed thermal pad; 3-pin configuration optimized for high-current PCB thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2940CT-10/NOPB and TLV1117-10CDCYR, the L4940D2T10-TR uniquely combines 1.5 A capability, 450 mV dropout, reverse-polarity blocking, and D2PAK thermal performance-making it the sole option among the three for ruggedized 10 V battery-powered systems requiring >1 A and fault resilience.

Availability

L4940D2T10-TR is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive cabin control units, and test & measurement equipment requiring stable component supply with guaranteed long-term manufacturability.

Supply support for L4940D2T10-TR 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.

The L4940 series belongs to ST's legacy linear regulator product line, engineered specifically for high-reliability, low-dropout operation in battery-powered and industrial equipment where robustness and thermal efficiency are critical.

FAQ

What is the minimum input voltage required for regulation at full 1.5 A load?

The L4940D2T10-TR requires a minimum input voltage of 10.5 V to maintain 10 V output at 1.5 A, based on its 500 mV typical dropout voltage. At 11.7 V input (as specified in Table 6), it delivers full regulation across temperature and line variations. Input below 10.5 V causes output collapse.

Does the D2PAK package require soldering to a thermal pad on the PCB?

Yes-the D2PAK package features an exposed metal tab (pin 2 ground) that must be soldered to a large copper pour or thermal pad on the PCB to achieve the rated R_thJA = 62.5 °C/W. Omitting this connection degrades thermal performance by >40%, risking thermal shutdown under sustained 1.5 A load.

Can L4940D2T10-TR replace L4940V10 in existing TO-220 designs?

No-L4940D2T10-TR uses D2PAK (TO-263) footprint and thermal design rules, while L4940V10 uses TO-220. Pinout is identical (Input-Ground-Output), but PCB layout, thermal relief, and mounting differ significantly. Direct replacement requires board redesign to accommodate D2PAK pad geometry and thermal mass.

Is external capacitor compensation required for stability?

No-L4940D2T10-TR is internally compensated and stable with standard 0.1 µF input and 22 µF output ceramic or tantalum capacitors, as verified in Figure 3 test circuit and Table 4–7 conditions. Adding ESR or capacitance beyond datasheet recommendations may degrade transient response or cause oscillation.