Microchip Technology LR645N3-G-P013

Overview

LR645N3-G-P013 from Microchip Technology is a high-input voltage, fixed-output linear regulator in TO-92 package, delivering 10V ±0.7V output at up to 3.0mA continuous current with 50µA typical quiescent supply current and 15–450V input range. It serves as an off-line SMPS startup supply, eliminating high-wattage start-up resistors in AC/DC power converters.

For engineers reviewing the LR645N3-G-P013 datasheet, LR645N3-G-P013 pinout, LR645N3-G-P013 application, or LR645N3-G-P013 equivalent, key selection criteria include its 450V absolute maximum input rating, -55°C to +150°C operating temperature range, 0.1mV/V line regulation, 150µA max input quiescent current, and suitability for pulse-load startup circuits requiring galvanically isolated auxiliary supplies.

Technical Context

The LR645N3-G-P013 implements a monolithic high-voltage linear regulator architecture with internal pass transistor and bandgap reference, optimized for transient startup duty cycles rather than continuous regulation. Its design integrates high-voltage input stage capable of withstanding 450V DC, low-leakage shutdown behavior (<0.1µA off-state leakage), and thermal protection validated across -55°C to +150°C junction temperature range.

Unlike standard low-voltage regulators, LR645N3-G-P013 operates without external biasing or auxiliary winding support - it draws only leakage current after startup, enabling <3mW continuous dissipation in TO-92 package. Its output is internally trimmed to 10V nominal (9.3–10.7V at 25°C, 9.0–11.5V over temperature) with no external adjustment pins.

Key Specifications

Pinout & Package

LR645N3-G-P013 uses a 3-lead TO-92 package (Microchip package code N3) with molded plastic body, axial lead configuration, and Pb-free matte tin plating per JEDEC standards. Pin 1 = VIN, Pin 2 = GND, Pin 3 = VOUT.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-input voltage linear regulator applications.

Compared with LR645N3-G-P013, LR645N5-G offers 2.4× higher continuous power handling in TO-220 form factor, while LR645N8-G provides SMT compatibility with 2.2× higher dissipation than TO-92 - both retain identical electrical specs and functional behavior but differ in thermal capability and mounting method.

Availability

LR645N3-G-P013 is available at Aetrix Electronics and suitable for off-line SMPS startup circuits, noisy-input regulators, and appliance control logic supplies requiring stable component supply with long lifecycle assurance.

Supply support for LR645N3-G-P013 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

Microchip Technology Inc. is a leading provider of microcontrollers, analog devices, and timing solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The LR645 product line was developed specifically for high-input voltage startup and biasing applications in AC/DC power conversion, targeting elimination of power-wasting startup resistors in industrial, appliance, and lighting power supplies.

FAQ

What is the maximum input voltage rating for LR645N3-G-P013?

The LR645N3-G-P013 has an absolute maximum input voltage rating of 450V DC, verified per Microchip DS20005384A. This allows direct connection to rectified 277VAC mains without external voltage limiting. Operation above 450V risks permanent damage; sustained operation near this limit requires thermal derating per Table 1-2 in the datasheet. The LR645N3-G-P013 maintains regulation from 15V to 450V under all specified conditions.

Does LR645N3-G-P013 provide galvanic isolation?

No, LR645N3-G-P013 does not provide galvanic isolation. As explicitly stated in the datasheet warning, lethal voltages may appear on all pins when operated from AC line. System-level isolation must be implemented externally using transformers, optocouplers, or isolated DC/DC modules. The LR645N3-G-P013 functions solely as a high-voltage linear regulator and must be placed on the primary (hot) side of any isolation barrier.

What is the output voltage tolerance of LR645N3-G-P013 over temperature?

The LR645N3-G-P013 delivers 10V nominal output with guaranteed tolerance of 9.0V to 11.5V across the full operating junction temperature range of -40°C to +125°C, as specified in Table 1-1. At 25°C, the tighter tolerance is 9.3V to 10.7V. This drift is inherent to the bandgap reference design and is fully characterized - no external compensation is required or supported for the fixed-output N3 variant.

Can LR645N3-G-P013 drive more than 3.0mA continuously?

No, LR645N3-G-P013 is rated for 3.0mA continuous output current in TO-92 package. Exceeding this limit causes thermal runaway due to its 132°C/W junction-to-ambient thermal resistance. For higher current, Microchip specifies the 8-lead adjustable LR645LG-G with external depletion-mode MOSFET (e.g., DN2540N5) to achieve 150mA. The LR645N3-G-P013 itself has no gate drive or trim capability - it is strictly a 3-terminal fixed-output device.

What package type and lead count does LR645N3-G-P013 use?

LR645N3-G-P013 uses a 3-lead TO-92 plastic package (Microchip package code N3), with leads arranged in straight-line configuration: Pin 1 = VIN, Pin 2 = GND, Pin 3 = VOUT. The "P013" suffix denotes 2000-unit ammo pack packaging format. This through-hole package is RoHS-compliant (G suffix) and features matte tin plating per JEDEC e3 standard.