Product Overview
1A Adjustable Buck Switching Converter - 52 kHz TO-220-5 Simple Switcher
Condition
New old stock (NOS). Unused surplus in clean physical condition with straight through-hole leads and intact metal mounting tab. Markings legible: LM2575T -ADJ P+. Sold each.
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Product Overview
National Semiconductor LM2575T-ADJ is a monolithic step-down (buck) switching voltage regulator capable of driving a 1.0A load with high efficiency. Operating at an internal switching frequency of 52 kHz, this Simple Switcher family device simplifies power supply design by requiring a minimal number of external standard components. The adjustable output covers a wide range from 1.23V to 37V from an input voltage up to 40V, featuring integrated thermal shutdown and cycle-by-cycle current limiting for circuit protection.
Key Features
- Topology: Step-down (buck) switching regulator
- Output type: Adjustable from 1.23V to 37V
- Maximum continuous output current: 1.0A
- Input voltage range: 4V to 40V
- Internal switching frequency: 52 kHz
- Reference voltage: 1.23V
- Package: 5-pin TO-220 through-hole with integrated heatsink mounting tab
- Built-in protection: Thermal shutdown and cycle-by-cycle current limit
- Control input: TTL-compatible ON/OFF shutdown pin
Applications
- Stepping down industrial 24V DC bus rails to regulated 5V or 3.3V logic levels on custom control boards.
- Replacing inefficient linear 78xx regulators in battery-powered enclosures to reduce internal heat buildup.
- Bench prototyping variable-output DC power supplies for electronics hobbyists and makers.
- Restoring or servicing legacy embedded controllers, telecom interfaces, and automation modules that utilize National Simple Switcher regulators.
Frequently Asked Questions
What external components are required for operation?
Standard operation requires an input bypass capacitor, an output filter capacitor, an inductor, a catch diode, and two feedback resistors to set the target output voltage.
What is the function of the fifth pin on this TO-220 package?
Pin 5 serves as an ON/OFF shutdown control input. Holding it at a logic low allows normal regulator operation, while pulling it to a logic high puts the device into a low-power standby mode.
How do you distinguish this adjustable version from fixed-voltage LM2575 models?
The -ADJ suffix marked on the package body designates the adjustable feedback version, which uses an external resistive divider connected to pin 4 to set output voltage rather than an internal fixed resistor network. Order more and each piece costs less - the price-break table on this page spells it out.
National's Simple Switcher line made switching supplies feel less like black magic and more like assembling a four-piece puzzle. Bolt it to a heatsink, set your divider resistors, and your rail is up and running.
