Overview
The LM2576SX-12/NOPB is a monolithic integrated circuit from National Semiconductor, designed as a SIMPLE SWITCHER® 3A step-down (buck) switching regulator. This device is capable of driving a 3A load with excellent line and load regulation. It is available in a fixed output voltage of 12V and is part of the LM2576 series, which also includes other fixed output voltages and an adjustable output version. The LM2576SX-12/NOPB is known for its simplicity, requiring a minimum number of external components, and includes internal frequency compensation and a fixed-frequency oscillator. This regulator offers high efficiency, reducing the need for large heat sinks, and in some cases, no heat sink is required at all.
Key Specifications
| Parameter | Conditions | Typical Value | Minimum Value | Maximum Value |
|---|---|---|---|---|
| Output Voltage | VIN = 25V, ILOAD = 0.5A | 12V | 11.76V | 12.24V |
| Output Voltage | 0.5A ≤ ILOAD ≤ 3A, 15V ≤ VIN ≤ 40V | 12V | 11.52V | 12.48V |
| Maximum Supply Voltage | 40V (LM2576), 60V (LM2576HV) | |||
| Oscillator Frequency | 52 kHz | 47 kHz | 58 kHz | |
| Saturation Voltage | IOUT = 3A | 1.4V | 1.8V | |
| Current Limit | 5.8A | 4.2A | 6.9A | |
| Quiescent Current | 5 mA | 10 mA | ||
| Standby Quiescent Current | ON/OFF Pin = 5V (OFF) | 50 µA | 200 µA |
Key Features
- High-efficiency step-down switching regulator capable of delivering up to 3A DC load current.
- Fixed output voltage of 12V, with other versions available for 3.3V, 5V, 15V, and adjustable output.
- Wide input voltage range: up to 40V for LM2576 and up to 60V for LM2576HV.
- Internal frequency compensation and fixed-frequency oscillator.
- Guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions.
- External shutdown feature with 50 µA (typical) standby current.
- No heat sink required in many applications due to high efficiency.
- Simple to use, requiring a minimum number of external components.
Applications
The LM2576SX-12/NOPB is suitable for a variety of applications where a high-efficiency step-down voltage regulator is needed. These include:
- Power supplies for electronic devices requiring a stable 12V output.
- Industrial control systems.
- Medical equipment.
- Aerospace and military applications (with appropriate specifications).
- Automotive systems.
- Telecommunication equipment.
Q & A
- What is the maximum output current of the LM2576SX-12/NOPB?
The maximum output current is 3A. - What are the available output voltages in the LM2576 series?
The LM2576 series includes fixed output voltages of 3.3V, 5V, 12V, and 15V, as well as an adjustable output version. - What is the typical oscillator frequency of the LM2576?
The typical oscillator frequency is 52 kHz. - What is the maximum supply voltage for the LM2576 and LM2576HV?
The maximum supply voltage is 40V for the LM2576 and 60V for the LM2576HV. - Does the LM2576SX-12/NOPB require a heat sink?
No, in many applications, no heat sink is required due to its high efficiency. - How does the external shutdown feature work?
The external shutdown feature allows the device to be turned off by applying a voltage to the ON/OFF pin, resulting in a standby quiescent current of 50 µA (typical). - What is the quiescent current of the LM2576SX-12/NOPB?
The quiescent current is 5 mA (typical), with a maximum of 10 mA. - What is the current limit of the LM2576SX-12/NOPB?
The current limit is 5.8A (typical), with a minimum of 4.2A and a maximum of 6.9A. - What is the saturation voltage of the LM2576SX-12/NOPB?
The saturation voltage is 1.4V (typical), with a maximum of 1.8V. - What is the efficiency of the LM2576SX-12/NOPB?
The efficiency is typically around 88% at VIN = 15V and ILOAD = 3A.
