Overview
The LM2676SX-12 is a high-efficiency step-down (buck) switching regulator produced by National Semiconductor, now part of Texas Instruments. This monolithic integrated circuit provides all the active functions necessary for a buck switching regulator, capable of driving loads up to 3 A with excellent line and load regulation characteristics. The LM2676 series, including the LM2676SX-12, features a low ON-resistance DMOS power switch, which ensures high efficiency of over 90%. The device is available in fixed output voltages of 3.3 V, 5 V, and 12 V, as well as an adjustable output version.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Supply Voltage | 8 | 40 | V | |
| Output Voltage (LM2676SX-12) | 11.76 | 12 | 12.24 | V |
| Output Current | 3 | A | ||
| Efficiency | 94% | % | ||
| Switch ON-Resistance | 0.15 | 0.17 | 0.29 | Ω |
| Oscillator Frequency | 225 | 260 | 280 | kHz |
| Operating Junction Temperature | -40 | 125 | °C | |
| Standby Quiescent Current | 50 | 100 | 150 | µA |
| Current Limit | 3.8 | 4.5 | 5.25 | A |
Key Features
- High efficiency (> 90%) due to low ON-resistance DMOS power switch.
- Fixed output voltages of 3.3 V, 5 V, and 12 V, and an adjustable output version.
- Simple and easy to design with using off-the-shelf external components.
- Wide input voltage range: 8 V to 40 V.
- Fixed frequency internal oscillator at 260 kHz.
- Built-in thermal shutdown, current limiting, and ON/OFF control input.
- Low standby current of 50 µA when switched OFF.
- ±2% maximum output tolerance over full line and load conditions.
Applications
- Communication modules.
- Electricity meters.
- Calling button operating panels.
- Motor drives.
Q & A
- What is the maximum output current of the LM2676SX-12?
The maximum output current is 3 A. - What are the fixed output voltages available for the LM2676 series?
The fixed output voltages are 3.3 V, 5 V, and 12 V, along with an adjustable output version. - What is the efficiency of the LM2676SX-12?
The efficiency can be up to 94%. - What is the operating junction temperature range of the LM2676SX-12?
The operating junction temperature range is -40°C to 125°C. - How is the ON/OFF control implemented in the LM2676SX-12?
The ON/OFF control is implemented through an input pin that can be connected to ground or left open-circuited to enable or disable the regulator. - What is the standby quiescent current when the regulator is switched OFF?
The standby quiescent current is 50 µA. - What is the typical oscillator frequency of the LM2676SX-12?
The typical oscillator frequency is 260 kHz. - Does the LM2676SX-12 have built-in protection features?
Yes, it includes built-in thermal shutdown and current limiting. - What is the maximum output voltage tolerance of the LM2676SX-12?
The maximum output voltage tolerance is ±2% over full line and load conditions. - What types of capacitors are recommended for use with the LM2676SX-12?
Surface mount tantalum capacitors and through-hole aluminum electrolytic capacitors with low ESR ratings are recommended.
