Overview
The LM2678S-12/NOPB, produced by Texas Instruments, is a high-efficiency step-down (buck) switching regulator. It is part of the SIMPLE SWITCHER® family and is designed to provide all the active functions necessary for a step-down voltage regulator. This regulator is capable of driving up to 5-A loads with excellent line and load regulation characteristics. The LM2678 series includes fixed output voltages of 3.3 V, 5 V, and 12 V, as well as an adjustable output version ranging from 1.2 V to 37 V. The device features a low ON-resistance DMOS power switch, which enables high efficiency of up to 92%.
Key Specifications
| Parameter | Typical Value | Minimum Value | Maximum Value | Unit |
|---|---|---|---|---|
| Output Voltage (VOUT) | 12 | 11.76 | 12.24 | V |
| Input Voltage Range (VIN) | - | 8 | 40 | V |
| Maximum Output Current (IOUT) | 5 | - | - | A |
| Efficiency | 92% | - | - | % |
| Oscillator Frequency | 260 kHz | 225 kHz | 280 kHz | kHz |
| Operating Junction Temperature Range | - | -40°C | 125°C | °C |
| Switch ON-Resistance (RDS(ON)) | 0.14 Ω | 0.12 Ω | 0.225 Ω | Ω |
| Standby Quiescent Current | 50 μA | - | 100 μA | μA |
Key Features
- High efficiency up to 92% due to the use of a low ON-resistance DMOS power switch.
- Simple and easy to design using off-the-shelf external components.
- Fixed output voltages of 3.3 V, 5 V, and 12 V, and an adjustable output version from 1.2 V to 37 V.
- Wide input voltage range: 8 V to 40 V.
- 260-kHz fixed frequency internal oscillator.
- ±2% maximum output tolerance over full line and load conditions.
- Built-in thermal shutdown, current limiting, and ON/OFF control input.
- Low standby current of 50 μA when switched off.
Applications
- Simple-to-design, high-efficiency step-down switching regulators.
- Efficient system pre-regulator for linear voltage regulators.
- Battery chargers.
- General power supply applications requiring high efficiency and reliability.
Q & A
- What is the maximum output current of the LM2678S-12/NOPB?
The maximum output current is 5 A. - What are the fixed output voltage options available for the LM2678 series?
The fixed output voltage options are 3.3 V, 5 V, and 12 V. - What is the adjustable output voltage range for the LM2678?
The adjustable output voltage range is from 1.2 V to 37 V. - What is the typical efficiency of the LM2678S-12/NOPB?
The typical efficiency is up to 92%. - What is the operating junction temperature range for the LM2678?
The operating junction temperature range is from -40°C to 125°C. - How does the ON/OFF control input work on the LM2678?
The ON/OFF input provides electrical control to turn the regulator on or off. Connecting this pin to ground or a voltage less than 0.8 V turns the regulator off, reducing the current drain to 50 μA. - What is the oscillator frequency of the LM2678?
The oscillator frequency is 260 kHz. - What is the switch ON-resistance (RDS(ON)) of the LM2678?
The typical switch ON-resistance is 0.14 Ω. - What is the standby quiescent current when the LM2678 is switched off?
The standby quiescent current is 50 μA. - Does the LM2678 have built-in thermal protection?
Yes, the LM2678 has built-in thermal shutdown and current limiting features.
