Overview
The LM2678SD-ADJ/NOPB is a high-efficiency step-down voltage regulator from Texas Instruments, part of the SIMPLE SWITCHER® family. This monolithic integrated circuit is designed to provide all the active functions necessary for a buck switching regulator, capable of driving up to 5A loads with excellent line and load regulation characteristics. The regulator features a low ON-resistance DMOS power switch, which enables high efficiency of up to 92%. It is available in fixed output voltages of 3.3V, 5V, and 12V, as well as an adjustable output version ranging from 1.2V to 37V. The LM2678 is known for its simplicity and ease of design, requiring a minimum number of external components.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage Range | 8 | - | 40 | V |
| Output Voltage (Fixed Versions) | 3.3, 5, 12 | - | - | V |
| Output Voltage (Adjustable Version) | 1.2 | - | 37 | V |
| Output Current | 100 mA | - | 5 A | A |
| Switching Frequency | 225 kHz | 260 kHz | 280 kHz | kHz |
| Efficiency | - | Up to 92% | - | % |
| Quiescent Current | 4.2 mA | 6 mA | - | mA |
| Standby Quiescent Current | 50 μA | 100 μA | 150 μA | μA |
| Operating Junction Temperature Range | -40°C | - | 125°C | °C |
| Switch ON-Resistance | 0.12 Ω | 0.14 Ω | 0.225 Ω | Ω |
Key Features
- High efficiency up to 92% due to low ON-resistance DMOS power switch
- Simple and easy to design using off-the-shelf external components
- Fixed output voltages of 3.3V, 5V, and 12V, and an adjustable output version from 1.2V to 37V
- Wide input voltage range: 8V to 40V
- 260-kHz fixed frequency internal oscillator
- Low standby current of 50 μA when switched off
- ±2% maximum output tolerance over full line and load conditions
- Built-in thermal shutdown, current limiting, and ON/OFF control input
Applications
- Simple-to-design, high-efficiency step-down switching regulators
- Efficient system preregulator for linear voltage regulators
- Battery chargers
- General power supply applications requiring high current and efficiency
Q & A
- What is the maximum output current of the LM2678?
The LM2678 can drive up to 5A loads.
- What are the available fixed output voltages for the LM2678?
The fixed output voltages available are 3.3V, 5V, and 12V.
- What is the adjustable output voltage range for the LM2678?
The adjustable output voltage range is from 1.2V to 37V.
- What is the switching frequency of the LM2678?
The switching frequency is fixed at 260 kHz.
- What is the efficiency of the LM2678?
The efficiency can be up to 92%.
- What is the standby quiescent current when the LM2678 is switched off?
The standby quiescent current is 50 μA.
- What is the operating junction temperature range for the LM2678?
The operating junction temperature range is from -40°C to 125°C.
- Does the LM2678 have built-in protection features?
Yes, it includes thermal shutdown, current limiting, and ON/OFF control.
- How does the ON/OFF control work on the LM2678?
The ON/OFF control is achieved through the ON/OFF pin, which can be connected to ground or a voltage less than 0.8V to turn the regulator off.
- What is the output voltage tolerance of the LM2678?
The maximum output voltage tolerance is ±2% over full line and load conditions.
