Overview
The LM2678S-ADJ/NOPB is a high-efficiency step-down (buck) switching regulator produced by Texas Instruments. It is part of the SIMPLE SWITCHER® family, known for its simplicity and ease of design using off-the-shelf external components. This regulator is capable of driving up to 5-A loads with excellent line and load regulation characteristics. The LM2678S-ADJ/NOPB offers 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. It features a low ON-resistance DMOS power switch, which contributes to its high efficiency of up to 92%.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage Range | 8 | 40 | V | |
| Output Voltage (Adjustable) | 1.2 | 37 | V | |
| Output Current | 100 mA | 5 A | A | |
| Switch ON-Resistance | 0.12 | 0.14 | 0.225 | Ω |
| Oscillator Frequency | 225 kHz | 260 kHz | 280 kHz | kHz |
| Operating Junction Temperature | -40°C | 125°C | °C | |
| Quiescent Current | 4.2 mA | 6 mA | mA | |
| Standby Quiescent Current | 50 μA | 100 μA | 150 μA | μA |
| Current Limit | 6.1 A | 7 A | 8.3 A | A |
| Output Voltage Tolerance | ±2% | % |
Key Features
- High efficiency up to 92% due to 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.
- Built-in thermal shutdown, current limiting, and ON/OFF control input.
- Low standby current of 50 μA when switched off.
- ±2% maximum output voltage tolerance over full line and load conditions.
Applications
- Simple-to-design, high-efficiency step-down switching regulators.
- Efficient system pre-regulator for linear voltage regulators.
- Battery chargers.
- General-purpose power supplies requiring high efficiency and low component count.
Q & A
- What is the input voltage range of the LM2678S-ADJ/NOPB?
The input voltage range is from 8 V to 40 V.
- What are the available fixed output voltages for the LM2678S-ADJ/NOPB?
The fixed output voltages are 3.3 V, 5 V, and 12 V.
- What is the adjustable output voltage range for the LM2678S-ADJ/NOPB?
The adjustable output voltage range is from 1.2 V to 37 V.
- What is the maximum output current of the LM2678S-ADJ/NOPB?
The maximum output current is 5 A.
- What is the efficiency of the LM2678S-ADJ/NOPB?
The efficiency can be up to 92%.
- What is the oscillator frequency of the LM2678S-ADJ/NOPB?
The oscillator frequency is 260 kHz.
- What is the operating junction temperature range of the LM2678S-ADJ/NOPB?
The operating junction temperature range is from -40°C to 125°C.
- How does the ON/OFF control work on the LM2678S-ADJ/NOPB?
The ON/OFF control is achieved through the ON/OFF pin. Connecting this pin to ground or any voltage less than 0.8 V turns the regulator off, while a high voltage level or leaving it open-circuited turns it on.
- What is the standby quiescent current when the LM2678S-ADJ/NOPB is switched off?
The standby quiescent current is 50 μA when switched off.
- What are some common applications of the LM2678S-ADJ/NOPB?
Common applications include simple-to-design high-efficiency step-down switching regulators, efficient system pre-regulators for linear voltage regulators, and battery chargers.
