Overview
The LM3481-Q1 is a high-performance, low-side N-FET controller designed for use in boost, SEPIC, and flyback converters. This device, produced by Texas Instruments, is AEC-Q100 qualified, making it suitable for automotive applications. It operates over a wide supply voltage range of 2.97V to 48V and supports adjustable and synchronizable clock frequencies between 100 kHz and 1 MHz. The LM3481-Q1 features current mode control, which provides superior bandwidth and transient response, along with cycle-by-cycle current limiting and built-in protection features such as thermal shutdown, short-circuit protection, and overvoltage protection. The device is packaged in a 10-lead VSSOP (DGS) package and includes an internal push-pull driver with a 1A peak current capability and internal soft start to limit inrush current at start-up.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage Range | 2.97 | 48 | V | |
| Switching Frequency Range | 100 kHz | 1 MHz | ||
| Internal Reference Accuracy | ±1.5% | % (over temperature) | ||
| Shutdown Current | 10 | µA (over temperature) | ||
| Operating Temperature Range | -40 | 125 | °C | |
| Package Type | 10-Lead VSSOP (DGS) | |||
| Peak Current Capability | 1 | A |
Key Features
- AEC-Q100 Qualified for automotive applications with a device temperature grade 1: -40°C to +125°C, TA
- 10-Lead VSSOP package
- Internal push-pull driver with 1A peak current capability
- Current limit and thermal shutdown
- Frequency compensation optimized with a capacitor and a resistor
- Internal soft start
- Current mode operation with cycle-by-cycle current limiting
- Adjustable undervoltage lockout with hysteresis
- Pulse skipping at light loads
- Integrated current slope compensation
- Overvoltage protection and short-circuit protection
- Power-saving shutdown mode reducing total supply current to 5 µA
Applications
- Isolated Supply (Flyback) in traction inverters and on-board chargers
- Advanced Driver Assistance Systems (ADAS) - Driver monitoring
- Digital Cockpit and Head Unit
- Boost for audio amplifiers in portable speakers
- Wide input boost, SEPIC, flyback power modules
- Battery-powered boost, SEPIC, flyback converters
Q & A
- What is the supply voltage range of the LM3481-Q1?
The LM3481-Q1 operates over a wide supply voltage range of 2.97V to 48V.
- What are the adjustable and synchronizable clock frequency ranges of the LM3481-Q1?
The switching frequency can be adjusted to any value between 100 kHz and 1 MHz using a single external resistor or by synchronizing it to an external clock.
- What is the internal reference accuracy of the LM3481-Q1?
The internal reference accuracy is ±1.5% over temperature.
- What is the shutdown current of the LM3481-Q1?
The shutdown current is 10 µA over temperature.
- What type of package does the LM3481-Q1 come in?
The LM3481-Q1 is packaged in a 10-lead VSSOP (DGS) package.
- What is the peak current capability of the internal push-pull driver?
The internal push-pull driver has a peak current capability of 1A.
- Does the LM3481-Q1 have built-in protection features?
Yes, it includes thermal shutdown, short-circuit protection, and overvoltage protection.
- How does the LM3481-Q1 handle light load conditions?
The device features pulse skipping at light loads to maintain efficiency.
- What is the operating temperature range of the LM3481-Q1?
The operating temperature range is -40°C to +125°C.
- Can the LM3481-Q1 be used in automotive applications?
Yes, it is AEC-Q100 qualified for automotive applications.
