Overview
The LM3478MMX/NOPB, produced by Texas Instruments, is a versatile and high-efficiency Low-Side N-Channel MOSFET controller designed for use in various switching regulator topologies. This device is suitable for applications requiring boost, flyback, SEPIC, and other configurations. It operates over a wide supply voltage range of 2.97 V to 40 V, making it highly adaptable for different power supply needs. The LM3478 features a current mode control architecture, which provides superior bandwidth and transient response, along with cycle-by-cycle current limiting and adjustable switching frequency between 100 kHz and 1 MHz.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Input Voltage | 2.97 | - | 40 | V |
| Switching Frequency | 100 kHz | - | 1 MHz | - |
| Peak Driver Output Current | - | - | 1 A | - |
| Feedback Voltage | 1.2416 | 1.26 | 1.2843 | V |
| Thermal Shutdown | - | - | 165 °C | - |
| Shutdown Current | - | - | 10 µA | - |
| Package | - | - | 8-TSSOP, 8-MSOP | - |
Key Features
- Internal Push-Pull Driver With 1-A Peak Current Capability
- Current Limit and Thermal Shutdown
- Frequency Compensation Optimized With a Capacitor and a Resistor
- Internal Soft Start
- Current Mode Operation
- Undervoltage Lockout With Hysteresis
- Adjustable Switching Frequency (100 kHz to 1 MHz)
- ±2.5% (Over Temperature) Internal Reference
- Short-Circuit Protection and Overvoltage Protection
- Low Shutdown Current (less than 10 µA)
Applications
- Distributed Power Systems
- Battery Chargers
- Offline Power Supplies
- Telecom Power Supplies
- Automotive Power Systems
Q & A
- What is the input voltage range of the LM3478?
The input voltage range of the LM3478 is from 2.97 V to 40 V.
- What are the package options for the LM3478MMX/NOPB?
The LM3478MMX/NOPB is available in 8-TSSOP and 8-MSOP packages.
- How is the switching frequency adjusted on the LM3478?
The switching frequency can be adjusted using a single external resistor connected to the FA/SD pin.
- What is the peak driver output current of the LM3478?
The peak driver output current of the LM3478 is 1 A.
- Does the LM3478 have built-in thermal shutdown?
Yes, the LM3478 has built-in thermal shutdown at 165 °C.
- What is the shutdown current of the LM3478?
The shutdown current of the LM3478 is less than 10 µA.
- Does the LM3478 support overvoltage protection?
Yes, the LM3478 has overvoltage protection (OVP) for the output voltage.
- What are the typical applications of the LM3478?
The LM3478 is typically used in distributed power systems, battery chargers, offline power supplies, telecom power supplies, and automotive power systems.
- How does the LM3478 handle short-circuit conditions?
The LM3478 has short-circuit protection that reduces the switching frequency by a factor of 5 when a short circuit is detected.
- Does the LM3478 have an internal soft-start feature?
Yes, the LM3478 has an internal soft-start feature to limit inrush current at start-up.
