Overview
The LM3478MM/NOPB, produced by Texas Instruments, is a versatile Low-Side N-Channel MOSFET controller designed for use in switching regulators. It is suitable for various topologies such as boost, flyback, and SEPIC converters. The device operates using a fixed frequency, Pulse Width Modulated (PWM) current mode control architecture, which provides superior bandwidth and transient response along with cycle-by-cycle current limiting. The LM3478 can be operated at high switching frequencies, adjustable between 100 kHz and 1 MHz using a single external resistor, making it ideal for reducing overall solution size.
Key Specifications
| Parameter | Minimum | Typical | Maximum | Unit |
|---|---|---|---|---|
| Input Voltage | 2.97 | - | 40 | V |
| FB Pin Voltage | -0.4 | - | 7 | V |
| Peak Driver Output Current (<10µs) | - | - | 1 | A |
| Junction Temperature | -40 | - | 125 | °C |
| Switching Frequency | 100 kHz | - | 1 MHz | - |
| Internal Reference Accuracy | - | ±2.5% | - | % |
| Shutdown Current (Over Temperature) | - | 10 µA | - | A |
| Thermal Shutdown Temperature | - | 165 | - | °C |
Key Features
- 8-lead VSSOP-8 and SOIC-8 packages
- 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
- Overvoltage Protection (OVP)
- Short-Circuit Protection
- Power Saving Shutdown Mode reducing total supply current to 5 µA
- Adjustable Clock Frequency between 100 kHz and 1 MHz
Applications
- Distributed Power Systems
- Battery Chargers
- Offline Power Supplies
- Telecom Power Supplies
- Automotive Power Systems
Q & A
- What is the LM3478MM/NOPB used for? The LM3478MM/NOPB is used as a Low-Side N-Channel MOSFET controller for switching regulators in various power supply topologies.
- What are the package options for the LM3478? The LM3478 is available in 8-lead VSSOP-8 and SOIC-8 packages.
- What is the adjustable frequency range of the LM3478? The switching frequency can be adjusted between 100 kHz and 1 MHz using a single external resistor.
- Does the LM3478 have built-in protection features? Yes, it includes features such as thermal shutdown, short-circuit protection, and overvoltage protection.
- How does the LM3478 handle startup current? The LM3478 has an internal soft-start feature that limits the inrush current at startup.
- What is the shutdown current of the LM3478? The shutdown current is 10 µA over temperature.
- What is the thermal shutdown temperature of the LM3478? The thermal shutdown temperature is 165°C.
- Can the LM3478 be used in automotive applications? Yes, it is suitable for use in automotive power systems.
- How does the LM3478 control the output voltage? The LM3478 uses a PWM current mode control architecture with an error amplifier and feedback loop to control the output voltage.
- Is the LM3478 compatible with high-efficiency converters? Yes, it is designed for high-efficiency applications and can be used in continuous conduction mode (CCM) for higher efficiency and lower EMI.
