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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM3478
SNVS085X –JULY 2000–REVISED DECEMBER 2017
LM3478 High-Efficiency Low-Side N-Channel Controller for Switching Regulator
1
1 Features
1
• 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
• Create a Custom Design Using the LM3478 with
the WEBENCH Power Designer
2 Applications
• Distributed Power Systems
• Battery Chargers
• Offline Power Supplies
• Telecom Power Supplies
• Automotive Power Systems
• Wide Supply Voltage Range of 2.97 V to 40 V
• 100-kHz to 1-MHz Adjustable Clock Frequency
• ±2.5% (Over Temperature) Internal Reference
• 10-µA Shutdown Current (Over Temperature)
3 Description
The LM3478 is a versatile Low-Side N-Channel
MOSFET controller for switching regulators. It is
suitable for use in topologies requiring a low side
MOSFET, such as boost, flyback, SEPIC, etc.
Moreover, the LM3478 can be operated at extremely
high switching frequency in order to reduce the
overall solution size. The switching frequency of the
LM3478 can be adjusted to any value between 100
kHz and 1 MHz by using a single external resistor.
Current mode control provides superior bandwidth
and transient response, besides cycle-by-cycle
current limiting. Output current can be programmed
with a single external resistor.
The LM3478 has built-in features such as thermal
shutdown, short-circuit protection, over voltage
protection, etc. Power saving shutdown mode
reduces the total supply current to 5 µA and allows
power supply sequencing. Internal soft-start limits the
inrush current at start-up.
Device Information
(1)
PART NUMBER PACKAGE BODY SIZE (NOM)
LM3478
SOIC (8) 4.90 mm x 3.91 mm
VSSOP (8) 3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Typical High Efficiency Step-Up (Boost) Converter
