LM3478 Datasheet, PDF (1/32 Pages) National Semiconductor (TI) – High Efficiency Low-Side N-Channel Controller for Switching Regulator

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LM3478
LM3478-Q1
SNVS085V – JULY 2000 – REVISED FEBRUARY 2013
High-Efficiency Low-Side N-Channel Controller for Switching Regulator
Check for Samples: LM3478, LM3478-Q1
FEATURES
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•2 LM3478Q in VSSOP-8 package is AEC-Q100
qualified and manufactured on an Automotive
Grade Flow
• 8-lead VSSOP-8 and SOIC-8 packages
• 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
• Undervoltage Lockout with hysteresis
APPLICATIONS
• Distributed Power Systems
• Battery Chargers
• Offline Power Supplies
• Telecom Power Supplies
• Automotive Power Systems
KEY SPECIFICATIONS
• Wide supply voltage range of 2.97V to 40V
• 100kHz to 1MHz Adjustable clock frequency
• ±2.5% (over temperature) internal reference
• 10µA shutdown current (over temperature)
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 100kHz and 1MHz 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 5µA and allows power supply sequencing.
Internal soft-start limits the inrush current at start-up.
Typical Application Circuit
Figure 1. Typical High Efficiency Step-Up (Boost) Converter
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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