LM3481 (ACTIVE)

High-Efficiency Controller for Boost, SEPIC and Flyback DC-DC Converters

 

Description

The LM3481 device is a versatile Low-Side N-FET high-performance controller for switching regulators. The device is suitable for use in topologies requiring a low-side FET, such as boost, flyback, SEPIC, and so on. The LM3481 device can be operated at extremely high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481 device can be adjusted to any value between 100kHz and 1MHz by using a single external resistor or by synchronizing it to an external clock. Current mode control provides superior bandwidth and transient response in addition to cycle-by-cycle current limiting. Current limit can be programmed with a single external resistor.

The LM3481 device has built-in protection features such as thermal shutdown, short-circuit protection and overvoltage protection. 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.

Features

  • LM3481QMM are Automotive-Grade Products
    That are AEC-Q100 Grade 1 Qualified (–40°C to
    +125°C Operating Junction Temperature)
  • 10-Lead VSSOP Package
  • 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 Softstart
  • Current Mode Operation
  • Adjustable Undervoltage Lockout With Hysteresis
  • Pulse Skipping at Light Loads
  • Key Specifications
    • Wide Supply Voltage Range of 2.97 V to 48 V
    • 100-kHz to 1-MHz Adjustable and Synchronizable
      Clock Frequency
    • ±1.5% (Over Temperature) Internal
      Reference
    • 10-µA Shutdown Current (Over Temperature)

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Parametrics Compare all products in Boost Controller (External Switch)

 
Vin (Min) (V)
Vin (Max) (V)
Vout (Min) (V)
Vout (Max) (V)
Switch Current Limit (Typ) (A)
Regulated Outputs (#)
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Features
Iout (Max) (A)
Duty Cycle (Max) (%)
Operating Temperature Range (C)
Rating
Package Group
LM3481 LM3017 LM3478 LM3481-Q1 LM3488
2.97    5    2.97    2.97    2.97   
48    18    40    48    40   
1.275    6    1.26    1.275    1.26   
500    20    500    500    500   
10    1    10    10    10   
1    1    1    1    1   
100    400    100    100    100   
1000    400    1000    1000    1000   
3.7    0.001    2.7    3.7    2.7   
Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Pre-Bias Start-Up
UVLO Adjustable   
Enable
Load Disconnect   
Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Pre-Bias Start-Up   
Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Pre-Bias Start-Up
UVLO Adjustable   
Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Pre-Bias Start-Up   
10    1    10    10    10   
85    85    100    85    100   
-40 to 125    -40 to 125    -40 to 125    -40 to 125    -40 to 125   
Catalog    Catalog    Catalog    Automotive    Catalog   
VSSOP    WQFN    SOIC
VSSOP   
VSSOP    VSSOP   

Other qualified versions of LM3481

Version Part Number Definition
Automotive LM3481-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects
New! Interactive Design
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WEBENCH® Designer LM3481

  Min   Max Range
Vin  V 2.97 to 48.0V
Vout  V 1.26 to 300.0V
Iout  A ≤ 40A
Ambient Temp  °C -40 to 125°C


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