3-65V Wide Vin, Current Mode Synchronous Boost Controller with Multiphase Capability

3-65V Wide Vin, Current Mode Synchronous Boost Controller with Multiphase Capability - LM5122


The LM5122 is a multi-phase capable synchronous boost controller intended for high-efficiency synchronous boost regulator applications. The control method is based upon peak-current-mode control. Current-mode control provides inherent line feed forward, cycle-by-cycle current limiting, and ease of loop compensation.

The switching frequency is programmable up to 1 MHz. Higher efficiency is achieved by two robust N-channel MOSFET gate drivers with adaptive dead-time control. A user-selectable diode-emulation mode also enables discontinuous-mode operation for improved efficiency at light load conditions.

An internal charge pump allows 100% duty cycle for high-side synchronous switch (bypass operation). A 180° phase shifted clock output enables easy multi-phase interleaved configuration. Additional features include thermal shutdown, frequency synchronization, hiccup-mode current limit, and adjustable line undervoltage lockout.


  • Maximum Input Voltage: 65 V
  • Minimum Input Voltage: 3 V (4.5 V for Start-Up)
  • Output Voltage up to 100 V
  • Bypass (VOUT = VIN) Operation
  • 1.2-V Reference with ±1% Accuracy
  • Free-Run and Synchronizable Switching to 1 MHz
  • Peak-Current-Mode Control
  • Robust 3-A Integrated Gate Drivers
  • Adaptive Dead-Time Control
  • Optional Diode-Emulation Mode
  • Programmable Cycle-by-Cycle Current Limit
  • Hiccup-Mode Overload Protection
  • Programmable Line UVLO
  • Programmable Soft Start
  • Thermal Shutdown Protection
  • Low Shutdown Quiescent Current: 9 µA
  • Programmable Slope Compensation
  • Programmable Skip-Cycle Mode Reduces Standby Power
  • Allows External VCC Supply
  • Inductor DCR Current Sensing Capability
  • Multi-phase Capability
  • Thermally Enhanced 20 or 24-Pin HTSSOP
  • Create a Custom Design Using the LM5122 With the WEBENCH® Power Designer

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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)
Iout (Max) (A)
Duty Cycle (Max) (%)
Operating Temperature Range (C)
Package Group
LM5122 LM5121
3    3   
65    65   
3    3   
100    100   
20    20   
1    1   
50    50   
1000    1000   
4    4   
Frequency Synchronization
Phase Interleaving
Synchronous Rectification
UVLO Adjustable   
Adjustable Current Limit
Frequency Synchronization
Light Load Efficiency
Synchronous Rectification
UVLO Adjustable   
20    20   
100    100   
-40 to 125    -40 to 125   
Catalog    Catalog   

Other qualified versions of LM5122

Version Part Number Definition
Automotive LM5122-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects
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WEBENCH® Designer LM5122

  Min   Max Range
Vin  V 4.5 to 65.0V
Vout  V 4.5 to 100V
Iout  A ≤ 35A
Ambient Temp  °C -40 to 125°C

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