LM5121 (ACTIVE)

3-65V Wide Vin, Current Mode Synchronous Boost with Disconnection Switch Control

3-65V Wide Vin, Current Mode Synchronous Boost with Disconnection Switch Control - LM5121
 

Description

The LM5121 is a synchronous boost controller intended for high-efficiency, high-power 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 using two robust N-channel MOSFET gate drivers with adaptive dead-time control. A user-selectable diode emulation mode enables discontinuous mode operation for improved efficiency at light load conditions.

The LM5121 provides disconnection switch control which completely disconnects the output from the input during an output short or a shutdown condition. During start-up sequence, inrush current is limited by the disconnection switch control.

An internal charge pump allows 100% duty cycle operation of the high-side synchronous switch (Bypass operation). Additional features include thermal shutdown, frequency synchronization, hiccup mode current limit and adjustable line undervoltage lockout.

Features

  • AEC-Q100 Qualified with the following results:
    • Device Temperature Grade 1: –40°C to +125°C
      Ambient Operating Temperature Range
    • Device HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C6
  • Maximum Input Voltage: 65 V
  • Min Input Voltage: 3.0 V (4.5 V for startup)
  • Output Voltage Up to 100 V
  • Bypass (VOUT = VIN) Operation
  • 1.2-V Reference with ±1.0% Accuracy
  • Free-Run/Synchronizable up to 1 MHz
  • Peak Current Mode Control
  • Robust Integrated 3-A Gate Drivers
  • Adaptive Dead-Time Control
  • Optional Diode Emulation Mode
  • Programmable Cycle-by-Cycle Current Limit
  • 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
  • Supports External VCC Bias Supply Option
  • Load Disconnection in Shutdown Mode (True
    Shutdown)
  • Inrush Current Limiting
  • Hiccup Mode Short Circuit/Overload Protection
  • Circuit Breaker Function
  • Capable of Input Transient Suppression
  • Capable of Reverse Battery Protection
  • Thermally Enhanced 20-Pin HTSSOP

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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
LM5121 LM25122-Q1 LM5020 LM5022 LM5122 LM5122-Q1
3    3    13    6    3    3   
65    42    100    60    65    65   
3    3    1.25    1.25    3    3   
100    50    300    300    100    100   
20    20    10    10    20    20   
1    1    1    1    1    1   
50    50    175    170    50    50   
1000    600    1000    2200    1000    1000   
4    4    2    3.5    4    4   
Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Synchronous Rectification
UVLO Adjustable   
Enable
Frequency Synchronization
Phase Interleaving
Synchronous Rectification   
Enable
Frequency Synchronization
Pre-Bias Start-Up   
Enable
Frequency Synchronization
UVLO Adjustable   
Enable
Frequency Synchronization
Phase Interleaving
Synchronous Rectification
UVLO Adjustable   
Enable
Frequency Synchronization
Phase Interleaving
Synchronous Rectification
UVLO Adjustable   
20    20    10    10    20    20   
100    100    80    90    100    100   
-40 to 125    -40 to 125    -40 to 125    -40 to 125    -40 to 125    -40 to 125   
  Automotive          Automotive   
HTSSOP    HTSSOP    VSSOP
WSON   
VSSOP    HTSSOP
HTSSOP   
HTSSOP   

Other qualified versions of LM5121

Version Part Number Definition
Automotive LM5121-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects
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WEBENCH® Designer LM5121

  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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