LM25145 6V to 42V Synchronous Buck DC-DC Controller With Wide Duty Cycle Range | TI.com

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6V to 42V Synchronous Buck DC-DC Controller With Wide Duty Cycle Range



The LM25145 42-V synchronous buck controller is designed to regulate from a high input voltage source or from an input rail subject to high voltage transients, minimizing the need for external surge suppression components. A high-side switch minimum on-time of 40 ns facilitates large step-down ratios, enabling the direct step-down conversion from a 24 V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM25145 continues to operate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it well suited for high-performance industrial control, robotic, datacom, and RF power amplifier applications.

Forced-PWM (FPWM) operation eliminates frequency variation to minimize EMI, while a user-selectable diode emulation feature lowers current consumption at light-load conditions. Cycle-by-cycle overcurrent protection is accomplished by measuring the voltage drop across the low-side MOSFET or by using an optional current sense resistor. The adjustable switching frequency as high as 1 MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications.

The LM25145 voltage-mode controller drives external high-side and low-side N-channel power switches with robust 7.5-V gate drivers suitable for standard-threshold MOSFETs. Adaptively-timed gate drivers with 2.3-A source and 3.5-A sink capability minimize body diode conduction during switching transitions, reducing switching losses and improving thermal performance when driving MOSFETs at high input voltage and high frequency. The LM25145 can be powered from the output of the switching regulator or another available source, further improving efficiency.

A 180° out-of-phase clock output relative to the internal oscillator at SYNCOUT is ideal for cascaded or multi-channel power supplies to reduce input capacitor ripple current and EMI filter size. Additional features of the LM25145 include a configurable soft-start, an open-drain Power Good monitor for fault reporting and output monitoring, monotonic start-up into prebiased loads, integrated VCC bias supply regulator and bootstrap diode, external power supply tracking, precision enable input with hysteresis for adjustable line undervoltage lockout (UVLO), hiccup-mode overload protection, and thermal shutdown protection with automatic recovery.

The LM25145 controller is offered in a 3.5-mm × 4.5-mm thermally-enhanced, 20-pin VQFN package with additional spacing for high-voltage pins and wettable flanks for optical inspection of solder joint fillets.


  • Versatile Synchronous Buck DC-DC Controller
    • Wide Input Voltage Range of 6 V to 42 V
    • Adjustable Output Voltage From 0.8 V to 40 V
  • Meets EN55022 / CISPR 22 EMI Standards
  • Lossless RDS(on) or Shunt Current Sensing
  • Switching Frequency From 100 kHz to 1 MHz
    • SYNC In and SYNC Out Capability
  • 40-ns Minimum On-Time for High VIN / VOUT Ratio
  • 140-ns Minimum Off-Time for Low Dropout
  • 0.8-V Reference With ±1% Feedback Accuracy
  • 7.5-V Gate Drivers for Standard VTH MOSFETs
    • 14-ns Adaptive Dead-Time Control
    • 2.3-A Source and 3.5-A Sink Capability
    • Low-Side Soft-Start for Prebiased Start-Up
  • Adjustable Soft-Start or Optional Voltage Tracking
  • Fast Line and Load Transient Response
    • Voltage-Mode Control With Line Feedforward
    • High Gain-Bandwidth Error Amplifier
  • Precision Enable Input and Open-Drain Power Good Indicator for Sequencing and Control
  • Inherent Protection Features for Robust Design
    • Hiccup Mode Overcurrent Protection
    • Input UVLO With Hysteresis
    • VCC and Gate Drive UVLO Protection
    • Thermal Shutdown Protection With Hysteresis
  • VQFN-20 Package With Wettable Flanks
  • Create a Custom Design Using the LM25145 With WEBENCH® Power Designer

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WEBENCH® Designer LM25145

  Min   Max Range
Vin  V 6.0 to 42.0V
Vout  V 0.8 to 40V
Iout  A ≤ 20A
Ambient Temp  °C -40 to 125°C


Compare all products in Buck controllers (external switch) Email Download to Excel
Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (Max) (A) Regulated outputs (#) Number of Phases Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Duty cycle (Max) (%) Operating temperature range (C) Rating Package Group Type Control mode
LM25145 Order now 6     42     0.8     40     30     1     1     100     1000     1.8     Adjustable Current Limit
Frequency Synchronization
Light Load Efficiency
Power Good
Pre-Bias Start-Up
Synchronous Rectification
UVLO Adjustable    
99     -40 to 125     Catalog     VQFN | 20     Controller     Voltage Mode    
LM25116 Order now 6     42     1.215     36     20     1     1     50     1000     4.6     Adjustable Current Limit
Frequency Synchronization
Light Load Efficiency
Synchronous Rectification    
98     -40 to 125     Catalog     HTSSOP | 20     Controller     Current Mode    
LM25117 Order now 4.5     42     0.8     41     20     1     1     50     750     4.8     Adjustable Current Limit
Frequency Synchronization
Light Load Efficiency
Synchronous Rectification
UVLO Adjustable    
98     -40 to 125     Catalog     HTSSOP | 20
WQFN | 24    
Controller     Current Mode    
LM3150 Order now 6     42     0.6     40     12     1     1     200     1000     3.5     Adjustable Current Limit
Frequency Synchronization
Pre-Bias Start-Up
Synchronous Rectification
UVLO Adjustable    
96     -40 to 125     Catalog     HTSSOP | 14     Controller     COT with emulated ripple    
LM5116 Order now 6     100     1.215     80     20     1     1     50     1000     4.6