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Active Clamp Voltage Mode PWM Controller


Package | PIN: NHQ | 16
Temp: Q (-40 to 125)
Carrier: Cut Tape
Qty Price
1-9 $2.63
10-24 $2.37
25-99 $2.21
100-249 $1.93
250-499 $1.81
500-749 $1.54
750-999 $1.30
1000+ $1.24


  • Internal Start-Up Bias Regulator
  • 3A Compound Main Gate Driver
  • Programmable Line Under-Voltage Lockout (UVLO) with Adjustable Hysteresis
  • Voltage Mode Control with Feed-Forward
  • Adjustable Dual Mode Over-Current Protection
  • Programmable Overlap or Deadtime between the Main and Active Clamp Outputs
  • Volt x Second Maximum Duty Cycle Clamp
  • Programmable Soft-Start
  • Current Sense Leading Edge Blanking
  • Single Resistor Programmable Oscillator
  • Oscillator Up / Down Sync Capability
  • Precision 5V Reference
  • Thermal Shutdown


  • TSSOP-16
  • WSON-16 (5x5 mm) Thermally Enhanced

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Texas Instruments  LM5025BSD/NOPB

The LM5025B is a functional variant of the LM5025 active clamp PWM controller. The functional differences of the LM5025B are as follows:

  • The maximum PWM duty cycle is limited to less than 75% to reduce voltage stress on the power MOSFETs.
  • The CS2 hiccup mode threshold is increased to 0.5V
  • The CS2 filter discharge device is disabled
  • The VCC regulator continues to operate when the line UVLO is below the threshold of normal operation
  • The VREF regulator is switched off when the line UVLO input falls below the operating threshold
  • The internal 5kΩ COMP pin pull-up resistor is removed

The LM5025B PWM controller contains all of the features necessary to implement power converters utilizing the Active Clamp / Reset technique. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Two control outputs are provided, the main power switch control (OUT_A) and the active clamp switch control (OUT_B). The two internal compound gate drivers parallel both MOS and Bipolar devices, providing superior gate drive characteristics. This controller is designed for high-speed operation including an oscillator frequency range up to 1MHz and total PWM and current sense propagation delays less than 100ns.

The LM5025B includes a high-voltage start-up regulator that operates over a wide input range of 13V to 100V. Additional features include: Line Under Voltage Lockout (UVLO), softstart, oscillator UP/DOWN sync capability, precision reference and thermal shutdown.