LM25085A 4.5-42V Wide Vin, Constant On-Time Non-Synchronous PFET Buck Controller with 0.9V Reference | TI.com

LM25085A (ACTIVE)

4.5-42V Wide Vin, Constant On-Time Non-Synchronous PFET Buck Controller with 0.9V Reference

 

Description

The LM25085A is a functional variant of the LM25085 COT PFET Buck Switching Controller. The functional differences of the LM25085A are: The feedback reference voltage is 0.9V, the forced off-time after current limit detection is longer, and the soft-start time is shorter (1.8 ms).

The LM25085A is a high efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, efficient buck regulator for a wide range of applications. This high voltage controller contains a PFET gate driver and a high voltage bias regulator which operates over a wide 4.5V to 42V input range. The constant on-time regulation principle requires no loop compensation, simplifies circuit implementation, and results in ultra-fast load transient response. The operating frequency remains nearly constant with line and load variations due to the inverse relationship between the input voltage and the on-time. The PFET architecture allows 100% duty cycle operation for a low dropout voltage. Either the RDS(ON) of the PFET or an external sense resistor can be used to sense current for over-current detection.

Features

  • Wide 4.5V to 42V Input Voltage Range
  • Adjustable Current Limit using RDS(ON) or a Current Sense Resistor
  • Programmable Switching Frequency to 1MHz
  • No Loop Compensation Required
  • Ultra-Fast Transient Response
  • Nearly Constant Operating Frequency with Line and Load Variations
  • Adjustable Output Voltage from 0.9V
  • Precision ±2% Feedback Reference
  • Capable of 100% Duty Cycle Operation
  • Internal Soft-Start Timer
  • Integrated High Voltage Bias Regulator
  • Thermal Shutdown

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WEBENCH® Designer LM25085A

  Min   Max Range
Vin  V 4.5 to 42.0V
Vout  V 0.9 to 42V
Iout  A ≤ 10A
Ambient Temp  °C -40 to 125°C

Parametrics

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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
LM25085A Order now 4.5     42     0.9     42     10     1     1     50     1000     1.25     Adjustable Current Limit
Frequency Synchronization    
100     -40 to 125     Catalog     MSOP-PowerPAD | 8
VSSOP | 8
WSON | 8    
Controller     Constant on-time (COT)    
LM25085 Order now 4.5     42     1.25     42     10     1     1     50     1000     1.25     Adjustable Current Limit
Enable
Frequency Synchronization    
100     -40 to 125     Catalog     MSOP-PowerPAD | 8
VSSOP | 8
WSON | 8    
Controller     Constant on-time (COT)    
LM25085-Q1 Order now 4.5     42     1.25     42     10     1     1     50     1000     1.25     Adjustable Current Limit
Frequency Synchronization    
100     -40 to 125     Automotive     MSOP-PowerPAD | 8     Controller     Constant on-time (COT)    
LM5085 Order now 4.5     75     1.25     75     10     1     1     50     1000     1.3     Adjustable Current Limit
Enable
Frequency Synchronization    
100     -40 to 125     Catalog     MSOP-PowerPAD | 8
VSSOP | 8
WSON | 8    
Controller     Constant on-time (COT)    
LM5085-Q1 Order now 4.5     75     1.25     75     10     1     1     50     1000     1.3     Adjustable Current Limit
Enable
Frequency Synchronization    
100     -40 to 125     Automotive