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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Parametrics Compare all products in Buck controllers (external switch)

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

Design tool

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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