LM5085_15 Datasheet, PDF (1/33 Pages) Texas Instruments – 75V Constant On-Time PFET Buck Switching Controller

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LM5085, LM5085-Q1
SNVS565I – NOVEMBER 2008 – REVISED AUGUST 2015
LM5085/-Q1 75-V Constant On-Time PFET Buck Switching Controller
1 Features
•1 LM5085-Q1 is an Automotive Grade Product that
is AEC-Q100 Grade 1 Qualified (–40°C to 125°C
Operating Junction Temperature)
• Wide 4.5-V to 75-V Input Voltage Range
• Adjustable Current Limit Using R_DS(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 1.25 V
• Precision ±2% Feedback Reference
• Capable of 100% Duty Cycle Operation
• Internal Soft-start Timer
• Integrated High Voltage Bias Regulator
• Thermal Shutdown
• Package:
– HVSSOP-8
– VSSOP-8
– WSON-8
2 Applications
• Automotive Infotainment
• Battery/Super Capacitor Chargers
• LED Drivers
3 Description
The LM5085 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
4.5-V to 75-V input range. The constant on-time
regulation principle requires no loop compensation,
simplifies circuit implementation, and results in
ultrafast 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 R_DS(ON) of the PFET or an external
sense resistor can be used to sense current for over-
current detection.
Device Information⁽¹⁾
PART NUMBER PACKAGE
BODY SIZE (NOM)
VSSOP (8)
LM5085
HVSSOP (8)
3.00 mm x 3.00 mm
WSON (8)
LM5085-Q1
HVSSOP (8)
3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Typical Application, Basic Step Down Controller
4.5V to 75V
Input
V_IN
C_IN
GND
SHUTDOWN
LM5085
VIN
VCC
R_T
RT
ADJ
PGATE
ISEN
GND
FB
C_VCC
C_ADJ
R_ADJ
L1
Q1
D1
Cff
R_FB2
V_OUT
C_OUT
GND
R_FB1
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.