LM5008 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – High Voltage (100V) Step Down Switching Regulator

LM5008
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SNVS280G – APRIL 2004 – REVISED MARCH 2013
High-Voltage (100V) Step-Down Switching Regulator
Check for Samples: LM5008
FEATURES
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•2 Integrated 100V, N-Channel buck switch
• Internal V_CC regulator
• No loop compensation required
• Ultra-Fast transient response
• On time varies inversely with line voltage
• Operating frequency remains constant with
varying line voltage and load current
• Adjustable output voltage
• Highly efficient operation
• Precision internal reference
• Low bias current
• Intelligent current limit protection
• Thermal shutdown
• VSSOP-8 and WSON-8 (4mm x 4mm) Packages
DESCRIPTION
The LM5008 Step-Down Switching Regulator
features all of the functions needed to implement a
low cost, efficient, Buck bias regulator. This high
voltage regulator contains an 100 V N-Channel Buck
Switch. The device is easy to implement and is
provided in the VSSOP-8 and the thermally enhanced
WSON-8 packages. The regulator is based on a
hysteretic control scheme using an ON time inversely
proportional to V_IN. This feature allows the operating
frequency to remain relatively constant. The
hysteretic control requires no loop compensation. An
intelligent current limit is implemented with forced
OFF time, which is inversely proportional to Vout.
This scheme ensures short circuit protection while
providing minimum foldback. Other protection
features include: Thermal Shutdown, V_CC under-
voltage lockout, Gate drive under-voltage lockout,
and Max Duty Cycle limiter
APPLICATIONS
• Non-Isolated Telecommunication Buck
Regulator
• Secondary High Voltage Post Regulator
• +42V Automotive Systems
Connection Diagram
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SW
2
BST
3
R_CL
4
RTN
8
V_IN
7
V_CC
6
RON/SD
5
FB
Figure 1. 8-Lead VSSOP or WSON
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2
PRODUCTION DATA information is current as of publication date.
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