Document Number: MC34653
Rev. 8.0, 2/2007
1.0 A Negative Voltage Hot
The 34653 is a highly integrated -48 V hot swap controller with an
internal Power MOSFET. It provides the means to safely install and
remove boards from live -48 V backplanes without having to power
down the entire system. It regulates the inrush current, from the
supply to the load’s filter capacitor, to a user-programmable limit,
allowing the system to safely stabilize. A disable function allows the
user to disable the 34653 manually or through a microprocessor and
safely disconnect the load from the main power line.
The 34653 has active high and active low power good output
signals that can be used to directly enable a power module load.
Undervoltage and overvoltage detection circuitry monitors the input
voltage to check that it is within its operating range. A start-up delay
timer ensures that it is safe to turn on the Power MOSFET and charge
the load capacitor.
A two-level current limit approach to controlling the inrush current
and switching on the load limits the peak power dissipation in the
Power MOSFET. Both current limits are user programmable.
• Integrated Power MOSFET and Control IC in a Small Outline
• Input Voltage Operation Range from -39 V to -74 V
• Programmable Overcurrent Limit with Auto Retry
• Programmable Charging Current Limit Independent of Load
• Start-Up and Retry Delay Timer
• Overvoltage and Undervoltage Detection
• Active High and Low Power Good Output Signals
• Thermal Shutdown
• Pb-Free Packaging Designated by Suffix Code EF
EF SUFFIX (Pb-Free)
-40°C to 85°C
Figure 1. 34653 Simplified Application Diagram
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2007. All rights reserved.