SUMMIT
SMH4802
MICROELECTRONICS, Inc.
See Last Page
Preliminary Information
Programmable -48V Hot-Swap Controller with Forced Shut Down
FEATURES & APPLICATIONS
INTRODUCTION
l Soft Start Power Supply
The SMH4802 is designed to control in-rush current
during hot swapping of plug-in cards operating in a
distributed power environment. The device drives an
external power MOSFET switch that connects the supply
to the load and protects against over-current conditions
that might disrupt the host supply. It also provides under-
voltage and over-voltage monitoring of the host power
supply. When the source and drain voltages of the
external MOSFETs are within specification it will provide
a Power Good logic output that can be used to enable a
DC/DC converter. Additional features of the device
include: temperature sense or master enable input, a 5V
reference output for expanding monitor functions, and
duty-cycle or latched over-current protection modes. An
internal Shunt regulator allows a wide supply range. The
SMH4802 -48V Hot-Swap Controller also features a
simple software I2C Power On/Off Interface for remote
power control applications.
l Live Insertion into a -48V backplane
l ProgrammableControlofaDC/DCConverter
w I2C Power On/Off Control
l HighlyProgrammableCircuitBreaker
w Active In-rush Current Limiting
w Over-current Filter Circuit Breaker Immunity
to Voltage Steps and Current Spikes
l Programmable Forced Shutdown Timer
l Internal Shunt Regulator Allows a Wide Supply
Range
l 14-pin SOIC and 16-pin SSOP packages
APPLICATIONS
l -48VPowerDistribution
w Telecom Line Cards
w CentralOfficeSwitching
w HighAvailabilityServers
w HotBoardInsertion
Programmingofconfiguration, controlandcalibrationval-
ues by the user can be simplified with the SMX3200
interface adapter and a windows based GUI supplied by
Summit.
SIMPLIFIED APPLICATION DRAWING
–48V Ret
R
D
4
5
14
SDA SCL
V
DD
I2C
Header
Out+
DC/DC
Out–
V+
8
9
UV
On/
Off
12
10
PG#
FS#
SMH4802
V–
OV
3
EN/TS
DRAIN
SENSE
1
VSS
7
CBSENSE VGATE
5VREF
11
2
6
–48V A
–48V B
VSS
R
S
2062 SAD
Figure 1. The drawing illustrates the SMH4802 in a typical line-card application. It should be noted this is just an
example, and the specific component values are purposely not shown. Pin numbers reflect SOIC package.
©SUMMIT MICROELECTRONICS, Inc., 2003
•
1717 Fox Drive
•
San Jose, CA 95131
• Phone 408-436-9890 • FAX 408-436-9897 • www.summitmicro.com
Characteristics subject to change without notice
2062 2.3 6/19/03