sc4250listr Semtech Corporation, sc4250listr Datasheet

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sc4250listr

Manufacturer Part Number
sc4250listr
Description
Sc4250 Negative-voltage Hot-swap Controller
Manufacturer
Semtech Corporation
Datasheet
The SC4250 is a negative voltage hotswap controller
that allows the insertion of line cards into a live backplane.
The inrush current is programmable, and the closed loop
operation limits the maximum current even under short
circuit conditions. A built-in timing circuit prevents false
shutdown. The signal from the drain voltage is fed to the
timer, providing safety for the MOSFET when in linear
mode. The SC4250 latches off under abnormal condi-
tions The power has to be recycled in order to resume
operation.
The device comes in two options, PWRGD (SC4250H)
and PWRGD (SC4250L). These high or low signals can
be directly used to enable power modules.
Revision: April 6, 2005
POWER MANAGEMENT
Description
Typical Application Circuit
PWRGD/PWRGD
GND(remote)
GND
-- 48V
562k
9.31k
10.2k
R1
R2
R3
0.001
C2
1
2
3
4
PWRGD
OV
UV
VEE
/PWRGD
SC4250
U1
R4
0.01
Figure 1
DRAIN
SENSE
GATE
VCC
1
Features
Applications
8
7
6
5
Programmable slew of the inrush current when
used for hot insertion in the negative 24V and 48V
backplane
Closed loop operation limits the maximum current
even in short circuit condition
Built in timer prevents false shutdown when the
closed loop operation limits the current
Sensing the drain voltage allows for immediate
shutdown in short circuit conditions where current
spikes and noise are ignored
Power good signal
Input UVLO and OVLO sensing
Circuit breaker and retry
SO-8 package
Central office switching
-48V Distributed power systems
Power supply hotswap & inrush control
C3
0.33
Vee
VEE
R5
10
0.1
C1
R6
18k
Q1
Hot Swap Controller
C4
3.3nF
Negative Voltage
150
C5
SC4250
www.semtech.com

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sc4250listr Summary of contents

Page 1

POWER MANAGEMENT Description The SC4250 is a negative voltage hotswap controller that allows the insertion of line cards into a live backplane. The inrush current is programmable, and the closed loop operation limits the maximum current even under short circuit ...

Page 2

POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied ...

Page 3

POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified 25° 48V Values in bold apply over full operating temperature range ...

Page 4

POWER MANAGEMENT Pin Configuration TOP VIEW PWRGD/PWRGD VEE 4 (SO-8) Pin Descriptions ...

Page 5

POWER MANAGEMENT Block Diagrams Active High PWRGD Vcc 12.5V Reg 60mV + Vee SENSE Active Low PWRGD Vcc 12.5V Reg 60mV + Vee SENSE 2005 Semtech ...

Page 6

POWER MANAGEMENT Applications Information Insertion of a power circuit board into a live backplane would draw enormous inrush currents. This is mostly due to the charging of the bulk electrolytic capacitors at the input of the power module being plugged ...

Page 7

POWER MANAGEMENT Applications Information (Cont.) Resistor R4 sets the over-current trip. To choose R4, the user must determine the level of the current where it should trip rule of thumb, the over-current is set to be 200-300% of ...

Page 8

POWER MANAGEMENT Typical Characteristics Below are the snap-shots taken at start-up with different loading conditions and during the application of the over- current at the output of the circuit. For all figures, Ch1 Ch2: V DRAIN Figure 3. ...

Page 9

POWER MANAGEMENT Typical Characteristics (Cont.) The following set of snapshots demonstrates effectiveness of SC4250 circuit in the case where connection to the live back plane is very “bouncy”, which is usually the situation with manual replacements of the power cards. ...

Page 10

POWER MANAGEMENT Evaluation Board Schematic ND(rem ote) C1 0.1 R1 562k R2 9.31k C2(opt) R3 0.01 10.2k -- 48V Evaluation Board 2005 Semtech Corp. U1 SC4250H PWRGD/PWR AIN ...

Page 11

POWER MANAGEMENT Evaluation Board - Bill of Materials ...

Page 12

... SIDE VIEW -A- AND - DETERMINED AT DATUM PLANE -H- DIMENSIONS DIM INCHES (.205 .118 .050 X .024 Y .087 Y Z .291 Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 12 SC4250 DIMENSIONS INCHES MILLIMETERS NOM MAX MIN NOM MAX - - .069 1.35 1. .010 0.10 0. ...

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