LTC4252-1/LTC4252-2
LTC4252A-1/LTC4252A-2
Negative Voltage
Hot Swap Controllers
Fea T Descrip T
TM
n
Allows Safe Board Insertion and Removal from a
The LTC 4252 negative voltage Hot Swap controller
Live 48V Backplane
allows a board to be safely inserted and removed from a
n
Floating Topology Permits Very High Voltage Operation
live backplane. Output current is controlled by three stages
n
Current Limit With Circuit Breaker Timer
of current limiting: a timed circuit breaker, active current
n
Fast Response Time Limits Peak Fault Current
limiting and a fast feedforward path that limits peak current
n
Programmable Soft-Start Current Limit
under worst-case catastrophic fault conditions.
n
Programmable Timer with Drain Voltage
Adjustable undervoltage and overvoltage detectors dis-
Accelerated Response
connect the load whenever the input supply exceeds the
n
1% Undervoltage/Overvoltage Threshold Accuracy
desired operating range. The LTC4252s supply input is
(LTC4252A)
shunt regulated, allowing safe operation with very high
Adjustable Undervoltage/Overvoltage Protection
supply voltages. A multifunction timer delays initial start-
LTC4252-1/LTC4252A-1: Latch Off After Fault
up and controls the circuit breakers response time. The
LTC4252-2/LTC4252A-2: Automatic Retry After Fault
circuit breakers response time is accelerated by sensing
Available in 8-Pin and 10-Pin MSOP Packages
excessive MOSFET drain voltage, keeping the MOSFET
within its safe operating area (SOA). An adjustable soft-
a T
start circuit controls MOSFET inrush current at start-up.
n
Hot Board Insertion
The LTC4252-1/LTC4252A-1 latch off after a circuit breaker
n
Electronic Circuit Breaker
fault times out. The LTC4252-2/LTC4252A-2 provide au-
n
48V Distributed Power Systems
tomatic retry after a fault. The LTC4252A-1/LTC4252A-2
n
Negative Power Supply Control
feature tight 1% undervoltage/overvoltage threshold
n
Central Office Switching
accuracy. The LTC4252 is available in either an 8-pin
n
High Availability Servers
or 10-pin MSOP, while the LTC4252A is available in the
n
ATCA
10-pin MSOP.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Typical a T
Start-Up Behavior
48V/2.5A Hot Swap Controller
48RTN
R
IN +
C
L
3 1.8k IN SERIES
100F GATE
1/4W EACH
5V/DIV
C R3 LOAD
IN
D
IN
48RTN
**
1F 5.1k
DDZ13B
(SHORT PIN)
V
R1 IN EN
SENSE
402k
LTC4252-1 V
OUT
*
2.5A/DIV
1%
OV PWRGD
R 1M
D
UV DRAIN
R2
Q1
TIMER GATE V
32.4k OUT
IRF530S
20V/DIV
C
1%
T
SS SENSE
V
EE
0.33F
R R
C S
C1
C
SS 10 0.02
10nF
68nF C
C
18nF
PWRGD
10V/DIV
425212 TA01
48V
* M0C207 RECOMMENDED FOR HARSH ENVIRONMENTS
1ms/DIV 425212 TA01a
**DIODES, INC
425212fe
1
For more information www.linear.com/LTC4252-1
ion pplica
ions pplica
ion uresLTC4252-1/LTC4252-2
LTC4252A-1/LTC4252A-2
a Te Maxi Mu M r a T
All Voltages Referred to V (Note 1)
EE
Current into V (100s Pulse) .............................100mA Operating Temperature Range
IN
V , DRAIN Pin Minimum Voltage ........................ 0.3V LTC4252-1C/LTC4252-2C
IN
Input/Output Pins LTC4252A-1C/LTC4252A-2C .................... 0C to 70C
(Except SENSE and DRAIN) Voltage .......... 0.3V to 16V LTC4252-1I/LTC4252-2I
SENSE Pin Voltage .................................... 0.6V to 16V LTC4252A-1I/LTC4252A-2I ................. 40C to 85C
Current Out of SENSE Pin (20s Pulse) .......... 200mA Storage Temperature Range .................. 65C to 150C
Current into DRAIN Pin (100s Pulse) ...................20mA Lead Temperature (Soldering, 10 sec) ...................300C
Maximum Junction Temperature .......................... 125C
p in c F T
TOP VIEW
TOP VIEW
V 1 10 TIMER
IN
V 1 8 TIMER
IN
PWRGD 2 9 UV
SS 2 7 UV/OV
SS 3 8 OV
SENSE 3 6 DRAIN
SENSE 4 7 DRAIN
V 4 5 GATE
EE
V 5 6 GATE
EE
MS8 PACKAGE
MS PACKAGE
8-LEAD PLASTIC MSOP
10-LEAD PLASTIC MSOP
T = 125C, = 160C/W
JMAX JA
T = 125C, = 160C/W
JMAX JA
o r Der i n F Ma T
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4252-1CMS8#PBF LTC4252-1CMS8#TRPBF LTWM 8-Lead Plastic MSOP 0C to 70C
LTC4252-2CMS8#PBF LTC4252-2CMS8#TRPBF LTWP 8-Lead Plastic MSOP 0C to 70C
LTC4252-1IMS8#PBF LTC4252-1IMS8#TRPBF LTRQ 8-Lead Plastic MSOP 40C to 85C
LTC4252-2IMS8#PBF LTC4252-2IMS8#TRPBF LTRR 8-Lead Plastic MSOP 40C to 85C
LTC4252-1CMS#PBF LTC4252-1CMS#TRPBF LTWN 10-Lead Plastic MSOP 0C to 70C
LTC4252-2CMS#PBF LTC4252-2CMS#TRPBF LTWQ 10-Lead Plastic MSOP 0C to 70C
LTC4252A-1CMS#PBF LTC4252A-1CMS#TRPBF LTAFX 10-Lead Plastic MSOP 0C to 70C
LTC4252A-2CMS#PBF LTC4252A-2CMS#TRPBF LTAGE 10-Lead Plastic MSOP 0C to 70C
LTC4252-1IMS#PBF LTC4252-1IMS#TRPBF LTRS 10-Lead Plastic MSOP 40C to 85C
LTC4252-2IMS#PBF LTC4252-2IMS#TRPBF LTRT 10-Lead Plastic MSOP 40C to 85C
LTC4252A-1IMS#PBF LTC4252A-1IMS#TRPBF LTAFY 10-Lead Plastic MSOP 40C to 85C
LTC4252A-2IMS#PBF LTC4252A-2IMS#TRPBF LTAGF 10-Lead Plastic MSOP 40C to 85C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to: