Document
LT1640L/LT1640H Negative Voltage Hot Swap Controller
FEATURES
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DESCRIPTION
The LT®1640L/LT1640H is an 8-pin, negative voltage Hot SwapTM controller that allows a board to be safely inserted and removed from a live backplane. Inrush current is limited to a programmable value by controlling the gate voltage of an external N-channel pass transistor. The pass transistor is turned off if the input voltage is less than the programmable undervoltage threshold or greater than the overvoltage threshold. A programmable electronic circuit breaker protects the system against shorts. The PWRGD (LTC1640L) or PWRGD (LTC1640H) signal can be used to directly enable a power module. The LT1640L is designed for modules with a low enable input and the LT1640H for modules with a high enable input. The LT1640L/LT1640H is available in 8-pin PDIP and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation.
Allows Safe Board Insertion and Removal from a Live – 48V Backplane Operates from –10V to – 80V Programmable Inrush Current Programmable Electronic Circuit Breaker Programmable Overvoltage Protection Programmable Undervoltage Lockout Power Good Control Output
U APPLICATIONS
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Central Office Switching – 48V Distributed Power Systems Negative Power Supply Control
TYPICAL APPLICATION
Input Inrush Current
GND R4 562k 1% UV = 37V R5 9.09k 1% R6 10k 1% 8 VDD 3 UV LT1640L 2 OV VEE 4 SENSE 5 C1 33nF 24V GATE 6 R2 10Ω 5% R3 10k 5% C2 3.3nF 100V 2 1 C3 0.1µF 100V ON/OFF 9 VOUT+ VIN 8 SENSE + 7 TRIM 6 SENSE – 5 VOUT– VIN–
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CONTACT BOUNCE
PWRGD 1
OV = 71V
DRAIN 7
R1 0.02Ω 5% – 48V
Q1 IRF530
5V
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C4 100µF 100V 4
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C5 100µF 16V
1640 F07b
LUCENT JW050A1-E
1640 TA01
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LT1640L/LT1640H ABSOLUTE MAXIMUM RATINGS U W W U W
(Note 1), All Voltages Referred to VEE
Supply Voltage (VDD – VEE) .................... – 0.3V to 100V DRAIN, PWRGD, PWRGD Pins ............... – 0.3V to 100V SENSE, GATE Pins .................................... – 0.3V to 20V UV, OV Pins .............................................. – 0.3V to 60V Maximum Junction Temperature ......................... 125°C
Operating Temperature Range LT1640LC/LT1640HC ............................. 0°C to 70°C LT1640LI/LT1640HI .......................... – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C
PACKAGE/ORDER I FOR ATIO
TOP VIEW PWRGD 1 OV 2 UV 3 VEE 4 N8 PACKAGE 8-LEAD PDIP 8 7 6 5 VDD DRAIN GATE SENSE
ORDER PART NUMBER LT1640LCN8 LT1640LCS8 LT1640LIN8 LT1640LIS8 S8 PART MARKING 1640L 1640LI
PWRGD 1 OV 2 UV 3 VEE 4 N8 PACKAGE 8-LEAD PDIP
S8 PACKAGE 8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 120°C/W (N8) TJMAX = 125°C, θJA = 150°C/W (S8)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL DC VDD IDD VCB IPU IPD ISENSE ∆VGATE VUVH VUVL VUVHY IINUV VOVH VOVL VOVHY IINOV Supply Voltage Supply Cu.