LINEAR TECHNOLOGY LT1640AL LT1640AH Specification Sheet User Guide
Summary
Engineers designing industrial or telecom backplanes will find this Negative Voltage Hot Swap Controller essential. This robust solution ensures safe, reliable connection and disconnection of circuit boards from live -48V distributed power systems across a wide operational range (-10V to -80V). The manual details advanced overcurrent protection features, including programmable inrush current limiting, adjustable overvoltage/undervoltage detection, and electronic circuit breaking. Ideal for Central Office Switching and high-reliability applications requiring maximum board integrity during power cycling.
Page 1 Text Content
LT1640AL/LT1640AH Negative Voltage Hot Swap Controller
FEATURES DESCRIPTIO Allows Safe Board Insertion and Removal The LT®1640AL/LT1640AH are 8-pin, negative voltage from a Live –48V Backplane Hot Swap TM controllers that allow a board to be safely Operates from –10V to –80V inserted and removed from a live backplane. Inrush cur- Programmable Inrush Current rent is limited to a programmable value by controlling the Allows 50m A of Reverse Drain Pin Current gate voltage of an external N-channel pass transistor. The
Programmable Electronic Circuit Breaker pass transistor is turned off if the input voltage is less than Programmable Overvoltage Protection the programmable undervoltage threshold or greater than Programmable Undervoltage Lockout the overvoltage threshold. A programmable electronic Power Good Control Output circuit breaker protects the system against shorts. The PWRGD (LT1640AL) or PWRGD (LT1640AH) signal can be used to directly enable a power module. The LT1640AL
APPLICATIO S
is designed for modules with a low enable input and the LT1640AH for modules with a high enable input.
Central Office Switching –48V Distributed Power Systems The LT1640AL/LT1640AH are available in 8-pin PDIP and Negative Power Supply Control SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO (SHORT PIN)
Input Inrush Current
1% CONTACT BOUNCE
UV = 37V UV
9.09k LT1640AL PWRGD
OV = 71V OV
VEE SENSE GATE DRAIN
Q1 IRF530 ON/OFF
VIN VOUT 5V
* DIODES INC. SMAT70A SENSE+
† THESE COMPONENTS ARE APPLICATION C3 C4 C5 0.1µF 100µF TRIM 100µF
SPECIFIC AND MUST BE SELECTED BASED
UPON OPERATING CONDITIONS AND DESIRED SENSE– PERFORMANCE. SEE APPLICATIONS –VIN
INFORMATION.
1640A TA01
LUCENT JW050A1-E
Page Summary Contents For LINEAR TECHNOLOGY LT1640AL LT1640AH Specification Sheet User Guide
Manual Details
| Brand | Linear |
|---|---|
| Pages | 16 |
| File Size | 315.82 KB |
| Published | June 16, 2026 |
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Frequently Asked Questions
What voltage range does the LT1640 support during hot swap?
It operates from –10V to –80V.
Can the inrush current be limited?
Yes, the inrush current is programmable by controlling a resistor (R4).
How is system power managed after board insertion?
The PWRGD signal can directly enable a power module. The LT1640AL uses this for modules with a low enable input.
Are there limits on overheating the chip?
The device has a maximum junction temperature (JMAX) of 125°C.