LTC1647-1 Datasheet, PDF (1/20 Pages) Linear Technology – Dual Hot Swap Controllers

LTC1647-1/LTC1647-2/LTC1647-3
Dual Hot Swap Controllers
FEATURES
s _{Allows Safe Board Insertion and Removal from a}
Live Backplane
s _{Programmable Electronic Circuit Breaker}
s _{FAULT Output Indication}
s _{Programmable Supply Voltage Power-Up Rate}
s _{High Side Drive for External MOSFET Switches}
s _{Controls Supply Voltages from 2.7V to 16.5V}
s _{Undervoltage Lockout}
U
APPLICATIO S
s _{Hot Board Insertion}
s _{Electronic Circuit Breaker}
s _{Portable Computer Device Bays}
s _{Hot Plug Disk Drive}
DESCRIPTIO
The LTC^®1647-1/LTC1647-2/LTC1647-3 are dual Hot
Swap^TM controllers that permit a board to be safely in-
serted and removed from a live backplane.
Using external N-channel MOSFETs, the board supply
voltages can be ramped up at a programmable rate. A high
side switch driver controls the MOSFET gates for supply
voltages ranging from 2.7V to 16.5V. A programmable
electronic circuit breaker protects against overloads and
shorts. The ON pins are used to control board power or
clear a fault.
The LTC1647-1 is a dual Hot Swap controller with a
common V_CC pin, separate ON pins and is available in an
SO-8 package. The LTC1647-2 is similar to the LTC1647-1
but combines a fault status flag with automatic retry at the
ON pins and is also available in the SO-8 package. The
LTC1647-3 has individual V_CC pins, ON pins and FAULT
status pins for each channel and is available in a 16-lead
narrow SSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
3.3V V_ID
SUPPLY
R1
0.1Ω
Q1
1/2 MMDF3N02HD
R2
10Ω
V_ID Controller for Two Device Bays
R3**
DEVICE #1
+
1394 PHY
C_LOAD* R4** _AND/OR
USB PORT
8
6
SENSE 1 GATE 1
1
2 ^VCC
ON1 ₃ ON1 _LTC1647-1
ON2
ON2
4
GND
SENSE 2 GATE 2
7
5
R5
0.1Ω
R6
10Ω
Q2
1/2 MMDF3N02HD
C1
4.7nF
* C_LOAD IS USER-SELECTED BASED
ON THE DEVICE REQUIREMENTS
** R3, R4, R7 AND R8 ARE OPTIONAL DISCHARGE
RESISTORS WHEN DEVICES ARE POWERED-OFF
Q1, Q2: ON SEMICONDUCTOR
C3
4.7nF
R7**
DEVICE #2
+
1394 PHY
C_LOAD* R8** _AND/OR
USB PORT
ON/OFF Sequence
V_ON
V_GATE
V_OUT
5ms/DIV
1647-1/2/3 TA01a
1647-1/2/3 TA01
1