LTC1645
Dual-Channel Hot Swap
Controller/Power Sequencer
FEATURES
DESCRIPTIO
TM
n
The LTC 1645 is a 2-channel Hot Swap controller that
Allows Safe Board Insertion and Removal from a
allows a board to be safely inserted and removed from a
Live Backplane
n
live backplane. Using external N-channel pass transistors,
Programmable Power Supply Sequencing
n
the supply voltages can be ramped at a programmable
Programmable Electronic Circuit Breaker
n
rate. Two high side switch drivers control the N-channel
User-Programmable Supply Voltage Power-Up and
gates for supply voltages ranging from 1.2V to 12V. The
Power-Down Rate
n
two channels can be set to ramp up and down separately,
High Side Drivers for External N-Channel FETs
n
or they can be programmed to rise and fall simultaneously,
Controls Supply Voltages from 1.2V to 12V
n
ensuring power supply tracking at the two outputs.
Ensures Proper Power-Up Behavior
n
Undervoltage Lockout
Programmable electronic circuit breakers protect against
n
Glitch Filter Protects Against Spurious RESET Signals
shorts at either output. The RESET output can be used to
n
8- and 14-Pin SO Packages
generate a system reset when a supply voltage falls below
U
a user-programmed voltage. An additional spare com-
APPLICATIO S
parator is available for monitoring a second supply
voltage.
n
Hot Board Insertion
n
The LTC1645 is available in the 8- and 14-pin SO packages.
Power Supply Sequencing
n
, LTC and LT are registered trademarks of Linear Technology Corporation.
Electronic Circuit Breaker
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
5V and 3.3V Hot Swap
5V and 3.3V Hot Swap Waveforms
V
0.005* IRF7413
OUT2
3.3V
V
IN2
+ 5A
C
LOAD2
ON
5V/DIV
V
0.005* IRF7413 OUT1
5V
V
IN1
+ 5A
C
10 LOAD1
GATEn
10
10V/DIV
0.01F
0.01F
25V
25V
V
OUT2
5V/DIV
SENSE1 GATE1 V SENSE2 GATE2
CC2
V
CC1
V
OUT1
LTC1645 5V/DIV
(8-LEAD)
ON
ON
10k
GND
1645 TA01
GND
*LRF1206-01-R005-J (IRC)
BACKPLANE PLUG-IN CARD
1645fa
1
CONNECTOR 2
CONNECTOR 1
U
ULTC1645
ABSOLUTE AXI U RATI GS
(Note 1)
Supply Voltage (V , V ) ................................. 13.2V Output Current
CC1 CC2
Input Voltage GATE1, GATE2............................................... 20mA
+
FB, ON, COMP ..................... 0.3V to (V + 0.3V) Operating Temperature Range
CC1
TIMER ................................................. 0.3V to 2.5V LTC1645C ............................................... 0 C to 70 C
SENSE1 ..................... (V 0.7V) to (V + 0.3V) LTC1645I............................................ 40 C to 85 C
CC1 CC1
SENSE2 ...................... (V 0.7V) to (V + 0.3V) Storage Temperature Range ................. 65 C to 150 C
CC1 CC2
Output Voltage Lead Temperature (Soldering, 10 sec).................. 300 C
RESET, COMPOUT, FAULT .....................0.3V to 16V
GATE1, GATE2................. Internally Limited (Note 3)
UUW
PACKAGE/ORDER I FOR ATIO
ORDER PART ORDER PART
TOP VIEW
NUMBER
NUMBER
TOP VIEW V 1 14 V
CC2 CC1
SENSE2 2 13 SENSE1
V 1 8 V
CC2 CC1
LTC1645CS8 LTC1645CS
GATE2 3 12 GATE1
SENSE2 2 7 SENSE1
LTC1645IS8 LTC1645IS
FAULT 4 11 TIMER
GATE2 3 6 GATE1
RESET 5 10 ON
GND ON
4 5
FB 6 9 COMPOUT
S8 PART MARKING
S8 PACKAGE +
GND 7 8 COMP
8-LEAD PLASTIC SO
T = 125 C, q = 150 C/ W
1645 S PACKAGE
JMAX JA
14-LEAD PLASTIC SO
1645I
T = 125 C, q = 110 C/ W
JMAX JA
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C.
A
2.375V V 12V, 1.2V V 12V unless otherwise noted (Note 2).
CC1 CC2
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
DC Characteristics
I V Supply Current ON = V = 5V, V = 3.3V l 1.1 2.0 mA
CC1 CC1 CC1 CC2
I V Supply Current ON = V = 5V, V = 3.3V l 0.28 0.4 mA
CC2 CC2 CC1 CC2
V V Undervoltage Lockout High to Low l 2.16 2.23 2.3 V
LKO1 CC1
V V Undervoltage Lockout High to Low l 1.06 1.12 1.18 V
LKO2 CC2
V V Undervoltage Lockout Hysteresis 25 mV
LKHn CCn
V FB Pin Voltage Threshold High to Low l 1.226 1.238 1.250 V
FB
D V FB Pin Threshold Line Regulation High to Low, V = 2.375V to 12V l 14 mV
FB CC1
V FB Pin Voltage Threshold Hysteresis 5 mV
FBHST
+
V COMP Pin Voltage Threshold High to Low l 1.226 1.238 1.250 V
COMP
+
D V COMP Pin Threshold Line Regulation High to Low, V = 2.375V to 12V l 14 mV
COMP CC1
+
V COMP Pin Voltage Threshold Hysteresis 5 mV
COMPHST
1645fa
2
U WWW