LTC1646CGN Linear Technology, LTC1646CGN Datasheet - Page 16

• Manufacturer Part Number: LTC1646CGN
• Description: IC CNTRLR HOTSWAP PCIDUAL 16SSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC1646CGN

• Applications: CompactPCI™
• Internal Switch(s): No
• Voltage - Supply: 3.3V, 5V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP (0.150", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
LTC1646
If no 3.3V supply is present, Figure 11 illustrates how the
LTC1646 should be configured. First, 3V
connected to 3V
5V
through a diode (BAV16W) to 5V
For applications where the BD_SEL# connector pin is
typically grounded on the backplane, the circuit in
Figure 12 allows the LTC1646 to be reset simply by
pressing a pushbutton switch on the CPCI plug-in board.
This arrangement eliminates the requirement to extract
and reinsert the CPCI board in order to reset the LTC1646’s
circuit breakers.
16
OUT
LONG GND
BD_SEL#
(Pin 5) and the LTC1646’s 3V
Figure 12. BD_SEL# Pushbutton Toggle Switch
COMPACT PCI
CONNECTOR
BACKPLANE
(MALE)
IN
(Pin 8), 3V
U
CIRCUIT CARD
COMPACT PCI
CONNECTOR
(FEMALE)
LONG
GND
5V
5V
U
COMPACT PCI
CONNECTOR
BACKPLANE
Z1: BZX84C6V2
BUTTON
SWITCH
(MALE)
PUSH-
100Ω
OUT
IN
(Pin 7) is connected to
W
.
V(I/0)
CIRCUIT CARD
COMPACT PCI
IN
CONNECTOR
1.2k
(FEMALE)
Figure 11. 5V Supply Only Typical Application
1k
pin is connected
SENSE
15
6
OFF/ON
GND
LTC1646
2.7Ω
U
(Pin 9) is
5V
1646 F12
IN
Z1
6
0.1µF
GND
3V
IN
8
3V
BAV16W
Overvoltage Transient Protection
Good engineering practice calls for bypassing the supply
rail of any analog circuit. Bypass capacitors are often
placed at the supply connection of every active device, in
addition to one or more large-value bulk bypass capacitors
per supply rail. If power is connected abruptly, the large
bypass capacitors slow the rate of rise of the supply
voltage and heavily damp any parasitic resonance of lead
or PC trace inductance working against the supply bypass
capacitors.
The opposite is true for LTC1646 Hot Swap circuits
mounted on plug-in cards. In most cases, there is no
supply bypass capacitor present on the powered 3.3V or
5V side of the MOSFET switch. An abrupt connection,
produced by inserting the board into a backplane connec-
tor, results in a fast rising edge applied on the 3.3V and the
5V line of the LTC1646.
SENSE
9
3
5V
1
0.007Ω
IN
12
LTC1646
5V
SENSE
2
4
11
IRF7413
GATE 5V
10
10Ω
OUT
5
1k
3V
5V
OUT
OUT
1646 F11
7
0.01µF
1646fa