LTC4216CMS View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC4216CMS' PDF : 24 Pages View PDF
LTC4216
Applications Information
An example with LTC4216 mounted on the backplane is
shown in Figure 15. In this case, the NPN transistor, Q1,
and two resistors, R7 and R8, form the PCB connection
sensing circuit with the ON pin. With the PCB out of the
backplane connector, Q1 base is tied to load supply through
R7, turning Q1 on and pulling the LTC4216’s ON pin low.
The base of Q1 is also wired to the backplane connector
pin. When the PCB is inserted into the backplane, Q1 base
is grounded through a short pin connection on the PCB.
This turns off Q1 and the LTC4216’s ON pin is allowed
to pull high to the load supply through R8, turning it on.
In the previous examples, the PCB connection sensing
circuits are not wired with interrupt capability from the
system controller. As shown in Figure 16, adding logic-
level discrete N-channel MOSFETs, M2 and M3, and a
couple of resistors allow interrupt control to the sensing
circuit. M2 is held on by its gate, pulling high through
R8 to the load supply until the PCB is mated firmly to
the backplane connector. A low logic-level for both the
ON/RST and ON/OFF signals turns M2 and M3 off, allowing
the ON pin to be pulled high and turning LTC4216 on. A
high logic-level for the ON/OFF signal turns off the device
and pulls the GATE low. The device is reset by pulling the
ON/RST signal high.
5V Hot Swap Application
Figure 17 shows a Hot Swap application circuit with VCC
and SENSEP pins connected together to a 5V load supply
(VIN). The resistive divider, R1/R2, sets the undervoltage
threshold for the load supply and allows the system to
start up only after the supply voltage rises above 4V.
The resistive divider, R3/R4, monitors VOUT and signals
BACKPLANE PCB EDGE
CONNECTOR CONNECTOR
(FEMALE) (MALE)
VCC
LONG
3.3V
VIN
1.5V
LONG
RX
10Ω
CY
330nF
RY RSENSE
M1
22Ω 0.004Ω Si4864DY
11 10
9
8
VOUT
R4
+ CLOAD
1.5V
5A
13k
4700µF
CX
100nF
SHORT
VCC SENSEP SENSEN GATE
2 ON
LTC4216
7 1%
FB
R3
10k
1%
R6
10k
R5
10k
µP
LOGIC
R2 R1 C4
3.3k 20k 10nF
1% 1%
12
FAULT
TIMER SS FILTER GND RESET 1
FAULT
RESET
GND
PCB CONNECTION
LONG SENSING
4
5
3
6
C1
C2
C3
10nF 10nF 68nF
4216 F14
Figure 14. Single Channel 1.5V Hot Swap Controller
BACKPLANE PCB EDGE
CONNECTOR CONNECTOR
RY RSENSE
M1
(FEMALE)
(MALE)
VIN
22Ω 0.004Ω Si4864DY
LONG
VOUT
3.3V
+
3.3V
Z1
RX
10Ω
CX
100nF
PCB
CONNECTION
SENSING
R7
R8
CY
330nF
10k 10k
Q1
R6
11 10
9
8
10k
2 VCC SENSEP SENSEN GATE
ON
12
FAULT
R5
LTC4216
10k
1
6 GND
TIMER
SS
RESET
FILTER
FB 7
LONG
SHORT
SHORT
SHORT
CLOAD
5A
1000µF
FAULT
RESET
R4
39.2k
1%
Z1: SMAJ6.0A
4
5
3
C1
C2
C3
10nF 4.7nF 33nF
R3
10k
1%
SHORT R9
100k
Q1: MMBT3904
4216 F15
Figure 15. Hot Swap Controller on Backplane with Staggered Pin Connections
For more information www.linear.com/LTC4216
4216fa
21
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