LTC4240 Linear Technology, LTC4240 Datasheet - Page 23
LTC4240
Manufacturer Part Number
LTC4240
Description
CompactPCI Hot Swap Controller with I2C Compatible Interface
Manufacturer
Linear Technology
Datasheet
1.LTC4240.pdf
(28 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LTC4240CGN
Manufacturer:
LINEAR/凌特
Quantity:
20 000
APPLICATIO S I FOR ATIO
than 2 A, then a 50K resistor can be connected directly
from the 1V bias voltage to the I/O line. However, many ICs
connected to the I/O lines can have leakage currents up to
10 A. For these applications, a 10k resistor is used but
must be disconnected when the board has been seated as
determined by the state of the BD_SEL# signal. Figure 14
shows a precharge circuit that uses a bus switch to
MEDIUM 5V
I/O PIN 128
MEDIUM 5V
I/O PIN 128
BD_SEL#
LONG 5V
GROUND
I/O PIN 1
BD_SEL#
GROUND
LONG 5V
I/O PIN 1
CONNECTOR
BACKPLANE
CompactPCI
CONNECTOR
CompactPCI
BACKPLANE
(MALE)
(MALE)
Figure 14. Precharge Bus Switch Application Circuit for 3.3V and Universal Hot Swap Boards
U
CONNECTOR
CompactPCI
BACKPLANE
U
CONNECTOR
(FEMALE)
CompactPCI
BACKPLANE
(FEMALE)
Figure 13.Precharge Application Circuit for 5V Signaling Systems
2.74
R22
Z4: 1PMT5.0AT3
*ADDITIONAL DETAILS OMITTED FOR CLARITY
2.74
R22
DATA BUS
W
DATA BUS
Z4
Z4
5V
5V
IN
IN
LONG
5V
R17
1.2k
U
5%
1k, 5%
51.1k, 5%
R18
R26
R17
1.2k
5%
R27
28
75k
21
5%
R
R
10
10
5%
I0128
5%
5V
OFF/ON
I01
Q4
MMBT3906
LONG
1k, 5%
IN
R18
GND
5V
connect the individual 10k precharge resistors to the
LTC4240 1V PRECHARGE pin. The electrical connection is
made (bus switches close) when the voltage on the
BD_SEL# pin of the plug-in card is above 4.4V, which
occurs just after the long pins have made contact. The bus
switches are subsequently electrically disconnected when
the board connector makes contact with the BD_SEL# pin
(bus switch OE pin is pulled high by Q4).
18 , 5%
28
21
100
R11
PRECHARGE
R
Z4: 1PMT5.0AT3
*ADDITIONAL DETAILS OMITTED FOR CLARITY
0.1 F
R
10
10
R
5%
I0128
5%
5V
OFF/ON
PRE1
I01
10k
5%
IN
GND
18
10
R
18 , 5%
PRE128
R11
OE
10k
5%
LTC4240*
PRECHARGE
OUT
V
BUS SWITCH
DD
C3, 4.7nF
PRECHARGE OUT
1V 10%
I
R
10k
5%
OUT
18
PRE1
LTC4240*
= 55mA
UP TO 128 I/O LINES
24
OUT
R9
IN
UP TO 128 I/O LINES
R
10k
5%
PRE128
C3, 4.7nF
24
R9
MMBT2222A
PRECHARGE OUT
MMBT2222A
I
DRIVE
OUT
Q3
1V 10%
DRIVE
17
= 55mA
Q3
17
I/O
I/O
12 , 5%
1k, 5%
I/O
I/O
R8
R7
12 , 5%
1k, 5%
LTC4240
R8
R7
BRIDGE
CHIP
PCI
BRIDGE
CHIP
PCI
3V
4240 F13
IN
3V
4240 F14
IN
23
4240f