LTC4240 Linear Technology, LTC4240 Datasheet - Page 22

• Manufacturer Part Number: LTC4240
• Description: CompactPCI Hot Swap Controller with I2C Compatible Interface
• Manufacturer: Linear Technology

LTC4240
APPLICATIO S I FOR ATIO
Table 6. R1 and R2 Resistor Values vs Precharge Voltages
V
1.5V
1.4V
1.3V
1.2V
1.1V
1V
22
PRECHARGE
V
PRECHARGE
Figure 11. Precharge Voltage Less Than 1V
GND
10
R11A
18
18
18
18
18
18
PRECHARGE OUT
R11A
=
4.7nF
C3
R11A + R11B
MEDIUM 5V
I/O PIN 128
LONG 3.3V
GROUND
LONG 5V
I/O PIN 1
R11A
U
24 , 5%
3.3V
9.09
7.15
5.36
3.65
1.78
R11B
R11B
LTC4240*
0
R9
PRECHARGE
• 1V
U
CONNECTOR
CompactPCI
BACKPLANE
18
(MALE)
V
0.9V
0.8V
0.7V
0.6V
0.5V
PRECHARGE
*ADDITIONAL DETAILS
OMITTED FOR CLARITY
W
DRIVE
MMBT2222A
CONNECTOR
CompactPCI
BACKPLANE
(FEMALE)
17
Q3
Figure 10. Precharge Application Circuit
16.2
14.7
12.1
9.09
R11A
11
12 , 5%
1k, 5%
R8
R7
2.74
1.74
R22
R21
DATA BUS
10 , 5%
10 , 5%
R
5V
3V
U
R
I0128
I01
IN
IN
3V
4240 F11
1.78
3.65
5.11
7.15
9.09
IN
R11B
21
22
5V
3V
PRECHARGE OUT
GND
IN
IN
*ADDITIONAL DETAILS OMITTED FOR CLARITY
I
10
OUT
18 , 5%
R11
Precharge resistors are used to connect the 1V bias
voltage to the CompactPCI connector I/O lines. This allows
live insertion of the I/O lines with minimal disturbance.
Figure 13 shows the precharge application circuit for 5V
signaling environments. The precharge resistor require-
ments are more stringent for 3.3V and Universal Hot Swap
signaling. If the total leakage current on the I/O line is less
1V 20%
= 55mA
PRECHARGE
18
V
R
10k
5%
PRECHARGE
Figure 12. Precharge Voltage Greater Than 1V
PRE1
4.7nF
C3
GND PRECHARGE
10
LTC4240*
24 , 5%
R11A
=
R
10k
5%
R9
PRE128
R11A + R11B
UP TO 128
I/O LINES
MMBT2222A
R11A
18
DRIVE
R11B
LTC4240*
Q3
PRECHARGE OUT
17
4.7nF
C3
• 1V
1k, 5%
I/O
I/O
12 , 5%
R8
24 , 5%
R7
R9
*ADDITIONAL DETAILS
OMITTED FOR CLARITY
BRIDGE
(21154)
PCI
DRIVE
MMBT2222A
4240 F10
3V
17
IN
Q3
12 , 5%
1k, 5%
R7
R8
3V
4240 F12
IN
4240f