Datasheet
LTC1646
15
1646fa
Figure 10. 3.3V Supply Only Typical Application
Figure 8. Precharge Voltage <1V Application Circuit
APPLICATIO S I FOR ATIO
WUUU
MMBT2222A
4.7nF
18Ω
18Ω
10Ω
10Ω
3k
3k
1k
0.005Ω
1%
1k
12Ω
1k
10k
1k
3k
1.2k
3V
IN
PRECHARGE OUT
1V ±10%
I
OUT
= ± 55mA
3V
IN
3V
IN
3V
SENSE
5V
SENSE
3V
OUT
3V
OUT
5V
OUT
3.3V
5V
IN
RESET#
I/O
PCI
BRIDGE
(21154)
DATA BUS
DATA LINE EXAMPLE
V(I/O)
V(I/O)
0.1µF
0.1µF
0.010µF
IRF7413
LOCAL_PCI_RST#
3.3V
OUT
7.6A
GATE
GND PRECHARGE DRIVE
RESETOUT
TIMER
OFF/ON
FAULT
PWRGD
RESETIN
LTC1646
15
891071211 5
2
1
613 14
3
4
16
1646 F10
Z1: BZX84C6V2
Z1
DATA BUS
BD_SEL#
HEALTHY#
PCI_RST#
COMPACT PCI
BACKPLANE
CONNECTOR
(MALE)
COMPACT PCI
CIRCUIT CARD
CONNECTOR
(FEMALE)
3.3V
LONG 3.3V
GROUND
I/O PIN 1
4
3
21
1.8Ω
MMBT2222A
4.7nF
18Ω
R1
R2
1k
12Ω
3V
IN
PRECHARGE OUT
1646 F08
GND PRECHARGE DRIVE
LTC1646*
61314
*ADDITIONAL DETAILS OMITTED FOR CLARITY
V
PRECHARGE
=
• 1V
R1
R1 + R2
MMBT2222A
4.7nF
18Ω
R1 R2
1k
12Ω
3V
IN
PRECHARGE OUT
1646 F09
GND PRECHARGE DRIVE
LTC1646*
613 14
*ADDITIONAL DETAILS OMITTED FOR CLARITY
V
PRECHARGE
=
• 1V
R1 + R2
R1
Figure 9. Precharge Voltage >1V Application Circuit
Other CompactPCI Applications
The LTC1646 can be easily configured for applications
where no 5V supply is present by simply tying the 5V
IN
and
5V
SENSE
pins to the 3V
IN
pin and tying the 5V
OUT
pin to the
3V
OUT
pin (Figure 10).
Table 5. R1 and R2 Resistor Values vs Precharge Voltage
V
PRECHARGE
R1 R2 V
PRECHARGE
R1 R2
1.5V 18Ω 9.09Ω 0.9V 16.2Ω 1.78Ω
1.4V 18Ω 7.15Ω 0.8V 14.7Ω 3.65Ω
1.3V 18Ω 5.36Ω 0.7V 12.1Ω 5.11Ω
1.2V 18Ω 3.65Ω 0.6V 11Ω 7.15Ω
1.1V 18Ω 1.78Ω 0.5V 9.09Ω 9.09Ω
1V 18Ω 0Ω