PCA9512B(2011) Просмотр технического описания (PDF) - NXP Semiconductors.
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PCA9512B Datasheet PDF : 24 Pages
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NXP Semiconductors
PCA9512A; PCA9512B
Level shifting hot swappable I2C-bus and SMBus bus buffer
8.8 Hot swapping and capacitance buffering application
Figure 7 through Figure 9 illustrate the usage of the PCA9512A in applications that take
advantage of both its hot swapping and capacitance buffering features. In all of these
applications, note that if the I/O cards were plugged directly into the backplane, all of the
backplane and card capacitances would add directly together, making rise time and
fall time requirements difficult to meet. Placing a bus buffer on the edge of each card,
however, isolates the card capacitance from the backplane. For a given I/O card, the
PCA9512A drives the capacitance of everything on the card and the backplane must drive
only the capacitance of the bus buffer, which is less than 10 pF, the connector, trace, and
all additional cards on the backplane.
See Application Note AN10160, ‘Hot Swap Bus Buffer’ for more information on
applications and technical assistance.
BACKPLANE
VCC2
BACKPLANE
CONNECTOR
BD_SEL
VCC
SDA
SCL
R1
10 kΩ
R2
10 kΩ
POWER SUPPLY
I/O PERIPHERAL CARD 1
HOT SWAP
C1
0.01 μF
R4
10 kΩ
R3
5.1 Ω
PCA9512A
VCC VCC2 SDAOUT
SDAIN
SCLOUT
SCLIN
C2 0.01 μF
GND
ACC
R5
10 kΩ
R6
10 kΩ
CARD1_SDA
CARD1_SCL
POWER SUPPLY
I/O PERIPHERAL CARD 2
HOT SWAP
C3
0.01 μF
R8
10 kΩ
R7
5.1 Ω
PCA9512A
VCC VCC2 SDAOUT
SDAIN
SCLOUT
SCLIN
C4 0.01 μF
GND
ACC
R9
10 kΩ
R10
10 kΩ
CARD2_SDA
CARD2_SCL
POWER SUPPLY
I/O PERIPHERAL CARD N
HOT SWAP
C5
0.01 μF
R12
10 kΩ
R11
5.1 Ω
PCA9512A
VCC VCC2 SDAOUT
SDAIN
SCLOUT
SCLIN
C6 0.01 μF
GND
ACC
R13
10 kΩ
R14
10 kΩ
CARDN_SDA
CARDN_SCL
002aab791
Fig 7.
Remark: Application assumes bus capacitance within ‘proper operation’ region of Figure 5 and Figure 6.
Hot swapping multiple I/O cards into a backplane using the PCA9512A in a cPCI, VME, and AdvancedTCA
system
PCA9512A_PCA9512B
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 5 — 5 January 2011
© NXP B.V. 2011. All rights reserved.
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