pca9518a NXP Semiconductors, pca9518a Datasheet - Page 6

• Manufacturer Part Number: pca9518a
• Description: Pca9518a Expandable 5-channel I?c-bus Hub
• Manufacturer: NXP Semiconductors

NXP Semiconductors
7. Application design-in information
PCA9518A_1
Product data sheet
Fig 5. Typical application: multiple expandable 5-channel I
SUBSYSTEM 5
SUBSYSTEM 6
not connected
100 kHz
400 kHz
disabled;
Only two of the five channels on the PCA9518A Device 2 are being used. EN3 and EN4 are connected to V
channels 3 and 4 and/or SDA3/SCL3 and SDA4/SCL4 are pulled up to V
I
2
C-bus port, but if unused then it must be pulled up to V
SDA
SDA
SCL
SCL
3.3 V
5 V
or 5 V
or 5 V
3.3 V
3.3 V
A typical application is shown in
on a 3.3 V I
100 kHz unless slave 3, slave 4 and slave 5 are isolated from the bus. Then the master
bus and slave 1, slave 2 and slave 6 can run at 400 kHz.
Any segment of the hub can talk to any other segment of the hub. Bus masters and slaves
can be located on any segment with 400 pF load allowed on each segment.
The PCA9518A is 5 V tolerant, so it does not require any additional circuitry to translate
between the different bus voltages.
When one port of the PCA9518A is pulled LOW by a device on the I
hysteresis type input detects the falling edge and drives the EXPxxx1 line LOW, when the
EXPxxx1 voltage is less than 0.5V
PCA9518A which is typically 0.5 V.
SDA1
SCL1
SDA2
SCL2
SDA3
SCL3
SDA4
SCL4
PCA9518A
DEVICE 2
V
V
DD
EXPSDA1
EXPSDA2
SS
EXPSCL1
EXPSCL2
2
SDA0
SCL0
C-bus while the slaves are connected to a 3.3 V or 5 V bus. All buses run at
EN1
EN2
EN3
EN4
Rev. 01 — 6 June 2007
3.3 V
DD
MASTER
400 kHz
Figure
BUS
since there is no enable pin.
DD
SDA
SCL
2
, the other ports are pulled down to the V
C-bus hubs
5. In this example, the system master is running
DD
. SDA0 and SCL0 can be used as a normal
EXPSDA1
EXPSDA2
EXPSCL1
EXPSCL2
SDA0
SCL0
EN1
EN2
EN3
EN4
Expandable 5-channel I
PCA9518A
DEVICE 1
V
V
DD
SS
SDA1
SDA2
SDA3
SDA4
SCL1
SCL2
SCL3
SCL4
PCA9518A
2
C-bus, a CMOS
3.3 V
3.3 V
5 V
5 V
© NXP B.V. 2007. All rights reserved.
SS
to disable
SDA
SCL
SDA
SCL
SDA
SCL
SDA
SCL
SUBSYSTEM 1
SUBSYSTEM 2
SUBSYSTEM 3
SUBSYSTEM 4
2
OL
C-bus hub
400 kHz
400 kHz
100 kHz
100 kHz
002aac535
of the
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