pca9548ad NXP Semiconductors, pca9548ad Datasheet - Page 8

• Manufacturer Part Number: pca9548ad
• Description: 8-channel I2c Switch With Reset
• Manufacturer: NXP Semiconductors

Philips Semiconductors
PCA9548A_2
Product data sheet
6.5 Voltage translation
The pass gate transistors of the PCA9548A are constructed such that the V
be used to limit the maximum voltage that will be passed from one I
Figure 7
PCA9548A is only tested at the points specified in
this data sheet). In order for the PCA9548A to act as a voltage translator, the V
voltage should be equal to, or lower than the lowest bus voltage. For example, if the main
bus was running at 5 V, and the downstream buses were 3.3 V and 2.7 V, then V
should be equal to or below 2.7 V to effectively clamp the downstream bus voltages.
Looking at
voltage is 3.5 V or lower, so the PCA9548A supply voltage could be set to 3.3 V. Pull-up
resistors can then be used to bring the bus voltages to their appropriate levels (see
Figure
More Information can be found in Application Note AN262: PCA954X family of I
multiplexers and switches .
Fig 7. Pass gate voltage versus supply voltage
(1) maximum
(2) typical
(3) minimum
14).
shows the voltage characteristics of the pass gate transistors (note that the
Figure
7, we see that V
V
Rev. 02 — 25 September 2006
o(sw)
(V)
5.0
4.0
3.0
2.0
1.0
2.0
2.5
o(sw)(max)
3.0
3.5
will be at 2.7 V when the PCA9548A supply
4.0
(1)
(2)
(3)
Section 10 “Static characteristics”
4.5
8-channel I
002aaa964
5.0
V
DD
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
(V)
5.5
2
C-bus switch with reset
PCA9548A
2
C-bus to another.
DD
voltage can
2
o(sw)
C/SMBus
o(sw)
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