pca9547bs NXP Semiconductors, pca9547bs Datasheet - Page 8

• Manufacturer Part Number: pca9547bs
• Description: Pca9547 8-channel I2c-bus Multiplexer With Reset
• Manufacturer: NXP Semiconductors

Philips Semiconductors
PCA9547_2
Product data sheet
6.5 Voltage translation
The pass gate transistors of the PCA9547 are constructed such that the V
be used to limit the maximum voltage that will be passed from one I
Figure 7
PCA9547 is only tested at the points specified in
data sheet). In order for the PCA9547 to act as a voltage translator, the V
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
equal to or below 2.7 V to effectively clamp the downstream bus voltages. Looking at
Figure
3.5 V or lower so the PCA9547 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
More information can be found in Application Note AN262, PCA954X family of I
multiplexers and switches .
Fig 7. Pass gate voltage as a function of supply voltage
(1) maximum
(2) typical
(3) minimum
7, we see that V
shows the voltage characteristics of the pass gate transistors (note that the
V
Rev. 02 — 12 September 2006
o(mux)
(V)
o(mux)(max)
5.0
4.0
3.0
2.0
1.0
2.0
2.5
will be at 2.7 V when the PCA9547 supply voltage is
3.0
3.5
4.0
8-channel I
Section 10 “Static characteristics”
(1)
(2)
(3)
4.5
002aab802
5.0
V
2
DD
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
C-bus multiplexer with reset
(V)
5.5
2
C-bus to another.
PCA9547
Figure
o(mux)
o(mux)
DD
voltage can
14).
should be
2
voltage
C/SMBus
of this
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