pca9544ad NXP Semiconductors, pca9544ad Datasheet - Page 6

• Manufacturer Part Number: pca9544ad
• Description: Pca9544a 4-channel I2c Multiplexer With Interrupt Logic
• Manufacturer: NXP Semiconductors

Philips Semiconductors
VOLTAGE TRANSLATION
The pass gate transistors of the PCA9544A are constructed such
that the V
will be passed from one I
2004 Sep 29
V
4-channel I
pass
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2.0
DD
voltage can be used to limit the maximum voltage that
2.5
Figure 6. V
TYPICAL
2
C multiplexer with interrupt logic
3.0
2
C-bus to another.
V
pass
MAXIMUM
3.5
pass
vs. V
DD
voltage
V
4.0
DD
4.5
MINIMUM
5.0
SW00820
5.5
6
Figure 6 shows the voltage characteristics of the pass gate
transistors (note that the graph was generated using the data
specified in the DC Characteristics section of this datasheet). In
order for the PCA9544A 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
2.7 V to effectively clamp the downstream bus voltages. Looking at
Figure 6, we see that V
PCA9544A supply voltage is 3.5 V or lower so the PCA9544A
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 13).
More Information can be found in Application Note AN262 PCA954X
family of I
2
C/SMBus multiplexers and switches.
pass
(max.) will be at 2.7 V when the
pass
should be equal to or below
PCA9544A
Product data sheet
pass