PCA9515 Philips Semiconductors (Acquired by NXP), PCA9515 Datasheet - Page 4

• Manufacturer Part Number: PCA9515
• Description: PCA9515; I2C Bus Repeater
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
APPLICATION INFORMATION
A typical application is shown in Figure 3. In this example, the
system master is running on a 3.3 V I
connected to a 5 V bus. Both buses run at 100 kHz unless the slave
bus is isolated and then the master bus can run at 400 kHz. Master
devices can be placed on either bus.
2002 May 13
I
2
BUS
MASTER
400 kHz
C bus repeater
V
OL
SDA
SCL
OF MASTER
3.3 V
Figure 3. Typical application
BUS0
SDA0
SCL0
EN
PCA9515
SDA1
SCL1
2
C-bus while the slave is
9th CLOCK PULSE
BUS1
5 V
SDA
SCL
SLAVE
100 kHz
Figure 4. Bus 0 waveform
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4
The PCA9515 is 5 V tolerant so it does not require any additional
circuitry to translate between the different bus voltages.
When one side of the PCA9515 is pulled low by a device on the
I
causes an internal driver on the other side to turn on, thus causing
the other side to also go low. The side driven low by the PCA9515
will typically be at V
In order to illustrate what would be seen in a typical application,
refer to Figure 4 and 5. If the bus master in Figure 3 were to write to
the slave through the PCA9515, we would see the waveform shown
in Figure 4 on Bus 0. This looks like a normal I
the falling edge of the 8th clock pulse. At that point, the master
releases the data line (SDA) while the slave pulls it low through the
PCA9515. Because the V
0.5 V, a step in the SDA will be seen. After the master has
transmitted the 9th clock pulse, the slave releases the data line.
2
C-bus, a CMOS hysteresis type input detects the falling edge and
OL
= 0.5 V.
OL
of the PCA9515 is typically around
V
OL
OF PCA9515
2 V/DIV
2
C transmission until
PCA9515
Product data
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