PCA9508D,118 NXP Semiconductors, PCA9508D,118 Datasheet - Page 6

• Manufacturer Part Number: PCA9508D,118
• Description: IC I2C/SMBUS BIDIR-REPEAT 8SOIC
• Manufacturer: NXP Semiconductors
• Type: Repeaterr

Specifications of PCA9508D,118

• Package / Case: 8-SOIC (3.9mm Width)
• Tx/rx Type: I²C Logic
• Delay Time: 170ns
• Capacitance - Input: 5.2pF
• Voltage - Supply: 2.7 V ~ 5.5 V
• Current - Supply: 170mA
• Mounting Type: Surface Mount
• Logic Family: SDA, SCL
• Propagation Delay Time: 170 ns
• Operating Supply Voltage: 0.9 V to 5.5 V
• Power Dissipation: 100 mW
• Operating Temperature Range: - 40 C to + 85 C
• Logic Type: I2C Bus
• Mounting Style: SMD/SMT
• Output Voltage: 0.52 V
• Function: I2C Bus Repeater
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: SO
• Pin Count: 8
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 935285665118; PCA9508D-T; PCA9508D-T

NXP Semiconductors
7. Application design-in information
PCA9508_1
Product data sheet
6.5 I
As with the standard I
HIGH levels on the buffered bus (standard open-collector configuration of the I
The size of these pull-up resistors depends on the system, but each side of the repeater
must have a pull-up resistor. This part designed to work with Standard-mode and
Fast-mode I
only specify 3 mA output drive; this limits the termination current to 3 mA in a generic
I
certain conditions higher termination currents can be used.
Please see application note AN255, I
additional information on sizing resistors and precautions when using more than one
PCA9508 in a system or using the PCA9508 in conjunction with other bus buffers.
A typical application is shown in
on a 3.3 V I
Master devices can be placed on either bus.
The PCA9508 is 5 V tolerant, so it does not require any additional circuitry to translate
between 0.9 V to 5.5 V bus voltages and 2.7 V to 5.5 V bus voltages.
When the A side of the PCA9508 is pulled LOW by a driver on the I
detects the falling edge when it goes below 0.5V
B side to turn on, causing the B side to pull down to about 0.5 V. When the B side of the
PCA9508 falls, first a CMOS hysteresis type input detects the falling edge and causes the
internal driver on the A side to turn on and pull the A side pin down to ground. In order to
illustrate what would be seen in a typical application, refer to
bus master in
in
except that the HIGH level may be as low as 0.9 V, and the turn on and turn off of the
acknowledge signals are slightly delayed.
2
2
Fig 4.
C-bus system where Standard-mode devices and multiple masters are possible. Under
C-bus systems
Figure 7
Typical application
would be observed on the A bus. This looks like a normal I
2
2
C-bus while the slave is connected to a 1.2 V bus. Both buses run at 400 kHz.
C-bus devices in addition to SMBus devices. Standard-mode I
Figure 4
MASTER
400 kHz
BUS
2
SDA
SCL
C-bus system, pull-up resistors are required to provide the logic
were to write to the slave through the PCA9508, waveforms shown
Rev. 01 — 28 April 2008
10 k
bus B
3.3 V
Figure
10 k
2
SDAB
SCLB
EN
Hot swappable level translating I
C/SMBus Repeaters, Hubs and Expanders for
V
4. In this example, the system master is running
CC(B)
PCA9508
V
CC(A)
CC(A)
SDAA
SCLA
10 k
and causes the internal driver on the
bus A
1.2 V
10 k
Figure 7
SDA
SCL
400 kHz
SLAVE
002aac654
2
C-bus, a comparator
2
C-bus transmission
and
PCA9508
© NXP B.V. 2008. All rights reserved.
2
C-bus repeater
2
Figure
C-bus devices
2
C-bus).
8. If the
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