1. General description
The PCA9516A is a CMOS integrated circuit intended for application in I
2
C-bus and
SMBus systems.
While retaining all the operating modes and features of the I
2
C-bus system, it permits
extension of the I
2
C-bus by buffering both the data (SDAn) and the clock (SCLn) lines,
thus enabling five buses of 400 pF.
The I
2
C-bus capacitance limit of 400 pF restricts the number of devices and bus length.
Using the PCA9516A enables the system designer to divide the bus into five segments off
of a hub where any segment-to-segment transition sees only one repeater delay.
It can also be used to run different buses at 5 V and 3.3 V or 400 kHz and 100 kHz buses
where the 100 kHz bus is isolated when 400 kHz operation of the other bus is required.
Two or more PCA9516As cannot be put in series. The PCA9516A design does not
allow this configuration. Since there is no direction pin, slightly different ‘legal’ low voltage
levels are used to avoid lock-up conditions between the input and the output of each
repeater in the hub. A ‘regular LOW’ applied at the input of a PCA9516A will be
propagated as a ‘buffered LOW’ with a slightly higher value on all the enabled outputs.
When this ‘buffered LOW’ is applied to another PCA9515A, PCA9516A, or PCA9518A in
series, the second PCA9515A, PCA9516A, or PCA9518A will not recognize it as a
‘regular LOW’ and will not propagate it as a ‘buffered LOW’ again. The
PCA9510A/9511A/9513A/9514A and PCA9512A cannot be used in series with the
PCA9515A, PCA9516A, or PCA9518A, but can be used in series with themselves since
they use shifting instead of static offsets to avoid lock-up conditions.
2. Features
n 5 channel, bidirectional buffer
n I
2
C-bus and SMBus compatible
n Active HIGH individual repeater enable input
n Open-drain input/outputs
n Lock-up free operation
n Supports arbitration and clock stretching across the repeater
n Accommodates Standard-mode and Fast-mode I
2
C-bus devices and multiple masters
n Powered-off high-impedance I
2
C-bus pins
n Operating supply voltage range of 2.3 V to 3.6 V
n 5.5 V tolerant I
2
C-bus and enable pins
PCA9516A
5-channel I
2
C-bus hub
Rev. 03 — 23 April 2009 Product data sheet
