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DESCRIPTION/ORDERING INFORMATION (CONTINUED)

PCA9515A

SCPS150A – DECEMBER 2005 – REVISED JUNE 2006

The PCA9515A has an active-high enable (EN) input with an internal pullup, which allows the user to select

when the repeater is active. This can be used to isolate a badly behaved slave on power-up reset. It never

state only when the global bus and the repeater port are in an idle state, to prevent system failures.

The PCA9515A also can be used to run two buses: one at 5-V interface levels and the other at 3.3-V interface

levels, or one at 400-kHz operating frequency and the other at 100-kHz operating frequency. If the two buses

are operating at different frequencies, the 100-kHz bus must be isolated when the 400-kHz operation of the

other bus is required. If the master is running at 400 kHz, the maximum system operating frequency may be less

than 400 kHz, because of the delays that are added by the repeater.

The output low levels for each internal buffer are approximately 0.5 V, but the input voltage of each internal

buffer must be 70 mV or more below the output low level, when the output internally is driven low. This prevents

a lockup condition from occurring when the input low condition is released.

Two or more PCA9515A devices cannot be used in series. The PCA9515A design does not allow this

configuration. Because there is no direction pin, slightly different valid low-voltage levels are used to avoid

lockup conditions between the input and the output of each repeater. A valid low applied at the input of a

PCA9515A is propagated as a buffered low with a slightly higher value on the enabled outputs. When this

buffered low is applied to another PCA9515A-type device in series, the second device does not recognize it as a

valid low and does not propagate it as a buffered low again.

The device contains a power-up control circuit that sets an internal latch to prevent the output circuits from

depends on the system, but each side of the repeater must have a pullup resistor. The device is designed to

Under certain conditions, high termination currents can be used.

TERMINAL FUNCTIONS

NO.

NAME

DESCRIPTION

1

NC

No internal connection

2

SCL0

Serial clock bus 0

3

SDA0

Serial data bus 0

4

GND

Supply ground

5

EN

Active-high repeater enable input

6

SDA1

Serial data bus 1

7

SCL1

Serial clock bus 1

8

Supply power

FUNCTION TABLE

INPUT

FUNCTION

EN

L

Outputs disabled

SDA0 = SDA1,

H

SCL0 = SCL1

2

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