PCA9517AD,112 NXP Semiconductors, PCA9517AD,112 Datasheet - Page 4

• Manufacturer Part Number: PCA9517AD,112
• Description: IC I2C BUS REPEATER 8-SOIC
• Manufacturer: NXP Semiconductors
• Type: Repeaterr

Specifications of PCA9517AD,112

• Tx/rx Type: I²C Logic
• Delay Time: 170ns
• Capacitance - Input: 6pF
• Voltage - Supply: 2.7 V ~ 5.5 V
• Current - Supply: 5mA
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935285763112; PCA9517AD; PCA9517AD

NXP Semiconductors
6. Functional description
PCA9517A_2
Product data sheet
6.1 Enable
6.2 I
Refer to
The PCA9517A enables I
without degradation of system performance. The PCA9517A contains two bidirectional
open-drain buffers specifically designed to support up-translation/down-translation
between the low voltage (as low as 0.9 V) and a 3.3 V or 5 V I
and I/Os are overvoltage tolerant to 5.5 V even when the device is unpowered (V
and/or V
drivers turned off until V
V
(EN) HIGH, a LOW level on port A (below 0.3V
(either SDA or SCL) on and drives port B down to about 0.5 V. When port A rises above
0.3V
the pin HIGH. When port B falls first and goes below 0.3V
on and port A pulls down to 0 V. The port B pull-down is not enabled unless the port B
voltage goes below 0.4 V. If the port B low voltage does not go below 0.5 V, the port A
driver will turn off when port B voltage is above 0.7V
below 0.4 V, the port B pull-down driver is enabled and port B will only be able to rise to
0.5 V until port A rises above 0.3V
the external pull-up resistor. The V
the port A input comparators and for the power good detect circuit. The PCA9517A logic
and all I/Os are powered by the V
The EN pin is active HIGH with an internal pull-up to V
when the repeater is active. This can be used to isolate a badly behaved slave on
power-up until after the system power-up reset. It should never change state during an
I
enabling part way through a bus cycle could confuse the I
The enable pin should only change state when the global bus and the repeater port are in
an idle state to prevent system failures.
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
specify 3 mA output drive; this limits the termination current to 3 mA in a generic I
system where Standard-mode devices and multiple masters are possible. Under 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
PCA9517A in a system or using the PCA9517A in conjunction with other bus buffers.
2
2
CC(A)
C-bus operation because disabling during a bus operation will hang the bus and
C-bus systems
CC(A)
can be applied in any sequence at power-up. After power-up and with the enable
2
C-bus devices in addition to SMBus devices. Standard mode I
Figure 1 “Functional diagram of
CC(A)
, the port B pull-down driver is turned off and the external pull-up resistor pulls
= 0 V). The PCA9517A includes a power-up circuit that keeps the output
2
C-bus system, pull-up resistors are required to provide the logic
CC(B)
Rev. 02 — 5 May 2008
2
C-bus or SMBus translation down to V
is above 2.5 V and the V
CC(B)
CC(A)
CC(A)
2
, then port B will continue to rise being pulled up by
C/SMBus Repeaters, Hubs and Expanders for
pin.
is only used to provide the 0.3V
PCA9517A”.
CC(A)
) turns the corresponding port B driver
CC(B)
Level translating I
CC(A)
CC(B)
. If the port B low voltage goes
2
CC(B)
C-bus parts being enabled.
is above 0.8 V. V
and allows the user to select
2
C-bus or SMBus. All inputs
the port A driver is turned
CC(A)
PCA9517A
2
C-bus devices only
as low as 0.9 V
© NXP B.V. 2008. All rights reserved.
CC(A)
2
C-bus repeater
CC(B)
reference to
2
C-bus).
CC(B)
and
2
C-bus
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