pca9519bs NXP Semiconductors, pca9519bs Datasheet - Page 4

• Manufacturer Part Number: pca9519bs
• Description: 4-channel Level Translating I2c-bus/smbus Repeater
• Manufacturer: NXP Semiconductors

NXP Semiconductors
6. Functional description
PCA9519_2
Product data sheet
Table 2.
[1]
[2]
Refer to
The PCA9519 enables I
without degradation of system performance. The PCA9519 contains 8 bidirectional
open-drain buffers specifically designed to support up-translation/down-translation
between the low voltage and 3.3 V SMBus or 5 V I
tolerant to 5.5 V even when the device is unpowered.
The PCA9519 includes a power-up circuit that keeps the output drivers turned off until
V
any sequence at power-up. After power-up and with the EN pin HIGH, a LOW level on the
port A (below approximately 0.15 V) turns the corresponding port B driver (either SDA or
SCL) on and drives the port B down to about 0 V. When port A rises above approximately
0.15 V, the port B pull-down driver is turned off and the external pull-up resistor pulls the
pin HIGH. When the port B falls first and goes below 0.3V
on and the port A pulls down to 0.2 V (typical). The port B pull-down is not enabled unless
the port A voltage goes below V
pull-down driver is enabled until the port A rises above approximately 0.15 V (V
the port B, if not externally driven LOW, will continue to rise being pulled up by the
external pull-up resistor.
Remark: Ground offset between the PCA9519 ground and the ground of devices on
port A of the PCA9519 must be avoided.
The reason for this cautionary remark is that a CMOS/NMOS open-drain capable of
sinking 3 mA of current at 0.4 V will have an output resistance of 133
Such a driver will share enough current with the port A output pull-down of the PCA9519
to be seen as a LOW as long as the ground offset is zero. If the ground offset is greater
than 0 V, then the driver resistance must be less. Since V
cold temperatures and the low end of the current distribution, the maximum ground offset
should not exceed 50 mV.
Bus repeaters that use an output offset are not interoperable with port A of the PCA9519
as their output LOW levels will not be recognized by the PCA9519 as a LOW. If the
PCA9519 is placed in an application where the V
go below its V
but port B will return HIGH, so it will not reproduce the port A input on port B. Such
applications should be avoided.
Symbol
B1
n.c.
CC(B)
HVQFN package die supply ground is connected to both the GND pin and the exposed center pad. The
GND pin must be connected to supply ground for proper device operation. For enhanced thermal, electrical,
and board-level performance, the exposed pad needs to be soldered to the board using a corresponding
thermal pad on the board, and for proper heat conduction through the board thermal vias need to be
incorporated in the PCB in the thermal pad region.
Port A and port B can be used for either SCL or SDA.
is above 2.5 V and the V
Figure 1 “Functional diagram of
Pin description
Pin
TSSOP20
2
-
ILc
it will pull the port B LOW initially when the port A input transitions LOW
Rev. 02 — 13 August 2007
2
HVQFN24
19
8, 9, 20, 21
C-bus or SMBus translation down to V
…continued
CC(A)
ILc
. If the port A low voltage goes below V
4-channel level translating I
Description
B1 port (SMBus/I
is above 0.8 V. V
PCA9519”.
IL
2
of the port A of the PCA9519 does not
C-bus. Port B I/Os are over-voltage
2
C-bus side)
CC(B)
ILc
CC(B)
and V
can be as low as 90 mV at
, the port A driver is turned
CC(A)
[2]
2
CC(A)
C-bus/SMBus repeater
as low as 1.0 V
PCA9519
can be applied in
© NXP B.V. 2007. All rights reserved.
or less (R = E / I).
ILc
, the port B
ILc
), then
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