TCA6424A
SCPS193B –JULY 2010–REVISED SEPTEMBER 2010
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DESCRIPTION/ORDERING INFORMATION (CONTINUED)
The bidirectional voltage level translation in the TCA6424A is provided through VCCI. VCCI should be connected to
the VCC of the external SCL/SDA lines. This indicates the VCC level of the I2C bus to the TCA6424A. The voltage
level on the P-port of the TCA6424A is determined by the VCCP
.
The TCA6424A consists of three 8-bit Configuration (input or output selection), Input, Output, and Polarity
Inversion (active high) registers. At power on, the I/Os are configured as inputs. However, the system master can
enable the I/Os as either inputs or outputs by writing to the I/O configuration bits. The data for each input or
output is kept in the corresponding input or output register. The polarity of the Input Port register can be inverted
with the Polarity Inversion register. All registers can be read by the system master.
The system master can reset the TCA6424A in the event of a timeout or other improper operation by asserting a
low in the RESET input. The power-on reset puts the registers in their default state and initializes the I2C/SMBus
state machine. The RESET pin causes the same reset/initialization to occur without depowering the part.
The TCA6424A open-drain interrupt (INT) output is activated when any input state differs from its corresponding
Input Port register state and is used to indicate to the system master that an input state has changed.
INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the
remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via
the I2C bus. Thus, the TCA6424A can remain a simple slave device.
The device P-port outputs have high-current sink capabilities for directly driving LEDs while consuming low
device current.
One hardware pin (ADDR) can be used to program and vary the fixed I2C address and allow up to two devices to
share the same I2C bus or SMBus.
ORDERING INFORMATION
TA
PACKAGE(1) (2)
Reel of 3000
TBD
ORDERABLE PART NUMBER
TOP-SIDE MARKING
QFN – RGJ
QFN – RSM
TCA6424ARGJR
PH424
TBD
–40°C to 85°C
TCA6424ARSMR
(1) Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
(2) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
2
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