TCA6424_10 Datasheet, PDF (3/29 Pages) Texas Instruments – LOW-VOLTAGE 24-BIT I2C AND SMBus I/O EXPANDER WITH INTERRUPT OUTPUT, RESET, AND CONFIGURATION REGISTERS

TCA6424
www.ti.com
SCPS175A – NOVEMBER 2007 – REVISED NOVEMBER 2009
TERMINAL
PIN NO.
NAME
22
P25
23
P26
24
P27
25
GND
26
ADDR
27
V_CCP
28
RESET
29
SCL
30
SDA
31
V_CCI
32
INT
Table 1. TERMINAL FUNCTIONS (continued)
DESCRIPTION
P-port input/output (push-pull design structure). At power on, P25 is configured as an input.
P-port input/output (push-pull design structure). At power on, P26 is configured as an input.
P-port input/output (push-pull design structure). At power on, P27 is configured as an input.
Ground
Address input. Connect directly to V_CCP or ground.
Supply voltage of TCA6424 for P port
Active-low reset input. Connect to V_CCP through a pullup resistor, if no active connection is used.
Serial clock bus. Connect to V_CCI through a pullup resistor.
Serial data bus. Connect to V_CCI through a pullup resistor.
Supply voltage of I²C bus. Connect directly to the V_CC of the external I²C master. Provides voltage-level
translation.
Interrupt output. Connect to V_CCI through a pullup resistor.
Voltage Translation
Table 2 shows how to set up V_CC levels for the necessary voltage translation between the I²C bus and the
TCA6424.
Table 2. Voltage Translation
V_CCI (SDA AND SCL OF I²C MASTER)
(V)
V_CCP (P PORT)
(V)
1.8
1.8
1.8
2.5
1.8
3.3
1.8
5
2.5
1.8
2.5
2.5
2.5
3.3
2.5
5
3.3
1.8
3.3
2.5
3.3
3.3
3.3
5
5
1.8
5
2.5
5
3.3
5
5
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Product Folder Link(s): TCA6424
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