Datasheet

TCA6424
www.ti.com SCPS175A –NOVEMBER 2007–REVISED NOVEMBER 2009
Table 1. TERMINAL FUNCTIONS (continued)
TERMINAL
DESCRIPTION
PIN NO. NAME
22 P25 P-port input/output (push-pull design structure). At power on, P25 is configured as an input.
23 P26 P-port input/output (push-pull design structure). At power on, P26 is configured as an input.
24 P27 P-port input/output (push-pull design structure). At power on, P27 is configured as an input.
25 GND Ground
26 ADDR Address input. Connect directly to V
CCP
or ground.
27 V
CCP
Supply voltage of TCA6424 for P port
28 RESET Active-low reset input. Connect to V
CCP
through a pullup resistor, if no active connection is used.
29 SCL Serial clock bus. Connect to V
CCI
through a pullup resistor.
30 SDA Serial data bus. Connect to V
CCI
through a pullup resistor.
Supply voltage of I
2
C bus. Connect directly to the V
CC
of the external I
2
C master. Provides voltage-level
31 V
CCI
translation.
32 INT 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 I
2
C bus and the
TCA6424.
Table 2. Voltage Translation
V
CCI
(SDA AND SCL OF I
2
C MASTER) V
CCP
(P PORT)
(V) (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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