MAX7323ATE Maxim Integrated, MAX7323ATE Datasheet - Page 13

• Manufacturer Part Number: MAX7323ATE
• Description: Interface - I/O Expanders I2C Port Expander w/4 P-P Out & 4 I/O
• Manufacturer: Maxim Integrated
• Series: MAX7323r

When driving LEDs from one of the four output ports
(O0, O1, O6, or O7), a resistor must be connected in
series with the LED to limit the LED current to no more
than 20mA. Connect the LED cathode to the MAX7323
port, and the LED anode to V+ through the series cur-
rent-limiting resistor, R
illuminate the LED. Choose the resistor value according
to the following formula:
where:
R
LED (Ω).
V
V
V
sinking I
I
For example, to operate a 2.2V red LED at 10mA from a
+5V supply:
LED
SUPPLY
LED
OL
LED
is the desired operating current of the LED (A).
is the output-low voltage of the MAX7323 when
is the forward voltage of the LED (V).
is the resistance of the resistor in series with the
LED
R
is the supply voltage used to drive the LED (V).
R
LED
LED
I
(V).
2
= (5 - 2.2 - 0.07) / 0.010 = 270Ω.
= (V
C Port Expander with 4 Push-Pull Outputs
______________________________________________________________________________________
SUPPLY
LED
. Set the port output low to
- V
SDA
SCL
LED
RST
AD0
AD2
Driving LED Loads
- V
OL
) / I
INPUT
FILTER
ON RESET
POWER-
LED
MAX7323
CONTROL
I
2
C
Figure 9. MAX7323 Push-Pull Output Port Structure
Figure 10. MAX7323 I/O Port Structure
and 4 Open-Drain I/Os
PULLUP
OUTPUT
ENABLE
INPUT
OUTPUT
MAX7323
PORTS
I/O
V+
V+
Functional Diagram
V+
O7
O0
O1
P2
P3
P4
P5
O6
INT
40kΩ
V+
G
MAX7323
D
S
PORTS
O0, O1, O6, O7
PORTS
P2–P5
13