MAX7323 Maxim, MAX7323 Datasheet - Page 14

• Manufacturer Part Number: MAX7323
• Description: The MAX7323 2-wire serial-interfaced peripheral features eight I/O ports
• Manufacturer: Maxim

I
and 4 Open-Drain I/Os
The MAX7323 can be used to drive loads, such as
relays, that draw more than 20mA by paralleling out-
puts. Use at least one output per 20mA of load current;
for example, a 5V, 330mW relay draws 66mA, and
therefore, requires four paralleled outputs. Any combi-
nation of outputs can be used as part of a load-sharing
design because any combination of ports can be set or
cleared at the same time by writing to the MAX7323. Do
not exceed a total sink current of 100mA for the device.
The MAX7323 must be protected from the negative volt-
age transient generated when switching off inductive
loads (such as relays), by connecting a reverse-biased
14
2
C Port Expander with 4 Push-Pull Outputs
______________________________________________________________________________________
Driving Load Currents Higher than 20mA
GND
AD0
AD2
RST
O0
O1
P2
P3
1
2
3
4
5
6
7
8
+
+
MAX7323
QSOP
16
15
14
13
12
11
10
9
V+
SDA
SCL
INT
O7
O6
P5
P4
diode across the inductive load. Choose the peak cur-
rent for the diode to be greater than the inductive load’s
operating current.
The MAX7323 operates with a supply voltage of +1.71V
to +5.5V over the -40°C to +125°C temperature range.
Bypass the supply to GND with a ceramic capacitor of
at least 0.047µF as close as possible to the device. For
the TQFN version, additionally connect the exposed
paddle to GND.
TOP VIEW
SDA
AD0
RST
V+
*EXPOSED PADDLE, CONNECTED TO GND
13
14
15
16
Power-Supply Considerations
+
12
1
*EP
+
MAX7323
Pin Configurations
11
TQFN
2
10
3
9
4
8
7
6
5
P5
P4
GND
P3