MAX7313 Maxim, MAX7313 Datasheet - Page 24

• Manufacturer Part Number: MAX7313
• Description: The MAX7313 I²C-compatible serial interfaced peripheral provides microprocessors with 16 I/O ports
• Manufacturer: Maxim

The MAX7313 can be used to drive loads drawing more
than 50mA, like relays and high-current white LEDs, by
paralleling outputs. Use at least one output per 50mA of
load current; for example, a 5V 330mW relay draws
66mA and needs two paralleled outputs to drive it.
Ensure that the paralleled outputs chosen are controlled
by the same blink phase register, i.e., select outputs
from the P0 through P7 range, or the P8 through P15
range. This way, the paralleled outputs are turned on
and off together. Do not use output O16 as part of a
load-sharing design. O16 cannot be switched at the
same time as any of the other outputs because it is con-
trolled by a different register.
The MAX7313 must be protected from the negative
voltage transient generated when switching off induc-
tive loads, such as relays, by connecting a reverse-
biased diode across the inductive load (Figure 18). The
peak current through the diode is the inductive load’s
operating current.
The MAX7313 operates with a power-supply voltage of
2V to 3.6V. Bypass the power supply to GND with at
least 0.047µF as close to the device as possible.
For the QFN version, connect the underside exposed
pad to GND.
16-Port I/O Expander with LED Intensity
Control, Interrupt, and Hot-Insertion Protection
24
Driving Load Currents Higher than 50mA
______________________________________________________________________________________
Power-Supply Considerations
Figure 18. Diode-Protected Switching Inductive Load
µC
0.047µF
SDA
SCL
I/O
2V TO 3.6V
SDA
SCL
INT/O16
AD0
AD1
AD2
V+
MAX7313
GND
P10
P11
P12
P13
P14
P15
P0
P1
P2
P3
P4
P5
P6
P7
P8
P9
BAS16
5V