Datasheet
MAX7314
Driving Load Currents Higher than 50mA
The MAX7314 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 MAX7314 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 19). The
peak current through the diode is the inductive load’s
operating current.
Power-Supply Considerations
The MAX7314 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.
18-Port GPIO with LED Intensity Control,
Interrupt, and Hot-Insertion Protection
22 ______________________________________________________________________________________
Table 14. Output Intensity Registers (continued)
REGISTER DATA
REGISTER
ADDRESS
CODE
(hex)
D7 D6 D5 D4 D3 D2 D1 D0
MSB LSB MSB
LSB
OUTPUTS P9, P8 INTENSITY
R/W
OUTPUT P9 INTENSITY OUTPUT P8 INTENSITY
Write output P9, P8 intensity
0
Read back output P9, P8 intensity
1
0x14
P9I3 P9I2 P9I1 P9I0 P8I3 P8I2 P8I1
P8I0
MSB LSB MSB
LSB
OUTPUTS P11, P10 INTENSITY
OUTPUT P11 INTENSITY OUTPUT P10 INTENSITY
Write output P11, P10 intensity
0
Read back output P11, P10 intensity
1
0x15
P11I3 P11I2 P11I1 P11I0 P10I3 P10I2 P10I1
P10I0
MSB LSB MSB
LSB
OUTPUTS P13, P12 INTENSITY
OUTPUT P13 INTENSITY OUTPUT P12 INTENSITY
Write output P13, P12 intensity
0
Read back output P13, P12 intensity
1
0x16
P13I3 P13I2 P13I1 P13I0 P12I3 P12I2 P12I1
P12I0
MSB LSB MSB
LSB
OUTPUTS P15, P14 INTENSITY
OUTPUT P15 INTENSITY OUTPUT P14 INTENSITY
Write output P15, P14 intensity
0
Read back output P15, P14 intensity
1
0x17
P15I3 P15I2 P15I1 P15I0 P14I3 P14I2 P14I1
P14I0
OUTPUT O16 INTENSITY See master, O16 intensity register (Table 13).