Detailed Description
MAX7319–MAX7329 Family Comparison
The MAX7324–MAX7327 family consists of four pin-
compatible, 16-port expanders that integrate the func-
tions of the MAX7320 and one of either the MAX7319,
MAX7321, MAX7322, or MAX7323.
Functional Overview
The MAX7326 is a general-purpose port expander
operating from a +1.71V to +5.5V supply that provides
12 push-pull output ports with 20mA sink, 10mA source
drive capability, and four CMOS input ports that are
overvoltage protected to +6V. The MAX7326 is rated to
sink a total of 100mA and source a total of 50mA from
all 12 combined outputs.
The MAX7326 is set to two of 32 I
2
C slave addresses
(see Tables 2 and 3) using address inputs AD0 and
AD2, and is accessed over an I
2
C serial interface up to
400kHz. Eight outputs use a different slave address
from the other four outputs and four inputs. Eight push-
pull outputs, O8–O15, use the 101xxxx addresses while
the four outputs O0, O1, O6, and O7 and inputs I2–I5
use addresses with 110xxxx. The RST input clears the
serial interface in case of a bus lockup, terminating any
serial transaction to or from the MAX7326.
MAX7326
I
2
C Port Expander with 12 Push-Pull Outputs
and 4 Inputs
_______________________________________________________________________________________ 5
8 Yes — 8
8 inputs and 8 push-pull outputs version:
8 input ports with programmable latching transition
detection interrupt and selectable pullups.
8 push-pull outputs with selectable default logic
levels.
Offers maximum versatility for automatic input
monitoring. An interrupt mask selects which inputs
cause an interrupt on transitions, and transition flags
— Up to 8 8
8 I/O and 8 push-pull outputs version:
8 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.
8 push-pull outputs with selectable default logic
levels.
Open-drain outputs can level shift the logic-high
state to a higher or lower voltage than V+ using
external pullup resistors, but pullups draw current
when output is low. Any open-drain port can be used
as an input by setting the open-drain output to logic-
high. Transition flags identify which open-drain port
inputs have changed (even if only for a transient)
since the ports were last read.
