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 MAX7319,
MAX7321, MAX7322, or MAX7323.
Functional Overview
The MAX7325 is a general-purpose port expander oper-
ating from a +1.71V to +5.5V supply with eight push-pull
outputs and eight open-drain I/O ports. Each open-drain
output is rated to sink 20mA, and the entire device is
rated to sink 100mA into all ports combined. The outputs
drive loads connected to supplies up to +5.5V.
The MAX7325 is set to two of 32 I
2
C slave addresses
(see Tables 2 and 3) using the address select inputs
AD0 and AD2, and is accessed over an I
2
C serial inter-
face up to 400kHz. The eight outputs and eight I/Os
have different slave addresses. The eight push-pull out-
puts have the 101xxxx addresses and the eight inputs
have addresses with 110xxxx. The RST input clears the
serial interface in case of a bus lockup, terminating any
serial transaction to or from the MAX7325.
Configure any port as a logic input by setting the port
output logic-high (logic-high for an open-drain output is
high impedance). When the MAX7325 is read through
the serial interface, the actual logic levels at the ports
are read back.
MAX7325
I
2
C Port Expander with 8 Push-Pull
and 8 Open-Drain I/Os
5
Maxim Integrated
PART
I
2
C
SLAVE
ADDRESS
INPUTS
INPUT
INTERRUPT
MASK
OPEN-
DRAIN
OUTPUTS
PUSH-
PULL
OUTPUTS
CONFIGURATION
16-PORT EXPANDERS
MAX7324 8 Yes — 8
8 input and 8 push-pull output versions:
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
identify which inputs have changed (even if only
for a transient) since the ports were last read.
MAX7325
101xxxx
and
110xxxx
Up to 8 — Up to 8 8
8 I/O and 8 push-pull output versions:
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.
Table 1. MAX7319–MAX7329 Family Comparison
