MAX7327 Maxim, MAX7327 Datasheet - Page 5

• Manufacturer Part Number: MAX7327
• Description: The MAX7327, a 2-wire serial-interfaced peripheral, features 12 push-pull outputs and four configurable open-drain I/O ports with selectable internal pullups and transition detection
• Manufacturer: Maxim

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.
The MAX7327 is a general-purpose port expander
operating from a +1.71V to +5.5V supply that provides
12 push-pull output ports with a 20mA sink, 10mA
source drive capability, and four open-drain I/O ports
with a 20mA sink capability. The four open-drain out-
puts are overvoltage protected to +6V.
Table 1. MAX7319–MAX7329 Family Comparison
16-PORT EXPANDERS
MAX7324
MAX7325
PART
MAX7319–MAX7329 Family Comparison
ADDRESS
101xxxx
110xxxx
SLAVE
and
I
2
C
_______________________________________________________________________________________
Detailed Description
INPUTS
Up to 8
8
I
Functional Overview
2
INTERRUPT
C Port Expander with 12 Push-Pull
INPUT
MASK
Yes
—
Outputs and 4 Open-Drain I/Os
OUTPUTS
Up to 8
OPEN-
DRAIN
—
OUTPUTS
PUSH-
PULL
The MAX7327 is set to two of 32 I
(see Tables 2 and 3) using address inputs AD2 and
AD0, and is accessed over an I
400kHz. Eight push-pull outputs use a different slave
address from the other four push-pull outputs and the
open-drain I/Os. The eight push-pull outputs, O8–O15,
use the 101xxxx addresses while the four outputs O0,
O1, O6, and O7 and the open-drain I/Os P2–P5 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 MAX7327.
Any of the four open-drain ports can be configured as a
logic input by setting the port output logic-high (logic-
high for an open-drain output is high impedance).
When the MAX7327 is read through the serial interface,
the actual logic levels at the ports are read back.
8
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
identify which inputs have changed (even if only for
a transient) since the ports were last read.
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.
CONFIGURATION
2
C serial interface up to
2
C slave addresses
5