MAX31911AUI+ Maxim Integrated, MAX31911AUI+ Datasheet - Page 9

• Manufacturer Part Number: MAX31911AUI+
• Description: Serializers & Deserializers - Serdes Octal Industrial Digital Serializer
• Manufacturer: Maxim Integrated
• Type: Serializerr

Specifications of MAX31911AUI+

• Rohs: yes
• Data Rate: 1 Mbit/s
• Input Type: Industrial Digital (IEC 61131-2 Types 1, 2, 3)
• Output Type: CMOS
• Number Of Inputs: 8
• Number Of Outputs: 1
• Operating Supply Voltage: 10 V to 36 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: TSSOP-28
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Part # Aliases: 90-31911+000

The filtered outputs of the input comparators are
latched into a shift register at the falling edge of CS.
Clocking the CLK pin, while CS is held low, shifts the
latched data out of SOUT 1 bit at a time.
The internal data serializer comprises a 16-bit shift
register, containing 8 bits of data corresponding to
the eight field inputs, as well as an 8-bit status byte
containing supplementary status and CRC informa-
tion. The status byte contains 1 bit representing the
status of the field-supply voltage (UV), 1 bit represent-
ing the status of the internal temperature monitor (OT),
a 5-bit CRC code internally calculated and generated,
and a trailing 1 as a STOP bit.
The undervoltage (UV) bit is normally 0. If the supply
voltage falls below V
The UV bit returns to 0 once the supply voltage has
returned above V
The overtemperature (OT) bit is also normally 0. If the
junction temperature increases to above T
OT bit becomes a 1. The bit returns to 0 once the junc-
tion temperature has returned below T
The CRC code can be used to check data integrity during
transfer from the device to an external microcontroller. In
applications where the integrity of data transferred is not
of concern, the CRC bits can be ignored. The CRC uses
the following polynomial:
The number of bits in the internal serializer can be
selected between 8 bits or 16 bits. The MODESEL
pin is used to configure the serializer as an 8-bit
(disabling the status byte) or 16-bit shift register.
Table 1. Debounce Settings
Maxim Integrated
DB1
0
0
1
1
P(x) = x
ONUVLO
OFFUVLO
5
+ x
.
4
Reading Serial Data
+ x
, the UV becomes a 1.
2
+ x
0
ALRM
DB0
0
1
0
1
ALRM
.
Industrial, Octal, Digital Input
, the
In 8-bit mode, only the eight field input states are
transferred through the SPI port and the status byte is
ignored. Therefore, in multiple IC applications (input
channels greater than 8), if desired, only a single
status byte can be generated and transmitted for any
number of input channels.
The shift register contents are read only (no write
capability
interface.
For higher input counts than 8, multiple devices can
be cascaded. In this case, the SOUT pin of one device
should be connected to the SIN pin of the next device,
effectively cascading the internal shift registers. The
CLK and CS pins of all the devices should be con-
nected together in this configuration. See the
Port Operation
on operating the SPI interface.
The internal junction temperature of the device is con-
stantly monitored. An alarm is raised, by asserting the
FAULT pin, if the temperature rises above T
tion to asserting FAULT, the device sets the OT bit to a 1.
A supply voltage monitor circuit constantly monitors
the field-supply voltage. If this voltage falls below a
threshold (V
the FAULT pin, indicating that the part is experiencing
a fault condition and the data in the serializer is not
to be trusted. In addition, the device sets the UV bit
to a 1. Once the field-supply voltage has recovered
and goes above V
indicating normal operation of the part.
BINARY VALUE
Translator/Serializer
0
1
2
3
OFFUVLO
exists)
section for more detailed information
ONUVLO
), an alarm is raised by asserting
Supply Voltage Monitoring
through
Temperature Monitoring
, the FAULT pin is released,
MAX31911
DEBOUNCE TIME
the
0.75ms
25Fs
SPI-compatible
3ms
0
ALRM
. In addi-
Serial-
9