LM90CIMMX National Semiconductor, LM90CIMMX Datasheet - Page 13

• Manufacturer Part Number: LM90CIMMX
• Manufacturer: National Semiconductor

Specifications of LM90CIMMX

• Temperature Sensor Function: Temp Sensor
• Interface Type: Serial (2-Wire)
• Output Type: Digital
• Package Type: MSOP
• Operating Temperature (min): 0C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Lead Free Status / Rohs Status: Not Compliant

1.0 Functional Description
1.12 Fault Queue
In order to suppress erroneous ALERT or T_CRIT triggering
the LM90 incorporates a Fault Queue. The Fault Queue acts
to insure a remote temperature measurement is genuinely
beyond a HIGH, LOW or T_CRIT setpoint by not triggering
until three consecutive out of limit measurements have been
made, see Figure 10 . The fault queue defaults off upon
power-up and may be activated by setting bit D0 in the
Configuration register (09h) to “1”.
2.0 LM90 REGISTERS
2.1 COMMAND REGISTER
Selects which registers will be read from or written to. Data for this register should be transmitted during the Command Byte of
the SMBus write communication.
P0-P7: Command Select
Read Address
<
P7:P0
Command Select Address
00h
01h
02h
03h
04h
05h
06h
07h
08h
10h
12h
11h
NA
>
hex
Write Address
<
P7:P0
0Ch
0Dh
0Ah
0Bh
0Eh
0Fh
09h
11h
12h
NA
NA
NA
NA
>
hex
P7
<
P6
D7:D0
0000 0000
0000 0000
0000 0000
0000 0000
0000 1000
0000 0000
0000 0000
0000 0000
0000 0000
0000 0000
0100 0110
0100 0110
(Continued)
Power On Default State
>
P5
binary
Command Select
P4
8 (16 conv./sec)
13
<
P3
decimal
1.13 One-Shot Register
The One-Shot register is used to initiate a single conversion
and comparison cycle when the device is in standby mode,
after which the device returns to standby. This is not a data
register and it is the write operation that causes the one-shot
conversion. The data written to this address is irrelevant and
is not stored. A zero will always be read from this register.
D7:D0
70
70
0
0
0
0
0
0
0
0
0
FIGURE 10. Fault Queue Temperature Response
P2
>
P1
One Shot
Register
RHSHB
RTOHB
RLSHB
RTOLB
Name
RTHB
RTLB
LHS
LLS
SR
CR
LT
C
P0
Diagram
Local Temperature
Remote Temperature High Byte
Status Register
Configuration
Conversion Rate
Local HIGH Setpoint
Local LOW Setpoint
Remote HIGH Setpoint High
Byte
Remote LOW Setpoint High
Byte
Writing to this register will
initiate a one shot conversion
Remote Temperature Low Byte
Remote Temperature Offset
High Byte
Remote Temperature Offset
Low Byte
Register Function
20033730
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