LM75BIMMX-3+ Maxim Integrated Products, LM75BIMMX-3+ Datasheet - Page 5

• Manufacturer Part Number: LM75BIMMX-3+
• Description: IC TEMP SENSOR WATCHDOG 8MSOP
• Manufacturer: Maxim Integrated Products

Specifications of LM75BIMMX-3+

• Function: Temp Sensor, Watchdog
• Topology: ADC (Sigma Delta), Comparator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: I²C™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The LM75 temperature sensor measures temperature
and converts the data into digital form using a band-
gap type temperature sensor and a 9-bit delta-sigma
ADC. An I
access to conversion results. The LM75 accepts stan-
dard I
perature alarm (OS) trip thresholds, and configure other
characteristics. While reading the Temperature register,
any changes in temperature are ignored until the read
is completed. The Temperature register is updated for
the new temperature measurement upon completion of
the read operation.
In comparator mode (see Figure 1), the open-drain OS
output asserts when the temperature rises above the
limit programmed into the T
high impedance when the temperature falls below the
limit set in the T
operates as a thermostat, and the OS output can be
used to take action to reduce the temperature (e.g.,
turn on a cooling fan, reduce clock speed, or shut
down the system).
In interrupt mode, exceeding T
remains asserted until a read operation is performed on
any of the registers. Once OS has asserted due to
crossing above T
again only when the temperature drops below T
The output then remains asserted until it is reset by a
read. It is then asserted again if the temperature rises
above T
mode also resets OS.
Table 1. Slave Address
Table 2. Register Functions
X = Don’t care.
Temperature
Configuration
T
T
HYST
OS
REGISTER NAME
BIT 7
2
1
C commands to read the data, set the overtem-
OS
2
, and so on. Putting the LM75 into shutdown
C-compatible 2-wire serial interface allows
OS Output, T
HYST
Digital Temperature Sensor and Thermal
_______________________________________________________________________________________
OS
BIT 6
0
and is then reset, it is asserted
Detailed Description
register. In this mode the LM75
ADDRESS
(hex)
00
01
02
03
OS,
OS
OS
register, and becomes
and T
BIT 5
also asserts OS. OS
0
Watchdog with 2-Wire Interface
POR STATE
HYST
(hex)
000X
4B0X
500X
00
Limits
BIT 4
HYST
1
.
0000 0000 0XXX XXXX
0100 1011 0XXX XXXX
0101 0000 0XXX XXXX
POR STATE (binary)
The LM75 powers up to a known state, as indicated in
Table 2. Some of these settings are summarized as fol-
lowing:
From a software perspective, the LM75 appears as a set
of byte-wide registers that contain temperature data,
alarm threshold values, and control bits. A standard I
compatible, 2-wire serial interface reads temperature
data and writes control bits and alarm threshold data.
Each device responds to its own I
which is selected using A0, A1, and A2. See Table 1.
Figure 1. OS Output Temperature Response Diagram
0000 0000
(COMPARATOR MODE)
OS SET ACTIVE LOW
OS SET ACTIVE LOW
BIT 3
• Comparator mode
• T
• T
• OS active low
• Command byte pointer = 0x00
(INTERRUPT MODE)
A2
TEMPERATURE
OS
HYST
OS OUTPUT
OS OUTPUT
= +80°C
T
= +75°C
HYST
T
OS
BIT 2
I
A1
2
C-Compatible Bus Interface
Power-Up and Power-Down
POR STATE (°C)
OPERATION
75
80
—
—
READ
BIT 1
A0
OPERATION
2
C slave address,
READ
Read only
WRITE
READ/
R/W
R/W
R/W
BIT 0
R/W
OPERATION
READ
2
C-
5