lm75b-5.0-mdc National Semiconductor Corporation, lm75b-5.0-mdc Datasheet

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lm75b-5.0-mdc

Manufacturer Part Number
lm75b-5.0-mdc
Description
Digital Temperature Sensor And Thermal Watchdog With Two-wire Interface
Manufacturer
National Semiconductor Corporation
Datasheet
© 2005 National Semiconductor Corporation
LM75
Digital Temperature Sensor and Thermal Watchdog with
Two-Wire Interface
General Description
The LM75 is a temperature sensor, Delta-Sigma analog-to-
digital converter, and digital over-temperature detector with
I
read temperature. The open-drain Overtemperature Shut-
down (O.S.) output becomes active when the temperature
exceeds a programmable limit. This pin can operate in either
“Comparator” or “Interrupt” mode.
The host can program both the temperature alarm threshold
(T
away (T
tents of the LM75’s T
A1, A2) are available for address selection. The sensor
powers up in Comparator mode with default thresholds of
80˚C T
The LM75’s 3.0V to 5.5V supply voltage range, low supply
current and I
applications. These include thermal management and pro-
tection applications in personal computers, electronic test
equipment, and office electronics.
Features
n SOP-8 and Mini SOP-8 (MSOP) packages save space
n I
n Separate open-drain output pin operates as interrupt or
Simplified Block Diagram
2
I 2 C
C
OS
comparator/thermostat output
®
2
®
C Bus interface
is a registered trademark of Philips Corporation.
) and the temperature at which the alarm condition goes
interface. The host can query the LM75 at any time to
OS
HYST
and 75˚C T
). In addition, the host can read back the con-
2
C interface make it ideal for a wide range of
OS
HYST
and T
.
HYST
registers. Three pins (A0,
DS012658
n Register readback capability
n Power up defaults permit stand-alone operation as
n Shutdown mode to minimize power consumption
n Up to 8 LM75s can be connected to a single bus
n UL Recognized Component
Key Specifications
Applications
n System Thermal Management
n Personal Computers
n Office Electronics
n Electronic Test Equipment
j
j
j
thermostat
Supply Voltage
Supply Current
Temperature Accuracy
operating
shutdown
−25˚C to 100˚C
−55˚C to 125˚C
01265801
October 2005
www.national.com
3.0V to 5.5V
250 µA (typ)
1 mA (max)
±
±
4 µA (typ)
2˚C(max)
3˚C(max)

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lm75b-5.0-mdc Summary of contents

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... Separate open-drain output pin operates as interrupt or comparator/thermostat output Simplified Block Diagram ® registered trademark of Philips Corporation. © 2005 National Semiconductor Corporation n Register readback capability n Power up defaults permit stand-alone operation as thermostat n Shutdown mode to minimize power consumption LM75s can be connected to a single bus ...

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... Connection Diagram Ordering Information Package Order Number Marking LM75BIM-3 LM75BIM-3 LM75BIMX-3 LM75BIM-3 LM75BIMM-3 T01B LM75BIMMX-3 T01B LM75BIM-5 LM75BIM-5 LM75BIMX-5 LM75BIM-5 LM75BIMM-5 T00B LM75BIMMX-5 T00B LM75CIM-3 LM75CIM-3 LM75CIMX-3 LM75CIM-3 LM75CIMM-3 T01C LM75CIMMX-3 T01C LM75CIM-5 LM75CIM-5 LM75CIMX-5 LM75CIM-5 LM75CIMM-5 T00C LM75CIMMX-5 T00C Pin Descriptions ...

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Typical Application FIGURE 1. Typical Application 3 01265803 www.national.com ...

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... Soldering Information, Lead Temperature SOP and MSOP Package (Note 3) Vapor Phase (60 seconds) Infrared (15 seconds) Temperature-to-Digital Converter Characteristics Unless otherwise noted, these specifications apply for +V LM75CIMM-5 and +V = +3.3 Vdc for LM75BIM-3, LM75BIMM-3, LM75CIM-3, and LM75CIMM-3 (Note 6). Boldface limits S apply for all other limits T ...

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... Note 6: All part numbers of the LM75 will operate properly over the +V at their nominal supply voltage. Accuracy will typically degrade 1˚C/V of variation in +V Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). (Continued) = +3.3 Vdc for LM75BIM-3, LM75BIMM-3, LM75CIM-3, and ...

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... Note 13: Holding the SDA line low for a time greater than t High). FIGURE 2. Temperature-to-Digital Transfer Function (Non-linear scale for clarity) FIGURE 3. Printed Circuit Board Used for Thermal Resistance Specifications www.national.com will cause the LM75B to reset SDA to the IDLE state of the serial bus communication (SDA set TIMEOUT 6 01265805 01265806 ...

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... The LM75B has an integrated low-pass filter on both the SDA and the SCL line. These filters increase communi- cations reliability in noisy environments. 2. The LM75B also has a bus fault timeout feature. If the SDA line is held low for longer than t minimum to 325 ms maximum) the LM75B will reset to the IDLE state (SDA set to high impedance) and wait for a new start condition ...

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Functional Description above the nominal 1.7V power up threshold, the internal registers are reset to the power up default values listed above BUS INTERFACE The LM75 operates as a slave on the I line is ...

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Functional Description 1.4 TEMPERATURE DATA FORMAT Temperature data can be read from the Temperature, T Set Point, and T Set Point registers; and written to the HYST T Set Point, and T Set Point registers. Temperature OS HYST data ...

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Functional Description 1.10 INTERNAL REGISTER STRUCTURE There are four data registers in the LM75, selected by the Pointer register. At power-up the Pointer is set to “00”; the location for the Temperature Register. The Pointer register latches whatever the ...

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Functional Description 1.11 POINTER REGISTER (Selects which registers will be read from or written to P0-P1: Register Select P2–P7: Must be kept zero. 1.12 TEMPERATURE REGISTER (Read Only): D15 D14 D13 D12 ...

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www.national.com 12 ...

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13 www.national.com ...

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... FIGURE 8. Simple Fan Controller, Interface Optional www.national.com 3.1 DIGITAL NOISE ISSUES The LM75B features an integrated low-pass filter on both the SCL and the SDA digital lines to mitigate the effects of bus noise. Although this filtering makes the LM75B communica- tion robust in noisy environments, good layout practices are always recommended ...

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Typical Applications FIGURE 9. Data Acquisition System with Temperature Input via I FIGURE 10. Simple Thermostat, Interface Optional (Continued) 01265814 15 01265813 2 C Bus www.national.com ...

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Typical Applications FIGURE 11. Temperature Sensor with Loudmouth Alarm (Barking Watchdog) www.national.com (Continued) 16 01265815 ...

Page 17

... Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead (0.150" Wide) Molded Small Outline Package (SOP), JEDEC Order Number LM75CIM-3, LM75CIMX-3, LM75CIM-5, LM75CIMX-5, LM75BIM-3, LM75BIMX-3, LM75BIM-5, or LM75BIMX-5 NS Package Number M08A 17 www.national.com ...

Page 18

... Français Tel: +33 ( 8790 (JEDEC REGISTRATION NUMBER M0-187) Order Number LM75CIMM-3, LM75CIMMX-3, LM75CIMM-5, LM75CIMMX-5, LM75BIMM-3, LM75BIMMX-3, LM75BIMM-5, or LM75BIMMX-5 NS Package Number MUA08A 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system affect its safety or effectiveness ...

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