Document
LM92 ± 0.33˚C Accurate, 12-Bit + Sign Temperature Sensor and Thermal Window Comparator with Two-Wire Interface
March 2000
LM92 ± 0.33˚C Accurate, 12-Bit + Sign Temperature Sensor and Thermal Window Comparator with Two-Wire Interface
General Description
The LM92 is a digital temperature sensor and thermal window comparator with an I2C™ Serial Bus interface and an accuracy of ± 0.33˚C. The window-comparator architecture of the LM92 eases the design of temperature control systems. The open-drain Interrupt (INT) output becomes active whenever temperature goes outside a programmable window, while a separate Critical Temperature Alarm (T_CRIT_A) output becomes active when the temperature exceeds a programmable critical limit. The INT output can operate in either a comparator or event mode, while the T_CRIT_A output operates in comparator mode only. The host can program both the upper and lower limits of the window as well as the critical temperature limit. Programmable hysterisis as well as a fault queue are available to minimize false tripping. Two pins (A0, A1) are available for address selection. The sensor powers up with default thresholds of 2˚C THYST, 10˚C TLOW, 64˚C THIGH, and 80˚C T_CRIT. The LM92’s 2.7V to 5.5V supply voltage range, Serial Bus interface, 12-bit + sign output, and full-scale range of over 128˚C make it ideal for a wide range of applications. These include thermal management and protection applications in personal computers, electronic test equipment, office electronics, automotive, medical and HVAC applications. n n n n Shutdown mode to minimize power consumption Up to 4 LM92s can be connected to a single bus 12-bit + sign output Operation up to 150˚C
Key Specifications
n Supply Voltage n Supply Current operating shutdown n Temperature Accuracy 30˚C 10˚C to 50˚C −10˚C to 85˚C 125˚C −25˚C to 150˚C n Linearity n Resolution 2.7V to 5.5V 350µA (typ) 625µA (max) 5µA (typ)
± 0.33˚C(max) ± 0.50˚C(max) ± 1.0˚C(max) ± 1.25˚C(max) ± 1.5˚C(max) ± 0.5˚C(max)
0.0625˚C
Applications
n n n n n n n HVAC Medical Electronics Electronic Test Equipment System Thermal Management Personal Computers Office Electronics Automotive
Features
n Window comparison simplifies design of ACPI compatible temperature monitoring and control. n Serial Bus interface n Separate open-drain outputs for Interrupt and Critical Temperature shutdown
Simplified Block Diagram
DS101051-1
I2C ® is a registered trademark of Philips Corporation.
© 2000 National Semiconductor Corporation
DS101051
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LM92
Connection Diagram
SO-8
DS101051-2
LM92 See NS Package Number M08A
Ordering Information
Order Number LM92CIM LM92CIMX Supply Voltage 2.7V to 5.5V 2.7V to 5.5V 2500 Units on Tape and Reel Supplied As
Pin Descriptions
Label SDA SCL T_CRIT_A GND INT +V S A0–A1 Pin # 1 2 3 4 5 8 7,6 Function Serial Bi-Directional Data Line. Open Drain Output Serial Bus Clock Input Critical Temperature Alarm Open Drain Output Power Supply Ground Interrupt Open Drain Output Positive Supply Voltage Input User-Set Address Inputs Typical Connection From Controller From Controller Pull Up Resistor, Controller Interrupt Line or System Hardware Shutdown Ground Pull Up Resistor, Controller Interrupt Line DC Voltage from 2.7V to 5.5V Ground (Low, “0”) or +VS (High, “1”)
Typical Application
DS101051-3
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2
LM92
Absolute Maximum Ratings (Note 1)
Supply Voltage Voltage at any Pin Input Current at any Pin Package Input Current (Note 2) T_CRIT_A and INT Output Sink Current T_CRIT_A and INT Output Voltage Storage Temperature −0.3 V to 6.5V −0.3 V to (+VS + 0.3V) 5mA 20mA 10mA 6.5V −65˚C to +125˚C
Soldering Information, Lead Temperature SOP and MSOP Package (Note 3) Vapor Phase (60 seconds) Infrared (15 seconds) ESD Susceptibility (Note 4) Human Body Model Machine Model
215˚C 220˚C 2500V 250V
Operating Ratings(Notes 1, 5)
Specified Temperature Range (Note 6) Supply Voltage Range (+VS) TMIN to TMAX −55˚C to +150˚C +2.7V to +5.5V
Electrical Characteristics
Temperature-to-Digital Converter CharacteristicsUnless otherwise noted, these specifications apply for +VS =+2.7V to +5.5V for LM92CIM . Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ =+25˚C, unless otherwise noted. Parameter Accuracy (This is a summary. For more detailed information please see (Note 9)) Conditions T A = +30˚C, +VS = 3.3V to 4.0V T A = 10˚C or +50˚C, +VS = 3.3V to 4.0V T A = −10 ˚C or +85˚C, +VS = 3.3V to 4.0V T
A
Typical (Note 7)
Limits (Note 8)
Units (Limit)
± 0.33 ± 0.50 ± 1.00 ± 1.25 ± 1.50
13 0.0625 Bits ˚C ˚C (max)
= +125˚C, +VS = 4.0V
T A = −25˚C to 150˚C, +VS = 4.0V Resolution Linearity (Note 11) Offset Error of Transfer Function (Note 12) Offset Error of Transfer Function Supply Sensitivity Temperature Conversion Time Quiescent Current +VS = 4.0V 2.7V ≤ +VS < 3.6V 3.6V ≤ +VS≤ 5.5V (Note 13) I2C Inactive I2C Active Shutdown Mode T T T T
HYST LOW HIGH C
(Note 10)
± 0.5
˚C (max) ˚C (max) ˚C/V (max) ˚C/V (max)
500.