LM92_05 NSC [National Semiconductor], LM92_05 Datasheet

LM92_05

Manufacturer Part Number

LM92_05

Description

Manufacturer

NSC [National Semiconductor]

Datasheet

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LM92

Thermal Window Comparator with Two-Wire Interface

General Description

The LM92 is a digital temperature sensor and thermal win-

dow comparator with an I

accuracy of

of the LM92 eases the design of temperature control sys-

tems. The open-drain Interrupt (INT) output becomes active

whenever temperature goes outside a programmable win-

dow,

(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. Program-

mable 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 thresh-

olds of 2˚C T

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 elec-

tronics, automotive, medical and HVAC applications.

Features

n Window comparison simplifies design of ACPI

n Serial Bus interface

n Separate open-drain outputs for Interrupt and Critical

Simplified Block Diagram

I 2 C

compatible temperature monitoring and control.

Temperature shutdown

0.33˚C Accurate, 12-Bit + Sign Temperature Sensor and

is a registered trademark of Philips Corporation.

while

0.33˚C. The window-comparator architecture

HYST

separate

, 10˚C T

™

Critical

LOW

Serial Bus interface and an

, 64˚C T

Temperature Alarm

DS101051

HIGH

, and 80˚C

n Shutdown mode to minimize power consumption

n Up to 4 LM92s can be connected to a single bus

n 12-bit + sign output

n Operation up to 150˚C

Key Specifications

Applications

n HVAC

n Medical Electronics

n Electronic Test Equipment

n System Thermal Management

n Personal Computers

n Office Electronics

n Automotive

Accuracy

Supply Voltage

Supply Current

Temperature

Linearity

Resolution

operating

shutdown

10105101

−25˚C to 150˚C

−10˚C to 85˚C

10˚C to 50˚C

125˚C

30˚C

625 µA (max)

0.33˚C (max)

0.50˚C (max)

1.25˚C (max)

www.national.com

2.7V to 5.5V

350 µA (typ)

1.0˚C (max)

1.5˚C (max)

0.5˚C (max)

March 2005

5 µA (typ)

0.0625˚C

Related parts for LM92_05

LM92_05 Summary of contents

Page 1

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 win- 2 dow comparator with ™ Serial Bus interface and ...

Page 2

Connection Diagram Ordering Information Order Number LM92CIM LM92CIMX Pin Descriptions Label Pin # SDA 1 Serial Bi-Directional Data Line. Open Drain Output SCL 2 Serial Bus Clock Input T_CRIT_A 3 Critical Temperature Alarm Open Drain Output GND 4 Power Supply ...

Page 3

Absolute Maximum Ratings 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 ESD Susceptibility (Note 4) Electrical Characteristics Temperature-to-Digital Converter ...

Page 4

Digital DC Characteristics Unless otherwise noted, these specifications apply for + all other limits MIN MAX A Symbol Parameter V SDA and SCL Logical “1” Input IN(1) Voltage V SDA and SCL ...

Page 5

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating the device beyond its rated operating conditions. Note 2: When the input voltage (V ) ...

Page 6

Note 9: The limits found in the following table supersede the limits shown in the Electrical Characteristics Table. The Accuracy specification includes errors due to linearity, offset and gain. The accuracy specification includes effects of self heating with negligible digital ...

Page 7

Note 13: This specification is provided only to indicate how often temperature data is updated. The LM92 can be read at any time without regard to conversion state (and will yield last conversion result conversion is in process ...

Page 8

Functional Description The LM92 temperature sensor incorporates a band-gap type temperature sensor, 13-bit ADC, and a digital comparator with user-programmable upper and lower limit values. The comparator activates either the INT line for temperatures outside the T and T ...

Page 9

Functional Description Therefore, the complete slave address is Note: Event Interrupt mode is drawn as if the user is reading the part. If the user doesn’t read, the outputs would go low and stay ...

Page 10

Functional Description observed on these pins until pull-up current is provided from some external source, typically a pull-up resistor. Choice of resistor value depends on many system factors but, in gen- eral, the pull-up resistor should be as large ...

Page 11

Functional Description FIGURE 4. Inadvertent 8-Bit Read from 16-Bit Register where D7 is Zero (“0”) 1.9 POINTER REGISTER (Selects which registers will be read from or written to P0–P2: Register Select ...

Page 12

Functional Description D3–D15 T_CRIT Trip Temperature Data. Power up default is T HYST LOW HIGH T = 2˚C. HYST T is subtracted from T , and T_CRIT, and added to T HYST HIGH ...

Page 13

I C Timing Diagrams Typical 2-Byte Read From Preset Pointer Location Such as Temp or Comparison Registers Typical Pointer Set Followed by Immediate Read for 2-Byte Register such as Temp or Comparison Registers Typical 1-Byte Read from Configuration ...

Page 14

I C Timing Diagrams Typical Pointer Set Followed by Immediate Read from Configuration Register 3.0 Application Hints The temperature response graph in Figure 7 depicts a typi- cal application designed to meet ACPI requirements. In this type of ...

Page 15

Application Hints (Continued) Note: Event Interrupt mode is drawn as if the user is reading the part. If the user doesn’t read, the outputs would go low and stay that way until the LM92 is read. FIGURE 7. Temperature ...

Page 16

Typical Applications FIGURE 9. Remote HVAC temperature sensor communicates via 3 wires, including thermostat signals. FIGURE 10. ACPI Compatible Terminal Alarm Shutdown. By powering the LM92 from auxilary output of the power supply, a non-functioning overheated computer can be ...

Page 17

Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead (0.150" Wide) Molded Small Outline Package (SOP), JEDEC National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at ...

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