LM88EVALA National Semiconductor, LM88EVALA Datasheet

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LM88EVALA

Manufacturer Part Number
LM88EVALA
Description
Manufacturer
National Semiconductor
Datasheet
1.LM88EVALA.pdf (9 pages)

Specifications of LM88EVALA

Lead Free Status / Rohs Status
Not Compliant
© 2001 National Semiconductor Corporation
LM88
Factory Programmable Dual Remote-Diode Thermostat
General Description
The LM88 is a dual remote-diode temperature sensor with 3
digital comparators. The LM88 has 3 open-drain outputs
(O_SP0, O_SP1 and O_CRIT) that can be used as inter-
rupts or to signal system shutdown. The digital comparators
can be factory programmed to make a greater than or less
than comparison. When programmed for a greater than
comparison outputs:
sured by D0 or D1 exceed the associated setpoints of
T_SP0 or T_SP1.
either D0 or D1 exceeds setpoint T_CRIT.
T_CRIT can be set at 1˚C intervals from −40˚C to +125˚C.
T_SP0 and T_SP1 can be set at 4˚C intervals in the range of
T_CRIT +127˚C/−128˚C. Hysteresis for all comparators is
set to 1˚C. O_CRIT, in conjunction with T_CRIT, could be
used to prevent catastrophic damage to key subsystems
such as notebook Card Bus cards while O_SP0 and O_SP1,
in conjunction with T_SP0 and T_SP1, can warn of an
impending failure.
The LM88 is available in an 8-lead mini-small-outline pack-
age.
Applications
n Microprocessor Thermal Management
n Appliances
n Portable Battery Powered Systems
n Fan Control
n Industrial Process Control
n HVAC Systems
n Remote Temperature Sensing
n Electronic System Protection
Simplified Block Diagram and Connection Diagram
O_SP0 and O_SP1 activate when the temperatures mea-
O_CRIT activates when the temperature measured by
MSOP-8/MUA08A Package
Top View
DS101326
10132601
Features
n 2 external remote diode input channels
n 3 digital comparator outputs, 1 per remote diode and
n Factory programmable greater than or less than
n 1˚C comparator hysteresis
n 2 setpoints, T_SP0 and T_SP1, factory programmable in
n 1 setpoint, T_CRIT, factory programmable in 1˚C
n Active Low open-drain digital outputs
n 8-pin mini-SO plastic package
Key Specifications
ranges.
For simplicity, the effects of the hysteresis are not shown in the
temperature response diagram.
j
j
j
j
Range
+45˚C to +85˚C
+60˚C to +100˚C
j
Note: These are sample ranges. Contact factory for other
one T_CRIT common to both
comparisons
4˚C intervals
intervals
Power Supply Voltage
Power Supply Current
LM88 Temperature Range
Diode Setpoint Temperature
Diode Junction
Temperature
Temperature Trip Point Accuracy:
(T
DJ
)
±
±
LM88CIM
Accuracy
3˚C (max)
3˚C (max)
−40˚C to +85˚C
−40˚C to +85˚C
−40˚C to +85˚C
Temperature
0˚C to +125˚C
1.5 mA (max)
LM88CIM
10132602
www.national.com
August 2001
Range
2.8V–3.8V

LM88EVALA Summary of contents

Page 1

... Remote Temperature Sensing n Electronic System Protection Simplified Block Diagram and Connection Diagram MSOP-8/MUA08A Package Top View © 2001 National Semiconductor Corporation Features n 2 external remote diode input channels n 3 digital comparator outputs, 1 per remote diode and one T_CRIT common to both n Factory programmable greater than or less than comparisons n 1˚ ...

Page 2

Simplified Block Diagram and Connection Diagram Order Number Device Marking LM88CIMM-A T08A LM88CIMMX-A LM88CIMM-B T08A LM88CIMMX-B For other setpoints please contact the factory. Performance is dependent on temperature range. Typical Application FIGURE 1. Thermal Protection for Pentium www.national.com NS Package ...

Page 3

Absolute Maximum Ratings Input Voltage Input Current at any pin (Note 2) Package Input Current (Note 2) Package Dissipation 25˚C A (Note 4) Soldering Information MSOP Package (Note 6) : Vapor Phase (60 seconds) Infrared (15 seconds) ...

Page 4

LM88 Electrical Characteristics Note 2: When the input voltage ( any pin exceeds the power supply (V I maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input ...

Page 5

Functional Description a) When programmed for a greater than comparison FIGURE 2. Comparator output temperature response diagrams 1.1 PIN DESCRIPTIONS + V This is the positive supply voltage pin, which has a range of 2.8 to 3.8 volts. This ...

Page 6

Functional Description 1.2 TYPICAL PIN CONNECTION Pin Label D0+ D− D1+ GND O_CRIT O_SP1 O_SP1 + V 1.3 LM88 OPTIONS 1.3.1 Set-Point Values T_SP0 and T_SP1 are dependent on the value of T_CRIT: T_SP0 = T_CRIT + 4a + ...

Page 7

Application Hints (Continued) of the LM88’s temperature. The LM88 has been optimized to measure the remote diode of a Pentium type processor as shown in Figure discrete diode can also be used to sense the temperature ...

Page 8

Application Hints 8. The ideal place to connect the LM88’s GND pin is as close as possible to the processor GND associated with the sense diode. 9. Leakage current between D+ and GND should be kept to a minimum. ...

Page 9

... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...