LM92.pdf

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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 win-
dow comparator with an I
2
C
™
Serial Bus interface and an
accuracy of
±
0.33˚C. The window-comparator architecture
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, 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. 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
HYST
, 10˚C T
LOW
, 64˚C T
HIGH
, and 80˚C
T_CRIT.
The LM92’s 2.7V to 5.5V supply voltage range, Serial Bus in-
terface, 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.
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
j
Supply Voltage
j
Supply Current
2.7V to 5.5V
operating
shutdown
350µA (typ)
625µA (max)
5µA (typ)
30˚C
10˚C to 50˚C
−10˚C to 85˚C
125˚C
−25˚C to 150˚C
j
Temperature
Accuracy
j
Linearity
j
Resolution
±
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 +V
S
(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 (+V
S
+ 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 (+V
S
)
T
MIN
to T
MAX
−55˚C to +150˚C
+2.7V to +5.5V
Electrical Characteristics
Temperature-to-Digital Converter CharacteristicsUnless
otherwise noted, these specifications apply for +V
S
=+2.7V to +5.5V
for LM92CIM .
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
;
all other limits T
A
= T
J
=+25˚C, unless otherwise noted.
Parameter
Accuracy (This is a summary. For
more detailed information please
see (Note 9))
Conditions
T
A
= +30˚C, +V
S
= 3.3V to
4.0V
T
A
= 10˚C or +50˚C, +V
S
=
3.3V to 4.0V
T
A
= −10 ˚C or +85˚C, +V
S
=
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, +V
S
= 4.0V
T
A
= −25˚C to 150˚C, +V
S
=
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
+V
S
= 4.0V
2.7V
≤
+V
S
<
3.6V
3.6V
≤
+V
S
≤
5.5V
(Note 13)
I
2
C Inactive
I C Active
Shutdown Mode
T
T
T
T
HYST
LOW
HIGH
C
2
(Note 10)
±
0.5
˚C (max)
˚C (max)
˚C/V (max)
˚C/V (max)
500
0.35
0.35
5
2
10
64
80
1000
0.625
ms
mA
mA (max)
µA
˚C
˚C
˚C
˚C
Default Temperature
Default Temperature
Default Temperature
(Notes 15, 16)
(Note 16)
(Note 16)
(Note 16)
Default Temperature
3
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LM92
Electrical Characteristics
DIGITAL DC CHARACTERISTICSUnless
otherwise noted, these specifications apply for +V
S
=+2.7V to +5.5V for LM92CIM .
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
;
all other limits T
A
= T
J
=+25 ˚C, unless otherwise noted.
Symbol
V
IN(1)
Parameter
SDA and SCL Logical “1” Input
Voltage
SDA and SCL Logical “0” Input
Voltage
SDA and SCL Digital Input
Hysteresis
A0 and A1 Logical “1” Input
Voltage
A0 and A1 Logical “0” Input
Voltage
Logical “1” Input Current
Logical “0” Input Current
Capacitance of All Digital Inputs
High Level Output Current
Low Level Output Voltage
T_CRIT_A Output Saturation
Voltage
T_CRIT_A Delay
t
OF
Output Fall Time
C
I
L
Conditions
Typical
(Note 7)
Limits
(Note 8)
+V
S
x 0.7
+V
S
+0.3
Units
(Limit)
V (min)
V (max)
V (min)
V (max)
mV (min)
V (min)
V (max)
V (min)
V (max)
µA (max)
µA (max)
pF
µA (max)
V (max)
V (max)
Conversions
(max)
ns (max)
V
IN(0)
−0.3
+V
S
x 0.3
V
IN(HYST)
V
IN(1)
500
250
2.0
+V
S
+0.3
V
IN(0)
−0.3
0.7
I
IN(1)
I
IN(0)
C
IN
I
OH
V
OL
V
V
V
I
IN
IN
= + V
S
=0V
= + V
S
0.005
−0.005
20
1.0
−1.0
10
0.4
0.8
1
OH
OL
= 3 mA
I
OUT
= 4.0 mA
(Note 14)
= 400 pF
= 3 mA
250
O
SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS
Unless otherwise noted, these specifications apply for +V
S
=+2.7V
to +5.5V for LM92CIM .
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
;
all other limits T
A
= T
J
=+25 ˚C, unless otherwise
noted. CL (load capacitance) on output lines = 80 pF unless otherwise specified. Boldface limits apply for T
A
= T
J
= T
MIN
to
T
MAX
; all other limits T
A
= T
J
= +25 ˚C, unless otherwise noted.
The switching characteristics of the LM92 fully meet or exceed the published specifications of the I
2
C bus. The following pa-
rameters are the timing relationship between SCL and SDA signal related to the LM92. They are not the I
2
C bus specifica-
tions.
Symbol
t
1
t
2
t
3
t
4
t
5
t
TIMEOUT
SCL (Clock) Period
Data in Set-Up Time to SCL High
Data Out Stable after SCL Low
SDA Low Set-Up Time to SCL Low (Start Condition)
SDA High Hold Time after SCL High (Stop Condition)
SDA and SCL Time Low for Reset of Serial Interface
(Note 17)
Parameter
Conditions
Typical
(Note 7)
Limits
(Note 8)
2.5
1
100
0
100
100
75
300
Units
(Limit)
µs(min)
ms(max)
ns(min)
ns(min)
ns(min)
ns(min)
ms (min)
ms
(max)
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4
LM92
Electrical Characteristics
(Continued)
Serial Bus Communication
DS101051-4
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
I
) at any pin exceeds the power supplies (V
I
<
GND or V
I
>
+V
S
) the current at that pin should be limited to 5 mA. The 20 mA
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5 mA to four.
Note 3:
See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in a current National Semicon-
ductor Linear Data Book for other methods of soldering surface mount devices.
Note 4:
Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin.
Note 5:
LM92
θ
JA
(thermal resistance, junction-to-ambient) when attached to a printed circuit board with 2 oz. foil is 200 ˚C/W.
Note 6:
While the LM92 has a full-scale-range in excess of 128 ˚C, prolonged operation at temperatures above 125 ˚C is not recommended.
Note 7:
Typicals are at T
A
= 25 ˚C and represent most likely parametric norm.
Note 8:
Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
5
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