AQ297
3ºC Accurate with Hysteresis
Adjustable Thermostat
SOT23-5 Package
Product Specification
Revision 1.1
October 08, 2006
General Description
The device AQ297 is an adjustable accurate low-
power solid-state thermostat. The temperature trip
point can be set with one external resistor from 50ºC
to 150ºC with an accuracy of 3 degrees. The thermal
hysteresis is internally programmed to guarantee
stability at the transition point.
The device AQ297 is used to protect systems from
overheating above the normal rating of components like
capacitors, batteries, or any other temperature
sensitive component. The device AQ297 is also used in
battery management systems to stop the battery
charge when the battery temperature is outside of the
safe temperature range.
The output OT is an open drain output that can sink up
to 50mA when the threshold temperature is reached.
The minimum voltage of operation is 2.2 V.
Applications
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Battery Chargers
Electronic System protection
Fan Control
Microprocessor Thermal Management
HVAC Systems
Features
+/-3 degrees Celsius accuracy
Adjustable temperature trip point
Open-drain output capable of 50mA
Internally programmed thermal hysteresis
Low input voltage and current
Excellent power supply noise rejection
Offered in very small SOT23-5 package.
RoHS Compliant
Block Diagram
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AQ297
Acutechnology Semiconductor Inc.
AQ297
Pin Configuration
Pin Descriptions
Pin
num
1
2
3
4
5
Pin
Name
TREF
GND
TADJ
VCC
OT
Ground
Adjust pin, connects to temperature adjust resistor
V supply. Must be greater than 2.2V for normal operation.
Normally Open Drain, V
DSS
when thermal threshold is reached.
Function
Reference connects to temperature adjust resistor
Ordering Information
Device
AQ297
AQ297
Operating Tj
-55ºC
≤
150ºC
-55ºC
≤
150ºC
Initial
T
THRESH
120ºC
120ºC
Adjusted
T
THRESH
50-150ºC
50-150ºC
Tol.
±
3ºC
PKG
Type
SOT-23-5
SOT-23-5
Wrap
T&R
T&R
Ordering Number
AQ297GY-M5-AJ-TR
AQ297GY-M5-AJ-TRL
±
3ºC
Note:
The TRL parts are Lead Free and RoHS compliant.
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Rev. 1.1 October 08, 2006
Acutechnology Semiconductor Inc.
AQ297
Absolute Maximum Ratings
Stress greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. These stress ratings only, and functional operation of the device at these or any conditions beyond
those indicated under recommended Operating Conditions is not implied. Exposure to “Absolute Maximum
Rating” for extended periods may affect device reliability. Use of standard ESD handling precautions is
required.
Parameter
V
CC
Voltage
V
OT
Voltage
I
OT
Current
I
TREF
Current
I
TADJ
Current
Operating Junction Temperature
Lead Temperature (soldering 10 seconds)
Storage Temperature Range
Value
18
18
80
10
10
155
260
-65 to +150
Units
V
V
mA
mA
mA
ºC
ºC
ºC
Electrical Specifications
Electrical characteristics are guaranteed over the full temperature range -55ºC <Tj<150ºC unless otherwise
stated. Ambient temperature must be de-rated based upon power dissipation and package thermal
characteristics. Unless otherwise specified: VCC = 5V, TREF and TADJ = no connect, Tj =25ºC
Symbol
Parameter
Input Current
Input Current
Input Voltage
Output V
DSS
Output leakage current
Over temp Threshold
Over temp accuracy
Hysteresis
IC = 10mA Tj > trip
temperature
VCC = 16V
Unadjusted
Adjusted
117
-3
5
Tj > trip temperature
2.2
0.15
0.2
120
Conditions
Min
Typ
80
1.5
Max
120
2.0
16
0.25
0.4
123
3
Units
µA
mA
V
V
µA
ºC
ºC
ºC
I
VCC
I
VCC
V
CC
V
OT
I
OT
O
TT
T
OT
H
OT
Notes:
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Rev. 1.1 October 08, 2006
Acutechnology Semiconductor Inc.
AQ297
Typical Application
The device AQ297 is very simple to use. It is recommended to place the AQ297 in close proximity of the device
whose temperature is to be sensed. The device AQ297 has an open drain output which is capable of sinking up
to 50mA when the sensed temperature exceeds the trip point. The temperature trip point can be set by the
addition of an external resistor RSET between the TREF and the TADJ pins as depicted in FIG.1 below.
FIG.1
It is assumed that the temperature coefficient of the external resistor be close to zero as it commonly is.
Higher accuracy resistors guarantee higher accuracy temperature trip point.
The resistor RSET value should be selected according to the table below to determine the desired temperature
trip point. The table in particular shows the desired resistor value for the temperature range between 50ºC and
80ºC. If no external resistor is selected the temperature trip point will be 120ºC.
RSET vs Tthresh.
90.0
85.0
80.0
Temperature C
75.0
70.0
65.0
60.0
55.0
50.0
45.0
40.0
70.0
90.0
110.0
130.0
150.0
170.0
190.0
210.0
RSET in Kohms
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Rev. 1.1 October 08, 2006
Acutechnology Semiconductor Inc.
AQ297
Package Dimensions
SOT23-3, SOT23-4, SOT23-5, SOT23-6
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Rev. 1.1 October 08, 2006
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