
a
LowVoltage, Resistor Programmable
Thermostatic Swtch
ADT05
FEATURES
User-Programmable Temperature Setpoint
2.0
8
C Setpoint Accuracy
4.0
8
C Preset Hysteresis
Wide Supply Range (+2.7 V dc to +7.0 V dc)
Wide Temperature Range (–40
8
C to +150
8
C)
Low Power Dissipation (230
m
W @ 3.3 V)
APPLICATIONS
Industrial Process Control
Thermal Control Systems
CPU Monitoring (i.e., Pentium)
Computer Thermal Management Circuits
Fan Control
Handheld/Portable Electronic Equipment
T he ADT 05 is designed to operate on a single power supply
voltage from +2.7 V to +7.0 V facilitating operation in battery
powered applications as well as in industrial control systems.
Because of low power dissipation (230
μ
W @ 3.3 V), self-
heating errors are minimized and battery life is maximized.
An optional internal 200 k
pull-up resistor is included to
facilitate driving light loads such as CMOS inputs.
Alternatively, a low power LED indicator may be driven directly.
GE NE RAL DE SCRIPT ION
T he ADT 05 is a solid state thermostatic switch. Requiring only
one external programming resistor, the ADT 05 can be set to
switch accurately at any temperature in the wide operating range
of –40
°
C to +150
°
C. Using a novel circuit architecture, the
ADT 05 asserts an open collector output when the ambient
temperature exceeds the user-programmed setpoint temperature.
T he ADT 05 has approximately 4
°
C of hysteresis which prevents
rapid thermal on/off cycling.
FUNCT IONAL BLOCK DIAGRAM
5
GND
OUT
1
+V
S
4
R
SET
R
PULL–UP
3
2
TEMPERATURE
SENSOR
200k
SET–
POINT
ADT05
5
4
R
SET
1
2
3
ADT05
TOP VIEW
OUT
+2.7 TO +7.0V
Figure 1. Typical Application Circuit
Prelimnary
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Analog Devices, Inc., 1997
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703