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a
Low Voltage, Resistor Programmable
Thermostatic Switch
AD22105
© Analog Devices, Inc., 1996
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
User-Programmable Temperature Setpoint
2.08C Setpoint Accuracy
4.08C Preset Hysteresis
Wide Supply Range (+2.7 V dc to +7.0 V dc)
Wide Temperature Range (–408C to +1508C)
Low Power Dissipation (230 mW @ 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
The AD22105 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 µW @ 3.3 V), self-
heating errors are minimized and battery life is maximized.
An optional internal 200 kΩ pull-up resistor is included to
facilitate driving light loads such as CMOS inputs.
Alternatively, a low power LED indicator may be driven directly.
GENERAL DESCRIPTION
The AD22105 is a solid state thermostatic switch. Requiring
only one external programming resistor, the AD22105 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 AD22105 asserts an open collector output when the ambient
temperature exceeds the user-programmed setpoint temperature.
The AD22105 has approximately 4°C of hysteresis which prevents
rapid thermal on/off cycling.
FUNCTIONAL BLOCK DIAGRAM
1
2
3
4
8
7
6
5
NC
V
S
R
SET
NC
R
PULL–UP
OUT
GND
NC
TEMPERATURE
SENSOR
200kΩ
SET–
POINT
AD22105
12
3
4
8
7
65
OUT
+2.7V TO +7.0V
R
SET
AD22105
TOP VIEW
Figure 1. Typical Application Circuit
Verzeichnis
- ・ Konfiguration des Pinbelegungsdiagramms on Seite 4
- ・ Abmessungen des Paketumrisses on Seite 9
- ・ Teilenummerierungssystem on Seite 4
- ・ Blockdiagramm on Seite 1
- ・ Typisches Anwendungsschaltbild on Seite 1
- ・ Beschreibung der Funktionen on Seite 1
- ・ Technische Daten on Seite 3 Seite 4
- ・ Anwendungsbereich on Seite 1
- ・ Elektrische Spezifikation on Seite 5
