MAX6665 Datasheet, PDF (1/6 Pages) Maxim Integrated Products – Fan Controller/Driver with Factory- Programmed Temperature Thresholds

19-2056; Rev 0; 5/01
Fan Controller/Driver with Factory-
Programmed Temperature Thresholds
General Description
The MAX6665 is a fully integrated thermal switch with
an internal power transistor for driving a cooling fan
rated up to 24V and 250mA. When the MAX6665’s tem-
perature rises above a factory-programmed threshold,
the FANOUT pin becomes active and powers the fan.
The MAX6665 is available with factory-programmed fan
activation threshold temperatures from +40°C to +70°C
in 5°C increments. Accuracy of the fan activation trip
point is ±1°C (typ) and ±3°C (max). The trip point’s hys-
teresis is pin selectable to 1°C, 4°C, or 8°C. Two open-
drain logic outputs indicate overtemperature con-
ditions: WARN is activated when the temperature is
15°C above the fan activation threshold, and OT is acti-
vated when the temperature is 30°C above the thresh-
old. These features can be used to safely power down
systems that are overheated.
The MAX6665 operates from a +2.7V to +5.5V power
supply, and the associated fan can be powered from
4.5V to 24V. It is available in an 8-pin SO package and
operates from -40°C to +125°C.
Applications
Notebook and Desktop Computers
Servers
PC Power Supplies
Laboratory Instruments
Card Racks
Typical Operating Circuit
+4.5V TO +24V
100mA TO 250mA
COOLING FAN
Features
o On-Chip 250mA Fan Switch
o No External Components Required
o Factory-Programmed Thresholds
o Two Overtemperature Warning Signals
o Pin-Selectable 1°C, 4°C, and 8°C Hysteresis
o Low 65µA Supply Current
PART
MAX6665ASA40
MAX6665ASA45
MAX6665ASA50
MAX6665ASA55
MAX6665ASA60
MAX6665ASA65
MAX6665ASA70
*Exposed paddle
Ordering Information
TEMP.
RANGE
-40°C to
+125°C
-40°C to
+125°C
-40°C to
+125°C
-40°C to
+125°C
-40°C to
+125°C
-40°C to
+125°C
-40°C to
+125°C
PIN-
THRESHOLD
PACKAGE
8 SO-EP*
40°C
8 SO-EP*
45°C
8 SO-EP*
50°C
8 SO-EP*
55°C
8 SO-EP*
60°C
8 SO-EP*
65°C
8 SO-EP*
70°C
Pin Configuration
+3.3V
1µF
V_DD
FANOUT
MAX6665
HYST
WARN
FORCEON
OT
GND ^FANON
V_DD
100kΩ
V_DD
100kΩ
TOP VIEW
GND 1
FORCEON 2
HYST 3
FANON 4
MAX6665
8 FANOUT
7 V_DD
6 WARN
5 OT
SO
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