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鈥檚 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擄C to +70擄C
in 5擄C increments. Accuracy of the fan activation trip
point is 鹵1擄C (typ) and 鹵3擄C (max). The trip point鈥檚 hys-
teresis is pin selectable to 1擄C, 4擄C, or 8擄C. Two open-
drain logic outputs indicate overtemperature con-
ditions:
WARN
is activated when the temperature is
15擄C above the fan activation threshold, and
OT
is acti-
vated when the temperature is 30擄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擄C to +125擄C.
o
On-Chip 250mA Fan Switch
o
No External Components Required
o
Factory-Programmed Thresholds
o
Two Overtemperature Warning Signals
o
Pin-Selectable 1擄C, 4擄C, and 8擄C Hysteresis
o
Low 65碌A(chǔ) Supply Current
Features
MAX6665
Ordering Information
PART
MAX6665ASA40
MAX6665ASA45
MAX6665ASA50
MAX6665ASA55
MAX6665ASA60
MAX6665ASA65
MAX6665ASA70
TEMP.
RANGE
-40擄C to
+125擄C
-40擄C to
+125擄C
-40擄C to
+125擄C
-40擄C to
+125擄C
-40擄C to
+125擄C
-40擄C to
+125擄C
-40擄C to
+125擄C
PIN-
PACKAGE
8 SO-EP*
8 SO-EP*
8 SO-EP*
8 SO-EP*
8 SO-EP*
8 SO-EP*
8 SO-EP*
THRESHOLD
40擄C
45擄C
50擄C
55擄C
60擄C
65擄C
70擄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
*Exposed paddle
Pin Configuration
TOP VIEW
+3.3V
1碌F
V
DD
FANOUT
V
DD
100k鈩?/div>
MAX6665
HYST
WARN
GND
V
DD
100k鈩?/div>
1
8
7
FANOUT
V
DD
WARN
OT
FORCEON
2
MAX6665
HYST
3
6
5
FORCEON
GND
OT
FANON
FANON
4
SO
________________________________________________________________
Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
Maxim
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