Rainbow Electronics MAX6665 - Manual

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
Features
♦ On-Chip 250mA Fan Switch
♦ No External Components Required
♦ Factory-Programmed Thresholds
♦ Two Overtemperature Warning Signals
♦ Pin-Selectable 1°C, 4°C, and 8°C Hysteresis
♦ Low 65µA Supply Current
MAX6665
Fan Controller/Driver with Factory-
Programmed Temperature Thresholds
________________________________________________________________ Maxim Integrated Products 1
FANON
1
2
8
7 V DD
HYST
GND
SO
TOP VIEW
3
4
6
5
MAX6665
FORCEON
FANOUT
WARN
OT
Pin Configuration
V DD
FANON
GND
HYST
V DD
+3.3V
+4.5V TO +24V
100mA TO 250mA
COOLING FAN
100k Ω
1 µF
MAX6665
FORCEON
FANOUT
WARN
OT
V DD
100k Ω
Typical Operating Circuit
19-2056; Rev 0; 5/01
Ordering Information
PART
TEMP.
RANGE
PIN-
PACKAGE
THRESHOLD
MAX6665ASA40
-40 °C to
+125 °C
8 SO-EP* 40 °C
MAX6665ASA45
-40 °C to
+125 °C
8 SO-EP* 45 °C
MAX6665ASA50
-40 °C to
+125 °C
8 SO-EP* 50 °C
MAX6665ASA55
-40 °C to
+125 °C
8 SO-EP* 55 °C
MAX6665ASA60
-40 °C to
+125 °C
8 SO-EP* 60 °C
MAX6665ASA65
-40 °C to
+125 °C
8 SO-EP* 65 °C
MAX6665ASA70
-40 °C to
+125 °C
8 SO-EP* 70 °C
*Exposed paddle
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.