Rainbow Electronics MAX6665 User 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 temperature 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 hysteresis is pin selectable to 1°C, 4°C, or 8°C. Two opendrain logic outputs indicate overtemperature conditions: WARN is activated when the temperature is
15°C above the fan activation threshold, and OT is activated when the temperature is 30°C above the threshold. 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
Pin Configuration
V
DD
FANON
GND
HYST
V
DD
+3.3V
+4.5V TO +24V
100mA TO 250mA
COOLING FAN
100kΩ
1µF
MAX6665
FORCEON
FANOUT
WARN
OT
V
DD
100kΩ
Typical Operating Circuit
19-2056; Rev 0; 5/01
Ordering Information
*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.
PART
MAX6665ASA40
MAX6665ASA45
MAX6665ASA50
MAX6665ASA55
MAX6665ASA60
MAX6665ASA65
MAX6665ASA70
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
PINPACKAGE
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
THRESHOLD
TOP VIEW
GND
FORCEON
HYST
FANON
1
2
MAX6665
3
4
SO
8
7 V
6
5
FANOUT
DD
WARN
OT
MAX6665
Fan Controller/Driver with FactoryProgrammed Temperature Thresholds
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1: Specifications over temperature are guaranteed by design. Parts are 100% production tested at 10°C below the tempera-
ture threshold.
V
DD
to GND..............................................................-0.3V to +6V
FANOUT to GND ....................................................-0.3V to +28V
FORCEON, HYST, FANON to GND............-0.3V to (V
DD
+ 0.3V)
WARN, OT to GND ...................................................-0.3V to +6V
FANOUT Continuous Current............................................400mA
All Other Pins ....................................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 19.6mW/°C above +70°C).............1568mW
Operating Temperature Range .........................-40°C to +125°C
Junction (storage) Temperature Range ............-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VDD= +2.7V to +5.5V, TA= -40°C to +125°C. Typical values are at VDD= +3.3V and TA= +25°C, unless otherwise noted.) (Note 1)
Supply Voltage VDD pin 2.7 5.5 V
Supply Current No load 65 200 µA
FANOUT Drive Voltage FANOUT pin 26 V
FAN OUT Outp ut C ur rent C ap ab ility
FANOUT Leakage Current V
FANOUT Threshold, T
FANOUT Threshold Error -3 ±1+3°C
FANOUT Hysteresis
WARN Threshold Relative to FANOUT temperature threshold +15 °C
OT Threshold Relative to FANOUT temperature threshold +30 °C
WARN and OT Hysteresis 2 °C
FANON Output High Voltage I
FANON Output Low Voltage I
W ARN and O T Outp ut V ol tag e Low
Open-Drain Leakage Current V
Input Low Voltage FORCEON and HYST pins 0.3V
Input High Voltage FORCEON and HYST pins 0.7V
Input Current
PARAMETER CONDITIONS MIN TYP MAX UNITS
TH
V
V
MAX6665ASA40 40
MAX6665ASA45 45
MAX6665ASA50 50
MAX6665ASA55 55
MAX6665ASA60 60
MAX6665ASA65 65
MAX6665ASA70 70
HYST is unconnected 1
HYST ≤ 0.3V
HYST ≥ 0.7V
FANON
FANON
I
WARN
I
WARN
FORCEON connected to VDD or GND -1 +1
HYST connected to V
< 0.8V 250
FANOUT
< 0.6V, TA≤ TTH +10°C, VCC≥ +3.3V 250
FANOUT
= 26V, TA = +60°C3µA
FANOUT
DD
DD
= 0.5mA source 2.0 V
= 0.5mA sink 0.7 V
= 1.2mA or I OT = 1.2mA sink 0.3
= 20mA or I OT = 20mA sink 0.5
= 5.5V or V OT = 5.5V 0.1 µA
WARN
or GND -15 +15
DD
DD
4
8
DD
mA
°C
°C
V
V
V
µA
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