LTC1695 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1695' PDF : 20 Pages View PDF
LTC1695
APPLICATIONS INFORMATION
DC FAN SELECTION
The LTC1695, in the 5-lead SOT-23 package, caters mainly
to 5V brushless DC fans, in spot cooling and notebook
computer applications, that consume less than 1W maxi-
mum. These applications typically require fan footprints
on the order of 4000mm3 to 20000mm3. Such fan sizes
are common and commercially available. Examples of
these miniature fans are the “Ultra-thin DC fan” and
“Extra-mini DC fan” from SUNON Inc. Models in these
series range from 17mm to 40mm in size, weigh from 4
grams to 10 grams and provides airflow densities from
0.65 CFM to 6 CFM.
Users must consider parameters like physical size
(L • W • H), airflow (CFM), power dissipation (W) and
acoustically generated noise (dBA) when choosing a fan.
Users must also evaluate the fan’s I-V characteristics
versus fan speed and the start/stall characteristics of the
fan. Other factors include mechanical considerations such
as low cost sleeve bearings or ball bearings that have
better long term reliability. Finally, users must consider if
the fan requires any input protection features such as
reverse-voltage protection. All of these factors affect the
fan’s cost.
Table 3 lists some 5V fan manufacturer’s contact informa-
tion.
Table 3. 5V DC Fan Manufacturers
Manufacturer
Address
SUNON Inc.
1075 W. Lambert Rd., Brea, CA 92821
Tel: (714)255-0208
Website: http://www.sunon.com
Advanced Technology 1280 Liberty Way, Vista, CA 92083
Company
Tel: (760)727-7430
Nidec America
152 Will Dr., Canton, MA 02021
Tel: (781)828-6216
Website: http://nidec.com
NMB Technologies Inc. 9730 Independence Ave., Chatsworth, CA 91311
Tel: (818)341-3355
Website: http://www.nmbtech.com
Micronel
1280 Liberty Way, Vista, CA 92083
Tel: (760)727-7400
Website: http://www.micronel.com
Table 4 lists some 5V brushless DC fans suitable for typical
LTC1695 fan speed control applications. Figure 5 shows
the measured I-V characteristics of these fans. For a
particular fan selection, users must determine the mini-
mum DAC output voltage code below which the fan stalls.
Most fans continue to consume current, even in a stalled
condition.
Table 4. Some 5V DC Fans’ Characteristics
Manufacturer Part Number Airflow Power Size
(CFM) (W) (L • W • H)mm3
SUNON
KDE0501PFB2-8 0.65 0.50 20 • 20 • 10
ATC
AD0205HB-G51 0.80 0.45 25 • 25 • 10
SUNON
KDE0502PFB2-8 1.70 0.60 25 • 25 • 10
SUNON
KDE0503PFB2-8 3.20 0.60 30 • 30 • 10
SUNON
KDE0535PFB2-8 4.80 0.70 35 • 35 • 10
Micronel
F41MM-005XK-9 6.10 0.70 40 • 40 • 12
150
KDE0501PFB2-8
KDE0535PFB2-8
125
KDE0502PFB2-8
AD0205HB-G51
KDE0503PFB2-8
100
F41MM-005XK-9
75
50
25
0
0
TA = 25°C
1
2
3
4
TERMINAL VOLTAGE (V)
5
1695 • F05
Figure 5. I-V Characteristics of 5V
Brushless DC Fan Samples
16
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