TC642 Microchip, TC642 Datasheet - Page 15
![no-image](/images/no-image-200.jpg)
TC642
Manufacturer Part Number
TC642
Description
PWM Fan Speed Controller
Manufacturer
Microchip
Datasheet
1.TC642.pdf
(28 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
TC642BEOA
Manufacturer:
NS
Quantity:
6 245
Company:
Part Number:
TC642BEOA713
Manufacturer:
MICROCHIP
Quantity:
12 000
Company:
Part Number:
TC642BEPA
Manufacturer:
MICROCHIP
Quantity:
12 000
Company:
Part Number:
TC642BEUA
Manufacturer:
MICROCHIP
Quantity:
12 000
Company:
Part Number:
TC642BEUA713
Manufacturer:
MICROCHIPTECHNOLOGY
Quantity:
12 000
Part Number:
TC642COA
Manufacturer:
MICROCHI
Quantity:
20 000
Part Number:
TC642COA713
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
Part Number:
TC642EOA
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
Part Number:
TC642EUA
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
5.7
Noise present on the V
erroneous operation of the FAULT output. As a result,
these inputs should be bypassed with a 0.01 F
capacitor mounted as close to the package as is possi-
ble. This is particularly true of V
driven from a high impedance source (such as a ther-
mistor). In addition, the V
with a 1 µF capacitor. Grounds should be kept as short
as possible. To keep fan noise off the TC642 ground
pin, individual ground returns for the TC642 and the low
side of the fan current sense resistor should be used.
FIGURE 5-9:
2002 Microchip Technology Inc.
Shutdown
Fan
Power Supply Routing and
Bypassing
(Optional)
10 k
R
8
Design Example.
IN
DD
and V
input should be bypassed
+5V
Q
2
MIN
20.5 k
3.83 k
IN
+5V
R
R
, which is usually
1
2
inputs may cause
R
18 k
R5
33 k
6
C
0.01 F
C
0.01 µF
@ 25˚C
10 k
B
B
C
1 F
NTC
1
1
3
2
C
V
V
1 F
F
MIN
IN
C
B
+
+5V
V
DD
TC642
8
Design Example
Step 1. Calculate R
Step 2. Set minimum fan speed V
Step 3. Design the output circuit.
GND
4
having a resistance of 10 k
and 4.65 k
R
Q
R
SENSE
R
Limit the divider current to 100 µA from which
R
Maximum fan motor current = 250 mA.
FAULT
V
2
7
1
1
5
OUT
= 3.83 k
= 800 .
= 20.5 k
= 33 k
beta is chosen at 50 from which
6
7
5
1
and R
Thermal Fault
at T
and R
C
0.1 F
Fan/
MAX
SENSE
6
2
= 18 k
based on using an NTC
(45°C) (see Figure 5-9).
MIN
DS21444C-page 15
800
TC642
R
= 1.8V.
7
at T
+12V
Fan
MIN
Q
R
1
SENSE
2.2
(25°C)