TC642COA Microchip Technology, TC642COA Datasheet - Page 13

• Manufacturer Part Number: TC642COA
• Description: IC PWM FAN SPEED CONTRLR 8-SOIC
• Manufacturer: Microchip Technology
• Type: Controller - PWM Fanr

Specifications of TC642COA

• Package / Case: 8-SOIC (3.9mm Width)
• Operating Temperature: 0°C ~ 70°C
• Applications: Fan Controller, Brushless (BLDC)
• Number Of Outputs: 1
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Product: Fan / Motor Controllers / Drivers
• Operating Supply Voltage: 6 V
• Supply Current: 1 mA
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Some applications require the fan to be powered from
the negative 12V supply to keep motor noise out of the
positive voltage power supplies. As is shown in
Figure 5-8, zener diode D
ply voltage, holding transistor Q
FIGURE 5-7:
FIGURE 5-8:
V
2002 Microchip Technology Inc.
OUT
a) Single Bipolar Transistor
R
BASE
Output Drive Transistor Circuit Topologies.
Powering the Fan From a -12V Supply.
V DD
1
GND
Fan
offsets the -12V power sup-
*Note: Value depends on the specific application and is shown for example only.
Q
R
1
SENSE
1
off when V
TC642
+5V
GND
V
V
DD
OUT
OUT
V
OUT
is low.
R
BASE
b) Darlington Transistor Pair
12.0V
Zener
D
1
R
2.2 k
2
*
When V
increases by V
otherwise consistent with the case of fan operation
from +12V.
Q
V
1
GND
R
10 k
Fan
DD
4
*
R
OUT
Q
SENSE
2
-12V
Fan
Q
is high, the voltage at the anode of D
R
2.2
1
OUT
*
3
*
, causing Q
V
OUT
1
c) N-Channel MOSFET
to turn on. Operation is
DS21444C-page 13
TC642
V
GND
Fan
DD
R
Q
SENSE
1
1