TC646EOA Microchip Technology, TC646EOA Datasheet - Page 14
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TC646EOA
Manufacturer Part Number
TC646EOA
Description
IC PWM FAN SPEED CTRLR 8-SOIC
Manufacturer
Microchip Technology
Type
Controller - PWM Fanr
Datasheet
1.TC646VOA.pdf
(28 pages)
Specifications of TC646EOA
Applications
Fan Controller, Brushless (BLDC)
Number Of Outputs
1
Voltage - Supply
3 V ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Motor Type
PWM
No. Of Outputs
1
Output Current
5mA
Output Voltage
4.4V
Supply Voltage Range
3V To 5.5V
Driver Case Style
SOIC
No. Of Pins
8
Operating Temperature Range
-40°C To +85°C
Product
Fan / Motor Controllers / Drivers
Operating Supply Voltage
3 V to 5.5 V
Supply Current
1 mA
Mounting Style
SMD/SMT
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Output
-
Voltage - Load
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
TC646EOA
Manufacturer:
ROHM
Quantity:
6 264
Company:
Part Number:
TC646EOA713
Manufacturer:
MICROCHIP
Quantity:
12 000
TC646
A base-current limiting resistor is required with bipolar
transistors. This is shown in Figure 5-6.
FIGURE 5-6:
R
FIGURE 5-7:
DS21446C-page 14
V
BASE
OUT
V
OH
.
= 80% V
R
a) Single Bipolar Transistor
BASE
DD
+ V
Circuit For Determining
Output Drive Transistor Circuit Topologies.
R
GND
V
Fan
R BASE
BASE
DD
Q
V
R
1
V
SENSE
BE (SAT)
–
R SENSE
+
+
V
–
GND
V
–
Fan
OUT
DD
R
Q
SENSE
1
R
BASE
b) Darlington Transistor Pair
The correct value for this resistor can be determined as
follows:
V
“Electrical Characteristics”; V
chosen transistor data sheet. It is now possible to solve
for R
EQUATION
Some applications benefit from the fan being powered
from a negative supply to keep motor noise out of the
positive supply rails. This can be accomplished as
shown in Figure 5-8. Zener diode D
power supply voltage, holding transistor Q
V
anode of D
Operation is otherwise the same as in the case of fan
operation from +12V.
Q
OH
OUT
1
GND
V
Fan
DD
BASE
is specified as 80% of V
is low. When V
V
V
V
I
Q
BASE
R
OH
R SENSE
R BASE
2
SENSE
R
.
BASE
1
increases by V
=
= V
= I
= R
= I
V
V
OH
FAN
FAN
OUT
R SENSE
BASE
OUT
- V
/ h
x R
2002 Microchip Technology Inc.
BE (SAT)
x I
FE
is high, the voltage at the
OUT
SENSE
I
BASE
+ V
BASE
BE (SAT)
, causing Q
c) N-Channel MOSFET
BE (SAT)
- V
DD
R SENSE
1
offsets the -12V
is given in the
in Section 1.0,
V
GND
+ V
Fan
DD
1
1
R BASE
to turn on.
Q
off when
R
1
SENSE