TC646EUA Microchip Technology, TC646EUA Datasheet - Page 16

• Manufacturer Part Number: TC646EUA
• Description: IC PWM FAN SPEED CTRLR 8-MSOP
• Manufacturer: Microchip Technology
• Type: Controller - PWM Fanr

Specifications of TC646EUA

• 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-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Motor Type: PWM
• No. Of Outputs: 1
• Output Current: 5mA
• Output Voltage: 4.4V
• Supply Voltage Range: 3V To 5.5V
• Driver Case Style: MSOP
• 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

TC646
Design Example
Step 1. Calculate R
Step 2. Set auto-shutdown level V
Step 3. Design the output circuit.
FIGURE 5-9:
5.8
In a system containing a microcontroller or other host
intelligence, the TC646 can be effectively managed as
a CPU peripheral. Routine fan control functions can be
performed by the TC646 without controller intervention.
The microcontroller receives temperature data from
one or more points throughout the system. It calculates
a fan operating speed based on an algorithm specifi-
cally designed for the application at hand. The proces-
sor controls fan speed using complementary port bits
I/O1 through I/O3. Resistors R
ance) form a crude 3-bit DAC that translates the 3-bit
code from the processor's outputs into a 1.6V DC con-
trol signal. A monolithic DAC or digital pot may be used
instead of the circuit shown in Figure 5-10.
DS21446C-page 16
Shutdown
Reset
having a resistance of 10 k
and 4.65 k
Limit the divider current to 100 µA from which
R
R
beta is chosen at 50 from which R
R
R
TC646 as a Microcontroller
Peripheral
Maximum fan motor current = 250 mA. Q
5
6
(Optional)
1
2
= 33 k
= 18 k
= 20.5 k
= 3.83 k
Open-Drain
Device
1
at T
and R
Design Example.
MAX
2
+5V
(45°C) (See Figure 5-9).
based on using an NTC
1
through R
R
20.5 k
R
3.83 k
1
+5V
2
AS
18 k
R
33 k
R
= 1.8V.
5
6
at T
C
0.01 F
6
7
C
0.01 F
MIN
B
(5% toler-
= 800 .
@ 25˚C
B
C
1 F
10 k
NTC
1
(25°C)
3
1
2
C
V
V
F
AS
IN
1
C
1 F
B
+5V
V
DD
TC646
8
With V
when the controller's output code is 000[B]. Output
codes 001[B] to 111[B] operate the fan from roughly
40% to 100% of full speed. An open-drain output from
the processor (I/O0) can be used to reset the TC646
following detection of a fault condition. The FAULT out-
put can be connected to the controller's interrupt input,
or to another I/O pin, for polled operation.
GND
4
AS
SENSE
set at 1.8V, the TC646 enters auto-shutdown
FAULT
V
OUT
5
6
7
Fan/Thermal
C
2002 Microchip Technology Inc.
0.1 F
SENSE
Fault
R
800
7
+12V
Fan
Q
1
R
2.2
SENSE