TC648BEOA [MICROCHIP]
BRUSHLESS DC MOTOR CONTROLLER, PDSO8, 0.150 INCH, PLASTIC, SOIC-8;
| 型号： | TC648BEOA |
| 厂家： | 
MICROCHIP |
| 描述： | BRUSHLESS DC MOTOR CONTROLLER, PDSO8, 0.150 INCH, PLASTIC, SOIC-8 电动机控制 光电二极管 |
| 文件： | 总36页 (文件大小：470K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TC646B/TC648B/TC649B
PWM Fan Speed Controllers With Auto-Shutdown, Fan
Restart and FanSense™ Technology for Fault Detection
Features
Description
• Temperature-Proportional Fan Speed for Acoustic
Noise Reduction and Longer Fan Life
The TC646B/TC648B/TC649B devices are new ver-
sions of the existing TC646/TC648/TC649 fan speed
controllers. These devices are switch-mode fan speed
controllers that incorporate a new fan auto-restart func-
tion. Temperature-proportional speed control is accom-
plished using pulse width modulation. A thermistor (or
other voltage output temperature sensor) connected to
the VIN input supplies the required control voltage of
1.20V to 2.60V (typical) for 0% to 100% PWM duty
cycle. The auto-shutdown threshold/temperature is set
by a simple resistor divider on the VAS input. An inte-
grated Start-Up Timer ensures reliable fan motor start-
up at turn-on, coming out of shutdown mode, auto-
shutdown mode or following a transient fault. A logic
low applied to VIN (pin 1) causes fan shutdown.
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC646B/
TC648B/TC649B Supply Voltage
- Supports any Fan Voltage
• FanSense™ Fault Detection Circuit Protects
Against Fan Failure and Aids System Testing
(TC646B/TC649B)
• Automatic Shutdown Mode for “Green” Systems
• Supports Low Cost NTC/PTC Thermistors
• Over-Temperature Indication (TC646B/TC648B)
• Fan Auto-Restart
The TC646B and TC649B also feature Microchip
Technology's proprietary FanSense technology for
increasing system reliability. In normal fan operation, a
pulse train is present at SENSE (pin 5). A missing-
pulse detector monitors this pin during fan operation. A
stalled, open or unconnected fan causes the TC646B/
TC649B device to turn the VOUT output on full (100%
duty cycle). If the fan fault persists (a fan current pulse
is not detected within a 32/f period), the FAULT output
goes low. Even with the FAULT output low, the VOUT
output is on full during the fan fault condition in order to
attempt to restart the fan. FAULT (TC646B) or OTF
(TC648B) is also asserted if the PWM reaches 100%
duty cycle, indicating that maximum cooling capability
has been reached and a possible overheating condition
exists.
• Space-Saving 8-Pin MSOP Package
Applications
• Personal Computers & Servers
• LCD Projectors
• Datacom & Telecom Equipment
• Fan Trays
• File Servers
• General-Purpose Fan Speed Control
Package Types
MSOP, PDIP, SOIC
The TC646B, TC648B and TC649B devices are avail-
able in 8-pin plastic MSOP, SOIC and PDIP packages.
The specified temperature range of these devices is
-40 to +85ºC.
VIN
CF
8
7
6
5
VDD
1
2
3
4
VOUT
TC646B
TC649B
VAS
GND
FAULT
SENSE
VIN
8
VDD
VOUT
OTF
NC
1
CF
VAS
2
3
4
7
6
5
TC648B
GND
2002-2013 Microchip Technology Inc.
DS21755C-page 1
TC646B/TC648B/TC649B
Functional Block Diagram
TC646B/TC649B
VOTF
VDD
VIN
Note
Note: The VOTF comparator
is for the TC646B device only.
Control
Logic
CF
Clock
Generator
3xTPWM
Timer
VOUT
Start-up
Timer
VAS
FAULT
VSHDN
Missing
Pulse
Detect
SENSE
10 k
GND
70 mV
(typ)
TC648B
VOTF
VDD
VIN
Control
Logic
CF
Clock
Generator
VOUT
Start-up
Timer
VAS
OTF
NC
VSHDN
GND
DS21755C-page 2
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
1.0
ELECTRICAL
PIN FUNCTION TABLE
CHARACTERISTICS
Name
Function
Analog Input
Absolute Maximum Ratings†
VIN
CF
Supply Voltage (V ) .......................................................6.0V
Analog Output
Analog Input
Ground
DD
Input Voltage, Any Pin................(GND - 0.3V) to (V +0.3V)
DD
VAS
Operating Temperature Range ....................- 40°C to +125°C
GND
Maximum Junction Temperature, T ...........................+150°C
J
SENSE/NC
Analog Input.
ESD Protection on all pins ........................................... > 3 kV
No Connect (NC) for TC648B
† Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied. Expo-
sure to maximum rating conditions for extended periods may
affect device reliability.
FAULT/OTF
Digital (Open-Drain) Output
OTF for TC648B
VOUT
VDD
Digital Output
Power Supply Input
ELECTRICAL CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all limits are specified for -40°C < T < +85°C, V = 3.0V to 5.5V.
A
DD
Parameters
Supply Voltage
Sym
Min
Typ
Max
Units
Conditions
V
3.0
—
—
5.5
V
DD
Supply Current, Operating
I
200
400
µA
Pins 6, 7 Open,
= 1 µF, V = V
C(MAX)
DD
C
F
IN
Supply Current, Shutdown Mode
I
—
30
—
µA
Pins 6, 7 Open,
DD(SHDN)
C
= 1 µF, V = 0.35V
F
IN
V
Output
OUT
Sink Current at V
Output
I
1.0
5.0
—
—
—
—
mA
mA
V
V
= 10% of V
DD
OUT
OL
OL
Source Current at V
Output
I
= 80% of V
OH DD
OUT
OH
V
, V Inputs
IN AS
Input Voltage at V for 100% PWM
Duty Cycle
V
2.45
2.60
2.75
V
V
IN
C(MAX)
Over-Temperature Indication
Threshold
V
V
+
For TC646B and TC648B
For TC646B and TC648B
OTF
C(MAX)
20 mV
Over-Temperature Indication
Threshold Hysteresis
V
80
mV
OTF-HYS
V
- V
V
C(SPAN)
1.3
—
1.4
70
1.5
—
V
C(MAX)
C(MIN)
Hysteresis on Auto-Shutdown
Comparator
V
mV
HAS
Auto-Shutdown Threshold
V
V
V
-
—
—
V
V
V
AS
C(MAX)
C(MAX)
C(SPAN)
Voltage Applied to V to Ensure
V
—
V
DD
x 0.13
—
IN
SHDN
Shutdown Mode
Voltage Applied to V to Release
V
V
x 0.19
—
—
V
V
= 5V
DD
IN
REL
DD
Shutdown Mode
Hysteresis on V
, V
V
0.03 X
—
V
SHDN
REL
HYST
V
DD
V
, V Input Leakage
I
- 1.0
Note 1: Ensured by design, tested during characterization.
2: For V < 3.7V, t and t timers are typically 13/f.
—
+1.0
µA
Note 1
IN AS
IN
DD
STARTUP
MP
2002-2013 Microchip Technology Inc.
DS21755C-page 3
TC646B/TC648B/TC649B
ELECTRICAL CHARACTERISTICS (CONTINUED)
Electrical Specifications: Unless otherwise specified, all limits are specified for -40°C < T < +85°C, V = 3.0V to 5.5V.
A
DD
Parameters
Sym
Min
Typ
Max
Units
Conditions
Pulse-Width Modulator
PWM Frequency
f
26
30
34
Hz
C
= 1.0 µF
PWM
F
SENSE Input (TC646B & TC649B)
SENSE Input Threshold Voltage
with Respect to GND
V
50
—
70
90
—
mV
TH(SENSE)
Blanking time to ignore pulse due
t
3.0
µsec
BLANK
to V
turn-on
OUT
FAULT / OTF Output
Output Low Voltage
Missing Pulse Detector Timer
Start-up Timer
V
—
—
—
—
—
32/f
32/f
3/f
0.3
—
—
—
V
I
= 2.5 mA
OL
OL
t
sec
sec
sec
TC646B and TC649B, Note 2
Note 2
MP
t
STARTUP
Diagnostic Timer
t
TC646B and TC649B
DIAG
Note 1: Ensured by design, tested during characterization.
2: For V < 3.7V, t and t timers are typically 13/f.
DD
STARTUP
MP
TEMPERATURE SPECIFICATIONS
Electrical Characteristics: Unless otherwise noted, all parameters apply at V = 3.0V to 5.5V
DD
Parameters
Temperature Ranges
Sym
Min
Typ
Max
Units
Conditions
Specified Temperature Range
T
-40
-40
-65
—
—
—
+85
+125
+150
°C
°C
°C
A
Operating Temperature Range
T
A
Storage Temperature Range
T
A
Thermal Package Resistances
Thermal Package Resistance, 8-Pin MSOP
Thermal Package Resistance, 8-Pin SOIC
Thermal Package Resistance, 8-Pin PDIP
—
—
—
200
155
125
—
—
—
°C/W
°C/W
°C/W
JA
JA
JA
DS21755C-page 4
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
TIMING SPECIFICATIONS
t
STARTUP
VOUT
FAULT / OTF
(TC646B and TC649B)
SENSE
FIGURE 1-1:
TC646B/TC648B/TC649B Start-up Timing.
33.3 msec (CF = 1 µF)
tDIAG
tMP
tMP
VOUT
FAULT
SENSE
FIGURE 1-2:
Fan Fault Occurrence (TC646B and TC649B).
tMP
VOUT
FAULT
Minimum 16 pulses
SENSE
FIGURE 1-3:
Recovery From Fan Fault (TC646B and TC649B).
2002-2013 Microchip Technology Inc.
DS21755C-page 5
TC646B/TC648B/TC649B
C2
C1
+
-
VDD
1 µF
0.1 µF
8
R1
VDD
1
K3
R6
VIN
7
C3
0.1 µF
VOUT
+
-
VIN
C8
Current
0.1 µF
+
-
limited
voltage
source
TC646B
TC648B
TC649B
R2
VDD
3
VAS
R5
C4
0.1 µF
K4
+
-
VAS
6
5
FAULT / OTF
Current
limited
voltage
source
+
-
2
CF
R4
SENSE
GND
K1
K2
R3
4
VSENSE
(pulse voltage source)
C7
.01 µF
C5
0.1 µF
C6
1 µF
TC646B and TC649B
Note: C5 and C7 are adjusted to get the necessary 1 µF value.
TC646B/TC648B/TC649B Electrical Characteristics Test Circuit.
FIGURE 1-4:
DS21755C-page 6
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
2.0
TYPICAL PERFORMANCE CURVES
Note:
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note: Unless otherwise indicated, VDD = 5V, TA = 25°C.
30.50
30.00
29.50
29.00
28.50
165
Pins 6 & 7 Open
CF = 1 µF
CF = 1.0ꢀF
VDD = 5.5V
160
155
150
145
140
135
130
125
VDD = 3.0V
VDD = 5.5V
VDD = 3.0V
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
FIGURE 2-1:
IDD vs. Temperature.
FIGURE 2-4:
PWM Frequency vs.
Temperature.
16
14
12
10
170
Pins 6 & 7 Open
CF = 1 µF
165
160
155
150
145
140
135
130
125
TA = +125ºC
TA = +90ºC
VDD = 5.0V
VDD = 5.5V
VDD = 4.0V
8
6
4
2
0
TA = -5ºC
VDD = 3.0V
TA = -40ºC
0
50 100 150 200 250 300 350 400 450 500 550 600
VOL (mV)
3
3.5
4
4.5
5
5.5
VDD (V)
FIGURE 2-2:
VOL
PWM Sink Current (IOL) vs.
FIGURE 2-5:
IDD vs. VDD.
.
16
14
12
10
8
30
27
24
21
18
VDD = 5.5V
VDD = 5.0V
VDD = 4.0V
VDD = 5.5V
VDD = 3.0V
VDD = 3.0V
6
4
Pins 6 & 7 Open
2
VIN = 0V
0
15
0
100
200
300
400
500
600
700
800
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
VDD - VOH (mV)
FIGURE 2-3:
PWM Source Current (IOH
)
FIGURE 2-6:
IDD Shutdown vs.
vs. VDD - VOH
.
Temperature.
2002-2013 Microchip Technology Inc.
DS21755C-page 7
TC646B/TC648B/TC649B
Note: Unless otherwise indicated, VDD = 5V, TA = 25°C.
70
74.0
73.5
73.0
72.5
72.0
71.5
71.0
70.5
70.0
69.5
IOL = 2.5 mA
VDD = 3.0V
60
VDD = 3.0V
VDD = 4.0V
50
VDD = 4.0V
40
VDD = 5.5V
30
VDD = 5.0V
VDD = 5.0V
VDD = 5.5V
20
10
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
FIGURE 2-7:
FAULT / OTF VOL vs.
FIGURE 2-10:
Sense Threshold
Temperature.
(VTH(SENSE)) vs. Temperature.
2.610
2.600
2.590
2.580
22
20
18
16
14
VDD = 5.5V
VDD = 5.0V
VDD = 4.0V
VDD = 5.0V
12
VDD = 5.5V
10
8
VDD = 3.0V
VDD = 3.0V
6
4
2
CF = 1 µF
-40 -25 -10
0
2.570
0
50
100
150
200
250
300
350
400
5
20 35 50 65 80 95 110 125
Temperature (ºC)
VOL (mV)
FIGURE 2-8:
VC(MAX) vs. Temperature.
FIGURE 2-11:
FAULT / OTF IOL vs. VOL.
1.220
1.210
1.200
1.190
1.180
45.00
40.00
35.00
30.00
25.00
20.00
15.00
CF = 1 µF
VOH = 0.8VDD
VDD = 5.5V
VDD = 5.0V
VDD = 4.0V
VDD = 5.0V
VDD = 3.0V
VDD = 3.0V
10.00
5.00
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
Temperature (ºC)
FIGURE 2-9:
VC(MIN) vs. Temperature.
FIGURE 2-12:
PWM Source Current (IOH)
vs. Temperature.
DS21755C-page 8
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
Note: Unless otherwise indicated, VDD = 5V, TA = 25°C.
30
25
20
15
10
5
2.630
2.625
2.620
2.615
2.610
2.605
2.600
2.595
VOL = 0.1VDD
VDD = 5.0V
VDD = 5.5V
VDD = 5.5V
VDD = 5.0V
VDD = 4.0V
VDD = 3.0V
VDD = 3.0V
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
FIGURE 2-13:
PWM Sink Current (IOL) vs.
FIGURE 2-16:
VOTF Threshold vs.
Temperature.
Temperature.
0.80
0.75
0.70
100
95
90
85
80
75
70
VDD = 5.5V
VDD = 5.0V
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
VDD = 5.5V
VDD = 4.0V
VDD = 3.0V
VDD = 3.0V
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
Temperature (ºC)
FIGURE 2-14:
VSHDN Threshold vs.
FIGURE 2-17:
Over-Temperature
Temperature.
Hysteresis (VOTF-HYS) vs. Temperature.
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
VDD = 5.5V
VDD = 5.0V
VDD = 4.0V
VDD = 3.0V
-40 -25 -10
5
20 35 50 65 80 95 110 125
Temperature (ºC)
FIGURE 2-15:
VREL Threshold vs.
Temperature.
2002-2013 Microchip Technology Inc.
DS21755C-page 9
TC646B/TC648B/TC649B
3.0
PIN FUNCTIONS
The descriptions of the pins are given in Table 3-1.
TABLE 3-1:
Pin
PIN FUNCTION TABLE
Name
Function
1
2
3
4
VIN
CF
Analog Input
Analog Output
Analog Input
Ground
VAS
GND
5
6
SENSE/NC
FAULT/OTF
Analog Input/No Connect. NC for TC648B.
Digital (Open-Drain) Output
OTF for TC648B
7
8
VOUT
VDD
Digital Output
Power Supply Input
3.1
Analog Input (V )
3.5
Digital (Open-Drain) Output
IN
(
)
FAULT/OTF
The thermistor network (or other temperature sensor)
connects to VIN. A voltage range of 1.20V to 2.60V (typ-
ical) on this pin drives an active duty cycle of 0% to
100% on the VOUT pin. The TC646B, TC648B and
TC649B devices enter shutdown mode when
0 VIN VSHDN. During shutdown, the FAULT/OTF
output is inactive and supply current falls to 30 µA
(typical).
FAULT/OTF goes low to indicate a fault condition.
When FAULT goes low due to a fan fault (TC646B and
TC649B devices), the output will remain low until the
fan fault condition has been removed (16 pulses have
been detected at the SENSE pin in a 32/f period). For
the TC646B and TC648B devices, the FAULT/OTF out-
put will also be asserted when the VIN voltage reaches
the VOTF threshold of 2.62V (typical). This gives an
over-temperature/100% fan speed indication.
3.2
Analog Output (C )
F
CF is the positive terminal for the PWM ramp generator
timing capacitor. The recommended value for the CF
capacitor is 1.0 µF for 30 Hz PWM operation.
3.6
Digital Output (V
)
OUT
VOUT is an active-high complimentary output that
drives the base of an external NPN transistor (via an
appropriate base resistor) or the gate of an N-channel
MOSFET. This output has asymmetrical drive. During a
fan fault condition, the VOUT output is continuously on.
3.3
Analog Input (V
)
AS
An external resistor divider connected to VAS sets the
auto-shutdown threshold. Auto-shutdown occurs when
VIN < VAS. The fan is automatically restarted when
VIN > (VAS + VHAS). During auto-shutdown, the
FAULT/OTF output is inactive and supply current falls
to 30 µA (typical).
3.7
Power Supply Input (V
)
DD
The VDD pin with respect to GND provides power to the
device. This bias supply voltage may be independent of
the fan power supply.
3.4
Analog Input (SENSE)
3.8
Ground (GND)
Pulses are detected at SENSE as fan rotation chops
the current through a sense resistor. The absence of
pulses indicates a fan fault condition.
Ground terminal.
3.9
No Connect (NC)
No internal connection.
DS21755C-page 10
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
The PWM approach to fan speed control results in
much less power dissipation in the drive element. This
allows smaller devices to be used and will not require
special heatsinking to remove the power being
dissipated in the package.
4.0
DEVICE OPERATION
The TC646B/TC648B/TC649B devices are a family of
temperature-proportional, PWM mode, fan speed con-
trollers. Features of the family include minimum fan
speed, fan auto-shutdown, fan auto-restart, remote
shutdown, over-temperature indication and fan fault
detection.
The other advantage of the PWM approach is that the
voltage being applied to the fan is always near 12V.
This eliminates any concern about not supplying a high
enough voltage to run the internal fan components,
which is very relevant in linear fan speed control.
The TC64XB family is slightly different from the original
TC64X family, which includes the TC642, TC646,
TC647, TC648 and TC649 devices. Changes have
been made to adjust the operation of the device during
a fan fault condition.
4.2
PWM Fan Speed Control
The TC646B, TC648B and TC649B devices implement
PWM fan speed control by varying the duty cycle of a
fixed-frequency pulse train. The duty cycle of a wave-
form is the on time divided by the total period of the
pulse. For example, if we take a 100 Hz waveform
(10 ms) with an on time of 5.0 ms, the duty cycle of this
waveform is 50% (5.0 ms / 10.0 ms). This example is
shown in Figure 4-1.
The key change to the TC64XB family of devices
(TC642B, TC647B, TC646B, TC648B, TC649B) is that
the FAULT and VOUT outputs no longer “latch” to a state
during a fan fault condition. The TC646B/TC648B/
TC649B family will continue to monitor the operation of
the fan so that when the fan returns to normal opera-
tion, the fan speed controller will also return to normal
operation (PWM mode). The operation and features of
these devices are discussed in the following sections.
t
4.1
Fan Speed Control Methods
The speed of a DC brushless fan is proportional to the
voltage across it. This relationship will vary from fan-to-
fan and should be characterized on an individual basis.
The speed versus applied voltage relationship can then
be used to set up the fan speed control algorithm.
ton
toff
There are two main methods for fan speed control. The
first is pulse width modulation (PWM) and the second
is linear. Using either method, the total system power
requirement to run the fan is equal. The difference
between the two methods is where the power is
consumed.
D = Duty Cycle
D = ton / t
t = Period
t = 1/f
f = Frequency
FIGURE 4-1:
Waveform.
Duty Cycle of a PWM
The following example compares the two methods for
a 12V, 120 mA fan running at 50% speed. With 6V
applied across the fan, the fan draws an average
current of 68 mA.
The TC646B/TC648B/TC649B devices generate a
pulse train with typical frequency of 30 Hz
a
(CF = 1 µF). The duty cycle can be varied from 0% to
100%. The pulse train generated by the TC646B/
TC648B/TC649B device drives the gate of an external
N-channel MOSFET or the base of an NPN transistor.
(shown in Figure 4-2). See Section 5.5, “Output Drive
Device Selection”, for more information on output drive
device selection.
Using a linear control method, there is 6V across the
fan and 6V across the drive element. With 6V and
68 mA, the drive element is dissipating 410 mW of
power.
Using the PWM approach, the fan voltage is modulated
at a 50% duty cycle, with most of the 12V being
dropped across the fan. With 50% duty cycle, the fan
draws a RMS current of 110 mA and an average cur-
rent of 72 mA. Using a MOSFET with a 1 RDS(on) (a
fairly typical value for this low current), the power dissi-
pation in the drive element would be: 12 mW (Irms2 *
RDS(on)). Using a standard 2N2222A NPN transistor
(assuming a Vce-sat of 0.8V), the power dissipation
would be 58 mW (Iavg* Vce-sat).
2002-2013 Microchip Technology Inc.
DS21755C-page 11
TC646B/TC648B/TC649B
start-up timer is activated again. If pulses are not
detected at the SENSE pin during this additional
period, the FAULT output will go low to indicate that a
fan fault condition has occurred. See Section 4.7,
“FAULT/OTF Output”, for more details.
12V
FAN
V
DD
4.4
PWM Frequency & Duty Cycle
Control (C & V Pins)
F
IN
D
S
The frequency of the PWM pulse train is controlled by
the CF pin. By attaching a capacitor to the CF pin, the
frequency of the PWM pulse train can be set to the
desired value. The typical PWM frequency for a 1.0 µF
capacitor is 30 Hz. The frequency can be adjusted by
raising or lowering the value of the capacitor. The CF
pin functions as a ramp generator. The voltage at this
pin will ramp from 1.20V to 2.60V (typically) as a saw-
tooth waveform. An example of this is shown in
Figure 4-3.
Q
DRIVE
TC646B
TC648B
TC649B
V
OUT
G
GND
FIGURE 4-2:
PWM Fan Drive.
By modulating the voltage applied to the gate of the
MOSFET (QDRIVE), the voltage that is applied to the
fan is also modulated. When the VOUT pulse is high, the
gate of the MOSFET is turned on, pulling the voltage at
the drain of QDRIVE to zero volts. This places the full
12V across the fan for the ton period of the pulse. When
the duty cycle of the drive pulse is 100% (full on,
ton = t), the fan will run at full speed. As the duty cycle
is decreased (pulse on time “ton” is lowered), the fan
will slow down proportionally. With the TC646B,
TC648B and TC649B devices, the duty cycle is con-
trolled by the VIN input and can also be terminated by
the VAS input (auto-shutdown). This is described in
more detail in Section 5.5, “Output Drive Device
Selection”.
2.8
CF = 1 µF
VCMAX
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
VCMIN
40
0
20
60
80
100
Time (msec)
FIGURE 4-3:
CF Pin Voltage.
4.3
Fan Start-up
The duty cycle of the PWM output is controlled by the
voltage at the VIN input pin. The duty cycle of the PWM
output is produced by comparing the voltage at the VIN
pin to the voltage ramp at the CF pin. When the voltage
at the VIN pin is 1.20V, the duty cycle will be 0%. When
the voltage at the VIN pin is 2.60V, the PWM duty cycle
will be 100% (these are both typical values). The
VIN-to-PWM duty cycle relationship is shown in
Figure 4-4.
Often overlooked in fan speed control is the actual
start-up control period. When starting a fan from a non-
operating condition (fan speed is zero revolutions per
minute (RPM)), the desired PWM duty cycle or average
fan voltage cannot be applied immediately. Since the
fan is at a rest position, the fan’s inertia must be over-
come to get it started. The best way to accomplish this
is to apply the full rated voltage to the fan for a minimum
of one second. This will ensure that in all operating
environments, the fan will start and operate properly.
An example of the start-up timing is shown in
Figure 1-1.
The lower value of 1.20V is referred to as “VCMIN” and
the 2.60V threshold is referred to as “VCMAX”. A calcu-
lation for duty cycle is shown in the equation below. The
voltage range between VCMIN and VCMAX is character-
ized as “VCSPAN“ and has a typical value of 1.4V, with
minimum and maximum values of 1.3V and 1.5V,
respectively.
A key feature of the TC646B/TC648B/TC649B devices
is the start-up timer. When power is first applied to the
device, or when the device is brought out of the shut-
down/auto-shutdown modes of operation, the VOUT
output will go to a high state for 32 PWM cycles (one
second for CF = 1 µF). This will drive the fan to full
speed for this time frame.
EQUATION
PWM DUTY CYCLE
(VIN - VCMIN) * 100
Duty Cycle (%) =
During the start-up period for the TC646B and TC649B
devices, the SENSE pin is being monitored for fan
pulses. If pulses are detected during this period, the fan
speed controller will then move to PWM operation. If
pulses are not detected during the start-up period, the
VCMAX - VCMIN
DS21755C-page 12
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
For the TC646B, TC648B and TC649B devices, the VIN
pin is also used as the shutdown pin. The VSHDN and
When the device is in shutdown/auto-shutdown mode,
the VOUT output is actively held low. The output can be
varied from 0% (full off) to 100% duty cycle (full on). As
previously discussed, the duty cycle of the VOUT output
is controlled via the VIN input voltage and can be termi-
nated based on the VAS voltage.
VREL threshold voltages are characterized in the “Elec-
trical Characteristics Table” of Section 1.0. If the VIN pin
voltage is pulled below the VSHDN threshold, the device
will shut down (VOUT output goes to a low state, the
FAULT/OTF pin is inactive). If the voltage on the VIN pin
then rises above the release threshold (VREL), the
device will go through a power-up sequence (assuming
that the VIN voltage is also higher than the voltage at
the VAS pin). The power-up sequence is shown later in
the “Behavioral Algorithm Flowcharts” of Section 4.9.
A base current-limiting resistor is required when using
a transistor as the external drive device in order to limit
the amount of drive current that is drawn from the VOUT
output.
The VOUT output can be directly connected to the gate
of an external MOSFET. One concern when doing this,
though, is that the fast turn-off time of the fan drive
MOSFET can cause a problem because the fan motor
looks like an inductor. When the MOSFET is turned off
quickly, the current in the fan wants to continue to flow
in the same direction. This causes the voltage at the
drain of the MOSFET to rise. If there aren’t any clamp
diodes internal to the fan, this voltage can rise above
the drain-to-source voltage rating of the MOSFET. For
this reason, an external clamp diode is suggested. This
is shown in Figure 4-5.
100
90
80
70
60
50
40
30
20
10
0
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
VIN (V)
FIGURE 4-4:
Cycle (Typical).
VIN Voltage vs. PWM Duty
Clamp Diode
FAN
4.5
Auto-Shutdown Mode (V
)
AS
For the TC646B, TC648B and TC649B devices, pin 3
is the VAS pin and is used for setting the auto-shutdown
threshold voltage.
Q1
VOUT
The auto-shutdown function provides a way to set a
threshold voltage (temperature) at which the fan will be
shut off. This way, if the temperature in the system
reaches a threshold at which the fan(s) no longer needs
to operate, the fan can be shutdown automatically.
RSENSE
The voltage range for the VAS pin is the same as the
voltage range for the VIN pin (1.20V to 2.60V). The volt-
age at the VAS pin is set in this range so that when the
voltage at the VIN pin decreases below the voltage at
the VAS pin (signifying that the threshold temperature
has been reached), the VOUT output is shut off (goes to
a low state). In auto-shutdown, the FAULT/OTF output
is inactive (high-impedance). Auto-shutdown mode is
exited when the VIN voltage exceeds the VAS voltage
by the auto-shutdown hysteresis voltage (VHAS). Upon
exiting auto-shutdown mode, the start-up timer is
triggered and the device returns to normal operation.
GND
Q1: N-Channel MOSFET
FIGURE 4-5:
Clamp Diode for Fan.
4.7 FAULT/OTF Output
The FAULT/OTF output is an open-drain, active-low
output. For the TC646B and TC649B devices, pin 6 is
labeled as the FAULT output and indicates when a fan
fault condition has occurred. For the TC646B device,
the FAULT output also indicates when an over-temper-
ature (OTF) condition has occurred. For the TC648B
device, pin 6 is the OTF output that indicates an over-
temperature (OTF) condition has occurred.
4.6
V
Output (PWM Output)
OUT
The VOUT output is a digital output designed for driving
the base of a transistor or the gate of a MOSFET. The
VOUT output is designed to be able to quickly raise the
base current or the gate voltage of the external drive
device to its final value.
2002-2013 Microchip Technology Inc.
DS21755C-page 13
TC646B/TC648B/TC649B
For the TC646B and TC648B devices, an over-temper-
4.8
Sensing Fan Operation (SENSE)
ature condition is indicated when the VIN input reaches
the VOTF threshold voltage (the VOTF threshold voltage
is typically 20 mV higher than the VCMAX threshold and
has 80 mV of hysteresis). This indicates that maximum
cooling capacity has been reached (the fan is at full
speed) and that an overheating situation can occur.
When the voltage at the VIN input falls below the VOTF
threshold voltage by the hysteresis value (VOTF-HYS),
the FAULT/OTF output will return to the high state (a
pull-up resistor is needed on the FAULT/OTF output).
The SENSE input is an analog input used to monitor
the fan’s operation (the TC648B device does not incor-
porate the fan sensing feature). It does this by sensing
fan current pulses that represent fan rotation. When a
fan rotates, commutation of the fan current occurs as
the fan poles pass the armatures of the motor. The
commutation of the fan current makes the current
waveshape appear as pulses. There are two typical
current waveforms of brushless DC fan motors,
illustrated in Figures 4-6 and 4-7.
For the TC646B/TC649B devices, a fan fault condition
is indicated when fan current pulses are no longer
detected at the SENSE pin. Pulses at the SENSE pin
indicate that the fan is spinning and conducting current.
If pulses are not detected at the SENSE pin for
32 PWM cycles, the 3-cycle diagnostic timer is fired.
This means that the VOUT output is high for 3 PWM
cycles. If pulses are detected in this 3-cycle period, nor-
mal PWM operation is resumed and no fan fault is indi-
cated. If no pulses are detected in the 3-cycle period,
the start-up timer is activated and the VOUT output is
driven high for 32 PWM cycles. If pulses are detected
during this time-frame, normal PWM operation is
resumed. If no pulses are detected during this time-
period, a fan fault condition exists and the FAULT
output is pulled low.
During a fan fault condition, the FAULT output will
remain low until the fault condition has been removed.
During this time, the VOUT output is driven high contin-
uously to attempt to restart the fan and the SENSE pin
is monitored for fan pulses. If a minimum of 16 pulses
are detected at the SENSE input over a 32 cycle time-
period (one second for CF = 1.0 µF), the fan fault con-
dition no longer exists. Therefore, The FAULT output is
released and the VOUT output returns to normal PWM
operation, as dictated by the VIN and VAS inputs.
FIGURE 4-6:
And Positive Commutation Current.
Fan Current With DC Offset
If the VIN voltage is pulled below the VSHDN level during
a fan fault condition, the FAULT output will be released
and the VOUT output will be shutdown (VOUT = 0V). If
the VIN voltage then increases above the VREL thresh-
old and is above the VAS voltage, the device will go
through the normal start-up routine.
If, during a fan fault condition, the voltage at the VIN pin
drops below the VAS voltage level, the TC646B/
TC649B device will continue to hold the FAULT line low
and drive the VOUT output to 100% duty cycle. If the fan
fault condition is then removed, the FAULT output will
be released and the TC646B/TC649B device will enter
auto-shutdown mode until the VIN voltage is brought
above the VAS voltage by the auto-shutdown hysteresis
value (VHAS). The TC646B/TC649B device will then
resume normal PWM mode operation.
FIGURE 4-7:
Commutation Pulses To Zero.
Fan Current With
The sink current capability of the FAULT output is listed
in the “Electrical Characteristics Table” of Section 1.0.
DS21755C-page 14
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
The SENSE pin senses positive voltage pulses that
have an amplitude of 70 mV (typical value). Each time
a pulse is detected, the missing pulse detector timer
(tMP) is reset. As previously stated, if the missing pulse
detector timer reaches the time for 32 cycles, the loop
for diagnosing a fan fault is engaged (diagnostic timer,
then the start-up timer).
The initial pulse blanker is also implemented to stop
false sensing of fan current pulses. When a fan is in a
locked rotor condition, the fan current no longer com-
mutates, it simply flows through one fan winding and is
a DC current. When a fan is in a locked rotor condition
and the TC646B/TC649B device is in PWM mode, it
will see one current pulse each time the VOUT output is
turned on. The initial pulse blanker allows the
TC646B/TC649B device to ignore this pulse and
recognize that the fan is in a fault condition.
Both of the fan current waveshapes shown in Figures
4-6 and 4-7 can be sensed with the sensing scheme
shown in Figure 4-8.
4.9
Behavioral Algorithms
The behavioral algorithms for the TC646B/TC649B
and TC648B devices are shown in Figure 4-9 and
Figure 4-10, respectively.
FAN
The behavioral algorithms show the step-by-step deci-
sion-making process for the fan speed controller oper-
ation. The TC646B and TC649B devices are very
similar with one exception: the TC649B device does
not implement the over-temperature portion of the
algorithm.
TC64XB
RISO
VOUT
SENSE
CSENSE
(0.1 µF typical)
RSENSE
GND
FIGURE 4-8:
Sensing Scheme For Fan
Current.
The fan current flowing through RSENSE generates a
voltage that is proportional to the current. The CSENSE
capacitor removes any DC portion of the voltage
across RSENSE and presents only the voltage pulse
portion to the SENSE pin of the TC646B/TC649B
devices.
The RSENSE and CSENSE values need to be selected so
that the voltage pulse provided to the SENSE pin is
70 mV (typical) in amplitude. Be sure to check the
sense pulse amplitude over all operating conditions
(duty cycles) as the current pulse amplitude will vary
with duty cycle. See Section 5.0, “Applications Informa-
tion”, for more details on selecting values for RSENSE
and CSENSE
.
Key features of the SENSE pin circuitry are an initial
blanking period after every VOUT pulse and an initial
pulse blanker.
The TC646B/TC649B sense circuitry has a blanking
period that occurs at the turn-on of each VOUT pulse.
During this blanking period, the sense circuitry ignores
any pulse information that is seen at the SENSE pin
input. This stops the TC646B/TC649B device from
falsely sensing a current pulse that is due to the fan
drive device turn-on.
2002-2013 Microchip Technology Inc.
DS21755C-page 15
TC646B/TC648B/TC649B
Normal
Operation
Power-Up
Power-on
Reset
FAULT = 1
Clear Missing
Pulse Detector
Yes
?
Shutdown
VOUT = 0
VIN < VSHDN
Yes
Shutdown
VOUT = 0
VIN < VSHDN
?
No
No
VIN > VREL
Yes
?
No
No
VIN > VREL?
Yes
Yes
Auto
Shutdown
VOUT = 0
Yes
Yes
V
IN < VAS
No
?
Auto-
Shutdown
VOUT = 0
V
IN < VAS
No
?
Power-Up
VIN
>
No
(VAS + VHAS
)
VIN
>
No
(VAS+ VHAS
)
VIN > VOTF?
Yes
Hot Start
Yes
Hot Start
FAULT = 0
Fire Start-up
Timer
(1 sec)
No
VOUT
Proportional
to VIN
TC646B Only
Fire Start-up
Timer
(1 sec)
No
Fan Pulse
Detected?
Yes
No
Fan Pulse
Detected?
Yes
Yes
Fan Pulse
Detected?
M.P.D.
Expired?
Yes
Fire
No
Normal
Operation
No
Diagnostic
Timer
Fan Fault
(100 msec)
Fan Fault
Fire Start-up
Timer
(1 sec)
No
Yes
Fan Pulse
Detected?
FAULT = Low,
VOUT = High
Yes
Fan Pulse
Detected?
Yes
No
No
Shutdown
OUT = 0
VIN< VSHDN
No
?
V
Fan Fault
Yes
V
IN > VREL?
Power-Up
No
16 Pulses
Detected?
Yes
Normal
Operation
FIGURE 4-9:
TC646B/TC649B Behavioral Algorithm.
DS21755C-page 16
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
Normal
Operation
Power-Up
VOUT
Proportional
to VIN
Power-on
Reset
OTF = 1
Yes
Minimum
Speed Mode
VAS = 0V
No
Yes
VIN > VOTF
?
No
OTF = 0
OTF = 1
Yes
Auto-
VIN < VAS
?
Shutdown
VOUT = 0
Yes
Auto
Shutdown
OUT = 0
No
V
IN < VAS
No
?
VIN
(VAS+ VHAS
>
No
V
)
Yes
Fire Start-up
Timer
(1 sec)
Normal
Operation
Minimum
Speed Mode
Yes
VIN = 0V
VOUT = 0
No
No
VIN > 1.20V
VOUT = 0
No
VIN > 1.20V
Yes
VOUT
Yes
Proportional
to VIN
Power-Up
Yes
VIN > VOTF
No
?
OTF = 0
OTF = 1
FIGURE 4-10:
TC648B Behavioral Algorithm.
2002-2013 Microchip Technology Inc.
DS21755C-page 17
TC646B/TC648B/TC649B
One of the simplest ways of sensing temperature over
a given range is to use a thermistor. By using a NTC
thermistor, as shown in Figure 5-1, a temperature-
variant voltage can be created.
5.0
5.1
APPLICATIONS INFORMATION
Setting the PWM Frequency
The PWM frequency of the VOUT output is set by the
capacitor value attached to the CF pin. The PWM fre-
quency will be 30 Hz (typical) for a 1 µF capacitor. The
relationship between frequency and capacitor value is
linear, making alternate frequency selections easy.
V
DD
I
DIV
As stated in previous sections, the PWM frequency
should be kept in the range of 15 Hz to 35 Hz. This will
eliminate the possibility of having audible frequencies
when varying the duty cycle of the fan drive.
R
R
T
1
2
V
IN
A very important factor to consider when selecting the
PWM frequency for the TC646B/TC648B/TC649B
devices is the RPM rating of the selected fan and the
minimum duty cycle that you will be operating at. For
fans that have a full-speed rating of 3000 RPM or less,
it is desirable to use a lower PWM frequency. A lower
PWM frequency allows for a longer time-period to mon-
itor the fan current pulses. The goal is to be able to
monitor at least two fan current pulses during the on-
time of the VOUT output.
R
FIGURE 5-1:
Temperature Sensing
Circuit.
Figure 5-1 represents a temperature-dependent, volt-
age divider circuit. RT is a conventional NTC thermistor,
R1 and R2 are standard resistors. R1 and RT form a par-
allel resistor combination that will be referred to as
RTEMP (RTEMP = R1 * RT / R1 + RT). As the temperature
increases, the value of RT decreases and the value of
RTEMP will decrease with it. Accordingly, the voltage at
VIN increases as temperature increases, giving the
desired relationship for the VIN input. R1 helps to linear-
ize the response of the SENSE network and aids in
obtaining the proper VIN voltages over the desired tem-
perature range. An example of this is shown in
Figure 5-2.
Example: The system design requirement is to operate
the fan at 50% duty cycle when ambient temperatures
are below 20°C. The fan full-speed RPM rating is
3000 RPM and has four current pulses per rotation. At
50% duty cycle, the fan will be operating at
approximately 1500 RPM.
EQUATION
60 1000
Time for one revolution (msec.) = ----------------------- = 40
1500
If less current draw from VDD is desired, a larger value
thermistor should be chosen. The voltage at the VIN pin
can also be generated by a voltage output temperature
sensor device. The key is to get the desired VIN volt-
age-to-system (or component) temperature relation-
ship.
If one fan revolution occurs in 40 msec, each fan pulse
occurs 10 msec apart. In order to detect two fan current
pulses, the on-time of the VOUT pulse must be at least
20 msec. With the duty cycle at 50%, the total period of
one cycle must be at least 40 msec, which makes the
PWM frequency 25 Hz. For this example, a PWM fre-
quency of 20 Hz is recommended. This would define a
CF capacitor value of 1.5 µF.
The following equations apply to the circuit in
Figure 5-1.
EQUATION
5.2
Temperature Sensor Design
V
R
As discussed in previous sections, the VIN analog input
has a range of 1.20V to 2.60V (typical), which repre-
sents a duty cycle range on the VOUT output of 0% to
100%, respectively. The VIN voltages can be thought of
as representing temperatures. The 1.20V level is the
low temperature at which the system requires very little
cooling. The 2.60V level is the high temperature, for
which the system needs maximum cooling capability
(100% fan speed).
DD
2
VT1 = ---------------------------------------------
R
T1 + R
TEMP
2
V
R
DD
2
VT2 = ---------------------------------------------
T2 + R
R
TEMP
2
In order to solve for the values of R1, R2, VIN and the
temperatures at which they are to occur, need to be
selected. The variables T1 and T2 represent the
selected temperatures. The value of the thermistor at
these two temperatures can be found in the thermistor
DS21755C-page 18
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
data sheet. With the values for the thermistor and the
values for VIN, you now have two equations from which
the values for R1 and R2 can be found.
5.4
FanSense Network
(R and C
)
SENSE
SENSE
The SENSE network (comprised of RSENSE and
SENSE) allows the TC646B and TC649B devices to
Example: The following design goals are desired:
C
• Duty Cycle = 50% (VIN = 1.90V) with Temperature
(T1) = 30°C
detect commutation of the fan motor. RSENSE converts
the fan current into a voltage. CSENSE AC couples this
voltage signal to the SENSE pin. The goal of the
SENSE network is to provide a voltage pulse to the
SENSE pin that has a minimum amplitude of 90 mV.
This will ensure that the current pulse caused by the
fan commutation is recognized by the TC646B/TC649B
device.
• Duty Cycle = 100% (VIN = 2.60V) with
Temperature (T2) = 60°C
Using a 100 k thermistor (25°C value), we look up the
thermistor values at the desired temperatures:
• RT (T1) = 79428 @ 30°C
• RT (T2) = 22593 @ 60°C
A 0.1 µF ceramic capacitor is recommended for
CSENSE. Smaller values will require that larger sense
resistors be used. Using a 0.1 µF capacitor results in
reasonable values for RSENSE. Figure 5-3 illustrates a
typical SENSE network.
Substituting these numbers into the given equations
produces the following numbers for R1 and R2.
• R1 = 34.8 k
• R2 = 14.7 k
140
120
100
80
4.000
3.500
3.000
2.500
2.000
1.500
1.000
0.500
0.000
FAN
VIN Voltage
R
ISO
V
OUT
715
60
NTC Thermistor
100 kꢁ @ 25ºC
40
20
SENSE
RTEMP
30
C
0
SENSE
R
SENSE
20
40
50
60
70
80
90 100
(0.1 µF typical)
Temperature (ºC)
Note:
See Table 5-1 for R
values.
SENSE
FIGURE 5-2:
How Thermistor Resistance,
VIN, and RTEMP Vary With Temperature.
FIGURE 5-3:
Typical Sense Network.
Figure 5-2 graphs RT, RTEMP (R1 in parallel with RT)
and VIN, versus temperature for the example shown
above.
The required value of RSENSE will change with the cur-
rent rating of the fan and the fan current waveshape. A
key point is that the current rating of the fan specified
by the manufacturer may be a worst-case rating, with
the actual current drawn by the fan being lower than
this rating. For the purposes of setting the value for
RSENSE, the operating fan current should be measured
to get the nominal value. This can be done by using an
oscilloscope current probe or using a voltage probe
with a low-value resistor (0.5). Another good tool for
this exercise is the TC642 Evaluation Board. This
board allows the RSENSE and CSENSE values to be eas-
ily changed while allowing the voltage waveforms to be
monitored to ensure the proper levels are being
reached.
5.3
Thermistor Selection
As with any component, there are a number of sources
for thermistors. A listing of companies that manufacture
thermistors can be found at www.temperatures.com/
thermivendors.html. This website lists over forty
suppliers of thermistor products. A brief list is shown
here:
-
-
-
-
Thermometrics®
Ametherm®
U.S. Sensor™
-
-
-
-
Quality Thermistor™
Sensor Scientific™
Vishay®
muRata®
Table 5-1 shows values of RSENSE according to the
nominal operating current of the fan. The fan currents
are average values. If the fan current falls between two
of the values listed, use the higher resistor value.
Advanced Thermal
Products™
2002-2013 Microchip Technology Inc.
DS21755C-page 19
TC646B/TC648B/TC649B
Another important factor to consider when selecting the
RSENSE value is the fan current value during a locked-
rotor condition. When a fan is in a locked-rotor condi-
tion (fan blades are stopped even though power is
being applied to the fan), the fan current can increase
dramatically (often 2.5 to 3.0 times the normal operat-
ing fan current). This will effect the power rating of the
RSENSE resistor selected.
TABLE 5-1:
FAN CURRENT VS. RSENSE
Nominal Fan Current
(mA)
RSENSE ()
50
9.1
4.7
3.0
2.4
2.0
1.8
1.5
1.3
1.2
1.0
100
150
200
250
300
350
400
450
500
When selecting the fan for the application, the current
draw of the fan during a locked-rotor condition should
be considered. Especially if multiple fans are being
used in the application.
There are two main types of fan designs when looking
at fan current draw during a locked-rotor condition.
The first is a fan that will simply draw high DC currents
when put into a locked-rotor condition. Many older fans
were designed this way. An example of this is a fan that
draws an average current of 100 mA during normal
operation. In a locked-rotor condition, this fan will draw
250 mA of average current. For this design, the
RSENSE power rating must be sized to handle the
250 mA condition. The fan bias supply must also take
this into account.
The values listed in Table 5-1 are for fans that have the
fan current waveshape shown in Figure 4-7. With this
waveshape, the average fan current is closer to the
peak value, which requires the resistor value to be
higher. When using a fan that has the fan current wave-
shape shown in Figure 4-6, the resistor value can often
be decreased since the current peaks are higher than
the average and it is the AC portion of the voltage that
gets coupled to the SENSE pin.
The second style design, which represents many of the
newer fan designs today, acts to limit the current in a
locked-rotor condition by going into a pulse mode of
operation. An example of the fan current waveshape
for this style fan is shown in Figure 5-5. The fan repre-
sented in Figure 5-5 is a Panasonic®, 12V, 220 mA fan.
During the on-time of the waveform, the fan current is
peaking up to 550 mA. Due to the pulse mode opera-
tion, the actual RMS current of the fan is very near the
220 mA rating. Because of this, the power rating for the
RSENSE resistor does not have to be oversized for this
application.
The key point when selecting an RSENSE value is to try
to minimize the value in order to minimize the power
dissipation in the resistor. In order to do this, it is critical
to know the waveshape of the fan current and not just
the average value.
Figure 5-4 shows some typical waveforms for the fan
current and the voltage at the SENSE pin.
FIGURE 5-4:
Typical Fan Current and
SENSE Pin Waveforms.
DS21755C-page 20
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
FIGURE 5-5:
Fan Current During a Locked Rotor Condition.
The following is recommended:
5.5
Output Drive Device Selection
• Ask how the fan is designed. If the fan has clamp
diodes internally, this problem will not be seen. If
the fan does not have internal clamp diodes, it is a
good idea to install one externally (Figure 5-6).
Putting a resistor between VOUT and the gate of
the MOSFET will also help slow down the turn-off
and limit this condition.
The TC646B/TC648B/TC649B is designed to drive an
external NPN transistor or N-channel MOSFET as the
fan speed modulating element. These two arrange-
ments are shown in Figure 5-7. For lower-current fans,
NPN transistors are a very economical choice for the
fan drive device. It is recommended that, for higher cur-
rent fans (300 mA and above), MOSFETs be used as
the fan drive device. Table 5-2 provides some possible
part numbers for use as the fan drive element.
When using a NPN transistor as the fan drive element,
a base current-limiting resistor must be used. This is
shown in Figure 5-7.
FAN
When using MOSFETs as the fan drive element, it is
very easy to turn the MOSFETs on and off at very high
rates. Because the gate capacitances of these small
MOSFETs are very low, the TC646B/TC648B/TC649B
can charge and discharge them very quickly, leading to
very fast edges. Of key concern is the turn-off edge of
the MOSFET. Since the fan motor winding is essentially
an inductor, once the MOSFET is turned off the current
that was flowing through the motor wants to continue to
flow. If the fan does not have internal clamp diodes
around the windings of the motor, there is no path for
this current to flow through and the voltage at the drain
of the MOSFET may rise until the drain-to-source rating
of the MOSFET is exceeded. This will most likely cause
the MOSFET to go into avalanche mode. Since there is
very little energy in this occurrence, it will probably not
fail the device, but it would be a long-term reliability
issue.
Q1
VOUT
RSENSE
GND
Q1: N-Channel MOSFET
FIGURE 5-6:
Clamp Diode For Fan Turn-
Off.
2002-2013 Microchip Technology Inc.
DS21755C-page 21
TC646B/TC648B/TC649B
Fan Bias
Fan Bias
FAN
FAN
RBASE
VOUT
Q1
Q1
VOUT
RSENSE
RSENSE
GND
GND
b) N-Channel MOSFET
a) Single Bipolar Transistor
FIGURE 5-7:
Output Drive Device Configurations.
FAN DRIVE DEVICE SELECTION TABLE (NOTE 2)
TABLE 5-2:
Device
Max Vbe sat /
Vgs(V)
VCE/VDS
Fan Current
(mA)
Suggested
Rbase ()
Package
Min hfe
(V)
MMBT2222A
MPS2222A
MPS6602
SI2302
SOT-23
TO-92
1.2
1.2
1.2
2.5
2.5
4.5
4.5
50
50
40
40
40
20
20
30
60
150
150
500
500
500
1000
500
800
800
TO-92
50
301
SOT-23
SOT-23
SO-8
NA
NA
NA
NA
Note 1
Note 1
Note 1
Note 1
MGSF1N02E
SI4410
SI2308
SOT-23
Note 1: A series gate resistor may be used in order to control the MOSFET turn-on and turn-off times.
2: These drive devices are suggestions only. Fan currents listed are for individual fans.
5.6
Bias Supply Bypassing and Noise
Filtering
5.7
Design Example/Typical
Application
The bias supply (VDD) for the TC646B/TC648B/
TC649B devices should be bypassed with a 1.0 µF
ceramic capacitor. This capacitor will help supply the
peak currents that are required to drive the base/gate
of the external fan drive devices.
The system has been designed with the following
components and criteria:
System inlet air ambient temperature ranges from 0ºC
to 50ºC. At 20ºC, system cooling is no longer required,
so the fan is to be turned off. Prior to turn-off, the fan
should be run at 40% of its full fan speed. Full fan
speed should be reached when the ambient air is 40ºC.
As the VIN pin controls the duty cycle in a linear fashion,
any noise on this pin can cause duty cycle jittering. For
this reason, the VIN pin should be bypassed with a
0.01 µF capacitor.
The system has a surface mount, NTC-style thermistor
in a 1206 package. The thermistor is mounted on a
daughtercard that is directly in the inlet air stream. The
thermistor is a NTC, 100 k @ 25ºC, Thermometrics®
part number NHQ104B425R5. The given Beta for the
thermistor is 4250. The system bias voltage to run the
fan controller is 5V, while the fan voltage is 12V.
In order to keep fan noise off of the TC646B/TC648B/
TC649B device ground, individual ground returns for
the TC646B/TC648B/TC649B and the low side of the
fan current sense resistor should be used.
DS21755C-page 22
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
The fan used in the system is a Panasonic®, Panaflo®-
series fan, model number FBA06T12H.
A fault indication is desired when the fan is in a locked-
rotor condition. This signal is used to indicate to the
system that cooling is not available and a warning
should be issued to the user. No fault indication from
the fan controller is necessary for an over-temperature
condition as this is being reported elsewhere.
Step 1: Gathering Information.
The first step in the design process is to gather the
needed data on the fan and thermistor. For the fan, it is
also a good idea to look at the fan current waveform, as
indicated earlier in the data sheet.
Fan Information: Panasonic number: FBA06T12H
- Voltage = 12V
- Current = 145 mA (data sheet number)
FIGURE 5-9:
FBA06T12H Locked-Rotor
Fan Current.
From Figure 5-9, it is seen that in a locked-rotor fault
condition, the fan goes into a pulsed current mode of
operation. During this mode, when the fan is conduct-
ing current, the peak current value is 360 mA for peri-
ods of 200 msec. This is significantly higher than the
average full fan speed current shown in Figure 5-8.
However, because of the pulse mode, the average fan
current in a locked-rotor condition is lower and was
measured at 68 mA. The RMS current during this
mode, which is necessary for current sense resistor
(RSENSE) value selection, was measured at 154 mA.
This is slightly higher than the RMS value during full fan
speed operation.
Thermistor Information: Thermometrics part number:
FIGURE 5-8:
FBA06T12H Fan Current
NHQ104B425R5
Waveform.
- Resistance Value: 100 k @ 25ºC
- Beta Value (): 4250
From the waveform in Figure 5-8, the fan current has
an average value of 120 mA, with peaks up to 150 mA.
This information will help in the selection of the RSENSE
and CSENSE values later on. Also of interest for the
RSENSE selection value is what the fan current does in
a locked-rotor condition.
From this information, the thermistor values at 20ºC
and 40ºC must be found. This information is needed in
order to select the proper resistor values for R1 and R2
(see Figure 5-13), which sets the VIN voltage.
The equation for determining the thermistor values is
shown below:
EQUATION
TO – T
RT = RTO exp ------------------------
T TO
RT0 is the thermistor value at 25ºC. T0 is 298.15 and T
is the temperature of interest. All temperatures are in
degrees kelvin.
Using this equation, the values for the thermistor are
found to be:
- RT (20ºC) = 127,462
- RT (40ºC) = 50,520
2002-2013 Microchip Technology Inc.
DS21755C-page 23
TC646B/TC648B/TC649B
Step 2: Selecting the Fan Controller.
Using standard 1% resistor values, the selected R1 and
R2 values are:
The requirements for the fan controller are that it have
auto-shutdown capability at 20ºC and also indicate a
fan fault condition. No over-temperature indication is
necessary. From these specifications, the proper
selection is the TC649B device.
- R1 = 237 k
- R2 = 45.3 k
A graph of the VIN voltage, thermistor resistance and
RTEMP resistance versus temperature for this
configuration is shown in Figure 5-10.
Step 3: Setting the PWM Frequency.
The fan is rated at 4200 RPM with a 12V input. The
goal is to run to a 40% duty cycle (roughly 40% fan
speed), which equates to approximately 1700 RPM. At
1700 RPM, one full fan revolution occurs every
35 msec. The fan being used is a four-pole fan that
gives four current pulses per revolution. With this infor-
mation, and viewing test results at 40% duty cycle, two
fan current pulses were always seen during the PWM
on time with a PWM frequency of 30 Hz. For this rea-
son, the CF value is selected to be 1.0 µF.
400
350
300
250
200
150
100
50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
VIN
NTC Thermistor
100 kꢁ @ 25ºC
RTEMP
10
Step 4: Setting the VIN Voltage.
0
0
20
30
40
50
60
70
80
90
From the design criteria, the desired duty cycle at 20ºC
is 40% and full fan speed should be reached at 40ºC.
Based on a VIN voltage range of 1.20V to 2.60V, which
Temperature (ºC)
FIGURE 5-10:
and RTEMP vs. Temperature
Thermistor Resistance, VIN
represents 0% to 100% duty cycle, the 40% duty cycle
voltage can be found using the following equation:
Step 5: Setting the Auto-Shutdown Voltage (VAS).
EQUATION
Setting the voltage for the auto-shutdown is done using
a simple resistor voltage divider. The criteria for the
voltage divider in this design is that it draw no more
than 100 µA of current. The required auto-shutdown
voltage was determined earlier in the selection of the
VIN voltage at 40% duty cycle, since this was also set
at the temperature that auto-shutdown is to occur
(20ºC).
VIN = (DC * 1.4V) + 1.20V
DC = Desired Duty Cycle
Using the above equation, the VIN values are
calculated to be:
- VIN (40%) = 1.76V
- VIN (100%) = 2.60V
- VAS = 1.76V
Using these values along with the thermistor resistance
values calculated earlier, the R1 and R2 resistor values
can now be calculated using the following equation:
Given this desired setpoint and knowing the desired
divider current, the following equations can be used to
solve for the resistor values for R3 and R4:
EQUATION
EQUATION
VDD R2
5V
VT1 = -----------------------------------------
RTEMPT1 + R2
IDIV
=
R3 + R4
VDD R2
5V * R4
R3 + R4
VT2 = -----------------------------------------
RTEMPT2 + R2
VAS
=
Using the equations above, the resistor values for R3
and R4 are found to be:
RTEMP is the parallel combination of R1 and the therm-
istor. V(T1) represents the VIN voltage at 20ºC and
V(T2) represents the VIN voltage at 40ºC. Solving the
equations simultaneously yields the following values
(VDD = 5V):
- R3 = 32.4 k
- R4 = 17.6 k
Using standard 1% resistor values yields the following
values:
- R1 = 238,455
- R2 = 45,161
- R3 = 32.4 k
- R4 = 17.8 k
DS21755C-page 24
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
Step 6: Selecting the Fan Drive Device (Q1).
Since the fan operating current is below 200 mA, a
transistor or MOSFET can be used as the fan drive
device. In order to reduce component count and cur-
rent draw, the drive device for this design is chosen to
be a N-channel MOSFET. Selecting from Table 5-2,
there are two MOSFETs that are good choices, the
MGSF1N02E and the SI2302. These devices have the
same pinout and are interchangeable for this design.
Step 7: Selecting the RSENSE and CSENSE Values.
The goal again for selecting these values is to ensure
that the signal at the SENSE pin is 90 mV in amplitude
under all operating conditions. This will ensure that the
pulses are detected by the TC649B device and that the
fan operation is detected.
The fan current waveform is shown in Figure 5-8, and
as discussed previously, with a waveform of this shape,
the current sense resistor values shown in Table 5-1 are
good reference values. Given the average fan operating
current was measured to be 120 mA, this falls between
two of the values listed in the table. For reference pur-
poses, both values have been tested and these results
are shown in Figures 5-11 (4.7) and 5-12 (3.0). The
selected CSENSE value is 0.1 µF, as this provides the
appropriate coupling of the voltage to the SENSE pin.
FIGURE 5-12:
3.0 sense resistor.
SENSE pin voltage with
Since the 3.0 value of sense resistor provides the
proper voltage to the SENSE pin, it is the correct choice
for this solution as it will also provide the lowest power
dissipation and the maximum amount of voltage to the
fan. Using the RMS fan current which was measured
previously, the power dissipation in the resistor during
a fan fault condition is 71 mW (Irms2 * RSENSE). This
number will set the wattage rating of the resistor that is
selected. The selected value will vary depending upon
the derating guidelines that are used.
Now that all the values have been selected, the sche-
matic representation of this design can be seen in
Figure 5-13.
FIGURE 5-11:
SENSE pin voltage with
4.7 sense resistor.
2002-2013 Microchip Technology Inc.
DS21755C-page 25
TC646B/TC648B/TC649B
+5V
+12V
Fan
+
CV
DD
Thermometrics®
100 k @25°C
R
1.0 µF
2371k
Panasonic®
12V, 140 mA
FBA06T12H
NHQ104B425R5
8
V
R
10 k
5
1
V
IN
DD
C
B
0.01 µF
6
FAULT
R
2
45.3k
+5V
R
32.4 k
Q
7
5
3
1
TC649B
V
OUT
SI2302
or
3
MGSF1N02E
V
AS
CB
0.01 µF
2
SENSE
C
0.1 µF
R
SENSE
4
C
F
RSENSE
3.0
17.8 k
C
1.0 µF
GND
4
F
FIGURE 5-13:
Design Example Schematic.
Bypass capacitor CVDD is added to the design to
decouple the bias voltage. This is good to have, espe-
cially when using a MOSFET as the drive device. This
helps to give a localized low-impedance source for the
current required to charge the gate capacitance of Q1.
Two other bypass capacitors (labeled as CB) were also
added to decouple the VIN and VAS nodes. These were
added simply to remove any noise present that might
cause false triggerings or PWM jitter. R5 is the pull-up
resistor for the FAULT output. The value for this resistor
is system-dependent.
DS21755C-page 26
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
6.0
6.1
PACKAGING INFORMATION
Package Marking Information
8-Lead PDIP (300 mil)
Example:
XXXXXXXXX
NNN
TC646BCPA
025
YYWW
0215
8-Lead SOIC (150 mil)
Example:
XXXXXX
TC646B
XXXYYWW
COA0215
NNN
025
Example:
8-Lead MSOP
TC646B
XXXXXX
YWWNNN
215025
Legend: XX...X Customer-specific information
Y
Year code (last digit of calendar year)
YY
WW
NNN
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
e
3
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator (
can be found on the outer packaging for this package.
*
)
3
e
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
2002-2013 Microchip Technology Inc.
DS21755C-page 27
TC646B/TC648B/TC649B
8-Lead Plastic Dual In-line (PA) – 300 mil (PDIP)
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E1
D
2
n
1
E
A2
A
L
c
A1
B1
B
p
eB
Units
INCHES*
NOM
MILLIMETERS
Dimension Limits
MIN
MAX
MIN
NOM
8
MAX
n
p
Number of Pins
Pitch
8
.100
.155
.130
2.54
Top to Seating Plane
A
.140
.170
3.56
2.92
3.94
3.30
4.32
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
A2
A1
E
.115
.015
.300
.240
.360
.125
.008
.045
.014
.310
5
.145
3.68
0.38
7.62
6.10
9.14
3.18
0.20
1.14
0.36
7.87
5
.313
.250
.373
.130
.012
.058
.018
.370
10
.325
.260
.385
.135
.015
.070
.022
.430
15
7.94
6.35
9.46
3.30
0.29
1.46
0.46
9.40
10
8.26
6.60
9.78
3.43
0.38
1.78
0.56
10.92
15
E1
D
Tip to Seating Plane
Lead Thickness
L
c
Upper Lead Width
B1
B
Lower Lead Width
Overall Row Spacing
Mold Draft Angle Top
Mold Draft Angle Bottom
§
eB
5
10
15
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-001
Drawing No. C04-018
DS21755C-page 28
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
8-Lead Plastic Small Outline (OA) – Narrow, 150 mil (SOIC)
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E
E1
p
D
2
B
n
1
h
45×
c
A2
A
f
L
A1
Units
INCHES*
NOM
MILLIMETERS
Dimension Limits
MIN
MAX
MIN
NOM
8
MAX
n
p
Number of Pins
Pitch
8
.050
.061
.056
.007
.237
.154
.193
.015
.025
4
1.27
Overall Height
A
.053
.069
1.35
1.32
1.55
1.42
0.18
6.02
3.91
4.90
0.38
0.62
4
1.75
Molded Package Thickness
Standoff
A2
A1
E
.052
.004
.228
.146
.189
.010
.019
0
.061
.010
.244
.157
.197
.020
.030
8
1.55
0.25
6.20
3.99
5.00
0.51
0.76
8
§
0.10
5.79
3.71
4.80
0.25
0.48
0
Overall Width
Molded Package Width
Overall Length
E1
D
h
Chamfer Distance
Foot Length
L
f
Foot Angle
c
Lead Thickness
Lead Width
.008
.013
0
.009
.017
12
.010
.020
15
0.20
0.33
0
0.23
0.42
12
0.25
0.51
15
B
Mold Draft Angle Top
Mold Draft Angle Bottom
0
12
15
0
12
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-012
Drawing No. C04-057
2002-2013 Microchip Technology Inc.
DS21755C-page 29
TC646B/TC648B/TC649B
8-Lead Plastic Micro Small Outline Package (UA) (MSOP)
Note: For the most current package drawings, please see the Microchip Packaging Specification located
at http://www.microchip.com/packaging
E
E1
p
D
2
B
n
1
α
A2
A
c
φ
A1
(F)
L
β
Units
Dimension Limits
INCHES
NOM
MILLIMETERS*
MIN
MAX
MIN
NOM
8
0.65 BSC
MAX
n
p
Number of Pins
Pitch
8
.026 BSC
Overall Height
Molded Package Thickness
Standoff
A
A2
A1
E
-
-
.043
.037
.006
-
-
0.85
-
1.10
0.95
0.15
.030
.000
.033
-
0.75
0.00
Overall Width
.193 TYP.
4.90 BSC
Molded Package Width
Overall Length
Foot Length
Footprint (Reference)
Foot Angle
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
*Controlling Parameter
Notes:
E1
D
L
F
φ
.118 BSC
.118 BSC
.024
.037 REF
3.00 BSC
3.00 BSC
0.60
0.95 REF
.016
.031
0.40
0.80
0°
.003
.009
5°
-
8°
.009
.016
15°
0°
0.08
0.22
5°
-
-
-
-
-
8°
0.23
0.40
15°
c
.006
.012
B
α
β
-
-
5°
15°
5°
15°
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254mm) per side.
JEDEC Equivalent: MO-187
Drawing No. C04-111
DS21755C-page 30
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
6.2
Taping Form
Component Taping Orientation for 8-Pin MSOP Devices
User Direction of Feed
PIN 1
W
P
Standard Reel Component Orientation
for 713 or TR Suffix Device
Carrier Tape, Number of Components Per Reel and Reel Size:
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
8-Pin MSOP
12 mm
8 mm
2500
13 in.
Component Taping Orientation for 8-Pin SOIC Devices
User Direction of Feed
PIN 1
W
P
Standard Reel Component Orientation
for 713 or TR Suffix Device
Carrier Tape, Number of Components Per Reel and Reel Size:
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
8-Pin SOIC
12 mm
8 mm
2500
13 in.
2002-2013 Microchip Technology Inc.
DS21755C-page 31
TC646B/TC648B/TC649B
7.0
REVISION HISTORY
Revision C (January 2013)
Added a note to each package outline drawing.
DS21755C-page 32
2002-2013 Microchip Technology Inc.
TC646B/TC648B/TC649B
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
Examples:
PART NO.
Device
X
/XX
a) TC646BEOA: SOIC package.
Temperature
Range
Package
b) TC646BEOA713: Tape and Reel,
SOIC package.
c) TC646BEPA: PDIP package.
d) TC646BEUA: MSOP package.
Device:
TC646B: PWM Fan Speed Controller with Fan
Restart, Auto-Shutdown, Fan Fault and
Over-Temp Detection
a) TC648BEOA: SOIC package.
b) TC648BEPA: PDIP package.
c) TC648BEUA: MSOP package.
TC648B: PWM Fan Speed Controller with Auto-
Shutdown and Over-Temp Detection
TC649B: PWM Fan Speed Controller with Fan
Restart, Auto-Shutdown and Fan Fault
Detection
d) TC648BEUA713: Tape and Reel,
MSOP package.
Temperature
Range:
E
= -40°C to +85°C
a) TC649BEOA: SOIC package.
b) TC649BEOATR: Tape and Reel,
SOIC package.
Package:
OA = Plastic SOIC, (150 mil Body), 8-lead
PA = Plastic DIP (300 mil Body), 8-lead
UA = Plastic Micro Small Outline (MSOP), 8-lead
713 = Tape and Reel (SOIC and MSOP)
(TC646B and TC648B only)
c) TC649BEPA: PDIP package.
d) TC649BEUA: MSOP package
TR = Tape and Reel (SOIC and MSOP) (TC649B
only)
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and
recommended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office
2. The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
Customer Notification System
Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
2002-2013 Microchip Technology Inc.
DS21755C-page 33
TC646B/TC648B/TC649B
NOTES:
DS21755C-page 34
2002-2013 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
FlashFlex, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,
PICSTART, PIC logo, rfPIC, SST, SST Logo, SuperFlash
and UNI/O are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
32
FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor,
MTP, SEEVAL and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Silicon Storage Technology is a registered trademark of
Microchip Technology Inc. in other countries.
Analog-for-the-Digital Age, Application Maestro, BodyCom,
chipKIT, chipKIT logo, CodeGuard, dsPICDEM,
dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,
ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial
Programming, ICSP, Mindi, MiWi, MPASM, MPF, MPLAB
Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code
Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,
PICtail, REAL ICE, rfLAB, Select Mode, SQI, Serial Quad I/O,
Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA
and Z-Scale are trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.
GestIC and ULPP are registered trademarks of Microchip
Technology Germany II GmbH & Co. & KG, a subsidiary of
Microchip Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2002-2013, Microchip Technology Incorporated, Printed in
the U.S.A., All Rights Reserved.
Printed on recycled paper.
ISBN: 9781620768976
QUALITY MANAGEMENT SYSTEM
CERTIFIED BY DNV
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
== ISO/TS 16949 ==
2002-2013 Microchip Technology Inc.
DS21755C-page 35
Worldwide Sales and Service
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://www.microchip.com/
support
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Harbour City, Kowloon
Hong Kong
Tel: 852-2401-1200
Fax: 852-2401-3431
India - Bangalore
Tel: 91-80-3090-4444
Fax: 91-80-3090-4123
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
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Tel: 91-20-2566-1512
Fax: 91-20-2566-1513
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
Web Address:
www.microchip.com
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Japan - Osaka
Tel: 81-6-6152-7160
Fax: 81-6-6152-9310
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
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Tel: 86-10-8569-7000
Fax: 86-10-8528-2104
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Japan - Tokyo
Tel: 81-3-6880- 3770
Fax: 81-3-6880-3771
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Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
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Tel: 82-53-744-4301
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Tel: 86-23-8980-9588
Fax: 86-23-8980-9500
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Tel: 630-285-0071
Fax: 630-285-0075
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Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
Korea - Seoul
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Tel: 86-571-2819-3187
Fax: 86-571-2819-3189
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
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Tel: 44-118-921-5869
Fax: 44-118-921-5820
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Tel: 216-447-0464
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Tel: 852-2943-5100
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Tel: 86-25-8473-2460
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Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
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Tel: 63-2-634-9065
Fax: 63-2-634-9069
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Tel: 248-538-2250
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Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
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Fax: 65-6334-8850
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Fax: 317-773-5453
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Tel: 86-24-2334-2829
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Fax: 886-3-5770-955
Los Angeles
China - Shenzhen
Tel: 86-755-8864-2200
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Tel: 886-7-213-7828
Fax: 886-7-330-9305
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Tel: 949-462-9523
Fax: 949-462-9608
China - Wuhan
Tel: 86-27-5980-5300
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Taiwan - Taipei
Tel: 886-2-2508-8600
Fax: 886-2-2508-0102
Santa Clara
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Fax: 408-961-6445
China - Xian
Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
Toronto
Mississauga, Ontario,
Canada
China - Xiamen
Tel: 905-673-0699
Fax: 905-673-6509
Tel: 86-592-2388138
Fax: 86-592-2388130
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
11/29/12
DS21755C-page 36
2002-2013 Microchip Technology Inc.
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