MICROCHIP TC647B

TC642B/TC647B
PWM Fan Speed Controllers With Minimum Fan Speed,
Fan Restart and FanSense™ Technology for Fault Detection
Features
Description
• Temperature-Proportional Fan Speed for Acoustic
Noise Reduction and Longer Fan Life
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC642B/TC647B
Supply Voltage
- Supports any Fan Voltage
• FanSense™ Fault Detection Circuit Protects
Against Fan Failure and Aids System Testing
• Shutdown Mode for "Green" Systems
• Supports Low Cost NTC/PTC Thermistors
• Over-Temperature Indication (TC642B only)
• Fan Auto-Restart
• Space-Saving 8-Pin MSOP Package
The TC642B/TC647B devices are new versions of the
existing TC642/TC647 fan speed controllers. These
devices are switch mode, fan speed controllers that
incorporate a new fan auto-restart function. Temperature-proportional speed control is accomplished 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. Minimum fan
speed is set by a simple resistor divider on the VMIN
input. An integrated Start-Up Timer ensures reliable
motor start-up at turn-on, coming out of shutdown
mode or following a transient fault. A logic-low applied
to VMIN (pin 3) causes fan shutdown.
Applications
•
•
•
•
•
•
Personal Computers & Servers
LCD Projectors
Datacom & Telecom Equipment
Fan Trays
File Servers
General Purpose Fan Speed Control
Package Types
MSOP, PDIP, SOIC
VIN 1
CF 2
VMIN 3
GND 4
TC642B
TC647B
8
VDD
7
VOUT
6
FAULT
5
SENSE
 2002-2013 Microchip Technology Inc.
The TC642B and TC647B 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 missingpulse detector monitors this pin during fan operation. A
stalled, open or unconnected fan causes the TC642B/
TC647B device to turn the VOUT output on full (100%
duty cycle). If the 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 is also asserted if the
PWM reaches 100% duty cycle (TC642B only), indicating that maximum cooling capability has been reached
and a possible overheating condition exists.
The TC642B and TC647B devices are available in 8-pin
plastic MSOP, SOIC and PDIP packages. The specified
temperature range of these devices is -40 to +85ºC.
DS21756C-page 1
TC642B/TC647B
Functional Block Diagram
TC642B/TC647B
VOTF
VIN
VDD
Note
Control
Logic
CF
3xTPWM
Timer
Clock
Generator
VMIN
VSHDN
DS21756C-page 2
VOUT
Start-up
Timer
Missing
Pulse
Detect
10 k
GND
Note: The VOTF comparator
is for the TC642B device only.
FAULT
SENSE
70 mV
(typ)
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
1.0
ELECTRICAL
CHARACTERISTICS
PIN FUNCTION TABLE
Name
Absolute Maximum Ratings †
Function
VIN
Analog Input
Supply Voltage (VDD) .......................................................6.0V
CF
Analog Output
Input Voltage, Any Pin................(GND - 0.3V) to (VDD +0.3V)
VMIN
Analog Input
Operating Temperature Range ....................- 40°C to +125°C
GND
Ground
Maximum Junction Temperature, TJ ........................... +150°C
SENSE
Analog Input
ESD Protection on all pins ........................................... > 3 kV
FAULT
Digital (Open-Drain) Output
† 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. Exposure to maximum rating conditions for extended periods may
affect device reliability.
VOUT
Digital Output
VDD
Power Supply Input
ELECTRICAL SPECIFICATIONS
Electrical Specifications: Unless otherwise specified, all limits are specified for -40°C < TA < +85°C, VDD = 3.0V to 5.5V.
Parameters
Sym
Min
Supply Voltage
VDD
3.0
—
5.5
V
Supply Current, Operating
IDD
—
200
400
µA
Pins 6, 7 Open,
CF = 1 µF, VIN = VC(MAX)
IDD(SHDN)
—
30
—
µA
Pins 6, 7 Open,
CF = 1 µF, VMIN = 0.35V
Sink Current at VOUT Output
IOL
1.0
—
—
mA
VOL = 10% of VDD
Source Current at VOUT Output
IOH
5.0
—
—
mA
VOH = 80% of VDD
VC(MAX)
2.45
2.60
2.75
V
Supply Current, Shutdown Mode
Typ
Max
Units
Conditions
VOUT Output
VIN, VMIN Inputs
Input Voltage at VIN or VMIN for 100%
PWM Duty Cycle
Over-Temperature Indication
Threshold
VOTF
VC(MAX) +
20 mV
V
For TC642B Only
Over-Temperature Indication
Threshold Hysteresis
VOTF-HYS
80
mV
For TC642B Only
VC(MAX) - VC(MIN)
VC(SPAN)
1.3
VMIN
VC(MAX) VC(SPAN)
Voltage Applied to VMIN to Ensure
Shutdown Mode
VSHDN
—
Voltage Applied to VMIN to Release
Shutdown Mode
VREL
Minimum Speed Threshold
Hysteresis on VSHDN, VREL
VIN, VMIN Input Leakage
1.4
1.5
V
VC(MAX)
V
—
VDD x 0.13
V
VDD x 0.19
—
—
V
VHYST
—
0.03 x VDD
—
V
IIN
- 1.0
—
+1.0
µA
Note 1
fPWM
26
30
34
Hz
CF = 1.0 µF
VDD = 5V
Pulse-Width Modulator
PWM Frequency
Note 1:
2:
Ensured by design, tested during characterization.
For VDD < 3.7V, tSTARTUP and tMP timers are typically 13/f.
 2002-2013 Microchip Technology Inc.
DS21756C-page 3
TC642B/TC647B
ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Specifications: Unless otherwise specified, all limits are specified for -40°C < TA < +85°C, VDD = 3.0V to 5.5V.
Parameters
Sym
Min
Typ
Max
Units
Conditions
SENSE Input Threshold Voltage with
Respect to GND
VTH(SENSE)
50
70
90
mV
Blanking time to ignore pulse due to
VOUT turn-on
tBLANK
—
3.0
—
µsec
Output Low Voltage
VOL
—
—
0.3
V
Missing Pulse Detector Timer
tMP
—
32/f
—
sec
Note 2
tSTARTUP
—
32/f
—
sec
Note 2
tDIAG
—
3/f
—
sec
SENSE Input
FAULT Output
Start-Up Timer
Diagnostic Timer
Note 1:
2:
IOL = 2.5 mA
Ensured by design, tested during characterization.
For VDD < 3.7V, tSTARTUP and tMP timers are typically 13/f.
TEMPERATURE SPECIFICATIONS
Electrical Characteristics: Unless otherwise noted, all parameters apply at VDD = 3.0V to 5.5V
Parameters
Symbol
Min
Typ
Max
Units
Specified Temperature Range
TA
-40
Operating Temperature Range
TA
-40
—
+85
°C
—
+125
Storage Temperature Range
TA
°C
-65
—
+150
°C
Conditions
Temperature Ranges:
Thermal Package Resistances:
Thermal Package Resistance, 8-Pin MSOP
JA
—
200
—
°C/W
Thermal Package Resistance, 8-Pin SOIC
JA
—
155
—
°C/W
Thermal Package Resistance, 8-Pin PDIP
JA
—
125
—
°C/W
DS21756C-page 4
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
TIMING SPECIFICATIONS
tSTARTUP
VOUT
FAULT
SENSE
FIGURE 1-1:
TC642B/TC647B Start-Up Timing.
33.3 msec (CF = 1 µF)
tDIAG
tMP
tMP
VOUT
FAULT
SENSE
FIGURE 1-2:
Fan Fault Occurrence.
tMP
VOUT
FAULT
Minimum 16 pulses
SENSE
FIGURE 1-3:
Recovery From Fan Fault.
 2002-2013 Microchip Technology Inc.
DS21756C-page 5
TC642B/TC647B
C2
1 µF
C1
0.1 µF
+
-
VDD
8
R1
+
-
VIN
1
C3
0.1 µF
VIN
VDD
K3
VOUT
R6
7
+
R2
+
-
VMIN
3
C4
0.1 µF
VMIN
VDD
TC642B
TC647B
R5
K4
FAULT
6
+
-
2
CF
GND
K1
C7
.01 µF
K2
C6
1 µF
4
C8
0.1 µF
Current
limited
voltage
source
SENSE
R4
5
R3
Current
limited
voltage
source
VSENSE
(pulse voltage source)
C5
0.1 µF
Note: C5 and C7 are adjusted to get the necessary 1 µF value.
FIGURE 1-4:
DS21756C-page 6
TC642B/TC647B Electrical Characteristics Test Circuit.
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
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
Pins 6 & 7 Open
CF = 1 µF
160
Oscillator Frequency (Hz)
165
VDD = 5.5V
IDD (µA)
155
150
145
VDD = 3.0V
140
135
130
CF = 1.0PF
VDD = 3.0V
30.00
VDD = 5.5V
29.50
29.00
28.50
125
-40
-25
-10
5
20
35
50
65
80
95
-40 -25 -10
110 125
5
FIGURE 2-1:
IDD vs. Temperature.
FIGURE 2-4:
Temperature.
16
35
50
80
95
110 125
PWM Frequency vs.
Pins 6 & 7 Open
CF = 1 µF
165
VDD = 5.0V
160
12
TA = +125ºC
TA = +90ºC
155
VDD = 5.5V
VDD = 4.0V
IDD (µA)
10
8
VDD = 3.0V
6
150
145
TA = -5ºC
140
4
135
2
TA = -40ºC
130
0
125
0
50 100 150 200 250 300 350 400 450 500 550 600
3
3.5
4
VOL (mV)
FIGURE 2-2:
VOL.
4.5
5
5.5
VDD (V)
PWM Sink Current (IOL) vs.
IDD vs. VDD.
FIGURE 2-5:
16
30
14
IDD Shutdown (µA)
VDD = 5.0V
12
IOH (mA)
65
170
14
IOL (mA)
20
Temperature (ºC)
Temperature (ºC)
VDD = 4.0V
10
VDD = 5.5V
8
VDD = 3.0V
6
4
24
VDD = 3.0V
21
18
2
0
VDD = 5.5V
27
Pins 6 & 7 Open
VMIN = 0V
15
0
100
200
300
400
500
600
700
800
-40
-25
VDD - VOH (mV)
FIGURE 2-3:
vs. VDD-VOH.
PWM Source Current (IOH)
 2002-2013 Microchip Technology Inc.
-10
5
20
35
50
65
80
95
110 125
Temperature (ºC)
FIGURE 2-6:
Temperature.
IDD Shutdown vs.
DS21756C-page 7
TC642B/TC647B
Note: Unless otherwise indicated, VDD = 5V, TA = +25°C.
70
74.0
IOL = 2.5 mA
73.5
VDD = 3.0V
50
VDD = 4.0V
40
30
VDD = 5.0V
VDD = 5.5V
20
VDD = 3.0V
73.0
VTH(SENSE) (mV)
FAULT VOL (mV)
60
VDD = 4.0V
72.5
72.0
71.5
VDD = 5.5V
71.0
VDD = 5.0V
70.5
70.0
10
69.5
-40
-25
-10
5
20
35
50
65
80
95
110 125
-40 -25 -10
5
Temperature (ºC)
FIGURE 2-7:
Temperature.
20
35
50
65
80
95
110 125
Temperature (ºC)
FIGURE 2-10:
Sense Threshold
(VTH(SENSE)) vs. Temperature.
FAULT VOL vs.
2.610
22
20
VDD = 5.0V
2.590
VDD = 3.0V
2.580
FAULT IOL (mA)
2.600
VC(MAX) (V)
18
VDD = 5.5V
16
VDD = 5.0V
14
12
VDD = 5.5V
VDD = 4.0V
10
8
VDD = 3.0V
6
4
2
CF = 1 µF
0
2.570
-40 -25 -10
5
20
35
50
65
80
0
95 110 125
50
100
150
VC(MAX) vs. Temperature.
FIGURE 2-8:
200
250
300
350
400
VOL (mV)
Temperature (ºC)
FAULT IOL vs. VOL.
FIGURE 2-11:
1.220
45.00
CF = 1 µF
VOH = 0.8VDD
40.00
VDD = 5.5V
VOUT IOH (mA)
VC(MIN) (V)
1.210
1.200
VDD = 5.0V
VDD = 3.0V
1.190
35.00
25.00
VDD = 4.0V
20.00
15.00
10.00
1.180
VDD = 5.0V
30.00
VDD = 3.0V
5.00
-40 -25 -10
5
20
35
50
65
80
95 110 125
-40 -25 -10
Temperature (ºC)
FIGURE 2-9:
DS21756C-page 8
VC(MIN) vs. Temperature.
5
20
35
50
65
80
95 110 125
Temperature (ºC)
FIGURE 2-12:
vs. Temperature.
PWM Source Current (IOH)
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
Note: Unless otherwise indicated, VDD = 5V, TA = +25°C.
30
25
VDD = 5.5V
2.625
VDD = 5.5V
VDD = 4.0V
15
VDD = 5.0V
2.620
VDD = 5.0V
20
VOTF (V)
VOUT IOL (mA)
2.630
VOL = 0.1VDD
10
2.615
VDD = 3.0V
2.610
2.605
VDD = 3.0V
5
2.600
0
2.595
-40
-25
-10
5
20
35
50
65
80
95
-40 -25 -10
110 125
5
Temperature (ºC)
FIGURE 2-13:
Temperature.
PWM Sink Current (IOL) vs.
FIGURE 2-16:
Temperature.
0.80
VOTF Hysteresis (mV)
VDD = 5.5V
0.70
VSHDN (V)
35
50
65
80
95 110 125
VOTF Threshold vs.
100
0.75
0.65
20
Temperature (ºC)
VDD = 5.0V
0.60
0.55
VDD = 4.0V
0.50
0.45
VDD = 3.0V
0.40
95
90
VDD = 5.5V
85
VDD = 3.0V
80
75
0.35
0.30
70
-40 -25 -10
5
20
35
50
65
80
95
110 125
Temperature (ºC)
VREL (V)
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
-25
-10
5
20
35
50
65
80
95
110 125
Temperature (ºC)
VSHDN Threshold vs.
FIGURE 2-14:
Temperature.
-40
FIGURE 2-17:
Over-Temperature
Hysteresis (VOTF-HYS ) vs. Temperature.
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:
Temperature.
VREL Threshold vs.
 2002-2013 Microchip Technology Inc.
DS21756C-page 9
TC642B/TC647B
3.0
PIN FUNCTIONS
3.5
The description of the pins are given in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
Pin
Name
1
VIN
Analog Input
2
CF
Analog Output
3.1
Function
The FAULT line goes low to indicate a fault condition.
When FAULT goes low due to a fan fault, 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 TC642B device, the FAULT
output will also be asserted when the VIN voltage
reaches the VOTF treshold of 2.62V (typical). This gives
an over-temperature/100% fan speed indication.
3
VMIN
Analog Input
4
GND
Ground
5
SENSE
Analog Input
3.6
6
FAULT
Digital (Open-Drain) Output
7
VOUT
Digital Output
8
VDD
Power Supply Input
VOUT is an active-high complimentary output and
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.
Analog Input (VIN)
The thermistor network (or other temperature sensor)
connects to VIN. A voltage range of 1.20V to 2.60V (typical) on this pin drives an active duty cycle of 0% to
100% on the VOUT pin.
3.2
Digital (Open-Drain) Output
(FAULT)
3.7
Digital Output (VOUT)
Power Supply Input (VDD)
The VDD pin with respect to GND provides power to the
device. This bias supply voltage may be independent of
the fan power supply.
Analog Output (CF)
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.
3.3
Analog Input (VMIN)
An external resistor divider connected to VMIN sets the
minimum fan speed by fixing the minimum PWM duty
cycle (1.20V to 2.60V = 0% to 100%, typical). The
TC642B and TC647B devices enter shutdown mode
when 0  VMIN  VSHDN. During shutdown, the FAULT
output is inactive and supply current falls to 30 µA
(typical).
3.4
Analog Input (SENSE)
Pulses are detected at SENSE as fan rotation chops
the current through a sense resistor. The absence of
pulses indicates a fan fault condition.
DS21756C-page 10
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
4.0
DEVICE OPERATION
The TC642B/TC647B devices are a family of temperature proportional, PWM mode, fan speed controllers.
Features of the family include minimum fan speed, fan
auto-shutdown mode, fan auto-restart, remote shutdown, over-temperature indication and fan fault
detection.
The TC642B/TC647B 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.
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 TC64XB family will
continue to monitor the operation of the fan so that
when the fan returns to normal operation, 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.
4.1
special heatsinking to remove the power being
dissipated in the package.
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.
4.2
PWM Fan Speed Control
The TC642B and TC647B devices implement PWM fan
speed control by varying the duty cycle of a fixed frequency pulse train. The duty cycle of a waveform is the
on time divided by the total period of the pulse. For
example, a 100 Hz waveform (10 ms) with an on time
of 5.0 ms has a duty cycle of 50% (5.0 ms / 10.0 ms).
This example is illustrated in Figure 4-1.
t
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.
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.
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.
ton
toff
D = Duty Cycle
D = ton / t
FIGURE 4-1:
Waveform.
t = Period
t = 1/f
f = Frequency
Duty Cycle of a PWM
The TC642B and TC647B generate a pulse train with a
typical frequency of 30 Hz (CF = 1 µF). The duty cycle
can be varied from 0% to 100%. The pulse train generated by the TC642B/TC647B 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.
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 an
RMS current of 110 mA and an average current of
72 mA. Using a MOSFET with a 1 RDS(on) (a fairly
typical value for this low current), the power dissipation
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).
The PWM approach to fan speed control results in
much less power dissipation in the drive element,
allowing smaller devices to be used while not requiring
 2002-2013 Microchip Technology Inc.
12V
FAN
VDD
D
TC642B VOUT
TC647B
QDRIVE
G
S
GND
FIGURE 4-2:
PWM Fan Drive.
DS21756C-page 11
TC642B/TC647B
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 TC642B and
TC647B devices, the duty cycle is controlled by either
the VIN or VMIN input, with the higher voltage setting the
duty cycle. This is described in more detail in Section
5.5, “Output Drive Device Selection”.
2.8
Fan Start-up
Often overlooked in fan speed control is the actual startup 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 can not be applied immediately. Since the fan is
at a rest position, the fan’s inertia must be overcome 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.
A key feature of the TC642B/TC647B device is the
start-up timer. When power is first applied to the device,
(when the device is brought out of the shutdown mode
of operation) the VOUT output will go to a high state for
32 PWM cycles (one second for CF = 1 F). This will
drive the fan to full speed for this time-frame.
During the start-up period, 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 (see Section 4.5, “Minimum Fan
Speed”, for more details on operation when coming out
of start-up). If pulses are not detected during the startup period, the start-up timer is activated again. If pulses
are not detected at the SENSE pin during this additional start-up period, the FAULT output will go low to
indicate that a fan fault condition has occurred. See
Section 4.7, “FAULT Output”, for more details.
PWM Frequency & Duty Cycle Control
(CF & VIN Pins)
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 F
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 sawtooth waveform. An example of this is shown in
Figure 4-3.
CF = 1 µF
2.6
VCMAX
2.4
CF Voltage (V)
4.3
4.4
2.2
2.0
1.8
1.6
1.4
1.2
VCMIN
1.0
0
20
40
FIGURE 4-3:
80
100
CF Pin Voltage.
The duty cycle of the PWM output is controlled by the
voltage at the VIN input pin (or the VMIN voltage, whichever is greater). 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.
The lower value of 1.20V is referred to as VCMIN and
the 2.60V threshold is referred to as VCMAX. A calculation for duty cycle is shown in the equation below. The
voltage range between VCMIN and VCMAX is characterized as VCSPAN and has a typical value of 1.4V with
minimum and maximum values of 1.3V and 1.5V,
respectively.
EQUATION
PWM DUTY CYCLE
Duty Cycle (%) =
DS21756C-page 12
60
Time (msec)
(VIN - VCMIN) * 100
VCMAX - VCMIN
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
If the voltage at the VIN pin falls below 1.76V, the duty
cycle of the VOUT output will not decrease below the
40% value that is now set by the voltage at the VMIN
pin. In this manner, the fan will continue to operate at
40% speed even when the temperature (voltage at VIN)
continues to decrease.
100
90
Duty Cycle (%)
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
The PWM duty cycle is also controlled by the VMIN pin
See Section 4.5, “Minimum Speed (VMIN Pin)”, for
more details on this function.
4.5
Minimum Speed (VMIN Pin)
For the TC642B and TC647B devices, pin 3 is the VMIN
pin. This pin is used for setting the minimum fan speed
threshold.
The minimum fan speed function provides a way to set
a threshold for a minimum duty cycle on the VOUT output. This in turn produces a minimum fan speed for the
user. The voltage range for the VMIN pin is the same as
that for the VIN pin (1.20V to 2.60V). The voltage at the
VMIN pin is set in this range so that as the voltage at the
VIN pin decreases below the VMIN voltage, the output
duty cycle will be controlled by the VMIN voltage. The
following equation can be used to determine the necessary voltage at VMIN for a desired minimum duty cycle
on VOUT.
EQUATION
VMIN VOLTAGE
VMIN (V) = (DC * 1.4) + 1.20
100
DC = Desired Duty Cycle
Example: If a minimum duty cycle of 40% is desired,
the VMIN voltage should be set to:
For the TC642B and TC647B devices, the VMIN pin is
also used as the shutdown pin. The VSHDN and VREL
threshold voltages are characterized in the “Electrical
Characteristics” table of Section 1.0. If the VMIN pin
voltage is pulled below the VSHDN threshold, the device
will shut down (VOUT output goes to a low state, the
FAULT pin is inactive). If the voltage on the VMIN pin
then rises above the release threshold (VREL), the
device will go through a Power-Up sequence. The
Power-Up sequence is shown later in Figure 4-9.
4.6
VOUT Output (PWM Output)
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.
When the device is in shutdown mode, the VOUT output
is actively held low. The output can be varied from 0%
duty cycle (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 along with the VMIN
voltage.
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. 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.
EXAMPLE 4-1:
VMIN (V) = (40 * 1.4) + 1.20
100
VMIN = 1.76V
 2002-2013 Microchip Technology Inc.
DS21756C-page 13
TC642B/TC647B
Clamp Diode
FAN
Q1
VOUT
RSENSE
GND
Q1: N-Channel MOSFET
FIGURE 4-5:
4.7
Clamp Diode for Fan.
FAULT Output
The FAULT output is an open-drain, active-low output.
For the TC642B and TC647B devices, the FAULT output indicates when a fan fault condition has occurred.
For the TC642B device, the FAULT output also indicates when an over-temperature (OTF) condition has
occurred.
For the TC642B device, an over-temperature condition
is indicated (FAULT output is pulled low) 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 output returns to
the high-state (a pull-up resistor is needed on the
FAULT output).
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 continuously 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 F), the fan fault condition no longer exists. The FAULT output is then
released and the VOUT output returns to normal PWM
operation, as dictated by the VIN and VMIN inputs.
If the VMIN 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 VMIN voltage then increases above
the VREL threshold, 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 VMIN voltage level, the TC642B/
TC647B 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 VOUT output will be driven to the
duty cycle that is being commanded by the VMIN input.
The sink current capability of the FAULT output is listed
in the “Electrical Characteristics” table of Section 1.0.
4.8
Sensing Fan Operation (SENSE)
The SENSE input is an analog input used to monitor
the fan’s operation. It does this by sensing fan current
pulses, which 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. These are shown in
Figures 4-6 and 4-7.
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, then normal PWM
operation is resumed and no fan fault is indicated. 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 timeframe, normal PWM operation is resumed. If no pulses
are detected during this time frame, a fan fault condition
exists and the FAULT output is pulled low.
DS21756C-page 14
FIGURE 4-6:
Fan Current With DC Offset
And Positive Commutation Current.
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
across RSENSE and presents only the voltage pulse
portion to the SENSE pin of the TC642B/TC647B
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 Information”, 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 TC642B/TC647B 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 TC642B/TC647B device from
falsely sensing a current pulse which is due to the fan
drive device turn-on.
FIGURE 4-7:
Fan Current With
Commutation Pulses To Zero.
The SENSE pin senses positive voltage pulses that
have an amplitude of 70 mV (typical value). When a
pulse is detected, the missing pulse detector timer 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).
Both of the fan current waveshapes that are shown in
Figures 4-6 and 4-7 can be sensed with the sensing
scheme shown in Figure 4-8.
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 commutates, it simply flows through one fan winding and is
a DC current. When a fan is in a locked rotor condition
and the TC642B/TC647B 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 TC642B/
TC647B device to ignore this pulse and recognize that
the fan is in a fault condition.
4.9
FAN
TC64XB
RISO
VOUT
Behavioral Algorithms
The behavioral algorithm for the TC642B/TC647B
devices is shown in Figure 4-9.
The behavioral algorithm shows the step-by-step decision-making process for the fan speed controller operation. The TC642B and TC647B devices are very
similar with one exception: the TC647B device does
not implement the over-temperature portion of the
algorithm.
SENSE
GND
FIGURE 4-8:
Current.
CSENSE
(0.1 µF typical) RSENSE
Sensing Scheme For Fan
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
 2002-2013 Microchip Technology Inc.
DS21756C-page 15
TC642B/TC647B
Power-Up
Normal
Operation
Power-on
Reset
FAULT = 1
Clear Missing
Pulse Detector
Yes
Shutdown
VOUT = 0
VMIN < VSHDN?
Yes
No
Shutdown
VOUT = 0
VMIN < VSHDN?
VMIN > VREL?
No
No
VMIN > VREL?
No
Yes
Yes
Fire Start-up
Timer
(1 sec)
VIN > VOTF?
Fire Start-up
Timer
(1 sec)
No
Fan Pulse
Detected?
Yes
Power-Up
FAULT = 0
Yes
No
Yes
Fan Pulse
Detected?
Normal
Operation
TC642B Only
VOUT
Proportional to Greater
of VIN or VMIN
No
Fan Fault
Yes
Fan Pulse
Detected?
No
No
M.P.D.
Expired?
Yes
Fire
Diagnostic
Timer
(100 msec)
Yes
Fan Fault
FAULT = Low,
VOUT = High
Fan Pulse
Detected?
Yes
No
Fire Start-up
Timer
(1 sec)
Fan Pulse
Detected?
No
VMIN<VSHDN?
Yes
Shutdown
VOUT = 0
Fan Fault
No
No
No
VMIN > VREL?
Yes
Power-Up
16 Pulses
Detected?
Yes
Normal
Operation
FIGURE 4-9:
DS21756C-page 16
TC642B/TC647B Behavioral Algorithm.
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
5.0
APPLICATIONS INFORMATION
5.1
Setting the PWM Frequency
The PWM frequency of the VOUT output is set by the
capacitor value attached to the CF pin. The PWM frequency will be 30 Hz (typical) for a 1 µF capacitor. The
relationship between frequency and capacitor value is
linear, making alternate frequency selections easy.
VDD
IDIV
RT
R1
VIN
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.
A very important factor to consider when selecting the
PWM frequency for the TC642B/TC647B devices is the
RPM rating of the selected fan and the minimum duty
cycle that the fan 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 monitor 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.
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 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 frequency of 20 Hz is recommended. This would define a
CF capacitor value of 1.5 µF.
5.2
Temperature Sensor Design
As discussed in previous sections, the VIN analog input
has a range of 1.20V to 2.60V (typical), which represents 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).
One of the simplest ways of sensing temperature over
a given range is to use a thermistor. By using an NTC
thermistor, as shown in Figure 5-1, a temperature
variant voltage can be created.
 2002-2013 Microchip Technology Inc.
R2
FIGURE 5-1:
Circuit.
Temperature Sensing
Figure 5-1 represents a temperature-dependent voltage divider circuit. RT is a conventional NTC thermistor,
while R1 and R2 are standard resistors. R1 and RT form
a parallel 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 linearize the response of the sense network and aids in
obtaining the proper VIN voltages over the desired temperature range. An example of this is shown in
Figure 5-2.
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 voltage
to system (or component) temperature relationship.
The following equations apply to the circuit in
Figure 5-1.
EQUATION
V DD  R2
V  T1  = -----------------------------------------RTEMP  T1  + R 2
V DD  R2
V  T2  = -----------------------------------------RTEMP  T2  + R 2
In order to solve for the values of R1 and R2, the values
for 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 data sheet. With the values for the
thermistor and the values for VIN, there are now two
equations from which the values for R1 and R2 can be
found.
DS21756C-page 17
TC642B/TC647B
Example: The following design goals are desired:
• Duty Cycle = 50% (VIN = 1.90 V) with
Temperature (T1) = 30°C
• Duty Cycle = 100% (VIN = 2.60 V) with
Temperature (T2) = 60°C
Using a 100 k thermistor (25°C value), look up the
thermistor values at the desired temperatures:
• RT (T1) = 79428 @ 30°C
• RT (T2) = 22593 @ 60°C
Substituting these numbers into the given equations
produces the following numbers for R1 and R2.
• R1 = 34.8 k
• R2 = 14.7 k
3.500
3.000
100
2.500
80
2.000
60
NTC Thermistor
100 k: @ 25ºC
40
20
20
30
40
50
60
70
80
90
1.000
RISO
VOUT
715 
0.000
100
Temperature (ºC)
FIGURE 5-2:
How Thermistor Resistance,
VIN, and RTEMP Vary With Temperature.
Figure 5-2 graphs RT, RTEMP (R1 in parallel with RT)
and VIN versus temperature for the example shown
above.
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®
- Quality Thermistor™
- Ametherm®
- Sensor Scientific™
- U.S. Sensors™
- Vishay®
- Advanced Thermal
Products™
- muRata®
DS21756C-page 18
FAN
1.500
0.500
RTEMP
0
5.3
The FanSense Network (comprised of RSENSE and
CSENSE) allows the TC642B and TC647B devices to
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 TC642B/TC647B
device.
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.
4.000
VIN Voltage
120
FanSense Network
(RSENSE and CSENSE)
VIN (V)
Network Resistance (k:)
140
5.4
SENSE
CSENSE
(0.1 µF typical)
RSENSE
Note: See Table 5-1 for RSENSE values.
FIGURE 5-3:
Typical Sense Network.
The required value of RSENSE will change with the current 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. 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 by 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 easily changed while
allowing the voltage waveforms to be monitored to
ensure the proper levels are being reached.
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.
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
TABLE 5-1:
FAN CURRENT VS. RSENSE
Nominal Fan Current
(mA)
RSENSE()
50
9.1
100
4.7
150
3.0
200
2.4
250
2.0
300
1.8
350
1.5
400
1.3
450
1.2
500
1.0
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 waveshape 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 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.
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 condition
(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 operating
fan current. This will effect the power rating of the
RSENSE resistor selected.
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 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 represented 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 operation, however, 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.
FIGURE 5-4:
Typical Fan Current and
SENSE Pin Waveforms.
 2002-2013 Microchip Technology Inc.
DS21756C-page 19
TC642B/TC647B
FIGURE 5-5:
5.5
Fan Current During a Locked Rotor Condition.
Output Drive Device Selection
The TC642B/TC647B is designed to drive an external
NPN transistor or N-channel MOSFET as the fan
speed modulating element. These two arrangements
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 current
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.
The following is recommended:
• 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 put 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.
When using a NPN transistor as the fan drive element,
a base current-limiting resistor must be used, as is
shown in Figure 5-7.
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 TC642B/TC647B 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.
DS21756C-page 20
FAN
VOUT
Q1
RSENSE
GND
Q1: N-Channel MOSFET
FIGURE 5-6:
Off.
Clamp Diode For Fan Turn-
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
Fan Bias
Fan Bias
FAN
FAN
RBASE
VOUT
Q1
Q1
VOUT
RSENSE
RSENSE
GND
GND
a) Single Bipolar Transistor
FIGURE 5-7:
TABLE 5-2:
Device
MMBT2222A
b) N-Channel MOSFET
Output Drive Device Configurations.
FAN DRIVE DEVICE SELECTION TABLE (NOTE 2)
Package
Max Vbe sat /
Vgs(V)
Min hfe
VCE/VDS
(V)
Fan Current
(mA)
Suggested
Rbase ()
SOT-23
1.2
50
40
150
800
MPS2222A
TO-92
1.2
50
40
150
800
MPS6602
TO-92
1.2
50
40
500
301
SI2302
SOT-23
2.5
NA
20
500
Note 1
MGSF1N02E
SOT-23
2.5
NA
20
500
Note 1
SI4410
SO-8
4.5
NA
30
1000
Note 1
SI2308
SOT-23
4.5
NA
60
500
Note 1
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
The bias supply (VDD) for the TC642B/TC647B devices
should be bypassed with a 1.0 F ceramic capacitor.
This capacitor will help supply the peak currents that
are required to drive the base/gate of the external fan
drive devices.
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.
In order to keep fan noise off of the TC642B/TC647B
device ground, individual ground returns for the
TC642B/TC647B and the low side of the fan current
sense resistor should be used.
 2002-2013 Microchip Technology Inc.
5.7
Design Example/Typical
Application
The system has been designed with the following
components and criteria.
System inlet air ambient temperature ranges from 0ºC
to 50ºC. At 20ºC and below, it is desired to have the
system cooling stay at a constant level. At 20ºC, the fan
should be run at 40% of its full fan speed. Full fan
speed should be reached when the ambient air is 40ºC.
The system has a surface mount, NTC-style thermistor
in a 1206 package. The thermistor is mounted on a
daughtercard, which 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 and the fan voltage is 12V.
DS21756C-page 21
TC642B/TC647B
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 (number from data sheet )
FIGURE 5-9:
fan current.
FBA06T12H Locked rotor
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 conducting current, the peak current value is 360 mA for periods 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.
FIGURE 5-8:
waveform.
FBA06T12H fan current
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.
Thermistor Information: Thermometrics part number:
NHQ104B425R5
Resistance Value: 100 k @ 25ºC
Beta Value (): 4250
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 = R TO exp -----------------------T ² TO
RT0 is the thermistor value at 25ºC. T0 is 298.15 and T
is the temperature of interest. All temperatures are
given in degrees kelvin.
Using this equation, the values for the thermistor are
found to be:
- RT (20ºC) = 127,462
- RT (40ºC) = 50,520
DS21756C-page 22
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
Step 3: Setting the PWM Frequency.
The fan is rated at 4200 RPM with a 12V input. Since
the goal is to run to a 40% duty cycle (roughly 40% fan
speed), which equates to approximately 1700 RPM,
we can assume one full fan revolution occurs every
35 msec. The fan being used is a four-pole fan that
gives four current pulses per revolution. Knowing this
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 reason, the CF
value is selected to be 1.0 F.
Step 4: Setting the VIN Voltage.
From the design criteria, the desired duty cycle at 20ºC
is 40%, while full fan speed should be reached at 40ºC.
Based on a VIN voltage range of 1.20V to 2.60V, which
represents 0% to 100% duty cycle, the 40% duty cycle
voltage can be found using the following equation:
- 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.
400
5.00
4.50
350
4.00
VIN
300
3.50
250
3.00
200
2.50
150
2.00
NTC Thermistor
100 k: @ 25ºC
100
VIN (V)
The requirements for the fan controller are that it have
minimum speed capability at 20ºC and also indicate a
fan fault condition. No over-temperature indication is
necessary. Based on these specifications, the proper
selection is the TC647B device.
Using standard 1% resistor values, the selected R1 and
R2 values are:
Network Resistance (k:)
Step 2: Selecting the Fan Controller.
1.50
1.00
50
RTEMP
0.50
0
0.00
0
10
20
30
40
50
60
70
80
90
Temperature (ºC)
FIGURE 5-10:
Thermistor Resistance, VIN,
and RTEMP vs. Temperature.
Step 5: Setting the Minimum Speed Voltage (VMIN).
EQUATION
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
Using these values in combination with the thermistor
resistance values calculated earlier, the R1 and R2
resistor values can now be calculated using the
following equation:
Setting the voltage for the minimum speed is accomplished 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 minimum
speed voltage was determined earlier in the selection
of the VIN voltage at 40% duty cycle, since this was also
set at the temperature which minimum speed is to
occur (20ºC).
- VMIN = 1.76V
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
V  T1  = -----------------------------------------R TEMP  T1  + R 2
IDIV =
VDD  R2
V  T2  = -----------------------------------------R TEMP  T2  + R 2
VMIN =
RTEMP is the parallel combination of R1 and the thermistor. 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):
5V
R3 + R4
5V*R4
R3 + R4
Using the equations above, the resistor values for R3
and R4 are found to be:
- R3 = 32.4 k
- R4 = 17.6 k
- R1 = 238,455
- R2 = 45,161
 2002-2013 Microchip Technology Inc.
DS21756C-page 23
TC642B/TC647B
Using standard 1% resistor values yields the following
values:
.
- R3 = 32.4 k
- R4 = 17.8 k
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 current 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 TC642B/TC647B 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 that the average fan operating current was measured to be 120 mA, this falls
between two of the values listed in the table. For reference purposes, 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 F as this provides the appropriate coupling of the voltage to the
SENSE pin.
FIGURE 5-12:
SENSE pin voltage with
3.0 sense resistor.
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 most voltage to the fan. Using the
RMS fan current that 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 schematic representation of this design can be seen in
Figure 5-13.
.
FIGURE 5-11:
SENSE pin voltage with
4.7 sense resistor.
DS21756C-page 24
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
+5V
R1
237 k
1V
IN
CB
0.01 µF
8
VDD
Panasonic®
Fan 12V, 140 mA
FBA06T12H
R5
10 k
FAULT
R2
45.3 k
+12V
+C
VDD
1.0 µF
Thermometrics®
100 k @25°C
NHQ104B425R5
6
+5V
R3
32.4 k
R4
17.8 k
FIGURE 5-13:
TC647B
3 V
MIN
CB
0.01 µF
2 C
F
CF
1.0 µF
SENSE
GND
Q1
SI2302
or
MGSF1N02E
VOUT 7
5
CSENSE
0.1 µF
RSENSE
3.0
4
Design Example Schematic.
Bypass capacitor CVDD is added to the design to
decouple the bias voltage. This is good to have, especially 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 VMIN 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.
 2002-2013 Microchip Technology Inc.
DS21756C-page 25
TC642B/TC647B
6.0
PACKAGING INFORMATION
6.1
Package Marking Information
8-Lead PDIP (300 mil)
XXXXXXXXX
NNN
YYWW
8-Lead SOIC (150 mil)
XXXXXX
XXXYYWW
NNN
XXXXXX
YWWNNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
DS21756C-page 26
TC642BCPA
025
0215
Example:
TC642B
COA0215
025
Example:
8-Lead MSOP
Note:
Example:
TC642B
215025
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
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.
TC642B/TC647B
8-Lead Plastic Dual In-line (P) – 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
p
eB
B
Units
Dimension Limits
n
p
Number of Pins
Pitch
Top to Seating Plane
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
Tip to Seating Plane
Lead Thickness
Upper Lead Width
Lower Lead Width
Overall Row Spacing
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
A
A2
A1
E
E1
D
L
c
§
B1
B
eB


MIN
.140
.115
.015
.300
.240
.360
.125
.008
.045
.014
.310
5
5
INCHES*
NOM
MAX
8
.100
.155
.130
.170
.145
.313
.250
.373
.130
.012
.058
.018
.370
10
10
.325
.260
.385
.135
.015
.070
.022
.430
15
15
MILLIMETERS
NOM
8
2.54
3.56
3.94
2.92
3.30
0.38
7.62
7.94
6.10
6.35
9.14
9.46
3.18
3.30
0.20
0.29
1.14
1.46
0.36
0.46
7.87
9.40
5
10
5
10
MIN
MAX
4.32
3.68
8.26
6.60
9.78
3.43
0.38
1.78
0.56
10.92
15
15
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
 2002-2013 Microchip Technology Inc.
DS21756C-page 27
TC642B/TC647B
8-Lead Plastic Small Outline (SN) – 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
Units
Dimension Limits
n
p
Number of Pins
Pitch
Overall Height
Molded Package Thickness
Standoff §
Overall Width
Molded Package Width
Overall Length
Chamfer Distance
Foot Length
Foot Angle
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
* Controlling Parameter
§ Significant Characteristic
A
A2
A1
E
E1
D
h
L
f
c
B


MIN
.053
.052
.004
.228
.146
.189
.010
.019
0
.008
.013
0
0
A1
INCHES*
NOM
8
.050
.061
.056
.007
.237
.154
.193
.015
.025
4
.009
.017
12
12
MAX
.069
.061
.010
.244
.157
.197
.020
.030
8
.010
.020
15
15
MILLIMETERS
NOM
8
1.27
1.35
1.55
1.32
1.42
0.10
0.18
5.79
6.02
3.71
3.91
4.80
4.90
0.25
0.38
0.48
0.62
0
4
0.20
0.23
0.33
0.42
0
12
0
12
MIN
MAX
1.75
1.55
0.25
6.20
3.99
5.00
0.51
0.76
8
0.25
0.51
15
15
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
DS21756C-page 28
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
8-Lead Plastic Micro Small Outline Package (MS) (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
n
p
MIN
INCHES
NOM
MAX
MILLIMETERS*
NOM
8
0.65 BSC
0.85
0.75
0.00
4.90 BSC
3.00 BSC
3.00 BSC
0.60
0.40
0.95 REF
0°
0.08
0.22
5°
5°
-
MIN
Number of Pins
8
Pitch
.026 BSC
Overall Height
A
.043
A2
Molded Package Thickness
.037
.030
.033
Standoff
A1
.006
.000
Overall Width
E
.193 TYP.
Molded Package Width
E1
.118 BSC
Overall Length
D
.118 BSC
Foot Length
L
.016
.024
.031
Footprint (Reference)
F
.037 REF
φ
0°
8°
Foot Angle
c
.003
.006
.009
Lead Thickness
.009
.012
.016
Lead Width
B
α
5°
15°
Mold Draft Angle Top
β
Mold Draft Angle Bottom
5°
15°
*Controlling Parameter
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed .010" (0.254mm) per side.
MAX
1.10
0.95
0.15
0.80
8°
0.23
0.40
15°
15°
JEDEC Equivalent: MO-187
Drawing No. C04-111
 2002-2013 Microchip Technology Inc.
DS21756C-page 29
TC642B/TC647B
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
8-Pin MSOP
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
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
8-Pin SOIC
DS21756C-page 30
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
12 mm
8 mm
2500
13 in.
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
7.0
REVISION HISTORY
Revision C (January 2013)
Added a note to each package outline drawing.
 2002-2013 Microchip Technology Inc.
DS21756C-page 31
TC642B/TC647B
DS21756C-page 32
 2002-2013 Microchip Technology Inc.
TC642B/TC647B
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
Device
Device:
X
/XX
Temperature
Range
Package
TC642B: PWM Fan Speed Controller with Minimum
Fan Speed, Fan Restart, Fan Fault Detection, and Over-Temp Detection.
TC647B: PWM Fan Speed Controller with Minimum
Fan Speed, Fan Restart, and Fan Fault
Detection.
Temperature
Range:
E
= -40°C to +85°C
Package:
OA
PA
UA
713
=
=
=
=
Examples:
a)
b)
c)
d)
a)
b)
c)
d)
TC642BEOA: SOIC package.
TC642BEOA713: Tape and Reel,
SOIC package.
TC642BEPA: PDIP package.
TC642BEUA: MSOP package.
TC647BEOA: SOIC package.
TC647BEPA: PDIP package.
TC647BEUA: MSOP package.
TC647BEUATR: Tape and Reel,
MSOP package.
Plastic SOIC, (150 mil Body), 8-lead
Plastic DIP (300 mil Body), 8-lead
Plastic Micro Small Outline (MSOP), 8-lead
Tape and Reel (SOIC and MSOP)
(TC642B only)
TR = Tape and Reel (SOIC and MSOP)
(TC647B 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.
2.
Your local Microchip sales office
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.
DS21756C-page 33
TC642B/TC647B
NOTES:
DS21756C-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, PIC32 logo, rfPIC, SST, SST Logo, SuperFlash
and UNI/O are registered trademarks of Microchip Technology
Incorporated in the U.S.A. and other countries.
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,
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Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA
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SQTP is a service mark of Microchip Technology Incorporated
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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: 9781620768983
QUALITY MANAGEMENT SYSTEM
CERTIFIED BY DNV
== ISO/TS 16949 ==
 2002-2013 Microchip Technology Inc.
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.
DS21756C-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
Web Address:
www.microchip.com
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
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
India - Pune
Tel: 91-20-2566-1512
Fax: 91-20-2566-1513
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
Japan - Osaka
Tel: 81-6-6152-7160
Fax: 81-6-6152-9310
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Chicago
Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
Cleveland
Independence, OH
Tel: 216-447-0464
Fax: 216-447-0643
Dallas
Addison, TX
Tel: 972-818-7423
Fax: 972-818-2924
Detroit
Farmington Hills, MI
Tel: 248-538-2250
Fax: 248-538-2260
Indianapolis
Noblesville, IN
Tel: 317-773-8323
Fax: 317-773-5453
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
Santa Clara
Santa Clara, CA
Tel: 408-961-6444
Fax: 408-961-6445
Toronto
Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Beijing
Tel: 86-10-8569-7000
Fax: 86-10-8528-2104
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
China - Chongqing
Tel: 86-23-8980-9588
Fax: 86-23-8980-9500
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Korea - Daegu
Tel: 82-53-744-4301
Fax: 82-53-744-4302
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
China - Hangzhou
Tel: 86-571-2819-3187
Fax: 86-571-2819-3189
Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
China - Hong Kong SAR
Tel: 852-2943-5100
Fax: 852-2401-3431
Malaysia - Kuala Lumpur
Tel: 60-3-6201-9857
Fax: 60-3-6201-9859
China - Nanjing
Tel: 86-25-8473-2460
Fax: 86-25-8473-2470
Malaysia - Penang
Tel: 60-4-227-8870
Fax: 60-4-227-4068
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850
China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393
Taiwan - Hsin Chu
Tel: 886-3-5778-366
Fax: 886-3-5770-955
China - Shenzhen
Tel: 86-755-8864-2200
Fax: 86-755-8203-1760
Taiwan - Kaohsiung
Tel: 886-7-213-7828
Fax: 886-7-330-9305
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
Taiwan - Taipei
Tel: 886-2-2508-8600
Fax: 886-2-2508-0102
China - Xian
Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
UK - Wokingham
Tel: 44-118-921-5869
Fax: 44-118-921-5820
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
DS21756C-page 36
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Japan - Tokyo
Tel: 81-3-6880- 3770
Fax: 81-3-6880-3771
11/29/12
 2002-2013 Microchip Technology Inc.