DTC646
PWM Fan Speed Controller with Auto-Shutdown
and FanSense™ Technology
Features
• Temperature Proportional Fan Speed for Acoustic
Control and Longer Fan Life
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC646
Supply Voltage
- Supports any Fan Voltage
• FanSense™ Fault Detection Circuits Protect
Against Fan Failure and Aid System Testing
• Shutdown Mode for "Green" Systems
• Supports Low Cost NTC/PTC Thermistors
• Space Saving 8-Pin MSOP Package
• Over-temperature Indication
Applications
•
•
•
•
•
•
•
Power Supplies
Computers
File Servers
Portable Computers
Telecom Equipment
UPS, Power Amps
General Purpose Fan Speed Control
Available Tools
• Fan Controller Demonstration Board (TC642DEMO)
• Fan Controller Evaluation Kit (TC642EV)
Package Types
SOIC/PDIP/MSOP
VIN
1
CF
2
VAS
GND
8
VDD
7
VOUT
3
6
FAULT
4
5
SENSE
TC646
General Description
The TC646 is a switch mode, fan speed controller for
use with brushless DC fans. Temperature proportional
speed control is accomplished using pulse width modulation (PWM). A thermistor (or other voltage output
temperature sensor) connected to the VIN input furnishes the required control voltage of 1.25V to 2.65V
(typical) for 0% to 100% PWM duty cycle. The TC646
automatically suspends fan operation when measured
temperature (VIN) is below a user programmed
minimum setting (VAS). An integrated Start-up Timer
ensures reliable motor start-up at turn-on, coming out
of shutdown mode, auto-shutdown mode or following a
transient fault.
The TC646 features 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 TC646 to trigger its Start-up
Timer once. If the fault persists, the FAULT output goes
low and the device is latched in its shutdown mode.
FAULT is also asserted if the PWM reaches 100% duty
cycle, indicating a possible thermal runaway situation,
although the fan continues to run. See Section 5.0,
“Typical Applications”, for more information and system
design guidelines.
The TC646 is available in the 8-pin plastic DIP, SOIC
and MSOP packages and is available in the industrial
and extended commercial temperature ranges.
2002-2012 Microchip Technology Inc.
DS21446D-page 1
TC646
Functional Block Diagram
VIN
+
VOTF
–
VDD
–
OTF
PWM
+
Control
Logic
VOUT
CF
3 x TPWM
Timer
Clock
Generator
–
VAS
Start-up
Timer
+
FAULT
SHDN
–
Missing
Pulse
Detect.
+
–
GND
TC646
+
VSHDN
10kΩ
SENSE
70mV (typ.)
DS21446D-page 2
2002-2012 Microchip Technology Inc.
TC646
1.0
ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings*
Supply Voltage ......................................................... 6V
Input Voltage, Any Pin..... (GND – 0.3V) to (VDD+0.3V)
*Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are
stress ratings only and functional operation of the device at
these or any other conditions above those indicated in the
operation sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Package Thermal Resistance:
PDIP (RJA)............................................. 125°C/W
SOIC (RJA) ............................................ 155°C/W
MSOP (RJA) .......................................... 200°C/W
Specified Temperature Range............ -40°C to +125°C
Storage Temperature Range.............. -65°C to +150°C
DC ELECTRICAL SPECIFICATIONS
Electrical Characteristics: Unless otherwise specified, TMIN TA TMAX, VDD = 3.0V to 5.5V
Symbol
Parameter
Min
Typ
Max
Units
Test Conditions
VDD
Supply Voltage
3.0
—
5.5
V
IDD
Supply Current, Operating
—
0.5
1.0
mA
Pins 6, 7 Open,
CF = 1 µF, VIN = VC(MAX)
IDD(SHDN)
Supply Current, Shutdown/
Auto-shutdown Mode
—
25
—
µA
Pins 6, 7 Open;
Note 1
CF =1 µF, VIN = 0.35V
IIN
VIN, VAS Input Leakage
-1.0
—
+1.0
µA
Note 1
VOUT Output
tR
VOUT Rise Time
—
—
50
µsec
IOH = 5 mA, Note 1
tF
VOUT Fall Time
—
—
50
µsec
IOL = 1 mA, Note 1
tSHDN
Pulse Width(On VIN) to Clear
Fault Mode
30
—
—
µsec VSHDN, VHYST
Specifications,
Note 1
IOL
Sink Current at VOUT Output
1.0
—
—
mA
VOL = 10% of VDD
IOH
Source Current at VOUT
Output
5.0
—
—
mA
VOH = 80% of VDD
SENSE Input Threshold
Voltage with Respect to GND
50
70
90
mV
Note 1
SENSE Input
VTH(SENSE)
FAULT Output
VOL
Output Low Voltage
—
—
0.3
V
IOL = 2.5 mA
tMP
Missing Pulse Detector Timer
—
32/F
—
Sec
CF = 1.0 µF
tSTARTUP
Start-up Timer
—
32/F
—
Sec
CF = 1.0 µF
tDIAG
Diagnostic Timer
—
3/F
—
Sec
CF = 1.0 µF
Note 1: Ensured by design, not tested.
2002-2012 Microchip Technology Inc.
DS21446D-page 3
TC646
DC ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics: Unless otherwise specified, TMIN TA TMAX, VDD = 3.0V to 5.5V
Symbol
Parameter
Min
Typ
Max
Units
VC(MAX),VOTF Voltage at VIN for 100% Duty
Cycle and Overtemp. Fault
2.5
2.65
2.8
V
VC(SPAN)
VC(MAX) - VC(MIN)
1.3
1.4
1.5
V
VAS
Auto-shutdown Threshold
VC(MAX) ~
VC(SPAN)
—
VC(MAX)
V
VSHDN
Voltage Applied to VIN to
ensure Reset/Shutdown
—
—
VDD x 0.13
V
VREL
Voltage Applied to VIN to
Release Reset Mode
VDD x 0.19
—
—
V
VHYST
Hysteresis on VSHDN, VREL
—
0.01 x VDD
—
V
VHAS
Hysteresis on Auto-shutdown
Comparator
—
70
—
mV
26
30
34
Hz
Test Conditions
VIN, VAS Inputs
VDD = 5V,
See Figure 5-11
Pulse Width Modulator
FOSC
PWM Frequency
CF = 1.0 µF
Note 1: Ensured by design, not tested.
DS21446D-page 4
2002-2012 Microchip Technology Inc.
TC646
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Pin No.
PIN FUNCTION TABLE
Symbol
Description
2.3
Analog Input (VAS)
An external resistor divider connected to the VAS input
sets the auto-shutdown threshold. Auto-shutdown
occurs when VIN VAS. The fan is automatically
restarted when VIN (VAS + VHAS) (see Section 5.0,
“Typical Applications”, for more details).
1
VIN
Analog Input
2
CF
Analog Output
2.4
GND denotes the ground terminal.
3
VAS
Analog Input
4
GND
Ground Terminal
5
SENSE
Analog Input
6
FAULT
Digital (Open Collector) Output
7
VOUT
Digital Output
8
VDD
Power Supply Input
2.1
Analog Input (VIN)
The thermistor network (or other temperature sensor)
connects to the VIN input. A voltage range of 1.25V to
2.65V (typical) on this pin drives an active duty cycle of
0% to 100% on the VOUT pin. The TC646 enters shutdown mode when VIN VSHDN. During shutdown, the
FAULT output is inactive, and supply current falls to
25 µA (typical). The TC646 exits shutdown mode
when VIN VREL (see Section 5.0, “Typical
Applications”, for details).
2.2
Analog Output (CF)
CF is the positive terminal for the PWM ramp generator
timing capacitor. The recommended CF is 1 µF for
30 Hz PWM operation.
2.5
Ground (GND)
Analog Input (SENSE)
Pulses are detected at the SENSE pin as fan rotation
chops the current through a sense resistor (RSENSE).
The absence of pulses indicates a fault (see
Section 5.0, “Typical Applications”, for more details).
2.6
Digital Output (FAULT)
The FAULT line goes low to indicate a fault condition.
When FAULT goes low due to a fan fault condition, the
device is latched in shutdown mode until deliberately
cleared or until power is cycled. FAULT will also be
asserted when the PWM reaches 100% duty cycle,
indicating that maximum cooling capability has been
reached and a possible over-temperature condition
may occur. This is a non-latching state and the FAULT
output will go high when the PWM duty cycle goes
below 100%.
2.7
Digital Output (VOUT)
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 (see
Section 1.0, “Electrical Characteristics”).
2.8
Power Supply Input (VDD)
VDD may be independent of the fan’s power supply
(see Section 1.0, “Electrical Characteristics”).
2002-2012 Microchip Technology Inc.
DS21446D-page 5
TC646
3.0
DETAILED DESCRIPTION
3.5
3.1
PWM
The TC646 detects faults in two ways:
The PWM circuit consists of a ramp generator and
threshold detector. The frequency of the PWM is
determined by the value of the capacitor connected to
the CF input. A frequency of 30 Hz is recommended
(CF = 1 µF). The PWM is also the time base for the
Start-up Timer (see Section 3.3, “Start-Up Timer”). The
PWM voltage control range is 1.25V to 2.65V (typical)
for 0% to 100% output duty cycle.
3.2
VOUT Output
The VOUT pin is designed to drive a low cost transistor
or MOSFET as the low side, power switching element
in the system. Various examples of driver circuits will be
shown throughout this data sheet. This output has
asymmetric complementary drive and is optimized for
driving NPN transistors or N-channel MOSFETs. Since
the system relies on PWM rather than linear control,
the power dissipation in the power switch is kept to a
minimum. Generally, very small devices (TO-92 or SOT
packages) will suffice.
3.3
Start-Up Timer
To ensure reliable fan start-up, the Start-up Timer turns
the VOUT output on for 32 cycles of the PWM whenever
the fan is started from the off state. This occurs at
power-up and when coming out of shutdown or autoshutdown mode. If the PWM frequency is 30 Hz
(CF = 1 µF), the resulting start-up time will be approximately one second. If a fan fault is detected, the Diagnostic Timer is triggered once, followed by the Start-up
Timer. If the fault persists, the device is shut down (see
Section 3.5, “FAULT Output”).
3.4
SENSE Input
(FanSense™ Technology)
The SENSE input (Pin 5) is connected to a low value
current sensing resistor in the ground return leg of the
fan circuit. During normal fan operation, commutation
occurs as each pole of the fan is energized. This
causes brief interruptions in the fan current, seen as
pulses across the sense resistor. If the device is not in
auto-shutdown or shutdown mode, and pulses are not
appearing at the SENSE input, a fault exists.
The short, rapid change in fan current (high dI/dt)
causes a corresponding dV/dt across the sense
resistor, RSENSE. The waveform on RSENSE is
differentiated and converted to a logic-level pulse-train
by CSENSE and the internal signal processing circuitry.
The presence and frequency of this pulse-train is a
direct indication of fan operation. See Section 5.0,
“Typical Applications”, for more details.
DS21446D-page 6
FAULT Output
First, pulses appearing at SENSE due to the PWM
turning on are blanked, with the remaining pulses being
filtered by a missing pulse detector. If consecutive
pulses are not detected for thirty-two PWM cycles
(1 Sec if CF = 1 µF), the Diagnostic Timer is activated
and VOUT is driven high continuously for three PWM
cycles (100 msec if CF = 1 µF). If a pulse is not
detected within this window, the Start-up Timer is triggered (see Section 3.3, “Start-up Timer”). This should
clear a transient fault condition. If the missing pulse
detector times out again, the PWM is stopped and
FAULT goes low. When FAULT is activated due to this
condition, the device is latched in shutdown mode and
will remain off indefinitely. Therefore, the TC646 is prevented from attempting to drive a fan under catastrophic fault conditions.
One of two things will restore operation: Cycling power
off and then on again or pulling VIN below VSHDN and
releasing it to a level above VREL. When one of these
two conditions is satisfied, the normal start-up cycle is
triggered and operation will resume if the fault has been
cleared.
The second condition by which the TC646 asserts a
FAULT is when the PWM control voltage applied to VIN
becomes greater than that needed to drive 100% duty
cycle (see Section 1.0, “Electrical Characteristics”).
This indicates that the fan is at maximum drive and the
potential exists for system overheating. Either heat dissipation in the system has gone beyond the cooling
system’s design limits or some subtle fault exists (such
as fan bearing failure or an airflow obstruction). This
output may be treated as a “System Overheat” warning
and be used to trigger system shutdown or some other
corrective action.
However, in this case, the fan will continue to run even
when FAULT is asserted. If the system is allowed to
continue operation, and the temperature (and thus VIN)
falls, the FAULT output will become inactive when VIN
< VOTF.
3.6
Auto-Shutdown Mode
If the voltage on VIN becomes less than the voltage on
VAS, the fan is automatically shut off (auto-shutdown
mode). The TC646 exits auto-shutdown mode when
the voltage on VIN becomes higher than the voltage on
VAS by VHAS (the auto-shutdown Hysteresis Voltage
(see Figure 3-1)). The Start-up Timer is triggered and
normal operation is resumed upon exiting auto-shutdown mode. The FAULT output is unconditionally
inactive in auto-shutdown mode.
2002-2012 Microchip Technology Inc.
TC646
TC646
Status
Normal
Operation
Normal
Operation
Auto-Shutdown
Mode
ShutDown
Normal
Operation
HI
2.6V
VAS + VHAS
VAS
TEMP.
1.2V
tRESET
VIN
VREL
VSHDN
LO
GND
Time
FIGURE 3-1:
TC646 Nominal Operation.
Entering shutdown mode also performs a complete
device reset. Shutdown mode resets the TC646 into its
power-up state. The Start-up and Fault Timers, and any
current faults, are cleared. FAULT is unconditionally
inactive in shutdown mode. Upon exiting shutdown
mode (VIN > VREL), the Start-up Timer will be triggered
and normal operation will resume, assuming no fault
conditions exist and VIN > VAS + VHAS
If a fan fault has occurred and the device has latched
itself into shutdown mode, performing a reset will not
clear the fault unless VIN > (VAS + VHAS). If VIN is not
greater than (VAS + VHAS) upon exiting shutdown
mode, the fan will not be restarted. Consequently, there
is no way to establish that the fan fault has been
cleared. To ensure that a complete reset takes place,
the user’s circuitry must ensure that VIN > (VAS + VHAS)
when the device is released from shutdown mode. A
recommended algorithm for management of the TC646
by a host microcontroller or other external circuitry is
given in Section 5.0, “Typical Applications”. A small
amount of hysteresis, typically one percent of VDD
(50 mV at VDD = 5.0V), is designed into the VSHDN/
VREL threshold. The levels specified for VSHDN and
VREL in Section 1.0, “Electrical Characteristics”,
include this hysteresis plus adequate margin to
account for normal variations in the absolute value of
the threshold and hysteresis.
Note: If VIN < VAS when the device exits shutdown
mode, the fan will not restart as it will be in auto-shutdown mode.
CAUTION: Shutdown mode is unconditional. That is,
the fan will remain off as long as the VIN pin is being
held low or VIN < VAS + VHAS.
3.7
Shutdown Mode (Reset)
If an unconditional shutdown and/or device reset is
desired, the TC646 may be placed in shutdown mode
by forcing VIN to a logic low (i.e., VIN < VSHDN) (see
Figure 3-1). In this mode, all functions cease and the
FAULT output is unconditionally inactive. The TC646
should not be shut down unless all heat producing
activity in the system is at a negligible level. The TC646
exits shutdown mode when VIN becomes greater than
VREL, the release voltage.
2002-2012 Microchip Technology Inc.
DS21446D-page 7
TC646
4.0
SYSTEM BEHAVIOR
The flowcharts describing the TC646’s behavioral
algorithm are shown in Figure 4-1. They can be
summarized as follows:
4.1
Power-Up
(1) Assuming the device is not being held in auto-shutdown mode (VIN > VAS)..........
(2) Turn VOUT output on for 32 cycles of the PWM
clock. This ensures that the fan will start from a
dead stop.
4.3
Fan Fault
Fan fault is an infinite loop wherein the TC646 is
latched in shutdown mode. This mode can only be
released by a reset (i.e., VIN being brought below
VSHDN, then above (VAS + VHAS), or by power-cycling).
(1) While in this state, FAULT is latched on (low) and
the VOUT output is disabled.
(2) A reset sequence applied to the VIN pin will exit the
loop to Power-up.
(3) End.
(3) During this Start-up Timer, if a fan pulse is
detected, branch to Normal Operation; if none are
received…
(4) Activate the 32-cycle Start-up Timer one more time
and look for fan pulse; if a fan pulse is detected,
proceed to Normal Operation; if none are
received…
(5) Proceed to Fan Fault.
(6) End.
4.2
Normal Operation
“Normal Operation” is an endless loop which may only
be exited by entering shutdown mode, auto-shutdown
mode or Fan Fault. The loop can be thought of as
executing at the frequency of the oscillator and PWM.
(1) Reset the missing pulse detector.
(2) Is the TC646 in shutdown or auto-shutdown
mode?
If so...
a. VOUT duty cycle goes to zero.
b. FAULT is disabled.
c. Exit the loop and wait for VIN > (VAS + VHAS) to
resume operation.
(3) If an over-temperature fault occurs (VIN > VOTF),
activate FAULT; release FAULT when
VIN< VOTF.
(4) Drive VOUT to a duty cycle proportional to VIN on
a cycle by cycle basis.
(5) If a fan pulse is detected, branch back to the
start of the loop (1).
(6) If the missing pulse detector times out …
(7) Activate the 3-cycle Diagnostic Timer and look
for pulses; if a fan pulse is detected, branch
back to the start of the loop (1); if none are
received…
(8) Activate the 32-cycle Start-up Timer and look for
pulses; if a fan pulse is detected, branch back to
the start of the loop (1); if none are received…
(9) Quit Normal Operation and go to Fan Fault.
(10) End.
DS21446D-page 8
2002-2012 Microchip Technology Inc.
TC646
Normal
Operation
Power-Up
Clear Missing
Pulse Detector
Power-on
Reset
FAULT = 1
Yes
VIN < VSHDN?
Shutdown
VOUT = 0
No
Yes
VIN > VREL?
VIN < VSHDN?
No
No
VIN > VREL
No
Yes
Yes
Yes
VIN < VAS?
AutoShutdown
VOUT = 0
VIN < VAS?
Auto
Shutdown
VOUT = 0
No
No
Yes
Power-Up
No
VIN >
(VAS + VHAS)
Yes
VIN >
No
(VAS + VHAS)
VIN > VOTF?
Yes
No
Yes
Hot Start
Shutdown
VOUT = 0
FAULT = 0
Hot Start
VOUT
Proportional
to VIN
Fire Start-up
Timer
(1 SEC)
No
Fan Pulse
Detected?
Yes
Fire Start-up
YES
Timer
(1 SEC)
Fan Pulse
Detected?
Yes
No
Yes
No
M.P.D.
Expired?
Yes
Fan Pulse
Detected?
Fire
Diagnostic
Timer
(100msec)
No
Normal
Operation
Fan Fault
Yes
No
Fan Pulse
Detected?
Fire Start-up
Timer
(1 sec)
Fan Fault
Yes
FAULT = 0,
VOUT = 0
No
No
Auto-Shutdown
FAULT = 1
VOUT = 0
VIN < VSHDN ?
Yes
Yes
No
VIN > VREL ?
Fan Pulse
Detected?
No
Fan Fault
Cycling
Power
Yes
No
VIN > (VAS + VHAS)?
Yes
Power-Up
FIGURE 4-1:
TC646 Behavioral Algorithm Flowchart.
2002-2012 Microchip Technology Inc.
DS21446D-page 9
TC646
5.0
TYPICAL APPLICATIONS
The TC642 demonstration and prototyping board
(TC642DEMO) and the TC642 Evaluation Kit
(TC642EV) provide working examples of TC646 circuits and prototyping aids. The TC642DEMO is a
printed circuit board optimized for small size and ease
of inclusion into system prototypes. The TC642EV is a
larger board intended for benchtop development and
analysis. At the very least, anyone contemplating a
design using the TC646 should consult the documentation for both TC642EV (DS21403) and TC642DEMO
(DS21401). Figure 5-1 shows the base schematic for
the TC642DEMO.
Designing with the TC646 involves the following:
(1) The temperature sensor network must be
configured to deliver 1.25V to 2.65V on VIN for 0%
to 100% of the temperature range to be regulated.
(2) The auto-shutdown temperature must be set
with a voltage divider on VAS.
(3) The output drive transistor and associated circuitry
must be selected.
(4) The SENSE network, RSENSE and CSENSE, must
be designed for maximum efficiency while
delivering adequate signal amplitude.
(5) If shutdown capability is desired, the drive requirements of the external signal or circuit must be
considered.
+5V*
CB
1μF
+12V
NTC
R1
8
1
Shutdown**
VIN
Fan
VDD
CB
0.01μF
R2
6
FAULT
Thermal
Shutdown
+5V
Q1
RBASE
TC646
R3
VOUT
7
3 V
AS
CB
0.01μF
2
5
SENSE
CSENSE
CF
R4
CF
1μF
RSENSE
GND
4
NOTES: *See cautions regarding latch-up considerations in Section 5.0, "Typical Applications".
**Optional. See Section 5.0, "Typical Applications", for details.
FIGURE 5-1:
DS21446D-page 10
Typical Application Circuit.
2002-2012 Microchip Technology Inc.
TC646
5.1
Temperature Sensor Design
EQUATION
VDD x R2
The temperature signal connected to VIN must output a
voltage in the range of 1.25V to 2.65V (typical) for 0%
to 100% of the temperature range of interest. The
circuit in Figure 5-2 illustrates a convenient way to
provide this signal.
VDD
R1 = 100 kΩ
NTC Thermistor
100 kΩ@25˚C
VIN
R2 = 23.2kΩ
FIGURE 5-2:
Circuit.
Temperature Sensing
Figure 5-2 shows a simple temperature dependent
voltage divider circuit. RT1 is a conventional NTC
thermistor, while R1 and R2 are standard resistors. The
supply voltage, VDD, is divided between R2 and the parallel combination of RT1 and R1. For convenience, the
parallel combination of RT1 and R1 will be referred to as
RTEMP. The resistance of the thermistor at various temperatures is obtained from the manufacturer’s specifications. Thermistors are often referred to in terms of
their resistance at 25°C.
Generally, the thermistor shown in Figure 5-2 is a nonlinear device with a negative temperature coefficient
(also called an NTC thermistor). In Figure 5-2, R1 is
used to linearize the thermistor temperature response
and R2 is used to produce a positive temperature
coefficient at the VIN node. As an added benefit, this
configuration produces an output voltage delta of 1.4V,
which is well within the range of the VC(SPAN)
specification of the TC646. A 100 kNTC thermistor is
selected for this application in order to keep IDIV at a
minimum.
For the voltage range at VIN to be equal to 1.25V to
2.65V, the temperature range of this configuration is
0°C to 50°C. If a different temperature range is required
from this circuit, R1 should be chosen to equal the
resistance value of the thermistor at the center of this
new temperature range. It is suggested that a maximum temperature range of 50°C be used with this circuit due to thermistor linearity limitations. With this
change, R2 is adjusted according to the following
equations:
2002-2012 Microchip Technology Inc.
VDD x R2
RTEMP (T2) + R2
= V(T2)
Where T1 and T2 are the chosen temperatures and
RTEMP is the parallel combination of the thermistor
and R1.
IDIV
RT1
= V(T1)
RTEMP (T1) + R2
These two equations facilitate solving for the two
unknown variables, R1 and R2. More information about
thermistors may be obtained from AN679, “Temperature Sensing Technologies”, and AN685, “Thermistors
In Single Supply Temperature Sensing Circuits”, which
can be downloaded from Microchip’s web site at
www.microchip.com.
5.2
Auto-Shutdown Temperature
Design
A voltage divider on VAS sets the temperature where
the part is automatically shut down if the sensed
temperature at VIN drops below the set temperature at
VAS (i.e., VIN < VAS). As with the VIN input, 1.25V to
2.65V corresponds to the temperature range of interest
from T1 to T2, respectively. Assuming that the
temperature sensor network designed above is linearly
related to temperature, the shutdown temperature TAS
is related to T2 and T1 by:
EQUATION
2.65V - 1.25V
T2 - T1
1.4V
VAS = T - T
2
1
(
)
=
VAS - 1.25V
TAS - T1
( TAS - T1) + 1.25V
For example, if 1.25V and 2.65V at VIN corresponds to
a temperature range of T1 = 0°C to T2 = 125°C, and the
auto-shutdown temperature desired is 25°C, then VAS
voltage is:
EQUATION
1.4V
VAS =
(25 - 0) + 1.25V = 1.53V
(125 - 0)
The VAS voltage may be set using a simple resistor
divider as shown in Figure 5-3.
DS21446D-page 11
TC646
5.3
VDD
R1
One boundary condition which may impact the selection of the minimum fan speed is the irregular activation
of the Diagnostic Timer due to the TC646 “missing” fan
commutation pulses at low speeds. This is a natural
consequence of low PWM duty cycles (typically 25% or
less). Recall that the SENSE function detects commutation of the fan as disturbances in the current through
RSENSE. These can only occur when the fan is energized (i.e., VOUT is “on”). At very low duty cycles, the
VOUT output is “off” most of the time. The fan may be
rotating normally, but the commutation events are
occurring during the PWM’s off-time.
IIN
IDIV
VAS
R2
GND
FIGURE 5-3:
VAS CIRCUIT
Per Section 1.0, “Electrical Characteristics”, the leakage current at the VAS pin is no more than 1 µA. It is
conservative to design for a divider current, IDIV, of
100 µA. If VDD = 5.0V then…
EQUATION
IDIV = 1e–4A =
R1 + R2 =
5.0V
R1 + R2
5.0V
1e–4A
, therefore
= 50,000 = 50k
We can further specify R1 and R2 by the condition that
the divider voltage is equal to our desired VAS. This
yields:
EQUATION
VAS =
VDD x R2
R1 + R2
Solving for the relationship between R1 and R2 results
in:
EQUATION
R1 = R2 x
VDD - VAS
VAS
5 - 1.53
= R2 x
Operations at Low Duty Cycle
1.53
The phase relationship between the fan’s commutation
and the PWM edges tends to “walk around” as the
system operates. At certain points, the TC646 may fail
to capture a pulse within the 32-cycle missing pulse
detector window. If this happens, the 3-cycle
Diagnostic Timer will be activated, the VOUT output will
be active continuously for three cycles and, if the fan is
operating normally, a pulse will be detected. If all is
well, the system will return to normal operation. There
is no harm in this behavior, but it may be audible to the
user as the fan accelerates briefly when the Diagnostic
Timer fires. For this reason, it is recommended that VAS
be set no lower than 1.8V.
5.4
FanSense™ Network
(RSENSE and CSENSE)
The FanSense network, comprised of RSENSE and
CSENSE, allows the TC646 to detect commutation of
the fan motor (FanSense™ technology). This network
can be thought of as a differentiator and threshold
detector. The function of RSENSE is to convert the fan
current into a voltage. CSENSE serves to AC-couple this
voltage signal and provide a ground-referenced input to
the SENSE pin. Designing a proper SENSE network is
simply a matter of scaling RSENSE to provide the
necessary amount of gain (i.e., the current-to-voltage
conversion ratio). A 0.1 µF ceramic capacitor is
recommended for CSENSE. Smaller values require
larger sense resistors, and higher value capacitors are
bulkier and more expensive. Using a 0.1 µF capacitor
results in reasonable values for RSENSE. Figure 5-4
illustrates a typical SENSE network. Figure 5-5 shows
the waveforms observed using a typical SENSE network.
In the case of this example, R1 = (2.27) R2.
Substituting this relationship back into the original
equation yields the resistor values:
R2 = 15.3 k, and
R1 = 34.7 k
In this case, the standard values of 34.8 k and
15.4 k are very close to the calculated values and
would be more than adequate.
DS21446D-page 12
2002-2012 Microchip Technology Inc.
TC646
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
Fan
RBASE
VOUT
Q1
SENSE
CSENSE
(0.1 μF Typ.)
RSENSE
5.5
SENSE Network.
Tek Run: 10.0kS/s Sample
[
T
]
Waveform @ Sense Resistor
GND
1
Waveform @ Sense Pin
90mV
50mV
GND
T
2
Ch1 100mV
FIGURE 5-5:
Ch2
100mV
M5.00ms Ch1
142mV
SENSE Waveforms.
Table 5-1 lists the recommended values of RSENSE
based on the nominal operating current of the fan. Note
that the current draw specified by the fan manufacturer
may be a worst-case rating for near-stall conditions and
not the fan’s nominal operating current. The values in
Table 5-1 refer to actual average operating current. If
the fan current falls between two of the values listed,
use the higher resistor value. The end result of employing Table 5-1 is that the signal developed across the
sense resistor is approximately 450 mV in amplitude.
2002-2012 Microchip Technology Inc.
Output Drive Transistor Selection
The TC646 is designed to drive an external transistor
or MOSFET for modulating power to the fan. This is
shown as Q1 in Figures 5-1, 5-4, 5-6, 5-7, 5-8 and 5-9.
The VOUT pin has a minimum source current of 5 mA
and a minimum sink current of 1 mA. Bipolar transistors
or MOSFETs may be used as the power switching
element, as shown in Figure 5-7. When high current
gain is needed to drive larger fans, two transistors may
be used in a Darlington configuration. These circuit
topologies are shown in Figure 5-7: (a) shows a single
NPN transistor used as the switching element; (b)
illustrates the Darlington pair; and (c) shows an Nchannel MOSFET.
GND
FIGURE 5-4:
RSENSE VS. FAN CURRENT
TABLE 5-1:
VDD
One major advantage of the TC646’s PWM control
scheme versus linear speed control is that the power
dissipation in the pass element is kept very low.
Generally, low cost devices in very small packages,
such as TO-92 or SOT, can be used effectively. For
fans with nominal operating currents of no more than
200 mA, a single transistor usually suffices. Above
200 mA, the Darlington or MOSFET solution is
recommended. For the fan sensing function to work
correctly, it is imperative that the pass transistor be fully
saturated when “on”.
Table 5-2 gives examples of some commonly available
transistors and MOSFETs. This table should be used
as a guide only since there are many transistors and
MOSFETs which will work just as well as those listed.
The critical issues when choosing a device to use as
Q1 are: (1) the breakdown voltage (V(BR)CEO or VDS
(MOSFET)) must be large enough to withstand the
highest voltage applied to the fan (Note: This will occur
when the fan is off); (2) 5 mA of base drive current must
be enough to saturate the transistor when conducting
the full fan current (transistor must have sufficient
gain); (3) the VOUT voltage must be high enough to sufficiently drive the gate of the MOSFET to minimize the
RDS(on) of the device; (4) rated fan current draw must
be within the transistor's/MOSFET's current handling
capability; and (5) power dissipation must be kept
within the limits of the chosen device.
DS21446D-page 13
TC646
A base-current limiting resistor is required with bipolar
transistors. This is shown in Figure 5-6.
The correct value for this resistor can be determined as
follows:
VDD
RBASE
–
RBASE
+
VBE(SAT)–
+V
= VRSENSE + VBE(SAT) + VRBASE
VRSENSE
= IFAN x RSENSE
VRBASE
= RBASE x IBASE
IBASE
= IFAN / hFE
VOH is specified as 80% of VDD in Section 1.0,
“Electrical Characteristics”; VBE(SAT) is given in the
chosen transistor data sheet. It is now possible to solve
for RBASE.
Fan
VOH = 80% VDD
VOH
EQUATION
Q1
RBASE =
VOH - VBE(SAT) - VRSENSE
IBASE
+
VRSENSE
Some applications benefit from the fan being powered
from a negative supply to keep motor noise out of the
positive supply rails. This can be accomplished as
shown in Figure 5-8. Zener diode D1 offsets the -12V
power supply voltage, holding transistor Q1 off when
VOUT is low. When VOUT is high, the voltage at the
anode of D1 increases by VOUT, causing Q1 to turn on.
Operation is otherwise the same as in the case of fan
operation from +12V.
RSENSE
–
GND
FIGURE 5-6:
RBASE.
Circuit For Determining
VDD
VDD
VDD
Fan
Fan
Fan
RBASE
RBASE
VOUT
Q1
VOUT
Q1
VOUT
Q1
Q2
RSENSE
GND
a) Single Bipolar Transistor
FIGURE 5-7:
DS21446D-page 14
RSENSE
RSENSE
GND
b) Darlington Transistor Pair
GND
c) N-Channel MOSFET
Output Drive Transistor Circuit Topologies.
2002-2012 Microchip Technology Inc.
TC646
+5V
VDD
R2*
2.2 kΩ
VOUT
D1
12.0V
Zener
Fan
TC646
Q1*
R4*
10 kΩ
GND
R3*
2.2Ω
-12V
NOTE: *Value depends on the specific application and is shown for example only.
FIGURE 5-8:
TABLE 5-2:
Device
MMBT2222A
MPS2222A
MPS6602
Power the Fan from a -12V Supply.
TRANSISTORS AND MOSFETS FOR Q1 (VDD = 5V)
Package
Max. VBE(sat)/VGS
(V)
Min. HFE
VCEO/VDS
(V)
Fan Current
(mA)
Suggested
RBASE ()
SOT-23
1.2
50
40
150
800
TO-92
1.2
50
40
150
800
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.
5.6
Latch-up Considerations
As with any CMOS IC, the potential exists for latch-up
if signals are applied to the device which are outside
the power supply range. This is of particular concern
during power-up if the external circuitry (such as the
sensor network, VAS divider or shutdown circuit) is
powered by a supply different from that of the TC646.
Care should be taken to ensure that the TC646’s VDD
supply powers up first. If possible, the networks
attached to VIN and VAS should connect to the VDD supply at the same physical location as the IC itself. Even
if the IC and any external networks are powered by the
same supply, physical separation of the connecting
points can result in enough parasitic capacitance and/
or inductance in the power supply connections to delay
one power supply “routing” versus another.
2002-2012 Microchip Technology Inc.
5.7
Power Supply Routing and
Bypassing
Noise present on the VIN and VAS inputs may cause
erroneous operation of the FAULT output. As a result,
these inputs should be bypassed with a 0.01 µF
capacitor mounted as close to the package as possible.
This is especially true of VIN, which is usually driven
from a high impedance source (such as a thermistor).
In addition, the VDD input should be bypassed with a
1 µF capacitor. Grounds should be kept as short as
possible. To keep fan noise off the TC646 ground pin,
individual ground returns for the TC646 and the low
side of the fan current sense resistor should be used.
DS21446D-page 15
TC646
Design Example
Step 1. Calculate R1 and R2 based on using an NTC
having a resistance of 10 k at TMIN (25°C)
and 4.65 k at TMAX (45°C) (See Figure 5-9).
R1 = 20.5 k
R2 = 3.83 k
Step 2. Set auto-shutdown level VAS = 1.8V.
Limit the divider current to 100 µA from which
R5 = 33 k
R6 = 18 k
Step 3. Design the output circuit.
Maximum fan motor current = 250 mA. Q1
beta is chosen at 50 from which R7 = 800 .
+5V
+12V
+5V
Open-Drain
Device
NTC
10 kΩ
@ 25˚C
R1
20.5 kΩ
Reset
Shutdown
(Optional)
CB
1 μF
1
VIN
R2
3.83 kΩ
8
4
VDD
GND
Fan
CB
0.01 μF
6
FAULT
Fan/Thermal
Fault
R7
800Ω
+5V
TC646
VOUT
R5
33 kΩ
Q1
7
3 VAS
CB
0.01 μF
SENSE
2
R6
18 kΩ
CF
5
CSENSE
0.1 μF
RSENSE
2.2Ω
C1
1 μF
FIGURE 5-9:
5.8
Design Example.
TC646 as a Microcontroller
Peripheral
In a system containing a microcontroller or other host
intelligence, the TC646 can be effectively managed as
a CPU peripheral. Routine fan control functions can be
performed by the TC646 without controller intervention.
The microcontroller receives temperature data from
one or more points throughout the system. It calculates
a fan operating speed based on an algorithm specifically designed for the application at hand. The processor controls fan speed using complementary port bits
I/O1 through I/O3. Resistors R1 through R6 (5% tolerance) form a crude 3-bit DAC that translates the 3-bit
code from the processor's outputs into a 1.6V DC control signal. A monolithic DAC or digital pot may be used
instead of the circuit shown in Figure 5-10.
DS21446D-page 16
With VAS set at 1.8V, the TC646 enters auto-shutdown
when the controller's output code is 000[B]. Output
codes 001[B] to 111[B] operate the fan from roughly
40% to 100% of full speed. An open-drain output from
the processor (I/O0) can be used to reset the TC646
following detection of a fault condition. The FAULT output can be connected to the controller's interrupt input,
or to another I/O pin, for polled operation.
2002-2012 Microchip Technology Inc.
TC646
+12V
+5V
(RESET) (Optional)
Open-Drain
I/O0
Outputs
R1
110 kΩ
(MSB)
I/O1
R2
240 kΩ
CMOS I/O2
Outputs
R3
360 kΩ
I/O3
(LSB)
Analog or Digital
Temperature
Data from one or
more Sensors
CMOS
Microcontroller
R5
1.5 kΩ
+5V
+5V
1 V
IN
VDD 8
CB
.01 μF
+
R7
R4 33 kΩ
18 kΩ
+5V
R
2 C
F
TC646
1 μF
3
8
18 kΩ
CB
VAS
FAULT
6
.01 μF
4
R6
1 kΩ
VOUT 7
GND
SENSE
5
Fan
+ CB
1 μF R9
800Ω
2N2222A
+5V
R10
10 kΩ
0.1 μF
R11
2.2Ω
GND
FIGURE 5-10:
INT
TC646 as a Microcontroller Peripheral.
VRELEASE vs. Temperature
1.0
VDD = 5.5V
0.9
VDD = 5.0V
VRELEASE (V)
0.8
0.7
VDD = 4.0V
0.6
VDD = 3.0V
0.5
0.4
0˚C
25˚C
85˚C
TEMPERATURE
FIGURE 5-11:
VRELEASE vs. Temperature.
2002-2012 Microchip Technology Inc.
DS21446D-page 17
TC646
6.0
PACKAGING INFORMATION
6.1
Package Marking Information
8-Lead PDIP (300 mil)
XXXXXXXX
NNN
YYWW
TC646VPA
025
0215
8-Lead SOIC (150 mil)
XXXXXXXX
YYWW
NNN
8-Lead MSOP
XXXXXX
YWWNNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
DS21446D-page 18
Example:
Example:
TC646VOA
0215
025
Example:
TC646E
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.
2002-2012 Microchip Technology Inc.
TC646
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
2002-2012 Microchip Technology Inc.
DS21446D-page 19
TC646
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
DS21446D-page 20
2002-2012 Microchip Technology Inc.
TC646
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
p
E1
D
2
B
n
1
A2
A
c
A1
(F)
L
Number of Pins
Pitch
Overall Height
MILLIMETERS*
INCHES
Units
Dimension Limits
n
p
MAX
NOM
MIN
MIN
NOM
0.65
.026
.044
A
1.18
.038
0.76
.006
0.05
.193
.200
.114
.118
.114
.118
L
.016
.035
Foot Angle
F
Lead Thickness
c
.004
Lead Width
B
.010
Mold Draft Angle Top
Mold Draft Angle Bottom
Molded Package Thickness
A2
.030
Standoff
A1
.002
E
.184
Molded Package Width
E1
Overall Length
D
Foot Length
Footprint (Reference)
§
Overall Width
MAX
8
8
0.86
0.97
4.67
4.90
.5.08
.122
2.90
3.00
3.10
.122
2.90
3.00
3.10
.022
.028
0.40
0.55
0.70
.037
.039
0.90
0.95
1.00
6
0
.006
.008
0.10
0.15
0.20
.012
.016
0.25
0.30
0.40
.034
0
0.15
6
7
7
7
7
*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.
Drawing No. C04-111
2002-2012 Microchip Technology Inc.
DS21446D-page 21
TC646
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 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 (Narrow) Devices
User Direction of Feed
PIN 1
W
P
Standard Reel Component Orientation
for 713 Suffix Device
Carrier Tape, Number of Components Per Reel and Reel Size
Package
8-Pin SOIC (N)
DS21446D-page 22
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
12 mm
8 mm
2500
13 in
2002-2012 Microchip Technology Inc.
TC646
7.0
REVISION HISTORY
Revision D (December 2012)
Added a note to each package outline drawing.
2002-2012 Microchip Technology Inc.
DS21446D-page 23
TC646
NOTES:
DS21446D-page 24
2002-2012 Microchip Technology Inc.
THE MICROCHIP WEB SITE
CUSTOMER SUPPORT
Microchip provides online support via our WWW site at
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Field Application Engineer (FAE)
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Customers
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Microchip’s customer notification service helps keep
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specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com. Under “Support”, click on
“Customer Change Notification” and follow the
registration instructions.
2002-2012 Microchip Technology Inc.
DS21446D-page 25
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip
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Literature Number: DS21446D
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4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
DS21446D-page 26
2002-2012 Microchip Technology Inc.
TC646
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
X
/XX
Temperature
Range
Package
Device:
TC646:
PWM Fan Speed Controller w/Auto Shutdown
and Fault Detection
Temperature Range:
V
E
Package:
PA = Plastic DIP (300 mil Body), 8-lead *
OA = Plastic SOIC, (150 mil Body), 8-lead
UA = Plastic Micro Small Outline (MSOP), 8-lead
Examples:
a)
TC646VOA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, SOIC
package.
b)
TC646VUA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, MSOP
package.
c)
= 0C to +85C
= -40C to +85C
TC646VPA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, PDIP
package.
d)
TC646EOA713: PWM Fan Speed Controller
w/Auto Shutdown and Fault Detection, SOIC
package, Tape and Reel.
* PDIP package is only offerred in the V temp range
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.
New Customer Notification System
Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
2002-2012 Microchip Technology Inc.
DS21446D-page27
TC646
NOTES:
DS21446D-page 28
2002-2012 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,
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.
© 2002-2012, Microchip Technology Incorporated, Printed in
the U.S.A., All Rights Reserved.
Printed on recycled paper.
ISBN: 9781620768273
QUALITY MANAGEMENT SYSTEM
CERTIFIED BY DNV
== ISO/TS 16949 ==
2002-2012 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.
DS21446D-page 29
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
DS21446D-page 30
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
2002-2012 Microchip Technology Inc.
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