TC652/TC653
Integrated Temperature Sensor & Brushless DC Fan
Controller with FanSense™ Detect & Over-Temperature
Features
• Integrated Temperature Sensing and Multi-speed
Fan Control
• FanSense™ Fan Fault Detect Circuitry
• Built-in Over-Temperature Alert (T
OVER
)
• Temperature Proportional Fan Speed Control for
Acoustic Noise Reduction and Longer Fan Life
• Pulse Width Modulation Output Drive for Cost
and Power Savings
• Solid-State Temperature Sensing
• ±1°C (Typical) Accuracy from 25°C to +70°C
• 2.8V – 5.5V Operating Range
• TC653 includes Auto Fan Shutdown
• Low Operating Current: 50µA (Typical)
Package Type
MSOP
V
DD
1
FAULT 2
SHDN 3
GND 4
8 PWM
TC652
TC653
7 GND
6 T
OVER
5 SENSE
General Description
The TC652/TC653 are integrated temperature sensors
and brushless DC fan speed controllers with
FanSense
™
technology. The TC652/TC653 measure
their junction temperature and control the speed of the
fan based on that temperature, making them especially
suited for applications in modern electronic equipment.
The FanSense
™
Fan Fault detect circuitry eliminates
the need for a more expensive 3-wire fan.
Temperature data is converted from the on-chip
thermal sensing element and translated into a
fractional fan speed from 40% to 100%. A temperature
selection guide in the data sheet is used to choose the
low and high temperature limits to control the fan. The
TC652/TC653 also include a single trip point over
temperature alert (T
OVER
) that eliminates the need for
additional temperature sensors. In addition, the TC653
includes an auto fan shutdown function for additional
power savings.
The TC652/TC653 are easy to use, require no software
overhead and are therefore the ideal choice for
implementing thermal management in a variety of
systems.
Applications
•
•
•
•
•
•
Thermal Protection For Personal Computers
Digital Set-Top Boxes
Notebook Computers
Data Communications
Power Supplies
Projectors
Related Literature
• Application Note: AN771
Device Selection Table
Part Number
TC652XXVUA
TC653XXVUA
Package
8-Pin MSOP
8-Pin MSOP
Temperature Range
-40°C to +125°C
-40°C to +125°C
X
A
B
C
D
E
F
G
Temperature
25
30
35
40
45
50
55
The "X" denotes a suffix for temperature threshold settings.
Contact factory for other temperature ranges.
2002 Microchip Technology Inc.
DS21453B-page 1
©
TC652/TC653
Typical Application Diagram
+12V
DC Fan
300mA
Max.
1k
1 V
DD
2 FAULT
3 SHDN
4 GND
PWM 8
GND 7
T
OVER
6
SENSE 5
C
SENSE
GND
SHDN Control
Fan Fault Alert
µController
Over-Temp
Alert
R
SENSE
2Ω
FanSense™
0.01µF
+5V V
DD
TC652
TC653
©
DS21453B-page 2
2002 Microchip Technology Inc.
TC652/TC653
1.0
ELECTRICAL
CHARACTERISTICS
*Stresses above those listed under "Absolute Maximum Rat-
ings" 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. Expo-
sure to Absolute Maximum Rating conditions for extended
periods may affect device reliability.
Absolute Maximum Ratings*
Input Voltage (V
DD
to GND) ................................... +6V
Output Voltage (OUT to GND) ................................. 6V
Voltage On Any Pin ....... (GND – 0.3V) to (V
DD
+ 0.3V)
Package Thermal Resistance (θ
JA
)
........... 250°C/W
Operating Temperature Range ......... -40°C to +125°C
Storage Temperature ......................... -65°C to +150°C
TC652/TC653 ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
V
DD
= 2.8V to 5.5V, SHDN = V
DD
, T
A
= -40°C to 125°C unless otherwise specified.
Symbol
V
DD
I
DD
SHDN Input
V
IH
V
IL
PWM Output
V
OL
V
OH
t
R
t
F
f
OUT
t
STARTUP
V
TH (SENSE)
PWM Output Low Voltage
PWM Output High Voltage
PWM Rise Time
PWM Fall Time
PWM Frequency
Start-up Time
Sense Input
—
V
DD
– 0.5
—
—
10
—
—
—
—
10
10
15
32/f
OUT
70
0.3
—
—
—
—
—
—
V
V
µsec
µsec
Hz
sec
mV
V
DD
Rises from GND,
or SHDN Released
Sense Input Threshold
Voltage with Repect to
Ground
I
SINK
= 1mA
I
SOURCE
= 5mA
I
OH
= 5mA, 1nF from
PWM to GND
I
OL
= 1mA, 1nF from
PWM to GND
SHDN Input High Threshold
SHDN Input Low Threshold
65
—
—
—
—
15
%V
DD
%V
DD
Parameter
Supply Voltage
Supply Current
Min
2.8
—
Typ.
—
50
Max
5.5
90
Units
V
µA
PWM, FAULT, T
OVER
are
open
Test Conditions
Temperature Accuracy
T
H ACC
(T
H –
T
L
)
ACC
T
HYST
FAULT Output
V
HIGH
V
LOW
tmp
T
OVER
Output
V
HIGH
V
LOW
T
OVER
Note
ACC
High Temperature Accuracy
Temp. Range Accuracy
Auto-shutdown Hysteresis
T
H
- 3
-1.0
-2.5
—
T
H
—
—
(T
H
– T
L
)/5
T
H
+ 3
+1.0
+2.5
—
°C
°C
°C
°C
Note 1
(T
H
– T
L
)
≤
20°C
(T
H
– T
L
)
≥
20°C
TC653 Only
FAULT Output High Voltage
FAULT Output Low Voltage
Missing Pulse Detector
Time-out
V
DD
– 0.5
—
—
—
—
—
—
0.4
32/f
OUT
V
V
Sec
I
SOURCE
= 1.2mA
I
SINK
= 2.5mA
T
OVER
Output High Voltage
T
OVER
Output Low Voltage
Absolute Accuracy
Trip Point Hysteresis
Transition from 90% to 100% Duty Cycle.
V
DD
– 0.5
—
—
—
—
—
T
H
+ 10
5
—
0.4
—
—
V
V
°C
°C
I
SOURCE
= 1.2mA
I
SINK
= 2.5mA
At Trip Point
T
OVER HYST
1:
2002 Microchip Technology Inc.
DS21453B-page 3
©
TC652/TC653
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Pin No.
(8-Pin MSOP)
1
2
PIN FUNCTION TABLE
Symbol
V
DD
FAULT
Description
Power Supply Input. May be independent of fan power supply.
Fan Fault Alert, Active-Low Output. FAULT goes low to indicate a fan FAULT condition.
When FAULT occurs, the device is latched in Shutdown mode with PWM low. Toggling
the SHDN pin or cycling the V
DD
will release the part and fan from shutdown. FAULT will
unconditionally remain high during shutdown.
Fan Shutdown, Active-Low Input. During Shutdown mode the chip still monitors
temperature and T
OVER
is low if temperature rises above factory set point.
Ground return for all TC652/TC653 functions.
Detect Fan Pulses Input. Pulses are detected at this pin as fan rotation chops the current
through the sense resistor, R
SENSE
. The absence of pulses indicates a Fan Fault.
Over-Temperature Alert, Active-Low Output.
Ground.
PWM Fan Drive Output. Pulse width modulated rail-to-rail logic output. Nominal
Frequency is 15Hz.
3
4
5
6
7
8
SHDN
GND
SENSE
T
OVER
GND
PWM
©
DS21453B-page 4
2002 Microchip Technology Inc.
TC652/TC653
3.0
DETAILED DESCRIPTION
TABLE 3-2:
The TC652/TC653 acquire and convert their junction
temperature (T
J
) information from an on-chip solid
state sensor with a typical accuracy of ±1°C. The
temperature data is digitally stored in an internal
register. The register is compared with pre-defined
threshold values. The six threshold values are equally
distributed over a pre-defined range of temperatures
(See Table 3-1 and Table 3-2). The TC652/TC653
control the speed of a DC brushless fan using a
fractional speed control scheme. The output stage
requires only a 2N2222-type small-signal BJT for fans
up to 300mA. For larger current fans (up to 1 Amp) a
logic-level N-channel MOSFET may be used. In
addition to controlling the speed of the fan, the TC652/
TC653 include an on-chip over-temperature alarm
(T
OVER
) that gives a low-true signal when the
temperature of the chip exceeds T
H
by 10°C. This
feature eliminates the need for a separate temperature
sensor for over-temperature monitoring.
In normal fan operation, a pulse-train is present at
SENSE, Pin 5. A Missing Pulse Detector monitors this
pin during fan operation (FanSense
™
technology). A
stalled, open, or unconnected fan causes the TC652/
TC653 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. To release the fan from
shutdown, toggle the SHDN or V
DD
pin.
TEMPERATURE RANGE
DEFINITION FOR TC653
(AUTO-SHUTDOWN MODE)
PWM Duty Cycle
“OFF”
50%
60%
70%
80%
90%
100%
100% with Over-Temp Alert
(T
OVER
= L)
Temperature
(T = T
J
)
T < T
L
T
L
< = T < T
1
T
1
< = T < T
2
T
2
< =T < T
3
T
3
< =T < T
4
T
4
< = T < T
H
T
H
< = T < T
OV
T
OV
< = T
Note:
The temperature regions defined by the six tempera-
ture thresholds are pre-defined in the TC650/651 by means
of trimming. Once a T
L
and T
H
are programmed, the T
1
- T
4
thresholds are automatically equally spaced between T
L
and
T
H
.
FIGURE 3-1:
V
DD
FUNCTIONAL BLOCK
DIAGRAM
T
OVER
V+
SHDN
Duty Cycle
Logic
Control
Temperature
Set Point and
Trim Range
-
PWM
TABLE 3-1:
TEMPERATURE RANGE
DEFINITION FOR TC652
(MINIMUM-SPEED MODE)
PWM Duty Cycle
40%
50%
60%
70%
80%
90%
100%
100% with Over-Temp Alert
(T
OVER
= L)
AD Converter
Oscillator
Temperature
(T = T
J
)
T < T
L
T
L
< = T < T
1
T
1
< = T < T
2
T
2
< = T <T
3
T
3
< = T < T
4
T
4
< = T < T
H
T
H
< = T < T
OV
T
OV
< = T
Temp Sensor
Fan Detect
Logic
FAULT
+
CMPTR
-
90mV
20k
-
3.1
PWM Output
The PWM pin is designed to drive a low cost transistor
or MOSFET as the low side power switching element in
the system. This output has an asymmetric
complementary drive and is optimized for driving NPN
transistors or N-channel MOSFETs. Since the system
relies on PWM rather than linear power control, the
dissipation in the power switch is kept to a minimum.
Generally, very small devices (TO-92 or SOT
packages) will suffice. The frequency of the PWM is
about 15Hz. The PWM is also the time base for the
Start-up Timer (see paragraphs below). The PWM duty
cycle has a range of 40% to 100% for the TC652 and
50% to 100% for the TC653.
2002 Microchip Technology Inc.
DS21453B-page 5
©
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