TC648 Microchip, TC648 Datasheet - Page 5

• Manufacturer Part Number: TC648
• Description: Fan Speed Controller
• Manufacturer: Microchip

2.0
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
2.1
The thermistor network (or other temperature sensor)
connects to the V
2.65V (typical) on this pin drives an active duty cycle of
0% to 100% on the V
Applications”, for more details).
2.2
C
timing capacitor. The recommended C
30 Hz PWM operation.
1
2
3
4
5
6
7
8
F
Pin No.
2002 Microchip Technology Inc.
is the positive terminal for the PWM ramp generator
Analog Input (V
Analog Output (C
PIN DESCRIPTIONS
Symbol
V
GND
OTF
V
V
V
NC
C
OUT
AS
DD
IN
F
IN
PIN FUNCTION TABLE
input. A voltage range of 1.25V to
OUT
Analog Input
Analog Output
Analog Input
Ground Terminal
No Internal Connection
Digital (Open Collector) Output
Digital Output
Power Supply Input
pin (see Section 5.0, “Typical
IN
Description
)
F
)
F
is 1 µF for
2.3
An external resistor divider connected to the V
sets the auto-shutdown threshold. Auto-shutdown
occurs when V
current falls to 25 µA (typical). The fan is automatically
restarted when V
“Typical Applications” for more details).
2.4
GND denotes the ground Terminal.
2.5
No internal connection.
2.6
OTF goes low to indicate an over-temperature
condition. This occurs when the voltage at V
(see Section 1.0, "Electrical Characteristics"). An over-
temperature indication is a non-latching condition.
2.7
V
the base of an external NPN transistor (via an appropri-
ate base resistor) or the gate of an N-channel MOS-
FET. This output has asymmetrical drive (see
Section 1.0, “Electrical Characteristics”).
2.8
V
(see Section 1.0, “Electrical Characteristics”).
OUT
DD
may be independent of the fan’s power supply
is an active high complimentary output that drives
Analog Input (V
Ground (GND)
No Connect
Digital Output (OTF)
Digital Output (V
Power Supply Input (V
IN
IN
V
(V
AS
AS
. During shutdown, supply
+V
AS
OUT
HAS
)
) (see Section 5.0,
)
DS21448C-page 5
TC648
DD
)
IN
AS
> V
input
OTF