TC653AEVUA Microchip Technology, TC653AEVUA Datasheet - Page 6

• Manufacturer Part Number: TC653AEVUA
• Description: IC TEMP SENSOR/DC FAN CTLR 8MSOP
• Manufacturer: Microchip Technology
• Series: FanSense™r
• Type: Temperature Sensorr

Specifications of TC653AEVUA

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Oscillator, Register Bank
• Sensor Type: Internal
• Sensing Temperature: 25°C, 45°C Trip Points
• Output Type: Active Low
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 2.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Motor Type: DC Brushless
• No. Of Outputs: 1
• Output Current: 5mA
• Output Voltage: 2.3V
• Supply Voltage Range: 2.8V To 5.5V
• Driver Case Style: MSOP
• No. Of Pins: 8
• Operating Supply Voltage: 5.5 V
• Supply Current: 90 uA
• Mounting Style: SMD/SMT
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

TC652/TC653
3.2
To ensure reliable fan start-up, the Start-up Timer turns
PWM high for about 2 seconds whenever the fan is
started from the off state. This occurs at power-up and
when coming out of Shutdown mode.
3.3
The SENSE input, Pin 5, is connected to a low value
current sensing resistor in the ground return leg of the
fan circuit through the capacitor. 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 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, R
The waveform on R
verted to a logic-level pulse-train by C
internal signal processing circuitry. The presence and
frequency of this pulse-train is a direct indication of fan
operation.
3.4
This pin goes low to indicate a fan FAULT condition.
Pulses appearing at SENSE pin due to the PWM turn-
ing on are blanked and the remaining pulses are
filtered by a Missing Pulse Detector. If consecutive
pulses are not detected for 32 PWM cycles (about 2
sec), the PWM is Low and FAULT goes low. FAULT can
be disabled by momentarily toggling SHDN or V
or cycling system power. FAULT remains high during
Shutdown mode.
3.5
by 10°C (typical). 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 FAULT exists such as fan bearing failure or an
airflow obstruction. This output may be treated as a
“System Overheat” warning and used to trigger system
shutdown, or bring other fans to full speed in the
system. The fan will continue to run at 100% speed
while T
T
is at or near the T
falls through the T
maintains the T
temperature is 5°C above the trip point setting.
DS21453B-page 6
This pin goes low when the T
OVER
from “chattering” when measured temperature
OVER
Start-Up Timer
SENSE Input
(FanSense™ Technology)
FAULT
Over-Temperature Alert (T
is asserted. Built-in hysteresis prevents
OVER
H
+ 10°C trip point. As temperature
H
SENSE
+ 10°C trip point, hysteresis
output low until measured
is differentiated and con-
H
set point is exceeded
SENSE
OVER
and the
DD
SENSE
)
pin,
.
3.6
The fan can be unconditionally shutdown by pulling low
the SHDN pin. During shutdown, FAULT output is high
and PWM output is low. This is ideal for notebook
computers and other portable applications when you
need to change batteries and must not have the fan
running at that time. Thermal monitoring and T
still in operation during shutdown. I
is around 50µA.
3.7
The TC653 has auto-shutdown. If the temperature is
below the factory set point at minimum speed (T
PWM is low and the fan is automatically shut off (Auto-
shutdown mode). This feature is ideal for notebook
computers and other portable applications that need to
conserve as much battery power as possible and thus
run a fan when it is only absolutely needed. The TC653
will continue to be active so as to monitor temperature
for T
when the temperature rises above the factory set point
(T
3.8
The five temperature regions defined by the six
thresholds are defined in the TC652/TC653 by means
of factory trimming. Once a T
T
between T
4
1
).
thresholds are automatically equally spaced
OVER
Shutdown (SHDN)
Auto-Shutdown Mode
Temperature Selection Guide
(Minimum Fan Speed/Full Speed)
. The TC653 exits Auto-shutdown mode
L
and T
H
.
©
2002 Microchip Technology Inc.
L
and T
DD
H
shutdown current
are set, the T
OVER
are
1
L
),
–