TC654EUN Microchip Technology, TC654EUN Datasheet - Page 9

• Manufacturer Part Number: TC654EUN
• Description: IC PWM FAN SPEED CTRLR 10-MSOP
• Manufacturer: Microchip Technology
• Type: High Speed PWM Controllerr

Specifications of TC654EUN

• Number Of Outputs: 1
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Applications: Fan Controller, Brushless (BLDC)
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Output Current: 5 mA (Min)
• Operating Supply Voltage: 3 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Motor Type: PWM
• No. Of Outputs: 1
• Output Voltage: 4.4V
• Supply Voltage Range: 3V To 5.5V
• Driver Case Style: MSOP
• No. Of Pins: 10
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4.0
The TC654 and TC655 devices allow you to control,
monitor and communicate (via SMBus) fan speed for 2-
wire and 3-wire DC brushless fans. By pulse width
modulating (PWM) the voltage across the fan, the
TC654/TC655 controls fan speed according to the sys-
tem temperature.The goal of temperature proportional
fan speed control is to reduce fan power consumption,
increase fan life and reduce system acoustic noise.
With the TC654 and TC655 devices, fan speed can be
controlled by the analog input V
face, allowing for high system flexibility.
The TC654 and TC655 also measure and monitor fan
revolutions per minute (RPM). A fan’s speed (RPM) is
a measure of its health. As a fan’s bearings wear out,
the fan slows down and eventually stops (locked rotor).
By monitoring the fan’s RPM level, the TC654/TC655
devices can detect open, shorted, unconnected and
locked rotor fan conditions. The fan speed threshold
FIGURE 4-1:
2002 Microchip Technology Inc.
Microcontroller
DEVICE OPERATION
34.8 k
14.7 k
PICmicro
Note: Refer to Table 7-1 for R
R
R
1
2
R
+5 V
20 k
SCLK
®
Typical Application Circuit.
20 k
C
R
+5 V
+5 V
F
SDA
C
0.01 µF
1.0 µF
1
NTC Thermistor
100 k
IN
or the SMBus inter-
1
2
3
4
V
C
@ 25°C
IN
F
SCLK
SDA
SENSE1
TC654/TC655
GND
V
and R
DD
10
5
SENSE2
C
1 µF
SENSE1
SENSE2
2
FAULT
can be set to provide a predictive fan failure feature.
This feature can be used to give a system warning and,
in many cases, help to avoid a system thermal shut-
down condition. The fan RPM data and threshold reg-
isters are available over the SMBus interface which
allows for complete system control.
The TC654/TC655 devices are identical in every
aspect except for how they indicate an over-tempera-
ture condition. When V
cal), both devices will set OTF (bit 5<X>) in the Status
Register to a '1'. The TC655 will additionally pull the
FAULT output low during an over-temperature condi-
tion.
V
values.
OUT
+5 V
9
8
7
6
C
0.1 µF
SENSE1
C
0.1 µF
715
SENSE2
R
R
20 k
ISO1
+12 V
FAULT
TC654/TC655
FAN
IN
1
voltage exceeds 2.6 V (typi-
R
SENSE1
715
R
ISO2
R
SENSE2
DS21734A-page 9
+5 V
FAN
2