FSCT07A-UH5 STMicroelectronics, FSCT07A-UH5 Datasheet

IC CONTROLLER FAN SPEED IPPAK

FSCT07A-UH5

Manufacturer Part Number
FSCT07A-UH5
Description
IC CONTROLLER FAN SPEED IPPAK
Manufacturer
STMicroelectronics
Type
18 Line 3-5 Volt Low Capacitance SCSI Active Terminatorr
Datasheet

Specifications of FSCT07A-UH5

Applications
Fan Controller
Number Of Outputs
1
Voltage - Supply
9 V ~ 15 V
Operating Temperature
0°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
IPPAK-5
Product
Fan / Motor Controllers / Drivers
Operating Supply Voltage
7 V
Supply Current
3 mA
Mounting Style
Through Hole
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Output
-
Voltage - Load
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
FEATURES
BENEFITS
GENERAL DESCRIPTION
The FSCTxxA-UH5 is a high-integrated low cost fan speed controller suitable for PC desktops, notebooks
and server power supplies and also all kind of equipments where low cost ventilation system is needed. An
internal thermal sensor connected to the tab is used to regulate the fan speed. A continuous analog voltage
proportional to the tab temperature is produced at the OUT terminal and can control linearly an external
PNP transistor (Fan Transistor) connected in series with a Brushless DC Fan, in order to vary its speed.
The ON control terminal can be used to select two operation modes. If not connected (high impedance
state) ON mode is selected by default.
In Mode ON, the fan speed is regulated according to the tab temperature of the FSCT by adjusting the Vbe
voltage of the PNP fan Transistor. In low temperature conditions, the fan transistor voltage is limited to
about 5.5V (for a 12V fan) in order to guarantee a minimum voltage across the fan above its stalling voltage
and to keep it running (see figure 3).
This regulation is implemented with a high Fan supply voltage rejection.
The mode OFF allows to operate in green Mode. The fan is stopped as long as the temperature remains
below the TON threshold. When the temperature rises above TON the fan is forced to ON and the speed is
regulated according to the temperature as in the same way as mode ON. When temperature falls below
TOFF, the fan is automatically turned OFF. The hysteresis has been dimensioned large enough to reduce
ON/OFF oscillations during the green mode operation.
APPLICATIONS
September 2003 - Ed: 2A
COMPUTER AND SERVER POWER SUPPLY
TELECOM
LOW COST VENTILATION (consumer)
Built in thermal sensor
Brushless DC fan speed control
Linear control and regulation of the fan speed
according to the temperature
Green OFF mode operation with automatic
turn- ON in case of overtemperature
Voltage limitation above fan stall voltage
No external NTC required
Low cost integrated fan speed control
High integration: only one or two external com-
ponents
Reduced acoustic noise because of the linear
control of the external transistor
Power supply noise rejection
Good thermal coupling with heater
Reduced ON/OFF oscillation because of large
hysteresis
High current capability (base current higher
than 10 mA)
Higher accuracy than discrete circuit with NTC
Application Specific Discretes
®
A.S.D.
TM
Fig. 1: Block Diagram.
V
CC
FSCTxxA-UH5
FAN SPEED CONTROLER
VOLTAGE
SENSOR
REF.
TEMP.
COMPARATOR
HYSTERESIS
HYST.-EN
FSCTxxA-UH5
ON
GND
V
ON/OFF
LOW
T
IPPAK
DRIVER
REGULATION
ON
ON/OFF
HIGH
1
5
OUT
C
100nF
OUT
=
BIAS
1/11
F

Related parts for FSCT07A-UH5

FSCT07A-UH5 Summary of contents

Page 1

TM A.S.D. Application Specific Discretes APPLICATIONS COMPUTER AND SERVER POWER SUPPLY TELECOM LOW COST VENTILATION (consumer) FEATURES Built in thermal sensor Brushless DC fan speed control Linear control and regulation of the fan speed according to the temperature Green ...

Page 2

... OUT 20V OUT 50° 5V 125° 5V, T from 0° 15V 25° 80% FSCT17A-UH5 OUT V to OMS FSCT11A-UH5 20% V OMS FSCT07A-UH5 Value -0 125 -65 to 150 260 V CC -0.3 2 Value Min. Typ. Max. 1 0.55 0.7 5.3 5 0.5 155 165 175 100 107 114 Pin ...

Page 3

... Test conditions OUT OMS 12V 12V 12V FSCT17A-UH5 FSCT11A-UH5 OUT OL FSCT07A-UH5 FSCT17A-UH5 OUT FSCT11A-UH5 FSCT07A-UH5 V = 12V CC ON terminal shorted to ground range between V OUT Parameter other blocks FSCTxxA-UH5 Value Min. Typ. Max 102 107 0.3 ...

Page 4

FSCTxxA-UH5 Fig. 3: Temperature slopes OUT 5.3V OMS OUT V = 0.6V OL Fig versus V for mode ON (mA) CC 1.5 1.4 1.3 1 ...

Page 5

DETAILED DESCRIPTION & APPLICATION INFORMATION 1. OUTPUT CHARACTERISTIC VERSUS TEMPERATURE 1.1 FAN speed control As it's well known, BRUSHLESS DC motors present the advantage of a quasi-linear speed-voltage char- acteristic. Hence, the fan speed is varying linearly versus the voltage ...

Page 6

FSCTxxA-UH5 2. Hysteresis control (mode OFF) FSCT can be shut down by the ON signal. When, this signal is low, the OUT pin is at high level, i.e. the FAN is turned off. This mode enables to save the energy ...

Page 7

Fig. 8: Temperature evolution cases in mode OFF OFF 3. Internal temperature sensor 3.1 Temperature sensor linear response FSCT devices feature an internal temperature sensor. This sensor results directly from silicon properties actually ...

Page 8

FSCTxxA-UH5 Two components should be used to improve the heat exchange between the FSCT die and the heat sink, that the temperature has to be monitored. These components are: A thermal interface pad, in order to reduce the impact of ...

Page 9

These interfaces offer very low thermal resistance. For example, the Sil-Pad BERGQUIST, which is designed for low cost applications and low mounting pressures, present a typical thermal impedance of 0.45 °C.in²/W. This impedance can increase up to 0.92 °C.in²/W for ...

Page 10

FSCTxxA-UH5 Fig. 13: Step-down OUT voltage schematic. VCC VCC OUT {RD TEST 3 GND FSCT VCC {RD 5V1 2n2 REF 10/11 PARAMETERS 33k RN = ...

Page 11

... FSCT17A-UH5 FSCT17A FSCT11A-UH5 FSCT11A FSCT07A-UH5 FSCT07A Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice ...

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