2004 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev.1.0.3
Features
Output direct PWM drive for speed control
Selectable PWM frequency : internal or external
Versatile speed control inputs: A thermistor or PWM
input.
A wide range of operating voltage: 3.2V to 28V
Locked rotor protection with open collector output and
auto retry
Open collector hall output for speed feedback
Adjustable minimum speed
Thermistor disconnection protection
TSD protection.
Description
The FAN8460MTC/FAN8460MP is a single phase BLDC
motor driver with variable speed control using output direct
PWM method and it's typical application is DC cooling fans
with wide range of supply voltage(5/12/24V). This approach
eliminates the need for external pass devices such as BJT,
MOSFET. This solution also offers other advantages over
commonly used external PWM turning fan's power on and
off at fixed frequency. The external PWM increas stress on
fan and needs level translation in speed and alarm output
because these outputs share the fan's negative terminal.
In case of CPU cooling, digital controller can give speed
control command with PWM signal adjusting the duty. If a
system has no digital controller, the NTC thermistor input
mechanism can control fan speed with local or ambient tem-
perature sensing.These two kinds of input schemes can meet
various system requirements and applications.
14-MLP 4X4
14-TSSOP
Typical Applications
CPU Cooling Fans
Instrumentation Fans
Desktop PC Fans
Ordering Information
Device
Package
Operating Temp.
FAN8460MTC
14-TSSOP
-
30
C ~ 90
C
FAN8460MTCX
14-TSSOP
-
30
C ~ 90
C
FAN8460MPX
14-MLP 4x4
-
30
C ~ 90
C
FAN8460MTC/FAN8460MP
Single Phase Full Wave BLDC Motor Driver with
Variable Speed Control
FAN8460MTC/FAN8460MP
3
Pin Definitions
Pin Number
Pin Name
I/O
Pin Function Description
Remark
1
H
-
A
Hall input -
2
H
+
A
Hall input
+
-
3
LD
A
Sawtooth wave generator for lock detector
and automatic restart
-
4
VREF
A
Reference voltage output
5
VPWM
I
PWM input for speed control
-
6
OUTA
A
Motor output A
-
7
GND
P
Ground
-
8
OUTB
A
Motor output B
-
9
VM
P
Power supply for output stage
-
10
VS
P
Power supply for signal block
11
VCON
A
Speed control signal
12
CT
A
Triangle waveform out
-
13
AL
O
Alarm output
Open collector
14
TACO
O
Speed output
Open collector
FAN8460MTC/FAN8460MP
4
Absolute Maximum Ratings (Ta = 25
C)
note :
1. Refer: EIA/JESD 51-2 & EIA/JESD 51-3 & EIA/JESD 51-5 & EIA/JESD 51-7
2. Case 1: Single layer PCB with 1 signal plane only, PCB size 76mm
114mm
1.6mm.
3. Case 2: Multi layer PCB with 1 signal, 1 power and 1 ground planes, PCB size 76mm
114mm
1.6mm, Cu plane sizes for
power and ground 74mm
74mm
0.035mm, thermal via hole pitch 0.9mm, via hole
size 0.3mm, 6 via hole.
4. Should not exceed P
D
or ASO value.
5.
I
OPEAK time is within 2us.
Parameter
Symbol
Value
Unit
Maximum power supply voltage
VS
MAX,
VM
MAX
32
V
Thermal resistance
Rja
143 (FAN8460MTC)
o
C/W
150 (FAN8460MP case1)
o
C/W
45 (FAN8460MP case2)
o
C/W
Maximum power dissipation
P
DMAX
870 (FAN8460MTC)
mW
800 (FAN8460MP case1)
mW
2700 (FAN8460MP case2)
mW
Maximum output voltage
V
OMAX
36
V
Maximum output current
I
OMAX
0.8
note
A
Maximum output peak current
I
OPEAK
1.2
note
A
Maximum Taco/Alarm output current
I
TACO/AL
5
mA
Taco/Alarm output sustain voltage
V
TACO/AL
36
V
Hall output withstanding voltage
V
HO
36
V
VPWM Input voltage
V
VPWM
-0.3~ VS
V
Operating temperature
T
OPR
-
30 ~ 90
C
Storage temperature
T
STG
-
55 ~ 150
C
Case 1
Case 2
Remark
Pd is measured
base on the JE-
DEC/STD(JESD
51-2)
Pd= 0.8W
Pd= 2.7W
PCB(glass-epoxy)
Power
plane(Cu)
plane(Cu)
GND
Via
FAN8460MTC/FAN8460MP
5
Power Dissipation Curve
Recommended Operating Conditions
(Ta = 25
C)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Supply voltage for signal block
VS
3.2
-
28
V
Supply voltage for output stage
VM
3.2
-
28
V
175
150
125
100
50
25
0
1,000
2,000
3,000
Pd [mW]
Ambient Temperature, Ta [
C]
0
75
case2
14TSSOP
SOA
case1
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