MTD6508
3-Phase Sinusoidal Sensorless Brushless DC Fan Motor Driver
Features
• 180° Sinusoidal Drive for High Efficiency and Low
Acoustic Noise
• Position Sensorless BLDC Drivers
(no Hall Effect Sensor required)
• Integrated Power Transistors
• Supports 2V to 5.5V Power Supplies
• Variable Programming Resistor (R
PROG
) Setting
to fit Motor Constant (K
M
) Range from 3.25 mV/
Hz to 52 mV/Hz
• Speed Control through Power Supply Modulation
(PSM) and/or Pulse-Width Modulation (PWM)
• Built-in Frequency Generator: FG, FG/3 Output
Signal (FG/2 and FG/6 Option are available upon
request)
• Output PWM Slew Rate Control Programmable
with an External Resistor for Start-up
(Adjustable version)
• Phase Target Selection for Regulation
(Adjustable Version)
• Start-up Strength Selection (Adjustable Version)
• Start-up Output Current Controlled by PWM
• Output Current Soft Start
• Built-in Lock-up Protection and Automatic
Recovery Circuit
• Built-in Overcurrent Limitation
• Built-in Thermal Shutdown Protection
• Built-in Overvoltage Protection
• Low Minimal Start-up Speed for Low-Speed
Operation
• Packages:
- 10-Lead 3 mm x 3 mm x 0.5 mm UDFN
- 16-Lead 4 mm x 4 mm x 0.5 mm UQFN
(Adjustable version)
Description
The MTD6508 device is a 3-phase, full-wave
sensorless driver for brushless DC (BLDC) motors. It
features a 180° sinusoidal drive, high torque output and
silent drive. With adaptive features, parameters and a
wide range of power supplies (2V to 5.5V), the
MTD6508 is intended to cover a broad range of motor
characteristics while requiring minimum external
components. Speed control can be achieved through
either power supply modulation (PSM) or pulse-width
modulation (PWM).
Compact packaging and a minimal bill of materials
make the MTD6508 device extremely cost-efficient in
fan applications. For example, the CPU cooling fans in
notebook computers require designs that provide low
acoustic noise, low mechanical vibration and are highly
efficient. The frequency generator (FG) output enables
precision speed control in closed-loop applications.
The MTD6508 device includes Lock-up Protection
mode to turn off the output current when the motor is in
a lock condition, with an automatic recovery feature to
restart the fan when the lock condition is removed.
Motor overcurrent limitation and thermal shutdown
protection are included for safety-enhanced operations.
The MTD6508 is available in compact, thermally-
enhanced, 10-Lead 3 mm x 3 mm x 0.5 mm UDFN
packages and 16-Lead 4 mm x 4 mm x 0.5 mm
UQFN packages.
Applications
• Notebook CPU Cooling Fans
• 5V 3-Phase BLDC Motors
2015 Microchip Technology Inc.
DS20005359A-page 1
MTD6508
1.0
ELECTRICAL
CHARACTERISTICS
† Notice:
Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only, and functional operation of
the device at those or any other conditions above those
indicated in the operational listings of this specification
is not implied. Exposure to maximum rating conditions
for extended periods may affect device reliability.
Note 1:
I
OUT
is also internally limited, according
to the limits defined in the
Electrical
Characteristics
table.
2:
Reference Printed Circuit Board (PCB)
according to JEDEC standard EIA/JESD
51-9.
Absolute Maximum Ratings†
Power Supply Voltage (V
DD_MAX
) ...................... -0.7 to +7.0V
Maximum Output Current (I
OUT_MAX
)
(1)
....................1000 mA
Maximum Output Voltage (V
OUT_MAX
) ............... -0.7 to +7.0V
FG Maximum Output Voltage (V
FG_MAX
) ........... -0.7 to +7.0V
FG Maximum Output Current (I
FG_MAX
) ......................5.0 mA
V
BIAS
Maximum Voltage (V
BIAS_MAX
) ................ -0.7 to +4.0V
PWM Maximum Voltage (V
PWM_MAX
) ................ -0.7 to +7.0V
Allowable Power Dissipation (P
D_MAX
)
(2)
........................1.5W
Maximum Junction Temperature (T
J
) .......................... +150°C
ESD protection on all pins
2
kV
ELECTRICAL CHARACTERISTICS
Electrical Specifications:
Unless otherwise specified, all limits are established for V
DD
= 2.0V to 5.5V, T
A
= +25°C
Parameters
Power Supply Voltage
Power Supply Current
Standby Current
OUTX High Resistance
OUTX Low Resistance
OUTX Total Resistance
V
BIAS
Internal
Supply Voltage
PWM Input Frequency
PWM Input H Level
PWM Input L Level
FG3_SEL Input H Level
FG3_SEL Input L Level
FG Output Pin Low-Level
Voltage
FG Output Pin Leakage
Current
Lock Protection
Operating Time
Lock Protection Waiting Time
Overcurrent Protection
Note 1:
2:
Sym.
V
DD
I
VDD
I
VDD_STB
R
ON(H)
R
ON(L)
R
ON(H+L)
V
BIAS
f
PWM
V
PWM_H
V
PWM_L
V
FG3_SEL_L
V
OL_FG
I
LH_FG
T
RUN
T
WAIT
I
OC_MOT
Min.
2
—
—
—
—
—
—
—
1
0.55
V
DD
0
0
—
-10
—
5
—
Typ.
—
5
15
0.75
0.75
1.5
3
V
DD
– 0.2
—
—
—
—
—
—
—
0.5
5.5
750
Max.
5.5
10
25
—
—
—
—
—
100
V
DD
0.2
V
DD
V
BIAS
0.2
V
DD
0.25
10
1
6
—
Units
V
mA
µA
Ω
Ω
Ω
V
V
kHz
V
V
V
V
V
µA
s
s
mA
Note 1
Note 2
V
DD
4.5V
V
DD
4.5V
V
DD
4.5V
V
DD
4.5V
I
FG
= -1 mA
V
FG
= 5.5V
V
DD
= 5V
PWM = 0V, V
DD
= 5V
(Standby mode)
I
OUT
= 0.5A, V
DD
= 5V
I
OUT
= 0.5A, V
DD
= 5V
I
OUT
= 0.5A, V
DD
= 5V
V
DD
= 3.2V to 5.5V
V
DD
< 3.2V
Conditions
V
FG3_SEL_H
V
BIAS
– 0.5
Related to the internal oscillator frequency (see
Figure 2-1)
750 mA is the standard option for MTD6508. Additional overcurrent protection levels are available upon
request. Please contact factory for different overcurrent protection values.
2015 Microchip Technology Inc.
DS20005359A-page 5
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