LB11961
Single-Phase Full-Wave
Fan Motor Driver
Overview
The LB11961 is a single-phase bipolar drive motor driver that easily
implements direct PWM motor drive systems with excellent efficiency. The
LB11961 is optimal for fan motor drive in personal computer power supply
systems and CPU cooling fan systems.
www.onsemi.com
Features
• Single-phase full-wave drive (16V, 1.0A transistors are built in)
• Built-in variable speed function controlled by a thermistor input
The LB11961 can implement quiet, low-vibration variable speed control
using externally clocked high side transistor direct PWM drive.
• Built-in regenerative diode (Di); only requires a minimal number of external
components.
• Built-in HB
• Minimum speed setting pin (allows full-speed mode operation at startup)
• Operates in full-speed mode when the thermistor is removed.
• Built-in lock protection and automatic recovery circuits
• FG (speed detection) and RD (lock detection) outputs
• Built-in thermal shutdown circuit
HSSOP14 (225mil)
XXXXXXXXXX
YMDDD
Applications
• Personal computer power supply systems
• CPU cooling fan systems
XXXXX = Specific Device Code
Y = Year
M = Month
DDD = Additional Traceability Data
Specifications
Absolute Maximum Ratings at Ta = 25C (Note1)
Parameter
VCC maximum output voltage
Symbol
Conditions
Ratings
Unit
VCC max
18
V
OUT pin maximum output current
IOUT max
1.0
A
OUT pin output voltage
VOUT max
18
V
HB maximum output current
IHB max
10
mA
VTH input pin voltage
VTH max
6
V
RD/FG output pin output voltage
VRD/FG
18
V
10
mA
max
RD/FG output current
IRD/FG
Allowable power dissipation
Pd max
When mounted
on a circuit
board (Note2)
ORDERING INFORMATION
See detailed ordering and shipping
information on page 8 of this data
sheet.
W
1.1
Operating temperature
Topr
-30 to +90
C
Storage temperature
Tstg
-55 to +150
C
1. Stresses exceeding those listed in the Maximum Rating table may damage the device. If any of
these limits are exceeded, device functionality should not be assumed, damage may occur and
reliability may be affected.
2. Specified circuit board : 114.3 76.1 1.6mm3, glass epoxy.
© Semiconductor Components Industries, LLC, 2016
November 2016- Rev. 1
1
Publication Order Number:
LB11961/D
LB11961
Recommended Operating Conditions at Ta = 25C (Note3)
Parameter
Symbol
Conditions
Ratings
Unit
VCC supply voltage
VCC
4.5 to 16
V
VTH input level voltage range
VTH
0 to 9
V
Hall sensor input common-mode
VICM
0.2 to 3
V
input voltage range
3. Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond the
Recommended Operating Ranges limits may affect device reliability.
Electrical Characteristics Unless otherwise specified Ta 25C, VCC = 12V (Note4)
Ratings
Parameter
Symbol
Conditions
Unit
min
Circuit current
6VREG voltage
ICC1
Drive mode
ICC2
Lock protection mode
V6VREG
HB voltage
VHB
CPWM high-level voltage
I6VREG = 5mA
IHB = 5mA
VCRH
typ
max
12
18
24
mA
8
11
16
mA
V
5.8
6
6.2
1.10
1.25
1.40
V
3.45
3.6
3.75
V
1.95
2.05
2.15
18
25
32
CPWM low-level voltage
VCRL
CPWM oscillator frequency
FPWM
CT pin high-level voltage
VCTH
3.45
3.6
3.75
V
CT pin low-level voltage
VCTL
1.55
1.7
1.85
V
C = 100pF
V
kHz
ICT charge current
ICT1
1.5
2
2.5
A
ICT discharge current
ICT2
0.15
0.2
0.25
A
ICT charge/discharge current
RCT
8.5
10
11.5
ratio
OUT output low saturation
VOL
IO = 200mA
0.2
0.3
V
VOH
IO = 200mA
0.9
1.1
V
Zero peak value (including offset and
10
20
mV
0.2
0.3
V
30
A
voltage
OUT output high saturation
voltage
Hall sensor input sensitivity
VHN
hysteresis)
RD/FG output pin low-level
VRDL/FGL
IRD/FG = 5mA
IRDL/FGL
VRD/FG = 7V
voltage
RD/FG output pin leakage
current
4. Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not
be indicated by the Electrical Characteristics if operated under different conditions.
Pd max – Ta
Allowable power dissipation, Pd max – W
1.2
Specified circuit board : 114.3×76.1×1.6mm3
glass epoxy board
1.1
1.0
0.8
0.6
0.53
0.4
0.2
0
– 30
– 10
10
30
50
70
90
110
Ambient temperature, Ta – °C
www.onsemi.com
2
LB11961
Package Dimensions
unit : mm
HSSOP14 (225mil)
CASE 944AA
ISSUE A
SOLDERING FOOTPRINT*
5.80
1.0
(Unit: mm)
0.32
0.65
NOTES: 1. The measurements are not to guarantee but for reference only.
2. Land pattern design in Fin area to be altered in response to
customer’s individual application.
www.onsemi.com
3
LB11961
Truth Table
VTH
IN-
IN+
Low
High
Low
(open)
Low
High
High
Low
Low
High
-
High
Low
-
Low
High
High
CPWM
CT
High
Low
Low
-
High
OUT1
OUT2
FG
High
Low
Low
Low
High
Off
Off
Low
Low
Low
Off
Off
High
Off
Low
Off
High
Off
RD
Mode
During rotation drive
(PWM off)
On
During rotation regeneration
(PWM on)
Off
Lock protection
CPWM – High is the state where CPWM > VTH, and CPWM– Low is the state where CPWM < VTH.
Open : The LB11961 operates in full-speed mode when the thermistor is removed.
Pin Assignment
F-GND
(P-GND)
F-GND
(P-GND)
OUT2
1
14
OUT1
VCC
2
13
S-GND
RMI
3
12
CT
VTH
4
11
6VREG
CPWM
5
10
IN-
FG
6
9
HB
RD
7
8
IN+
LB11961
TOP VIEW
F-GND (P-GND) : The motor system ground and the heat sink. Since the heat generated Since the heat generated by the
chip is dissipated through F-GND, the thermal resistance is lowered by increasing the area of the copper
foil and solder surface in the printed circuit pattern.
S-GND :
Control system ground
www.onsemi.com
4
LB11961
Block Diagram
FG
RD
Thermal
protection circuit
VCC
Constant
voltage
6VREG
Delay circuit
Control
circuit
1.3V
HB
Hall
OUT2
M
IN
Delay circuit
OUT1
IN
Amplifier with
hysteresis
Charge/discharge
circuit
S-GND
CT
VTH
Oscillator
circuit
CPWM
www.onsemi.com
5
P-GND
LB11961
Application Circuit Example
*2
CM
VCC
HB
*7
IN
H
FG
*3
IN
6VREG
RD
*6
*5
RMI
*8
OUT1
VTH
OUT2
CPWM
CP = 100pF
*4
CT
F-GND
*1
CT = 0.47F to 1F
S-GND
F-GND
*1. Power supply and ground lines
P-GND is connected to the motor power supply system and S-GND is connected to the control circuit power supply
system.
These two systems should be formed from separate lines and the control system external components should be
connected to S-GND.
*2. Regeneration power supply stabilization capacitor
The capacitor CM provides power supply stabilization for both PWM drive and kickback absorption. A capacitor with a
value of over 0.1µF is used for CM. A large capacitor must be used when the coil inductance is large or when the coil
resistance is low. Since this IC adopts a technique in which switching is performed by the high side transistor and
regeneration is handled by the low side transistor, the pattern connecting CM to VM and P-GND must be as wide and as
short as possible.
*3. Hall sensor input
Lines that are as short as possible must be used to prevent noise from entering the system. The Hall sensor input circuit
consists of a comparator with hysteresis (20mV). We recommend that the Hall sensor input level be at least three times
this hysteresis, i.e. at least 60mVp-p.
*4. PWM oscillator frequency setting capacitor
If a value of 100pF is used for CP, the oscillator frequency will be f = 25kHz, and this will be the basic frequency of the
PWM signal.
*5. RD output
This is an open collector output. It outputs a low level when the motor is turning and a high level when it is stopped. This
pin must be left open if unused.
www.onsemi.com
6
LB11961
*6. FG output
This is an open collector output, and a rotation count detection function can be implemented using this FG output, which
corresponds to the phase switching. This pin must be left open if unused.
*7. HB pin
This pin provides a Hall effect sensor bias constant-voltage output of 1.25V.
*8. RMI pin
Connect this pin to VTH if unused. Even if unused, the IC is set internally to operate at a 10% drive duty at the voltage
corresponding to the lowest speed. (The capacitor is used to set up full-speed mode at startup.)
Control Timing Chart
(VCC 28%)
THERMISTOR
REMOVED
Internal lowest speed setting voltage
f = 25kHz (CP=100pF)
High on duty
3.6V
(VCC 30%)
RMI voltage
CPWM
2.0V
(VCC 16%)
Low on duty
0V
Set minimum
speed
Full speed mode
PWM control variable speed mode
Low
temperature
High
temperature
12V
VCC
0V
FG
1. Set minimum speed mode
A VTH voltage level is generated when the thermistor detects the set temperature. At low temperatures, the fan
motor turns at the lowest speed, which is set with the RMI pin. The LB11961 compares the CPWM oscillator
voltage with the RMI pin voltage and sets the duty for the lowest drive state.
2. High speed low speed mode
The PWM signal is controlled by comparing the CPWM oscillation voltage that cycles between 1.2V and 3. 8V and
the VTH voltage.
When the VTH voltage is lower, the high and low side transistors are turned on, and when the VTH voltage is higher,
the high side transistor is turned off and the coil current is regenerated through the low side transistor. Thus the
output on duty increases as the VTH voltage becomes lower, the coil current increases, and the motor speed
increases.
Rotation speed feedback is provided by the FG output.
3. Full-speed mode
The LB11961 switches to full-speed mode above a certain temperature.
4. Thermistor removed mode
If the thermistor is removed, the VTH input voltage will rise. However, the output will go to full drive at 100% and
the motor will run at full speed.
www.onsemi.com
7
LB11961
ORDERING INFORMATION
Device
LB11961-MPB-H
Package
Wire Bond
Shipping(Qty/Packing)
HSSOP14(225mil)
Au-wire
70 / Fan-fold
Au-wire
2000 / Tape & Reel
Cu-wire
2000 / Tape & Reel
(Pb-Free / Halogen Free)
LB11961-TLM-H
HSSOP14(225mil)
(Pb-Free / Halogen Free)
LB11961-W-AH
HSSOP14(225mil)
(Pb-Free / Halogen Free)
† For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D. http://www.onsemi.com/pub_link/Collateral/BRD8011-D.PDF
ON Semiconductor and the ON Semiconductor logo are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries
in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other
intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON
Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or
guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or
use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is
responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or
standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON
Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters,
including “Typicals” must be validated for each customer application by customer’s technical experts. ON Semiconductor does not convey any license under its
patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support
systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for
implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized application, Buyer shall
indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or
unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an
Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
www.onsemi.com
8