US890US891 DataSheet DownloadLink 4851

US890 / US891
Two-Coil Fan Driver – High Output Current
Features and Benefits
Application Examples
Peak output current up to 1200mA
Low start-up voltage
Low output resistance
High sensitivity integrated Hall Sensor
Power-efficient CMOS and power MOSFETs
Built-in output protection clamping diode
Locked rotor protection and auto-restart
Integrated tachometer (US890) or alarm (US891)
signal protected output
Low cost
2-coil fan driver with FG/RD output in
RoHS Compliant 4-pin VK package
5V/12V DC brushless motor/fan
PC, server, laptop cooling fan
Power supply cooling fan
Large and small fan size
Ordering Information
Part No.
US890
US891
Temperature Code
E (-40°C to 85°C)
E (-40°C to 85°C)
1 Functional Diagram
Package Code
VK (4-pin TO-92)
VK (4-pin TO-92)
2 General Description
The US890/891 is a one-chip solution for driving
two-coil brushless DC motors and fans.
Based on the advanced Melexis CMOS process,
the IC contains a Hall-effect sensor, dynamic
offset correction and powerful output drivers with
1200mA peak output current capability.
Specially designed for driving large fans, the
device is optimized for low start-up voltage.
Frequency Generator or Rotation Detection is
available. The open-drain output makes easier the
connectivity with any external interface such as
hardware monitoring or Super I/O IC.
These features are combined with the Melexis
patented no-VDD design to fit the IC in a small 4pin VK package.
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Two-Coil Fan Driver – High Output Current
Table of Contents
1 Functional Diagram ........................................................................................................ 1
2 General Description........................................................................................................ 1
3 Glossary of Terms .......................................................................................................... 3
4 Absolute Maximum Ratings ........................................................................................... 3
5 Pin Definitions and Descriptions................................................................................... 3
6 General Electrical Specifications .................................................................................. 4
7 Magnetic Specifications ................................................................................................. 4
8 Driver Output vs Magnetic Pole..................................................................................... 4
9 Detailed General Description ......................................................................................... 5
10 Unique Features............................................................................................................ 5
11 Performance Graphs .................................................................................................... 7
11.1 RDSON vs TA ............................................................................................................... 7
11.2 RDSON vs VDD ............................................................................................................. 7
11.3 Magnetic parameters vs TA ....................................................................................... 7
11.4 Magnetic parameters vs VDD ..................................................................................... 7
11.5 IDD vs TA .................................................................................................................... 7
11.6 IDD vs VDD .................................................................................................................. 7
12 Test conditions ............................................................................................................. 8
12.1 VDD – operating ......................................................................................................... 8
12.2 RDSON ........................................................................................................................ 8
12.3 IDD ............................................................................................................................. 8
12.4 FG/RD Output Low Voltage ...................................................................................... 8
13 Application Information................................................................................................ 9
13.1 Typical application circuit .......................................................................................... 9
13.2 Recommended circuit for ground disconnection protection....................................... 9
14 Application Comments ................................................................................................. 9
15 Standard information regarding manufacturability of Melexis products with
different soldering processes......................................................................................... 10
16 ESD Precautions ......................................................................................................... 10
17 VK Package Information (4-pin TO-92)...................................................................... 11
18 Disclaimer.................................................................................................................... 12
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Two-Coil Fan Driver – High Output Current
3 Glossary of Terms
Two-coil fan
MilliTesla (mT), Gauss
VDD
IDD
Peak output current
Continuous output current
Locked rotor
FG
RD
A fan with two-coil windings where current alternates from 1 coil to the other
depending on the direction of the magnetic field.
Units of magnetic flux density :
1mT = 10 Gauss
Voltage on the common point of the fan coils.
Current supplying the chip which flows through the coil connected to the
switched off output driver.
The current flowing in the coil at start-up, only limited by the coil resistance
RCOIL and the output driver resistance RDSON.
The average current flowing in the coil when the fan is spinning normally.
The state when the fan stopped spinning due to mechanical blockage.
Frequency generator or tachometer output
Rotation detection or alarm output
4 Absolute Maximum Ratings
Parameter
Symbol
Fan Supply Voltage
VDD
Peak Output Current
IOUTp
Continuous Output Current
IOUTc
FG/RD Pull-Up Voltage
VFG, RD
FG/RD Reverse Current
IFG_REV, RD_REV
Operating Temperature Range
TA
Junction Temperature
TJ
Storage Temperature Range
TS
Magnetic Flux Density
B
ESD Sensitivity (AEC Q100 002)
Table 1: Absolute maximum ratings
Value
18
1200
600
18
60
-40 to 85
125
-55 to 150
Unlimited
4
Units
V
mA
mA
V
mA
°C
°C
°C
mT
kV
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximumrated conditions for extended periods may affect device reliability.
5 Pin Definitions and Descriptions
Pin Name
Pin number
Function
FG (RD)
1
Frequency Generator (Rotation Detection) Open Drain Output
OUT1
2
Open Drain Coil Driver 1
OUT2
3
Open Drain Coil Driver 2
GND
4
Ground pin
Table 2: Pin definitions and descriptions
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Two-Coil Fan Driver – High Output Current
6 General Electrical Specifications
o
DC Operating Parameters TA = 25 C, VDD = 12V (unless otherwise specified)
Parameter
Fan Supply Voltage
Supply Current
OUT1, OUT2 ON Resistance
OUT1, OUT2 ON Resistance
OUT1, OUT2 Output Clamp Voltage
FG / RD Output Low Voltage
FG / RD Output Clamp Voltage
FG / RD Output Leakage Current
FG / RD Output Current Limit
Package Thermal Resistance
Locked Rotor Period
Locked Rotor Period
Locked Rotor Period
Locked Rotor Period
Output Switching Delay
Table 3: Electrical specifications
Symbol
VDD
IDD
RDSON 1,2
RDSON 1,2
VOUT1,2
VOL
VCLMP
ILEAK
IFGLIM
RTH
TON
TOFF
TON
TOFF
TDELAY
Test Conditions
Operating – RCOIL = 100Ω
Min
2.6(1)
VDD = 5V, TA = 25°C, IOUT = 300mA
VDD = 5V, TJ = 125°C, IOUT = 300mA
Typ
12
2.5
1
1.8
Max
18
4
1.4
2.5
0.33
25
0.15
23
200
0.25
1.5
0.53(2)
3.2(2)
50
0.5
36
IOL = 4mA
18
VFG (VRD) = 5V
VFG (VRD) = 12V
One-sided PCB, zero LFPM
VDD > 7V
VDD > 7V
VDD < 5.5V
VDD < 5.5V
“Dead time” when both drivers are off
0.37
2.25
10
0.75
4.51
Units
V
mA
Ω
Ω
V
V
V
µA
mA
°C/Watt
s
s
s
s
µs
Note 1: The minimal value of VDD should be determined using the following equation:
VDD =2.5V + RCOIL * IDD
Note 2: Typical values valid at 5.5V. The values increase at lower voltage to improve fan start-up reliability.
7 Magnetic Specifications
o
DC Operating Parameters TA = 25 C, VDD = 12V (unless otherwise specified)
Parameter
Symbol
Test Conditions
Operate point
BOP
Release point
BRP
Hysteresis
BHYST
Table 4: Magnetic specifications
Min
0
-6
2
Typ
4.5
Max
6
0
10
Units
mT
mT
mT
8 Driver Output vs Magnetic Pole
Parameter
North pole
South pole
Test Conditions
B < Brp
B > Bop
OUT1
High
Low
OUT2
Low
High
FG
High
Low
Table 5: Driver output vs magnetic pole
Note 1: The magnetic pole is applied facing the branded side of the package
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Two-Coil Fan Driver – High Output Current
9 Detailed General Description
The US890/891 is a one-chip solution for driving two-coil brushless DC motors and fans. Based on advanced
Melexis CMOS process, the chip contains a Hall-effect sensor, dynamic offset correction and powerful output
drivers with 1200mA peak output current capability.
The low side output coil drivers are fully protected against switching transients. So an external zener diode is
not needed to cut the high voltage spikes induced by the motor coils.
The US890 has an open-drain integrated tachometer FG output that follows the Hall signal.
In the US891, the open-drain rotation detection output RD is active low during normal spinning of the motor. It
goes high when the flux switching frequency becomes too low, which means the motor is blocked.
10 Unique Features
Specially designed for driving large fans, both ICs have LRP characteristics optimised for low start-up
voltage. At low VDD, fans typically take longer to start up than at higher VDD.
The motor start-up phase (from zero to maximum rotation speed) is illustrated below. Big fans with large
inertia may have slow start-up causing a longer first output pulse after power-on. If this pulse duration is
longer than the LRP TON period, the fan may falsely enter locked rotor condition.
The US890/891 provides an adequate and simple solution to prevent this by automatically adjusting the LRP
period at low voltage. It directly improves the motor start-up reliability.
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Two-Coil Fan Driver – High Output Current
According to the electrical specification table and the figure above, three behaviours can occur:
• VDD < 5.5V, TON/TOFF time periods are longer (from 0.53s / 3.2s typical at 5.5V)
The periods increase with operating voltage to improve start-up at very low voltage.
• VDD > 7V, TON/TOFF time periods are shorter (0.25s / 1.5s typical)
The periods at high voltage are about twice as short as at low voltage
• 5.5V < VDD < 7V, the switching event may slightly vary, but is kept within these limits.
A small hysteresis is implemented to avoid oscillation around the threshold voltage.
The typical mean threshold between the hysteresis is around 6.1V (TA=25°C).
This facilitates driving heavier fans and motors with large inertia without any external component (TON/TOFF is
increased or decreased depending on the fan supply voltage VDD).
The FG/RD output driver provides an over current protection limiting the current flowing in the FG/RD driver
while switched ON. It can occur if a too small pull-up resistor is used or if this resistor is short connected.
This protection reduces the risk of EOS damage on the FG/RD driver.
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Two-Coil Fan Driver – High Output Current
11 Performance Graphs
11.1 RDSON vs TA
11.2 RDSON vs VDD
2.5
2.5
Ta = -40°C
Ta = 85°C
Ta = 125°C
2
Ta = 25°C
Ta = 105°C
2
VDD = 2.5V
VDD = 5V
RDSon (ohms)
RDSon (ohms)
VDD = 18V
1.5
1
0.5
1.5
1
0.5
0
0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
90
100
110
120
0
1
2
3
4
5
6
7
8
Ta (°C)
6
3
3
Bop, VDD=2.5V
Bop, VDD=18V
Brp, VDD=2.5V
Brp, VDD=18V
Bhyst, VDD=2.5V
10
11
12
13
14
15
16
17
18
15
16
17
18
11.4 Magnetic parameters vs VDD
6
Magnetic field (mT)
Magnetic field (mT)
11.3 Magnetic parameters vs TA
0
9
VDD (Volts)
Bhyst, VDD=18V
-3
Bop, Ta=25°C
Brp, Ta=25°C
0
Bhyst, Ta=25°C
-3
-6
-6
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
90
100
110
120
0
1
2
3
4
5
6
7
Ta (°C)
8
9
10
11
12
13
14
VDD (Volts)
11.5 IDD vs TA
11.6 IDD vs VDD
4
4
VDD = 2.5V
VDD = 5V
VDD = 12V
3
3
IDD (mA)
IDD (mA)
VDD = 18V
2
1
2
Ta = -40°C
Ta = 25°C
Ta = 85°C
Ta = 105°C
Ta = 125°C
1
0
0
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
90
100
110
120
0
Ta (°C)
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2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
VDD (Volts)
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Two-Coil Fan Driver – High Output Current
12 Test conditions
12.1 VDD – operating
12.2 RDSON
12.3 IDD
12.4 FG/RD Output Low Voltage
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Two-Coil Fan Driver – High Output Current
13 Application Information
13.1 Typical application circuit
13.2 Recommended circuit for ground
disconnection protection
14 Application Comments
The application 13.1 shows the typical application including a diode D1 for additional reverse voltage
protection. Without this diode, the reverse current in each coil is equal to the fan peak current, as it is only
limited by its coil resistances. In some fan construction where the peak current is not so big, this situation
may be acceptable by both IC and coils for short period of time. However, a long exposure may seriously
affect the reliability or damage each of them by overheating.
The diode D1 connected in series between the supply voltage and the common point of the coils prevents
this reverse current to flow. It prevents such reverse voltage damage and best protects both IC and coils.
The application 13.2 is given in case the ground connection might be disconnected while the fan operates. At
this moment, the current flowing through the coils may circulate from the output (OUT1 or OUT2) to the
FG/RD output driver in reverse direction. High reverse current may damage the logic output driver.
A bypass capacitor connected between the coil common node and the device ground should prevent such
damage occurring by providing a close path to this current.
The value of the capacitor needs to be tuned with the motor characteristics. Higher inductance may require
higher capacitor value.
For 2-wire fan application (tachometer or alarm logical output not required), the FG/RD pin (#1) should be
connected to the device ground pin (#4).
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Two-Coil Fan Driver – High Output Current
15 Standard information regarding manufacturability of Melexis
products with different soldering processes
Our products are classified and qualified regarding soldering technology, solderability and moisture sensitivity
level according to following test methods:
Reflow Soldering SMD’s (Surface Mount Devices)
•
•
IPC/JEDEC J-STD-020
Moisture/Reflow Sensitivity Classification for Nonhermetic Solid State Surface Mount Devices
(classification reflow profiles according to table 5-2)
EIA/JEDEC JESD22-A113
Preconditioning of Nonhermetic Surface Mount Devices Prior to Reliability Testing
(reflow profiles according to table 2)
Wave Soldering SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
•
•
EN60749-20
Resistance of plastic- encapsulated SMD’s to combined effect of moisture and soldering heat
EIA/JEDEC JESD22-B106 and EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Iron Soldering THD’s (Through Hole Devices)
•
EN60749-15
Resistance to soldering temperature for through-hole mounted devices
Solderability SMD’s (Surface Mount Devices) and THD’s (Through Hole Devices)
•
EIA/JEDEC JESD22-B102 and EN60749-21
Solderability
For all soldering technologies deviating from above mentioned standard conditions (regarding peak
temperature, temperature gradient, temperature profile etc) additional classification and qualification tests
have to be agreed upon with Melexis.
The application of Wave Soldering for SMD’s is allowed only after consulting Melexis regarding assurance of
adhesive strength between device and board.
Melexis is contributing to global environmental conservation by promoting lead free solutions. For more
information on qualifications of RoHS compliant products (RoHS = European directive on the Restriction Of
the use of certain Hazardous Substances) please visit the quality page on our website:
http://www.melexis.com/quality.aspx
16 ESD Precautions
Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control procedures whenever handling semiconductor products.
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Two-Coil Fan Driver – High Output Current
17 VK Package Information (4-pin TO-92)
1.55+/-0.10
4.20+/-0.10
0.73+/-0.10
0.46
+0.02
- 0.03
5°+2
-1 (2X)
Notes:
1. All dimensions are in millimeters
2. Package dimension exclude molding flash.
Mold flash shall not exceed 0.127mm.
3. To preserve reliability, it is recommended to
have total lead length equal to 2.5mm
minimum, measured from the package line.
4. VK package is a pin though-hole package,
hence adapted for wave soldering process.
A reflow soldering process is not
recommended with VK package as it may
seriously affect device reliability.
10.50+/-0.30
0.00
0.20
3°+2 (2X)
2.5 min
see note 3
1.42+/-0.10
E.D.M Process Surface Ro1.6~2.4um
3.65+/-0.10
5.22+/-0.10
Marking:
1st Line : US890 (US891) - Name of the device
0.38+/-0.03
1.27+/-0.03
3.81+/-0.03
5° +2
-1
(2X)
0.38+/-0.03
2nd Line : XXYWW
XX - lot number (last 2 digits)
Y - assembly year (last digit)
WW - assembly week number
0.30+/-0.10
(2X)
3°+2
(2X)
Hall plate location
1.9
1.3
0.52
Notes:
1. All dimensions are in millimeters
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Two-Coil Fan Driver – High Output Current
18 Disclaimer
Devices sold by Melexis are covered by the warranty and patent indemnification provisions appearing in its
Term of Sale. Melexis makes no warranty, express, statutory, implied, or by description regarding the
information set forth herein or regarding the freedom of the described devices from patent infringement.
Melexis reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with Melexis for current information. This
product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical lifesupport or life-sustaining equipment are specifically not recommended without additional processing by
Melexis for each application.
The information furnished by Melexis is believed to be correct and accurate. However, Melexis shall not be
liable to recipient or any third party for any damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interrupt of business or indirect, special incidental or consequential
damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical
data herein. No obligation or liability to recipient or any third party shall arise or flow out of Melexis’ rendering
of technical or other services.
© 2005 Melexis NV. All rights reserved.
For the latest version of this document, go to our website at
www.melexis.com
Or for additional information contact Melexis Direct:
Europe and Japan:
Phone: +32 1367 0495
E-mail: [email protected]
All other locations:
Phone: +1 603 223 2362
E-mail: [email protected]
ISO/TS 16949 and ISO14001 Certified
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