US62 / US63
62
Two-c Fan Driver
coil
Features and Benefits
Low cost
High sensitivity Hall Sensor
Locked rotor protection and auto-r
restart
Power-efficient CMOS and power MOSFETs
er
Built-in output protection clamping diode
ng
Integrated tachometer (US62) or a
alarm (US63)
signal protected output
0
2-coil fan driver with FG/RD output in
ut
4-pin VK package RoHS Compliant
ant
0
0
0
0
0
0
Application Exampl
les
0
5/12V fans
0
Peak current up to 700mA
A
Ordering Code
Product Code
US63
US62
Temperature Code
E
E
Package Code
VK
VK
Option Code
AAA-000
AAA-000
Packing Form Code
BU
BU
Legend:
Temperature Code:
Package Code:
Option Code:
Packing Form:
Ordering example:
E for Temperature Range -40° to 85°
C
C
VK for
Plastic Single in Line
xxx-000: standard Version
000:
BU for Bulk
US63EVK-AAA-000-BU
US63EVK
1 Functional Diagram
2 General Descriptio
ion
The US62/63 is a one-chip solu
ution for driving two-
coil brushless DC cooling fans.
.
Based on the advanced Melexi CMOS process,
is
the IC contains a Hall-effect sen
ensor, dynamic
offset correction and low side o
output drivers.
Frequency Generator or Rotati Detection is
ion
available. The open-drain output makes easier the
utput
connectivity with any external inte
nterface such as
hardware monitoring or Super I/O IC.
These features are combined w the Melexis
with
patented no-V
DD
design to fit th IC in a small 4-
he
pin VK package.
3901000062
Rev 003
Page 1 of 11
Data Sheet
Apr/12
US62 / US63
Two-coil Fan Driver
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 Characteristics ............................................................................................... 4
8 Driver Output vs Magnetic Pole ..................................................................................... 4
9 Detailed General Description ......................................................................................... 5
10 Unique Features ............................................................................................................ 5
11 Performance Graphs .................................................................................................... 6
11.1 R
DSON
vs T
J
............................................................................................................... 6
11.2 R
DSON
vs V
DD
............................................................................................................. 6
11.3 Magnetic Parameters vs T
J
....................................................................................... 6
11.4 Magnetic Parameters vs V
DD
..................................................................................... 6
11.5 I
DD
vs V
DD
.................................................................................................................. 6
12 Test conditions ............................................................................................................. 7
12.1 V
DD
– operating ......................................................................................................... 7
12.2 R
DSON
........................................................................................................................ 7
12.3 I
DD
............................................................................................................................. 7
12.4 FG/RD Output Low Voltage ...................................................................................... 7
13 Application Information................................................................................................ 8
13.1 Typical application with pull-up resistor..................................................................... 8
13.2 Configuration for reverse voltage / ground hot-switch protection .............................. 8
14 Application Comments ................................................................................................. 8
15 Standard information regarding manufacturability of Melexis products with
different soldering processes........................................................................................... 9
16 ESD Precautions ........................................................................................................... 9
17 VK Package Information (4-pin TO-92)...................................................................... 10
18 Disclaimer.................................................................................................................... 11
3901000062
Rev 003
Page 2 of 11
Data Sheet
Apr/12
US62 / US63
Two-coil Fan Driver
3 Glossary of Terms
Two-coil fan
MilliTesla (mT), Gauss
V
DD
I
DD
Peak output current
Continuous output current
Locked rotor
FG
RD
LFPM
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
R
COIL
and the output driver resistance R
DSON.
The 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
Linear Feet Per Minute – Unit of airflow velocity
4 Absolute Maximum Ratings
Parameter
Symbol
Fan Supply Voltage
V
DD
Peak Output Current
I
OUTp
Continuous Output Current
I
OUTc
Operating Temperature Range
T
A
Junction Temperature
T
J
Storage Temperature Range
T
S
Magnetic Flux Density
B
ESD Sensitivity (AEC Q100 002)
-
Table 1: Absolute maximum ratings
Value
18
700
250
-40 to 85
125
-55 to 150
Unlimited
2
Units
V
mA
mA
°C
°C
°C
mT
kV
Exceeding the absolute maximum ratings may cause permanent damage. Exposure to absolute-maximum-
rated 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 signal
OUT1
2
Open Drain Coil Driver 1
OUT2
3
Open Drain Coil Driver 2
GND
4
Ground pin
Table 2: Pin definitions and descriptions US62 (US63)
3901000062
Rev 003
Page 3 of 11
Data Sheet
Apr/12
US62 / US63
Two-coil Fan Driver
6 General Electrical Specifications
DC Operating Parameters T
A
= 25
o
C, V
DD
= 5V to 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
Output Switching Delay
Table 3: Electrical specifications
Symbol
V
DD
I
DD
R
DSON 1,2
R
DSON 1,2
V
OUT1,2
V
OL
V
CLMP
I
LEAK
I
FGLIM
R
TH
T
ON
T
OFF
T
DELAY
Test Conditions
Operating – R
COIL
= 50
V
DD
= 5V
V
DD
= 12V
36
I
OL
= 10mA
18
V
FG
(V
RD
) = 18V
V
FG
(V
RD
) = 12V
One-sided PCB, zero LFPM
10
20
200
0.22
1.3
100
250
500
Min
3.2
(1)
Typ
2
3.5
2.5
Max
18
4
Units
V
mA
“Dead time” when both drivers are off
V
mV
V
µA
mA
°C/Watt
S
S
us
Note 1: The minimal value of VDD should be determined using the following equation:
V
DD
= 3V + R
COIL
* I
DD
7 Magnetic Characteristics
DC Operating Parameters T
A
= 25 C, V
DD
= 12V (unless otherwise specified)
Parameter
Symbol
Test Conditions
Operate point
B
OP
Release point
B
RP
Hysteresis
B
HYST
Table 4: Magnetic specifications
Min
-6
2
Typ
3
-3
6
Max
6
Units
mT
mT
mT
o
8 Driver Output vs Magnetic Pole
Parameter
Test Conditions
North pole
B < B
RP
South pole
B > B
OP
Table 5: Driver output vs magnetic pole
OUT1
High
Low
OUT2
Low
High
Note 1: The magnetic pole is applied facing the branded side of the package
3901000062
Rev 003
Page 4 of 11
Data Sheet
Apr/12
US62 / US63
62
Two-c Fan Driver
coil
9 Detailed General Descri
ription
The US62/63 is a one-chip solution for driving two-coil brushless DC fans. Based on advan
or
anced Melexis
CMOS process, the IC contains a Hall
ll-effect sensor, dynamic offset correction and low sid output drivers.
de
The output drivers OUT1 and OUT2 are fully protected against switching transients. So there is no need for
a
o the
an external zener diode to cut the high voltage spikes induced by the fan coils.
gh
The US62 has an open-drain integrate tachometer FG output that follows the Hall signal.
ed
.
In the US63, the open-drain rotation detection output RD is active low during normal spinn
de
nning of the motor. It
goes high when the flux switching frequen becomes too low, which means the motor is b
equency
blocked.
10 Unique Features
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 sho connected.
hort
This protection helps avoid EOS damage on the FG/RD driver.
age
The absence of a V
DD
pin enables the two low side output drivers and FG/RD signal outp to fit in a four-pin
e
put
VK package. The lack of a V
DD
pin decreases also the probability to damage the chip due to reverse voltage
de
connection, using the coil resistance to limit the reverse current. In this condition, the tota reverse current is
t
al
twice the peak current value of the fan used.
an
The built-in locked-rotor protection auto
tomatically shuts off the coil current when the rotor is mechanically
s
blocked, or the rotational speed becom too low. The fan tries to restart every 1.3 seconds until the rotation
mes
onds
of the shaft is allowed again. The On / Off cycling reduces the average current to 1/7 norm It is enough to
mal.
prevent overheating or damage to mo fans.
ost
3901000062
Rev 003
Page 5 of 11
Data Sheet
Apr/12