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US3881
CMOS Low Voltage Hall Effect Latch
US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 1
Features and Benefits
• Chopper stabilized amplifier stage
• Optimized for BDC motor applications
• New miniature package / thin, high reliability package
• Operation down to 2.2V
• CMOS for optimum stability, quality, and cost
Applications
• Solid state switch
• Brushless DC motor commutation
• Speed sensing
• Linear position sensing
• Angular position sensing
• Current sensing
Ordering Information
Part No. Temperature Suffix Package Temperature Range
US3881 E SO or UA -40oC to 85oC Commercial
US3881 L SO or UA -40oC to 150oC Automotive
* Contact factory or Sale Representative for legacy temperature options
Description
The US3881 is a bipolar Hall effect sensor IC fabricated from mixed signal CMOS technology. It incorporates advanced chopper stabilization techniques to provide accurate and stable magnetic
switch points. There are many applications for this
sensor in addition to those listed above. The design, specifications, and performance have been
optimized for commutation applications in 5V and
12V brushless DC motors.
The output transistor will be latched on (BOP) in the
presence of a sufficiently strong South pole magnetic field facing the marked side of the package.
Similarly, the output will be latched off (BRP) in the
presence of a North field.
The SOT-23 device is reversed from the UA package. The SOT-23 output transistor will be latched
on in the presence of a sufficiently strong North
pole magnetic field subjected to the marked face.
Functional Diagram
Note: Static sensitive device; please observe ESD precautions. Reverse VDD protection is not included. For reverse voltage protection, a 100Ω resistor in series with V
DD
is recommended.
Output
GND
V
DD
Voltage
Regulator
Chopper
SO Package
Pin 1 - V
DD
Pin 2 - Output
Pin 3 - GND
UA Package
Pin 1 - V
DD
Pin 2 - GND
Pin 3 - Output
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US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 2
US3881
CMOS Low Voltage Hall Effect Latch
US3881 Electrical Specifications
DC Operating Parameters: TA = 25, VDD = 12VDC (unless otherwise specified).
Parameter Symbol Test Conditions Min Typ Max Units
Supply Voltage VDD Operating 2.2 18 V
Supply Current IDD B<BOP 1.5 2.5 4.0 mA
Saturation Voltage V
DS(on)
I
OUT
= 20 mA, B>BOP 0.4 0.5 V
Output Leakage I
OFF
B<BRP, V
OUT
= 18V 0.01 5.0 ì A
Output Rise Time tr VDD = 12V, RL = 1.1KÙ, CL = 20pf 0.04 ì s
Output Fall Time tf VDD = 12V, RL = 1.1KÙ, CL = 20pf 0.18 ì s
US3881 Magnetic Specifications
DC Operating Parameters: TA = -40 to 150oC, VDD =12 VDC (unless otherwise specified). 1mT=10 Gauss.
Parameter Symbol Test Conditions Min Typ Max Units
Operating Point BOP 1.0 5.0 9.0 mT
Release Point BRP -9.0 -5.0 -1.0 mT
Hysteresis B
hys
5.5 10.0 12.0 mT
Melexis Inc. reserves the right to make changes without further notice to any products herein to improve reliability, function or design. Melexis
does not assume any liability arising from the use of any product or application of any product or circuit described herein.
Supply Voltage (Operating), VDD 18V
Supply Current (Fault), IDD 50mA
Output Voltage, V
OUT
18V
Output Current (Fault), I
OUT
50mA
Power Dissipation, PD 100mW
Operating Temperature Range, TA -40 to 150°C
Storage Temperature Range, TS -65 to 150°C
Maximum Junction Temp, TJ 175°C
ESD Sensitivity (All Pins) +/- 4KV
Absolute Maximum Ratings
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US3881
CMOS Low Voltage Hall Effect Latch
US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 3
Performance Graphs
12.5
Flux Density (mT)
Supply Voltage (V)
Typical Magnetic Switch Points
versus
Supply Voltage
3881
15
-7.5
-2.5
2.5
7.5
1050 20 25 30
B
OP
B
RP
-12.5
12.5
-12.5
Flux Density (mT)
Temperature (oC)
Typical Magnetic Switch Points
versus
Temperature
3881
80
-7.5
-2.5
2.5
7.5
0-40 120 160 20040
B
OP
B
HYS
B
RP
25
Output Voltage (V)
Flux Density (mT)
Output Voltage
versus
Flux Density
3881
0
5
10
15
20
-10-20-30
102
0
30
0
V
DD
V
out
B
OP
B
RP
12.5
-12.5
Flux Density (mT)
Temperature (oC)
Min/Max Magnetic Switch
Range
versus
Temperature
3881
80
-7.5
-2.5
2.5
7.5
0-40 120 160 20040
B
OP
Max
B
OP
Min
B
RP
Max
B
RP
Min
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US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 4
US3881
CMOS Low Voltage Hall Effect Latch
Performance Graphs
280
Solder Temperature (
o
C)
Time in Wave Solder (Seconds)
Wave Soldering Parameters
All Devices
15
200
220
240
260
1050 20 25 30
500
0
Package Power Dissipation (mW)
Temperature (oC)
Power Dissipation
versus
Temperature
All Devices
80
100
200
300
400
0-40 120 160 20040
SO Package
R
θ
JA
=575oC/W
UA Package
R
θJA
=206oC/W
5
0
Supply Current (mA)
Supply Voltage (V)
Typical Supply Current
versus
Supply Voltage
3881
15
1
2
3
4
1050 20 25 30
TA = -40oC
TA = 25oC
TA = 125oC
Performance Graphs
500
0
V
DS(ON)
(mV)
Temperature (oC)
Typical Saturation Voltage
versus
Temperature
VDD = 12 V, I
OUT
= 20mA
3881
80
100
200
300
400
0-40 120 160 20040
V
DS(ON)
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US3881
CMOS Low Voltage Hall Effect Latch
US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 5
Unique Features
CMOS Hall IC Technology
The chopper stabilized amplifier uses switched
capacitor techniques to eliminate the amplifier
offset voltage, which, in bipolar devices, is a
major source of temperature sensitive drift.
CMOS makes this advanced technique possible. The CMOS chip is also much smaller than
a bipolar chip, allowing very sophisticated circuitry to be placed in less space. The small chip
size also contributes to lower physical stress
and less power consumption.
Installation
Consider temperature coefficients of Hall IC and
magnetics, as well as air gap life time variations. Observe temperature limits during wave
soldering.
Applications
If reverse supply protection is desired, use a resistor in series with the VDD pin. The resistor will
limit the Supply Current (Fault), IDD, to 50 mA.
For severe EMC conditions, use the application
circuit below.
Automotive and Severe
Environment Protection Circuit
Hall IC
C1
4.7nF
C 2
4.7nF
V
DD
V
SS
OUT
R
L
1.2K
Supply
Voltage
D1
R1 100 Ω
Z1
Two Wire Optional Current
Biasing Circuit
R
L
R
b
Hall IC
Iout
I
DD
V
DD
The resistors Rb and RL can be used to bias the input current, Iin.
Refer to the part specification for limiting values. This circuit will help in
getting the precise ON and OFF currents desired.
BRP = Ioff = (VDD / Rb + I
DD
)
BOP = Ion = (Ioff + VDD / RL )
I
IN
Applications Examples
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US3881 CMOS Low Voltage Hall Effect Latch 3901003881 Rev 4.2 7/23/01 Page 6
US3881
CMOS Low Voltage Hall Effect Latch
Physical Characteristics
U38
104
1 2 3
*
All Dimensions in millimeters
2.13
1.87
0.45
0.41
Marked
Surface
1.53
1.27
UA Hall Plate / Chip Location
1.60
1.40
45
o
Typical
4.30
3.90
2.64
2.34
0.84
0.63
3.20
2.80
1.75
1.55
0.48
0.43
0.20
0.00
0.41
0.35
1.30
1.24
2.57
2.51
5
o
Typical
45
o
Typical
0.38
Typical
(see note 3)
15.5
14.5
0.41
0.35
UA Package Dimensions
* MARKING:
Line 1:
1st digit (U) = Supplier (Melexis)
2nd and 3rd digits (38) = Series (3880)
Line 2:
1st digit (1) = Year (2001)
2nd and 3rd digits(04) = Week of Year
PINOUT:
Pin 1 V
DD
Pin 2 GND
Pin 3 Output
NOTES:
1.) Controlling dimension: mm
2.) Leads must be free of flash and
plating voids
3.) Do not bend leads within 1mm
of the lead to package interface.
4.) Package dimensions exclude
molding flash
5.) Tolerance is 0.254mm unless
otherwise specified
SOT-23 Hall Plate /
Chip Location
(Bottom View)
SOT-23 Package Dimensions
(Top View)
NOTES:
1. MARKING:
1st Digit (3) = Series (3881)
2nd Digit(1) = Year - 2001
Last Digits (04) = Week of Year
2. PINOUT (See Top View at left):
Pin 1 VDD
Pin 2 Output
Pin 3 GND
3. Controlling dimension: mm.
4. Lead thickness after solder plating will be 0.254
mm maximum.
5. Package dimensions exclude molding flash.
6. The end flash shall not exceed 0.127 mm on each
side of package.
7. Tolerance is +/- 0.254 mm unless otherwise
specified.
1.55
1.45
0.95
0.85
3104
1.30
1.00
0.10
0.00
3.10
2.70
3.00
2.60
0.50
0.35
1.80
1.50
chip
0.66
0.56
0.20
MIN
0.25
0.102.10
1.70
0.90
0.70
*
1
2
3
Pin #
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 USA and rest of the world
E-mail: [email protected] E-mail: [email protected]
Phone: 011-32-13-670-780 Phone: (603)-223-2362
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