AH1894

AH1894
PROGRAMMABLE HIGH SENSITIVITY
MICROPOWER OMNIPOLAR HALL-EFFECT SWITCH
Description
Pin Assignments
The AH1894 is a high sensitivity micropower magnetic range
selectable Omnipolar Hall effect switch IC with internal pull up and
(Top View)
pull down capability. Designed for portable and battery powered
equipment such as cellular phones and portable PCs to home
appliances
and
industrial
applications,
the
average
power
consumption is only 8uW at 1.85V. To support portable equipment the
AH1894 can operate over the supply range of 1.6V to 3.6V and uses
X1-DFN1216-4
a hibernating clocking system to minimize the power consumption. To
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minimize PCB space the AH1894 is available in small low profile
X1-DFN1216-4 and SOT553 packages.
(Top View)
The output is activated with either a north or south pole of sufficient
magnetic field strength. The user can select one of two magnetic
sensitivity bands via the BSEL pin without the addition of any external
components allowing a flexible but small solution. The band select
can be hardwired or be changed on the fly via a logic source such as
a micro-controller. When the magnetic flux density (B) is larger than
operate point (Bop), the output will be turned on (pulled low) and held
SOT553
until B is lower than release point (Brp).
Features
Applications

Omnipolar Operation (North or South pole)


Open and Close Detect for Cellular Phones
Programmable Operate and Release Points


Holster or cover detect for cellular phones and Tablet PCs
Supply Voltage of 1.6V to 3.6V


Cover or Display Switches in Portable PCs
Micropower Operation


Digital Still, Video Cameras and Handheld Gaming Consoles
Chopper Stabilized Design Provides:

Door, Lids and Tray Position Switches

Superior Temperature Stability

Level, Proximity and Position Switches

Minimal Switch Point Drift


Enhanced Immunity to Physical Stress

No External Pull-up Resistors Required

Good RF Noise Immunity

-40°C to +85°C Operating Temperature

Contact-Less Switches in Home Appliances and Industrial
Applications
High ESD capability of 8kV (Human Body Model) on VDD, GND
and OUTPUT Pins

Small Low Profile X1-DFN1216-4 and SOT553 Packages

Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
Typical Applications Circuit
Note:
4. CIN is for power stabilization and to strengthen the noise immunity, the recommended capacitance is 100nF typical.
AH1894
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AH1894
Pin Descriptions
Package: X1-DFN1216-4
Pin Number
1
Pin Name
OUTPUT
2
VDD
3
4
BSEL
GND
Function
Output Pin
Power Supply Input
Band Select
Ground Pin
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Package: SOT553
Pin Number
Pin Name
1
VDD
2
3
4
NC
BSEL
GND
5
Note:
OUTPUT
Function
Power Supply Input
No Connection (Note 5)
Band Select
Ground
Output
5. NC is “No Connection” pin and is not connected internally. This pin can be left open or tied to ground.
Functional Block Diagram
AH1894
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AH1894
Absolute Maximum Ratings (Note 6) (@TA = +25°C, unless otherwise specified.)
Symbol
Rating
Unit
VDD
Supply Voltage (Note 7)
6
V
VDD_REV
Reverse Supply Voltage
-0.3
V
IOUTPUT
Output current (source and sink)
3.5
mA
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B
Parameter
Magnetic Flux Density
PD
Package Power Dissipation
Ts
Storage Temperature Range
TJ
Maximum Junction Temperature
ESD HBM
Notes:
Unlimited
230
230
-65 to +150
X1-DFN1216-4
SOT553
VDD, GND and OUTPUT pins
BSEL pin
Human Body Model (HMB) ESD capability
mW
mW
°C
150
°C
8
6
kV
kV
6. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be
affected by exposure to absolute maximum rating conditions for extended periods of time.
7. The absolute maximum VDD of 6V is a transient stress rating and is not meant as a functional operating condition. It is not recommended to
operate the device at the absolute maximum rated conditions for any period of time.
Recommended Operating Conditions (@TA = +25°C, unless otherwise specified.)
Symbol
VDD
TA
Parameter
Conditions
Rating
Unit
Supply Voltage
Operating
1.6V to 3.6V
V
Operating Temperature Range
Operating
-40 to +85
°C
Electrical Characteristics (@TA = +25°C, VDD = 1.85V, unless otherwise specified.)
Symbol
VOL
VOH
Parameter
Output Low Voltage (on)
Output High Voltage (off)
IOUT = 1mA
IOUT = -1mA
Ioff
Output Leakage Current
VOUT = 3.6V, Output off
VSEL_LB
VSEL_HB
RPD_BSEL
BSEL pin input voltage – Low Band
BSEL pin input voltage – High Band
BSEL pin internal pull-down resistor
IDD(awake)
Supply Current
IDD(sleep)
IDD(avg)
Average Supply Current
Tawake
Tperiod
D.C.
Awake Time
Period
Duty Cycle
Notes:
Conditions
Min
—
VDD -0.2
Typ
0.1
VDD -0.1
Max
0.2
—
Unit
V
V
-
< 0.1
1
µA
0
1.4
—
—
—
50
0.5
3.6
—
V
V
kΩ
—
2.1
—
mA
During ‘sleep’ period,
TA = +25°C, VDD = 3V
—
2.5
—
mA
TA = +25°C, VDD = 1.85V
—
4.3
8
µA
TA = +25°C, VDD = 3.6V
—
7.2
13
µA
(Note 9)
(Note 9)
(Note 10)
—
—
—
50
50
0.1
100
100
—
µs
ms
%
(Note 8)
During ‘awake’ period,
TA = +25°C, VDD = 3V
8. BSEL pin internal pull-down resistor is only active during AWAKE time
9. When power is initially on, the operating VDD (1.6V to 3.6V) must be applied to guarantee the output sampling.
The output state is valid after the second operating phase (typical 100ms).
10. Transition time varies dependant on the timing of BSEL activation during the sleep and awake phases.
AH1894
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AH1894
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Electrical Characteristics (cont.)
Magnetic Characteristics (Note 11 &12) (TA = -40°C to +85°C, VDD = 1.85V, unless otherwise specified)
BSEL
Symbol
Low
Low
Low
Low
High
High
High
BopsLB (South pole to part marking side)
BopnLB (North pole to part marking side)
BrpsLB (South pole to part marking side)
BrpnLB (North pole to part marking side)
BopsHB (South pole to part marking side)
BopnHB (North pole to part marking side)
BrpsHB (South pole to part marking side)
High
—
BrpnHB (North pole to part marking side)
Bhy (|Bopx|-|Brpx|)
Notes:
Characteristics
Low Band - Operation Point
Low Band - Release Point
High Band - Operation Point
High Band - Release Point
Hysteresis
(1mT=10 Gauss)
Max
Unit
Min
Typ
15
-45
10
-35
25
-55
20
30
-30
20
-20
40
-40
30
45
-15
35
-10
55
-25
45
-45
—
-30
10
-20
—
Gauss
11. Typical data is at TA = +25C, VDD = 1.85V.
12. Maximum and minimum parameters values over the operating temperature range are not tested in production, they are guaranteed by design, process
control and characterization. The magnetic characteristics may vary with supply voltage, operating temperature and after soldering.
The AH1894 includes a band select pin (BSEL) so that the operate (Bops and Bopn) and release (Brps and Brpn) points can be adjusted between
two pre-defined ranges. The BSEL can be hard wired within the application circuit or the band can be selected on the fly by using the BSEL pin as
a logic input. This feature allows the AH1894 sensitivity to be changed by firmware within the application without the addition of any external
components. If the BSEL pin is left open circuit the AH1894 defaults to low band.
AH1894
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AH1894
Application Notes
Applications Circuit 1 – Low Band
Leaving the BSEL pin unconnected or connecting the BSEL pin to ground permanently configures the AH1894 into its high sensitivity mode
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(lower switching thresholds), requiring a reduced magnetic flux density to activate its output (Low Band).
Applications Circuit 2 – High Band
Connecting the BSEL pin to VDD or applying a voltage greater than 1.4V configures the AH1894 into its low sensitivity mode (higher switching
threshold), requiring a higher magnetic flux density to activate its output (High Band).
Applications Circuit 3 – Adjustable Sensitivity
To enhance the flexibility within the application the sensitivity can be adjusted with a standard logic signal allowing it to be controlled by a microcontroller or a logic source. This allows the sensitivity to be changed within the application without a hardware change. Whenever the sensitivity
band selection is changed, allow for band selection changeover to complete and output to be valid.
AH1894
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AH1894
Application Notes (cont.)
Bands Select Change Timing and Valid Output
Whenever band selection BSEL pin input is changed, allow for band selection changeover to complete and stabilize. The output is valid only
after the second complete operating ‘awake’ phase after the band selection change is complete. Time taken for the output to be valid, after the
BSEL change, depends on timing of BSEL change during the sleep and awake phase; this time is up to 100ms typical and 200.1ms maximum
NEW PRODUCT
(TBC).
AH1894
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AH1894
Typical Operating Characteristics
Typical Switch Points Characteristics in Low Band (BSEL = Low) and High Band (BSEL = High)
V DD = 1.60V, BSEL = Low (GND)
60
60
50
50
20
Bops
Brps
10
Bhy
Gauss (G)
30
0
-10
Brpn
-20
30
Bopn
-30
-40
-50
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Bops
Brps
40
Gauss (G)
40
VDD = 1.60V, BSEL = High (V DD )
20
10
Bhy
0
-10
-20
-30
Brpn
-40
Bopn
-50
-60
-60
-50
-25
0
25
50
75
100
-50
-25
Temperature (°C)
60
60
50
50
75
100
VDD = 1.85V, BSEL = High (VDD )
Bops
Brps
40
40
30
Bops
30
20
Brps
Bhy
20
10
0
-10
Brpn
-20
Gauss (G)
Gauss (G)
50
Switch Points vs Temperature
VDD = 1.85V, BSEL = Low (GND)
Bopn
-30
Bhy
10
0
-10
-20
Brpn
-30
-40
-40
-50
-50
Bopn
-60
-60
-50
-25
0
25
50
75
-50
100
-25
0
25
50
75
100
Temperature (°C)
Temperature (°C)
Switch Points vs Temperature
Switch Points vs Temperature
VDD = 3.0V, BSEL = Low (GND)
V DD = 3.0V, BSEL = High (VDD )
60
50
50
40
40
Bops
Brps
Bhy
20
10
0
-10
Brpn
Bopn
-20
-30
Bops
Brps
30
20
Gauss (G)
30
Gauss (G)
25
Temperature (°C)
Switch Points vs Temperature
60
0
10
Bhy
0
-10
-20
-30
Brpn
-40
-40
Bopn
-50
-50
-60
-60
-50
-25
0
25
50
75
100
-50
-25
0
25
50
Temperature (°C)
Temperature (°C)
Switch Points vs Temperature
Switch Points vs Temperature
AH1894
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75
100
July 2013
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AH1894
Typical Operating Characteristics (cont.)
Typical Switch Points Characteristics in Low Band (BSEL = Low) and High Band (BSEL = High)
V DD = 3.60V, BSEL = Low (GND)
60
VDD = 3.60V, BSEL = High (V DD )
60
50
50
40
Gauss (G)
10
0
-10
Brpn
-20
30
Gauss (G)
20
Bopn
-30
20
Bhy
10
0
-10
-20
Brpn
-30
-40
-40
-50
-50
-60
Bopn
-60
-50
-25
0
25
50
75
100
-50
-25
0
Temperature (°C)
25
50
75
100
Temperature (°C)
Switch Points vs Temperature
Switch Points vs Temperature
Average Supply Current IDD (avg)
VDD = 1.60V to 3.60V
10
9
8
7
3.6V
6
5
1.85V
1.6V
4
3
2
1
0
-50
-25
0
25
50
75
100
Average Supply Current IDD (μA)
Average Supply Current IDD (μA)
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Bops
Brps
40
Bops
Brps
Bhy
30
10
9
8
6
Bhy
5
4
3
2
Brpn
Bopn
1
0
1.5
1.8
2.1
2.4
2.7
3
3.3
3.6
3.9
Supply voltage (V)
Average Supply Current vs. Temperature
Document number: DS35741 Rev. 1 - 2
Bops
Brps
7
Temperature (°C)
AH1894
TA = +25 °C
Average Supply Current vs. Supply Voltage
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AH1894
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Ordering Information
Part Number
Package
Code
Packaging
AH1894-FA-7
AH1894-Z-7
FA
Z
X1-DFN1216-4
SOT553
7” Tape and Reel
Quantity
Part Number Suffix
3000/Tape & Reel
-7
3000/Tape & Reel
-7
Marking Information
(1)
(2)
Package Type: X1-DFN1216-4
Part Number
AH1894-FA-7
Package
X1-DFN1216-4
Identification Code
B4
Part Number
AH1894-Z-7
Package
SOT553
Identification Code
B4
Package Type: SOT553
AH1894
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AH1894
Package Outline Dimensions (All dimensions in mm.)
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.
(1)
Package Type: X1-DFN1216-4
A
3
A
1
A
e
n
a
l
P
g
n
i
t
a
e
S
︶
°
5
4
x
2
.
0
'
C
︵
D
I
1
#
n
i
P
E
2
E
NEW PRODUCT
De
X1-DFN1216-4
Dim Min Max Typ
A
0.47 0.53 0.50
A1
0.00 0.05 0.02
A3
--0.13
b
0.15 0.25 0.20
D
1.15 1.25 1.20
D2
0.75 0.95 0.85
E
1.55 1.65 1.60
E2
0.55 0.75 0.65
e
0.65
L
0.20 0.30 0.25
Z
0.175
All Dimensions in mm
L
2
D
b
Z
Bottom View
Sensor Location
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Package Outline Dimensions (cont.) (All dimensions in mm.)
(2)
Package Type: SOT553
D
e1
E1/2
e
E/2
NEW PRODUCT
E1
E
L (5x)
F
R0.1 MAX.
TYP.
b (5x)
c
a
7°
A
SOT553
Dim
Min
Max
Typ
A
0.55
0.62
0.60
b
0.15
0.30
0.20
c
0.10
0.18
0.15
D
1.50
1.70
1.60
E
1.55
1.70
1.60
E1
1.10
1.25
1.20
e
0.50 BSC
e1
1.00 BSC
F
0.00
0.10
––
L
0.10
0.30
0.20
a
6°
8°
7°
All Dimensions in mm
TYP.
Sensor Location
AH1894
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Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
(1)
Package Type: X1-DFN1216-4
1
X C
X1-DFN1216-4
Y
NEW PRODUCT
1
Y
2
Y
Dimensions
Value
C
0.65
X
0.25
X1
0.90
Y
0.50
Y1
0.70
Y2
2.00
All Dimensions in mm
X
(2)
Package Type: SOT553
C2
Z
C2
SOT553
Dimensions
Value
Z
2.2
G
1.2
X
0.375
Y
0.5
C1
1.7
C2
0.5
All Dimensions in mm
C1
G
Y
X
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AH1894
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
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application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
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This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
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representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2013, Diodes Incorporated
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