Diodes AH921 User Manual

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Data Sheet

General Description

The AH921 is a Hall-effect latch designed in mixed
signal CMOS technology. It is quite suitable for use
in automotive, industrial and consumer applications.

Superior high-temperature performance is made
possible through dynamic offset cancellation, which
reduces the residual offset voltage normally caused
by device over-molding, temperature dependencies,
and thermal stress. The device integrates a voltage
regulator, Hall-voltage generator, small-signal
amplifier, chopper stabilization, schmitt trigger, and
is directly drivable by the output.

An on-board regulator permits operation with supply
voltage from 3.5V to 24V.

The AH921 is available in TO-92S-3 and SOT-2 3-3
packages, which are optimized for most applications.

TO-92S-3 SOT-23-3

Features

• Wide Operating Voltage Range from 3.5 to 24V

• Symmetrical Switch Points

• Chopper-stabilized Amplifier Stage

• Superior Temperature Stability

• Compact Size

• Built-in Pull-up Resistor

• ESD Rating: 3500V (Human Body Model)

Applications

• Brushless DC Motor Commutation

• Brushless DC Fan

• Solid-state Switch

• Revolution Counting

• Speed Detection

• High Sensitivity and Unconnected Switch

Figure 1. Package Types of AH92 1

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Pin Configuration

Z3 Package N Package

(TO-92S-3) (SOT-23-3)

3

3

2

1

(Front View) (Top View)

Figure 2. Pin Configuration of AH921

Pin Description

Pin Number

TO-92S-3 SOT-23-3

1 1 VCC Supply voltage

Pin Name Function

21

2 3 GND Ground pin
3 2 OUT Output pin

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Functional Block Diagram

A (B)
A for TO-92S-3
B for SOT-23-3

Hall Sense

VCC

1 (1)

Reference Voltage

Chopper

Switch

2 (3)

AMP

100k

GND

Figure 3. Functional Block Diagram of AH921

OUT

3 (2)

Ordering Information

AH921 -

Circuit Type

Package
Z3: TO-92S-3
N: SOT-23-3

G1: Green

TR: Tape & Reel
Blank: Bulk

Package

TO-92S-3 AH921Z3-G1 921 Bulk
SOT-23-3

Temperature

Range

-40 to 125°C

Part Number Marking ID Packing Type

AH921NTR-G1 GS6 Tape & Reel

BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS
compliant and green.

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Absolute Maximum Ratings (Note 1)

Parameter Symbol Value Unit

Supply Voltage VCC 28 V
Supply Current (Fault) ICC 5 mA
Output current (Continuous) I

Power Dissipation

Operating T em perature TA -50 to 150
Storage Temperature T
Maximum Junction Temperature TJ (Max) 165
ESD (Human Body Model) ESD 3500 V

25 mA

OUT

P

D

-65 to 150

STG

TO-92S-3 400
SOT-23-3

230

mW

ºC
ºC
ºC

Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to
the device. These are stress ratings only, and functional operation of the device at these or any other conditions
beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute
Maximum Ratings” for extended periods may affect device reliability.

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Supply Voltage V
Operating Temperature TA -40 125 ºC

CC

3.5 24 V

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Electrical Characteristics

V

=12V, TA=25°C, unless otherwise specified.

CC

Parameter Symbol Conditions Min Typ Max Unit

Supply Voltage VCC Operating 3.5 12 24 V

Supply Current ICC

VCC=12V, B<BRP 3.0 5.0 mA
V

=12V, B>BOP 3.0 5.0 mA

CC

Saturation Voltage V
Output Leakage Current I
Output Rising Time t
Output Falling Time t

I

SAT

LEAKAGE

FALLING

VCC=V

CL=20pF 0.4 2

RISING

CL=20pF 0.4 2

=20mA, B>BOP 185 500 mV

OUT

=24V, B<BRP 0.1 10

OUT

μA

μs
μs

Magnetic Characteristics

V

=12V, TA=25°C, unless otherwise specified.

CC

Parameter Symbol Min Typ Max Unit

Operating Point BOP 5 22 40 Gauss
Releasing Point BRP -40 -22 -5 Gauss
Hysteresis B

45 Gauss

HYS

Figure 4. Magnetic Flux Density of AH921

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Magnetic Characteristics (Continued)

South Pole

Output=Low (For TO-92S-3)

Output=High (For TO-92S-3)

North Pole

Figure 5. Output Status vs. Magnetic Pole

Package Type

TO-92S-3

SOT-23-3

Jul. 2011 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

Parameter Test condition Output

South Pole B＞BOP Low
North Pole B＜B
South Pole B＞BOP High
North Pole B＜B

Table 1. Output Status vs. Magnetic Pole

6

High

RP

Low

RP

Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Magnetic Characteristics (Continued)

Figure 6. Magnetic Thresholds

Note 2: BOP is determined by putting the device under magnetic field swept from BRP(Min) to BOP(Max) until the
output is switched on.
Note 3: B
output is switched off.

is determined by putting the device under magnetic field swept from BOP(Max) to BRP(Min) until the

RP

Test Circuit and Test Conditions

Figure 7. Test Circuit of AH921

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Test Circuit and Test Conditions (Continued)

Figure 8. Test Condition of AH921 (Supply Current)

Note 4: Output initial status is low when powering on.
Note 5: The supply current I

represents the average supply current. The output is open during measurement.

CC

Note 6: The device is put under the magnetic field: B<B

RP.

Figure 9. Test Condition of AH921 (Output Saturation Voltage)

Note 7: The output saturatio n volt a ge V
Note 8: The device is put under the magnetic field: B>B

Jul. 2011 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

is measured at VCC=3.5V and VCC=24V.

SAT

OP.

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Test Circuit and Test Conditions (Continued)

Figure 10. Test Condition of AH921 (Output Leakage Current)

Note 9: The device is put under the magnetic field: B<B

RP.

Typical Performance Characteristics

4.0

3.5

3.0

2.5

(mA)

CC

I

2.0

1.5

1.0

4 6 8 10 12 14 16 18 20 22 24

VCC (V)

TA=25oC

Figure 11. I

vs. VCC Figure 12. ICC vs. TA

CC

Jul. 2011 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

4.0

3.5

VCC=5V
VCC=12V

3.0

(mA)

CC

2.5

I

2.0

1.5

-25 0 25 50 75 100 125

TA (oC)

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Typical Performance Characteristics (Continued)

40

50

40

30

20

(Gauss)

HYS

10

/B

RP

/B

0

OP

B

-10

-20

4 8 12 16 20 24

VCC (V)

TA=25oC

B

OP

B

RP

B

HYS

30

20

(Gauss)

10

HYS

/B

RP

0

/B

OP

B

-10

-20

-25 0 25 50 75 100 125

TA (oC)

VCC=12V

B
B
B

OP

RP

HYS

Figure 13. B

OP/BRP/BHYS

vs. VCC Figure 14. BOP/BRP/B

HYS

vs. TA

180

160

140

120

100

(mV)

80

SAT

V

60

40

20

0

0 5 10 15 20 25

I

(mA)

OUT

TA=25oC
VCC=12V

240

220

200

180

(mV)

160

SAT

V

140

120

100

-25 0 25 50 75 100 125

TA (oC)

VCC=5V
VCC=12V

Figure 15. V

SAT

vs. I

Figure 16. V

OUT

SAT

vs. TA

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Typical Performance Characteristics (Continued)

450

400

350

300

250

(mW)

D

200

P

150

100

50

0

0 255075100125150

TA (oC)

SOT-23-3
TO-92S-3

Figure 17. P

vs. TA

D

T ypical Application

Output

C

L

0.1 F

V

CC

Figure 18. Typical Application Circuit of AH921

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Mechanical Dimensions

TO-92S-3 Unit: mm(inch)

°
°

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Data Sheet

HIGH SENSITIVITY CMOS HALL-EFFECT LATCH AH921

Mechanical Dimensions (Continued)

SOT-23-3 Unit: mm(inch)

0.300(0.012)

0.600(0.024)

1.500(0.059)

1.700(0.067)

2.650(0.104)

2.950(0.116)

°
°

MAX.

1.450(0.057)

Jul. 2011 Rev. 1. 2 BCD Semiconductor Manufacturing Limited

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BCD Semiconductor Manufacturing Limited

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particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use

of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or

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