Allegro A3421EKA, A3422LKA-TL, A3422LKA, A3422EKA-TL, A3422EKA Datasheet

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The A3421xKA and A3422xKA Hall-effect, direction-detection sensors are a new generation of special-function integrated sensors that are capable of sensing the direction of rotation of a ring magnet. These transducers provide separate digital outputs that provide information on magnet rotation speed, direction, and magnet pole count. These devices eliminate the major manufacturing hurdles encountered in fine-pitch direction-detection applications, namely maintaining accurate mechanical location between the two active Hall elements. Here, the two Hall elements are photolithographically aligned to better than 1 µm, as contrasted with 100 µm or worse mechanical location tolerance when manufactured discretely. These highly sensitive, temperature-stable, magnetic transducers are ideal for use in digital-encoder systems in the harsh environments of automotive or industrial applications. The A3421xKA is a high-hysteresis device designed for low-resolution pulse counting while the A3422xKA is a high-sensitivity device optimized for use with high-density magnets.

The A3421xKA and A3422xKA monolithic integrated circuits contain two independent Hall-effect latches whose digital outputs are internally coupled to CMOS logic circuitry that decodes signal speed and direction. Extremely low-drift BiCMOS circuitry is used for the amplifiers to ensure symmetry between the two latches so that signal quadrature can be maintained. An on-chip voltage regulator allows the use of these devices from a 4.5 V to 18 V supply. Both devices have standard open-collector outputs; the logic operation of both devices is the same.

Two operating temperature ranges are provided; suffix ‘E–’ is for the automotive and industrial temperature range of -40°C to +85°C, suffix ‘L–’ is for the automotive and military temperature range of

-40°C to +150°C. The 5-pin ‘KA’ SIP package provides a cost-competitive solution to linear magnetic sensing in harsh environments.

FEATURES

■ Internal Direction-Decoding Circuitry

■ Two Matched Hall Latches On A Single Substrate

■ Superior Temperature Stability

■ 4.5 V to 18 V Operation

Electrically Defined Power-On State Under-Voltage Lockout

HALL-EFFECT,

DIRECTION-DETECTION SENSORS

Always order by complete part number, e.g., A3421EKA .

1 432 5

Dwg. PH-015

SUPPLY

DIRECTION

GROUND

E1 OUTPUT

SPEED

LOGIC

E1 E2

Pinning is shown viewed from branded side.

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, VCC. . . . . . . . . . . . . 18 V

Magnetic Flux Density, B . . . . Unlimited

Output OFF Voltage, V

OUT

. . . . . . . . V

Output Sink Current, I

OUT

. . . . . . . 30 mA

Package Power Dissipation,

PD. . . . . . . . . . . . . . . . . . . . . . 500 mW

Operating Temperature Range, T

Suffix ‘EKA’ . . . . . . . -40˚C to +85˚C

Suffix ‘LKA’ . . . . . . -40˚C to +150˚C

Storage Temperature Range,

TS. . . . . . . . . . . . . . . -65˚C to +170˚C

3421

AND

3422

PRELIMINARY INFORMATION

(subject to change without notice)

September 6, 2000

Data Sheet

27650.1

3421

AND

3422

HALL-EFFECT, DIRECTION-DETECTION SENSORS

115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

FUNCTIONAL BLOCK DIAGRAM

TIMING DIAGRAM

OP1

RP1

Dwg. WH-012A

-B

RP2

OUT

(INTERNAL)

SPEED

(OUT

XOR OUTE2)

OP2

DIRECTION

CHANGE IN DIRECTION

SPEED

DIRECTION2

E1 OUTPUT

X X

Dwg. FH-018

GROUND

LOGIC

SUPPLY

POWER-ON

LOGIC

REG

UVLO

3421

AND

3422

HALL-EFFECT,

DIRECTION-DETECTION

SENSORS

www.allegromicro.com

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Supply Voltage Range V

Operating, TJ < 165°C

4.5 — 18 V

Output Leakage Current I

OFF

OUT

= VCC = 18 V — <1.0 10 µA

Output Saturation Voltage V

OUT(SAT)IOUT

= 20 mA — 0.21 0.50 V

Power-On State POS VCC = 0 → 5 V, OFF OFF OFF —

RP1

< B < B

OP1

, B

RP2

< B < B

OP2

Under-Voltage Lockout V

CC(UV)IOUT

= 20 mA, VCC = 0 → 5 V — 3.5 — V

Under-Voltage Hysteresis V

CC(hys)

Lockout (V

CC(UV)

) - Shutdown — 0.5 — V

Power-On Time t

VCC > 4.5 V — — 50 µs

Output Rise Time t

CL = 20 pF, RL = 820 Ω — 200 — ns

Output Fall Time t

CL = 20 pF, RL = 820 Ω — 200 — ns

Direction Change Delay t

CL = 20 pF, RL = 820 Ω 0.5 1.0 5.0 µs

Supply Current I

VCC = 8 V, All outputs OFF 5.0 9.0 18 mA

ELECTRICAL CHARACTERISTICS over operating temperature range.

50 75 100 125 175

0.5

0.1

ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS

TEMPERATURE IN °C

0.4

0.3

0.2

Dwg. GH-069

θJA

= 164°C/W

0.6

150

NOTES:1. Maximum supply voltage must be adjusted for power dissipation and ambient temperature.

2. Typical Data is at VCC = 12 V and TA = +25°C and is for design information only.

3421

AND

3422

HALL-EFFECT, DIRECTION-DETECTION SENSORS

115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

A3421xKA A3422xKA

Characteristic Symbol Test Conditions Min. Typ. Max. Min. Typ. Max. Units

Operate Point B

TA = -40°C 140 185 300 — 29 85 G

TA = +25°C 130 160 280 — 29 75 G

TA = Maximum 120 — 260 — — 75 G

Release Point

TA = -40°C -300 -190 -140 -85 -19 — G

TA = +25°C -280 -175 -130 -75 -18 — G

TA = Maximum -260 — -120 -75 -16 — G

Hysteresis B

hys

TA = -40°C 280 375 — 10 48 — G

TA = +25°C 260 335 — 10 46 — G

TA = Maximum 240 — — 10 — — G

Operate Differential B

OP1

- B

OP2

——±80 — — ±60 G

Release Differential B

RP1

- B

RP2

——±80 — — ±60 G

MAGNETIC CHARACTERISTICS over operating voltage range.

NOTES:1. Magnetic flux density is measured at most sensitive area of device,

nominally located 0.014” (0.37 mm) below the branded face of the package.

2. Typical Data is at VCC = 12 V and TA = +25°C and is for design information only.

3. As used here, negative flux densities are defined as less than zero (algebraic convention).

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