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 mechani-

cal 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-com-

petitive solution to linear magnetic sensing in harsh environments.

FEATURES

Electrically Defined Power-On State

Under-Voltage Lockout

HALL-EFFECT,

DIRECTION-DETECTION SENSORS

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

X

V

CC

1

4

3

2

5

Dwg. PH-015

LOGIC

X

E1

E2

Pinning is shown viewed from branded side.

ABSOLUTE MAXIMUM RATINGS

Magnetic Flux Density, B . . . .

Unlimited

Package Power Dissipation,

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

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

Storage Temperature Range,

3422

PRELIMINARY INFORMATION

(subject to change without notice)

September 6, 2000