Always order by complete part number, e.g., A3197LU .

3197

PROTECTED, HIGH-TEMPERATURE,

OPEN-COLLECTOR HALL-EFFECT LATCH

These open-collector Hall-effect latches are capable of sensing magnetic

fields while using an unprotected power supply. The A3197LLT and A3197LU

can provide position and speed information by providing a digital output for

magnetic fields that exceed their predefined switch points. These devices

operate down to zero speed and have switch points that are designed to be

extremely stable over a wide operating temperature and voltage range. The

latching characteristics make them ideal for use in pulse counting applications

when used with a multi-pole ring magnet. Thermal and output short-circuit

protection allow an increased wiring harness fault tolerance. The temperature

compensated switch points, the wide operating voltage range, and the integrated

protection make these devices ideal for use in automotive applications such as

transmission speed sensors and integrated wheel bearing speed sensors.

Each monolithic device contains an integrated Hall-effect transducer, a

temperature-compensated comparator, a voltage regulator, and a buffered 35 mA

output sink stage. Supply protection is made possible by the integration of

overvoltage and undervoltage shutdown circuitry that monitor supply fault

conditions and shut down the IC. Noise shutdown circuitry (patent applied for)

prevents the propagation of supply transients to the logic load. Output protec-

tion circuitry includes a current limit loop that limits the maximum output sink

current, and thermal protection circuitry that shuts down the device during an

over-heating condition such as with a shorted load.

The A3197LLT and A3197LU are rated for operation over an extended

temperature range of -40

°C to +150°C. They are supplied in a three-lead SIP

(suffix ‘U’) or a surface-mount SOT-89 (suffix ‘LT’).

FEATURES

I Internal Protection For Automotive (ISO/DIN) Transients

I Operation From Unregulated Supply

I Reverse Battery Protection

I Undervoltage Lockout

I Supply Noise-Suppression Circuitry

I Output Short-Circuit Protection

I Output Zener Clamp

I Thermal Protection

I Symmetrical Latching Switch Points

I Operable with Multipole Ring Magnets

ABSOLUTE MAXIMUM RATINGS

(100 ms) ................................... 115 V*

(continuous) ............................... 28 V*

(100 ms) ................................... -100 V

(continuous) ............................... -35 V

Magnetic Flux Density, B .......... Unlimited

Continuous Output Current,

Reverse Output Current,

Package Power Dissipation,

Operating Temperature Range,

*Fault condition, internal overvoltage shutdown

above 28 V; output current limited above 35 mA.

Dwg. PH-003-2

1

V

CC

3

2

PTCT