Allegro A3196LU, A3196LLT Datasheet

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 protec­tion 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

■ Internal Protection For Automotive (ISO/DIN) Transients

■ Operation From Unregulated Supply

■ Reverse Battery Protection

■ Undervoltage Lockout

■ Supply Noise-Suppression Circuitry

■ Output Short-Circuit Protection

■ Output Zener Clamp

■ Thermal Protection

■ Symmetrical Latching Switch Points

■ Operable with Multipole Ring Magnets

Data Sheet

27609.10A

ABSOLUTE MAXIMUM RATINGS

Supply Voltage, V

CC

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

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

Reverse Battery Voltage, V

RCC

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

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

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

Output OFF Voltage, V

OUT

................. 26 V

Reverse Output Voltage V

OUT

......... -0.5 V

Continuous Output Current,

I

OUT

.......................................... 35 mA*

Reverse Output Current,

I

OUT

........................................ -100 mA

Package Power Dissipation,

PD....................................... See Graph

Junction Temperature, TJ................. 170°C

Operating Temperature Range,

T

A

..........................................

-40°C to +150°C

Storage Temperature, TS.................. 170°C

*Fault condition, internal overvoltage shutdown
above 28 V; output current limited above 35 mA.

Dwg. PH-003-2

1

SUPPLY

V

CC

GROUND

32

OUTPUT

X

PTCT

3197

PROTECTED, HIGH-TEMP.,
OPEN-COLLECTOR
HALL-EFFECT LATCH

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

FUNCTIONAL BLOCK DIAGRAM

REG.

OUTPUT

3

X

Dwg. FH-012A

GROUND

V

CC

1

<1Ω

POWER UP &

TRANSIENT

PROTECTION

CURRENT

LIMIT

2

OVERVOLT.

LOCKOUT

THERMAL

SHUTDOWN

CONTROL

600

400

200

40 80 120

160

0

AMBIENT TEMPERATURE IN °C

ALLOWABLE PACKAGE POWER DISSIPATION IN mW

Dwg. GH-054A

"U" PACKAGE
R

θJA

= 183°C/W

"LT" PACKAGE
R

θJA

= 258°C/W

60 100 140 180

700

500

300

100

20

800

NOTE – Permitted duty cycle will be less than 100%
at maximum ambient temperature with high supply
voltages, i.e., TA ≥ 140°C, VCC ≥ 12 V, and the “LT”
package. The thermal shutdown circuitry does not
protect the device from these stresses (see Internal
Protective Features).

Copyright © 1995, 1999, Allegro MicroSystems, Inc.

3197

PROTECTED, HIGH-TEMP.,

OPEN-COLLECTOR

HALL-EFFECT LATCH

www.allegromicro.com

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Operate Point B

OP

TA = -40°C 60 130 200 G
T

A

= +25°C 50 110 160 G

TA = +150°C 40 105 150 G

Release Point B

RP

TA = -40°C -200 -140 -60 G
TA = +25°C -160 -120 -50 G
TA = +150°C -150 -100 -40 G

Hysteresis B

hys

TA = -40°C 150 270 — G

(BOP - BRP)T

A

= +25°C 130 230 — G

T

A

= +150°C 110 205 — G

ELECTRICAL CHARACTERISTICS
over operating voltage and temperature range

(unless otherwise specified).

MAGNETIC CHARACTERISTICS over operating voltage range

(unless otherwise specified).

NOTES:BOP = magnetic operate point (output turns ON); BRP = magnetic release point (output turns OFF).

As used here, negative flux densities are defined as less than zero (algebraic convention).
Typical values are at TA = +25°C and VCC = 12 V (unless otherwise specified).
* Fault condition. Device is shut down and operation is not possible.

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Supply Voltage V

CC

Operating (but VCC x ICC vs TA limited) V

CC(UV)

12 26 V

Overvoltage Shutdown* V

CC(OV)

B > B

OP

28 — 55 V

Undervoltage Shutdown* V

CC(UV)

B > B

OP

3.7 — 4.5 V

Output Voltage, On V

OUT(SAT)

B > B

OP, IOUT

= 30 mA, VCC = 16 V — 0.2 0.5 V

Output Leakage Current I

OFF

V

OUT

= 26 V — — 5.0 µA

Output Clamp Voltage V

OUT(CLMP)

B < BRP, VCC = 115 V*, I

OUT

= 0 28 32 40 V

Output Current Limit I

OUTMAX

B > BOP, V

OUT

= 12 V 355070mA

Supply Current I

CC

B < BRP, VCC = 24 V, I

OUT

= 0 — 5.2 9.0 mA

B > BOP, VCC = 24 V, I

OUT

= 20 mA — 7.8 12 mA

V

CC

= +115 V* — 8.0 17 mA

Reverse Battery Current* I

RCC

V

RCC

= -35 V* — -0.5 -5.0 mA

V

RCC

= -100 V* — -2.0 -10 mA

Output Rise Time t

r

CL = 20 pF, RL = 330 Ω, VBB = 12 V — 0.05 2.0 µs

Output Fall Time t

f

CL = 20 pF, RL = 330 Ω, VBB = 12 V — 0.30 5.0 µs

Thermal Shutdown Temp.* T

J

165 — 190 °C

Package Thermal Resist. R

θJA

“LT” Package — 258 — °C/W
“U” Package — 183 — °C/W

3197

PROTECTED, HIGH-TEMP.,
OPEN-COLLECTOR
HALL-EFFECT LATCH

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]

TYPICAL OPERATING CHARACTERISTICS

Output Saturation Voltage

Supply Current

0 25 50 75 100

AMBIENT TEMPERATURE IN °C

-50

Dwg. GH-052-2

125-25

SWITCH POINTS IN GAUSS

200

100

0

-100

-200

RELEASE POINT

OPERATE POINT

150

V = 5 V–24

V

CC

Switch Points

4.0

SUPPLY CURRENT IN mA

8.0

7.0

6.0

5.0

0 255075100

AMBIENT TEMPERATURE IN °C

-50

Dwg. GH-028-3

125-25 150

V = 5 V

CC

V = 5 V

CC

B ≥ B

OP

B ≤ B

RP

V = 24 V

CC

V = 24 V

CC

0 25 50 75

100

500

0

AMBIENT TEMPERATURE IN °C

400

200

-50

Dwg. GH-040-3

SATURATION VOLTAGE IN mV

150

-25

125

I = 30 m

A

OUT

300

100

CC

V = 12

V

I = 5 m

A

OUT

B ≥ B

OP