A1359 データシートの表示（PDF） - Allegro MicroSystems

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A1359

Factory-Programmed Dual Output Linear Hall Effect Sensor IC With Analog and Pulse Width Modulated Outputs

Allegro MicroSystems 

A1359

Factory-Programmed Dual Output Linear Hall Effect Sensor IC

With Analog and Pulse Width Modulated Outputs

Delay to Clamp A large magnetic input step may cause the

clamp to overshoot its steady state value. The delay to clamp,

tCLPVOUT , is defined as the time it takes for the output voltage

to settle within 1% of its steady state value after initially passing

through its steady state voltage. This is conceptually the same for

the PWM output duty cycle settling to the steady state value. (See

figure 4.)

Quiescent Voltage Output In the quiescent state (no signifi-

cant magnetic field: B = 0 G), the analog output, VOUT, is ratio-

metric to the supply voltage, VCC , throughout the entire operating

range of VCC . The PWM output, VPWMOUT , by virtue of being a

% duty-cycle will remain at 50% nominal throughout the entire

VCC operating range (4.5 to 5.5 V).

Quiescent Output Drift through Temperature Range Due

to internal component tolerances and thermal considerations, the

Quiescent Voltage Output, VOUT(Q) , may drift from its nominal

value across the operating ambient temperature, TA. For purposes

of specification, the Quiescent Voltage Output Drift Through

Temperature Range, ∆VOUT(Q) (mV), is defined as:

∆VOUT(Q) = VOUT(Q)(TA) – VOUT(Q)(25°C)

(1)

Sensitivity Assuming the sensitivity of the device is positive

(Positive Polarity: A1359LLETR-T), the presence of a south-

polarity magnetic field perpendicular to the branded surface of

the package face increases the output voltage from its quiescent

value toward the supply voltage rail. The amount of the output

VCLP(HIGH)

Magnetic Input Signal

tCLPPWM or

tCLPVOUT

VPWMOUT or VOUT

t1

t2

t1= time at which output voltage initially

reaches steady state clamp voltage

t2= time at which output voltage settles to

within 1% of steady state clamp voltage

voltage increase is proportional to the magnitude of the magnetic

field applied. Conversely, the application of a north polarity field

decreases the output voltage from its quiescent value. For the

case of the reverse polarity device (A1359LLETR-RP-T), the

presence of a south-polarity magnetic field perpendicular to the

branded surface of the package face decreases the output volt-

age from its quiescent value toward the ground rail. The amount

of the output voltage decrease is proportional to the magnitude

of the magnetic field applied. Conversely, the application of a

north polarity field increases the output voltage from its quiescent

value. This proportionality is specified as the magnetic sensitiv-

ity, Sens (mV/G), of the device and is defined as:

Sens = VOUT(BPOS) – VOUT(BNEG)

(2)

BPOS – BNEG

where BPOS and BNEG are two magnetic fields with opposite

polarities.

Sensitivity Temperature Coefficient Device sensitivity

changes as temperature changes, with respect to its programmed

Sensitivity Temperature Coefficient, TCSENS. TCSENS is pro-

grammed at 150°C, and calculated relative to the nominal

sensitivity programming temperature of 25°C. TCSENS (%/°C) is

defined as:

TCSENS

=

SensSTe2n–sTS1ensT1

×



100%



T21–T1

(3)

where T1 is the nominal Sens programming temperature of 25°C,

and T2 is the TCSENS programming temperature of 150°C. The

ideal value of Sens through the full ambient temperature range,

SensIDEAL(TA), is defined as:

SensIDEAL(TA) = SensT1× [100% +TCSENS (TA –T1)]

(4)

Sensitivity Drift Due to Package Hysteresis Package

stress and relaxation can cause the device sensitivity at TA = 25°C

to change during and after temperature cycling. This change in

sensitivity follows a hysteresis curve. For purposes of specifica-

tion, the Sensitivity Drift Due to Package Hysteresis, ∆SensPKG,

is defined as:

time (μs)

Figure 4. Definition of Delay to Clamp

∆SensPKG

=

Sens(25°C)2 – Sens(25°C)1

Sens(25°C)1

×100 (%)

(5)

Allegro MicroSystems, Inc.

7

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

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