Linear Hall-Effect Sensor IC with Analog Output
Available in a Miniature, Low-Profile Surface-Mount Package
A1315
6
Allegro MicroSystems, LLC
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
CHARACTERISTIC DEFINITIONS
Power-On Time. When the supply is ramped to its operating
voltage, the device output requires a finite time to react to an
input magnetic field. Power-On Time, tPO , is defined as the time
it takes for the output voltage to begin responding to an applied
magnetic field after the power supply has reached its minimum
specified operating voltage, VCC(min), as shown in figure 1.
Delay to Clamp. A large magnetic input step may cause the
clamp to overshoot its steady state value. The Delay to Clamp,
tCLP , 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, as shown in figure 2.
Quiescent Voltage Output. In the quiescent state (no signifi-
cant magnetic field: B = 0 G), the output, VOUT(Q), is at a con-
stant ratio to the supply voltage, VCC, across the entire operating
ranges of VCC and Operating Ambient Temperature, TA.
Quiescent Voltage Output Drift Across Temperature
Range. Due to internal component tolerances and thermal
considerations, the Quiescent Voltage Output, VOUT(Q), may
drift due to temperature changes within the Operating Ambient
Temperature, TA. For purposes of specification, the Quiescent
Voltage Output Drift Across Temperature Range, ∆VOUT(Q) (mV),
is defined as:
∆VOUT(Q) VOUT(Q)(TA) –VOUT(Q)(25°C)
=
(1)
Sensitivity. The amount of the output voltage change is propor-
tional to the magnitude and polarity of the magnetic field applied.
This proportionality is specified as the magnetic sensitivity,
Sens (mV/G), of the device and is defined as:
OUT(B+)
OUT(B–)
Sens = (2)
where B+ is the magnetic flux density in a positive field (south
polarity) and B– is the magnetic flux density in a negative field
(north polarity).
Sensitivity Temperature Coefficient. The device sensitiv-
ity changes as temperature changes, with respect to its Sensitiv-
ity Temperature Coefficient, TCSENS. TCSENS is programmed at
150°C, and calculated relative to the baseline sensitivity program-
ming temperature of 25°C. TCSENS is defined as:
SensT2 – SensT1
SensT1 T2–T1
1
TCSens =×
100 (%/°C)
(3)
where T1 is the baseline Sens programming temperature of 25°C,
and T2 is the TCSENS programming temperature of 150°C.
The ideal value of Sens across the full ambient temperature
range, SensIDEAL(TA), is defined as:
SensT1 × [100 (%) + TCSENS (TA –T1
SensIDEAL(TA) =
(4)
Sensitivity Drift Across Temperature Range. Second order
sensitivity temperature coefficient effects cause the magnetic
sensitivity, Sens, to drift from its ideal value across the operating
ambient temperature range, TA. For purposes of specification,
V
VCC
VCC(min)
VOUT
90% VOUT
0
t1= time at which power supply reaches
minimum specified operating voltage
t2=
time at which output voltage settles
within ±10% of its steady state value
under an applied magnetic field
t1t2
tPO
V
CC
(typ)
time (µs)
Magnetic Input Signal
Magnetic Input Signal
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
V
CLPHIGH
t1t2
tCLP
VOUT
VOUT (V)
Figure 1. Definition of Power On Time, tPO
Figure 2. Definition of Delay to Clamp, tCLP