Allegro ACS714 current sensor datasheet

Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS714
12
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
Power on Time versus External Filter Capacitance
0
20
40
60
80
100
120
140
160
180
200
01020304050
C
F
(nF)
C
F
(nF)
t
PO
(μs)
I
P
= 5 A
I
P
= 0 A
Noise versus External Filter Capacitance
1
1000
10
100
10000
0.01 0.1 1 10 100 1000
Noise
(p-p)
(mA)
Noise vs. Filter Cap
400
350
300
250
200
150
100
50
0
05025 75 100 125 150
t
r
(μs)
C
F
(nF)
Rise Time versus External Filter CapacitanceRise Time versus External Filter Capacitance
0
200
400
600
800
1000
1200
0 100 200 300 400 500
t
r
(μs)
C
F
(nF)
Expanded in chart at right
}
Excitation Signal
Output (mV)
15 A
Step Response
T
A
=25°C
C
F
(nF) t
r
(μs)
0 6.6
1 7.7
4.7 17.4
10 32.1
22 68.2
47 88.2
100 291.3
220 623.0
470 1120.0
Definitions of Dynamic Response Characteristics
Primary Current
Transducer Output
90
10
0
I (%)
Rise Time, t
r
t
Rise time (t
r
). The time interval between a) when the sensor
reaches 10% of its full scale value, and b) when it reaches 90%
of its full scale value. The rise time to a step response is used to
derive the bandwidth of the current sensor, in which ƒ(–3 dB) =
0.35 / t
r
. Both t
r
and t
RESPONSE
are detrimentally affected by eddy
current losses observed in the conductive IC ground plane.
Power-On Time (t
PO
). When the supply is ramped to its operat-
ing voltage, the device requires a finite time to power its internal
components before responding to an input magnetic field.
Power-On Time, t
PO
, is defined as the time it takes for the output
voltage to settle within ±10% of its steady state value under an
applied magnetic field, after the power supply has reached its
minimum specified operating voltage, V
CC
(min), as shown in the
chart at right.