ACS715
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
FEATURES AND BENEFITS
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DESRIPTION
Low-noise analog signal path
Device bandwidth is set via the FILTER pin
5 µs output rise time in response to step input current
80 kHz bandwidth
Total output error 1.5% typical at TA = 25°C
Small footprint, low-profile SOIC8 package
1.2 mΩ internal conductor resistance
2.1 kVRMS minimum isolation voltage from pins 1-4 to
pins 5-8
5.0 V, single supply operation
133 to 185 mV/A output sensitivity
Output voltage proportional to DC currents
Factory-trimmed for accuracy
Extremely stable output offset voltage
Nearly zero magnetic hysteresis
Ratiometric output from supply voltage
Operating temperature range, –40°C to 150°C
The Allegro™ ACS715 provides economical and precise
solutions for DC current sensing in automotive systems. The
device package allows for easy implementation by the customer.
Typical applications include motor control, load detection and
management, switch-mode power supplies, and overcurrent
fault protection.
The device consists of a precise, low-offset, linear Hall circuit
with a copper conduction path located near the surface of the
die. Applied current flowing through this copper conduction
path generates a magnetic field which the Hall IC converts into a
proportional voltage. Device accuracy is optimized through the
close proximity of the magnetic signal to the Hall transducer.
A precise, proportional voltage is provided by the low-offset,
chopper-stabilized BiCMOS Hall IC, which is programmed
for accuracy after packaging.
The output of the device has a positive slope (>VIOUT(Q))
when an increasing current flows through the primary copper
conduction path (from pins 1 and 2, to pins 3 and 4), which is
the path used for current sampling. The internal resistance of
this conductive path is 1.2 mΩ typical, providing low power
loss. The thickness of the copper conductor allows survival of
the device at up to 5× overcurrent conditions. The terminals
of the conductive path are electrically isolated from the signal
TÜV America
Certificate Number:
U8V 06 05 54214 010
Package: *-Pin SOIC (suffix LC)
Continued on the next page…
Approximate Scale 1:1
1
2
IP
IP+
VCC
IP+ VIOUT
ACS715
3
4
IP– FILTER
IP–
GND
+5 V
8
7
VOUT
CBYP
0.1 µF
6
5
CF
Typical Application 1.
The ACS715 outputs an analog signal, VOUT . that varies linearly with
the unidirectional DC primary sampled current, IP , within the range
specified. CF is recommended for noise management, with values that
depend on the application.
ACS715-DS, Rev. 10
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
DESCRIPTION (CONTINUED)
leads (pins 5 through 8). This allows the ACS715 to be used in
applications requiring electrical isolation without the use of optoisolators or other costly isolation techniques.
The ACS715 is provided in a small, surface mount SOIC8 package.
The leadframe is plated with 100% matte tin, which is compatible
with standard lead (Pb) free printed circuit board assembly processes.
Internally, the device is Pb-free, except for flip-chip high-temperature
Pb‑based solder balls, currently exempt from RoHS. The device is
fully calibrated prior to shipment from the factory.
Selection Guide
Part Number
Optimized Range, IP
(A)
Sensitivity, Sens
(Typ) (mV/A)
ACS715ELCTR-20A-T
0 to 20
185
ACS715ELCTR-30A-T
0 to 30
133
ACS715LLCTR-20A-T
0 to 20
185
ACS715LLCTR-30A-T
0 to 30
133
TA
(°C)
Packing*
–40 to 85
Tape and reel, 3000 pieces/reel
–40 to 150
*Contact Allegro for additional packing options.
TÜV America
Certificate Number:
U8V 06 05 54214 010
Parameter
Specification
Fire and Electric Shock
CAN/CSA-C22.2 No. 60950-1-03
UL 60950-1:2003
EN 60950-1:2001
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
2
ACS715
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
SPECIFICATIONS
Absolute Maximum Ratings
Characteristic
Rating
Unit
VCC
8
V
Reverse Supply Voltage
VRCC
–0.1
V
Output Voltage
VIOUT
8
V
Reverse Output Voltage
VRIOUT
–0.1
V
Output Current Source
IOUT(Source)
3
mA
10
mA
100
A
Supply Voltage
Output Current Sink
Symbol
IOUT(Sink)
Overcurrent Transient Tolerance
IP
Nominal Operating Ambient Temperature
TA
Maximum Junction Temperature
Storage Temperature
Notes
1 pulse, 100 ms
Range E
–40 to 85
ºC
Range L
–40 to 150
ºC
TJ(max)
165
ºC
Tstg
–65 to 170
ºC
Rating
Unit
Isolation Characteristics
Characteristic
Symbol
Notes
Dielectric Strength Test Voltage*
VISO
Agency type-tested for 60 seconds per
UL standard 60950-1, 1st Edition
2100
VAC
Working Voltage for Basic Isolation
VWFSI
For basic (single) isolation per UL standard 60950-1, 1st
Edition
354
VDC or Vpk
Working Voltage for Reinforced Isolation
VWFRI
For reinforced (double) isolation per UL standard 609501, 1st Edition
184
VDC or Vpk
* Allegro does not conduct 60-second testing. It is done only during the UL certification process.
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
3
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
+5 V
VCC
(Pin 8)
Hall Current
Drive
IP+
(Pin 1)
Sense Temperature
Coefficient Trim
Dynamic Offset
Cancellation
IP+
(Pin 2)
IP–
(Pin 3)
Signal
Recovery
VIOUT
(Pin 7)
Sense
Trim
IP–
(Pin 4)
0 Ampere
Offset Adjust
GND
(Pin 5)
FILTER
(Pin 6)
Functional Block Diagram
IP+
1
8
VCC
IP+
2
7
VIOUT
IP–
3
6
FILTER
IP–
4
5
GND
Package LC, 8-Pin SOIC Pin-out Diagram
Terminal List Table
Number
Name
1 and 2
IP+
Description
Input terminals for current being sampled; fused internally
3 and 4
IP–
5
GND
Output terminals for current being sampled; fused internally
6
FILTER
Terminal for external capacitor that sets bandwidth
7
VIOUT
Analog output signal
8
VCC
Signal ground terminal
Device power supply terminal
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
4
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
COMMON OPERATING CHARACTERISTICS1 over full range of TA, and VCC = 5 V, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
4.5
5.0
5.5
V
mA
ELECTRICAL CHARACTERISTICS
Supply Voltage
Supply Current
VCC
ICC
VCC = 5.0 V, output open
–
10
13
Output Capacitance Load
CLOAD
VIOUT to GND
–
–
10
nF
Output Resistive Load
RLOAD
VIOUT to GND
4.7
–
–
kΩ
mΩ
Primary Conductor Resistance
RPRIMARY
TA = 25°C
–
1.2
–
Rise Time
tr
IP = IP(max), TA = 25°C, COUT = 10 nF
–
3.5
–
μs
Frequency Bandwidth
f
–3 dB, TA = 25°C; IP is 10 A peak-to-peak
–
80
–
kHz
Over full range of IP , IP applied for 5 ms
–
±1.5
–
%
Unidirectional; IP = 0 A, TA = 25°C
–
VCC ×
0.1
–
V
Output reaches 90% of steady-state level, no capacitor on
FILTER pin; TJ = 25; 20 A present on leadframe
–
35
–
µs
12
–
G/A
Nonlinearity
Zero Current Output Voltage
Power-On Time
Magnetic
ELIN
VIOUT(Q)
tPO
Coupling2
Internal Filter Resistance3
–
RF(INT)
1.7
kΩ
1Device
may be operated at higher primary current levels, IP, and ambient, TA , and internal leadframe temperatures, TA , provided that the Maximum Junction Temperature, TJ(max), is not exceeded.
21G = 0.1 mT.
3R
F(INT) forms an RC circuit via the FILTER pin.
COMMON THERMAL CHARACTERISTICS1
Operating Internal Leadframe Temperature
TA
Min.
Typ.
Max.
Units
E range
–40
–
85
°C
L range
–40
–
150
°C
Value
Units
Junction-to-Lead Thermal Resistance2
RθJL
Mounted on the Allegro ASEK 715 evaluation board
5
°C/W
Junction-to-Ambient Thermal Resistance2,3
RθJA
Mounted on the Allegro 85-0322 evaluation board, includes the power
consumed by the board
23
°C/W
1Additional
thermal information is available on the Allegro website.
evaluation board has 1500 mm2 of 2 oz. copper on each side, connected to pins 1 and 2, and to pins 3 and 4, with thermal vias connecting the layers. Performance values include the power consumed by the PCB. Further details on the board are available from the Frequently Asked Questions document on our website.
Further information about board design and thermal performance also can be found in the Applications Information section of this datasheet.
3R
θJA values shown in this table are typical values, measured on the Allegro evaluation board. The actual thermal performance depends on the actual application board
design, the airflow in the application, and thermal interactions between the device and surrounding components through the PCB and the ambient air. To improve
thermal performance, see our applications material on the Allegro website.
2The Allegro
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
5
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
x20A PERFORMANCE CHARACTERISTICS over Range E: TA = –40°C to 85°C1, CF = 1 nF, and VCC = 5 V, unless otherwise specified
Characteristic
Optimized Accuracy Range
Sensitivity
Symbol
Test Conditions
IP
Sens
Over full range of IP, IP applied for 5 ms; TA = 25°C
Noise
Peak-to-peak, TA = 25°C, 2 kHz external filter, 185 mV/A
VNOISE(PP) programmed Sensitivity, CF = 47 nF, COUT = 10 nF, 2 kHz
bandwidth
Zero Current Output Slope
∆VOUT(Q)
Sensitivity Slope
∆Sens
Min.
Typ.
Max.
Units
0
–
20
A
178
185
190
mV/A
–
21
–
mV
mV/°C
TA = –40°C to 25°C
–
0.08
–
TA = 25°C to 150°C
–
0.16
–
mV/°C
TA = –40°C to 25°C
–
0.035
–
mV/A/°C
TA = 25°C to 150°C
Electrical Output Voltage
VOE
IP = 0 A
Total Output Error2
ETOT
IP = 20 A , IP applied for 5 ms; TA = 25°C
–
0.019
–
mV/A/°C
–40
–
40
mV
–
±1.5
–
%
1Device
may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not
exceeded.
2Percentage of I , with I = 20 A. Output filtered.
P
P
x20A PERFORMANCE CHARACTERISTICS over Range L: TA = –40°C to 150°C1, CF = 1 nF, and VCC = 5 V, unless otherwise
specified
Characteristic
Optimized Accuracy Range
Sensitivity
Symbol
IP
Sens
Noise
VNOISE(PP)
Zero Current Output Slope
∆VOUT(Q)
Sensitivity Slope
Electrical Output Voltage
Total Output Error2
Test Conditions
∆Sens
VOE
ETOT
Over full range of IP, IP applied for 5 ms; TA = 25°C
Over full range of IP, TA = –40°C to 150°C
Min.
Typ.
Max.
Units
0
–
20
A
–
185
–
mV/A
161
–
194
mV/A
Peak-to-peak, TA = 25°C, 2 kHz external filter, 185 mV/A
programmed Sensitivity, CF = 47 nF, COUT = 10 nF, 2 kHz
bandwidth
–
21
–
mV
mV/°C
TA = –40°C to 25°C
–
0.08
–
TA = 25°C to 150°C
–
0.16
–
mV/°C
TA = –40°C to 25°C
–
0.035
–
mV/A/°C
TA = 25°C to 150°C
–
0.019
–
mV/A/°C
–60
–
60
mV
IP = 20 A , IP applied for 5 ms; TA = 25°C
–
±1.5
–
%
IP = 20 A , IP applied for 5 ms; TA = –40°C to 150°C
–6
–
6
%
IP = 0 A
1Device
may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not
exceeded.
2Percentage of I , with I = 20 A. Output filtered.
P
P
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
6
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
x30A PERFORMANCE CHARACTERISTICS over Range E: TA = –40°C to 85°C1, CF = 1 nF, and VCC = 5 V, unless otherwise specified
Characteristic
Optimized Accuracy Range
Sensitivity
Symbol
Test Conditions
IP
Sens
Over full range of IP, IP applied for 5 ms; TA = 25°C
Noise
Peak-to-peak, TA = 25°C, 2 kHz external filter, 133 mV/A
VNOISE(PP) programmed Sensitivity, CF = 47 nF, COUT = 10 nF, 2 kHz
bandwidth
Zero Current Output Slope
∆VOUT(Q)
Sensitivity Slope
∆Sens
Min.
Typ.
Max.
Units
0
–
30
A
129
133
137
mV/A
–
15
–
mV
mV/°C
TA = –40°C to 25°C
–
0.06
–
TA = 25°C to 150°C
–
0.1
–
mV/°C
TA = –40°C to 25°C
–
0.007
–
mV/A/°C
TA = 25°C to 150°C
Electrical Output Voltage
VOE
IP = 0 A
Total Output Error2
ETOT
IP = 30 A , IP applied for 5 ms; TA = 25°C
–
–0.025
–
mV/A/°C
–30
–
30
mV
–
±1.5
–
%
1Device
may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not
exceeded.
2Percentage of I , with I = 30 A. Output filtered.
P
P
x30A PERFORMANCE CHARACTERISTICS over Range L: TA = –40°C to 150°C1, CF = 1 nF, and VCC = 5 V, unless otherwise
specified
Characteristic
Optimized Accuracy Range
Sensitivity
Symbol
IP
Sens
Noise
VNOISE(PP)
Zero Current Output Slope
∆VOUT(Q)
Sensitivity Slope
Electrical Output Voltage
Total Output Error2
Test Conditions
∆Sens
VOE
ETOT
Over full range of IP, IP applied for 5 ms; TA = 25°C
Over full range of IP, TA = –40°C to 150°C
Min.
Typ.
Max.
Units
0
–
30
A
–
133
–
mV/A
125
–
137
mV/A
Peak-to-peak, TA = 25°C, 2 kHz external filter, 133 mV/A
programmed Sensitivity, CF = 47 nF, COUT = 10 nF, 2 kHz
bandwidth
–
15
–
mV
mV/°C
TA = –40°C to 25°C
–
0.06
–
TA = 25°C to 150°C
–
0.1
–
mV/°C
TA = –40°C to 25°C
–
0.007
–
mV/A/°C
TA = 25°C to 150°C
–
–0.025
–
mV/A/°C
IP = 0 A, TA = 25ºC
–40
–
40
mV
IP = 0 A, TA = –40ºC to 150ºC
–60
–
60
mV
IP = 30 A , IP applied for 5 ms; TA = 25°C
–
±1.5
–
%
IP = 30 A , IP applied for 5 ms; TA = –40°C to 150°C
–5
–
5
%
1Device
may be operated at higher primary current levels, IP, and ambient temperatures, TA, provided that the Maximum Junction Temperature, TJ(max), is not
exceeded.
2Percentage of I , with I = 30 A. Output filtered.
P
P
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
7
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
CHARACTERISTIC PERFORMANCE
IP = 20 A, unless otherwise specified
Mean Supply Current versus Ambient Temperature
10.5
11.2
10.4
11.0
10.2
10.8
VCC = 5 V
ICC (mA)
Mean ICC (mA)
10.3
10.1
10.0
9.9
10.6
10.4
10.2
9.8
10.0
9.7
9.8
9.6
-50
-25
0
25
Supply Current versus Supply Voltage
50
75
100
125
9.6
4.5
150
4.6
4.7
4.8
4.9
TA (°C)
Magnetic Offset versus Ambient Temperature
5.5
0.25
–1.5
–2.0
–2.5
ELIN (%)
IOM (mA)
5.4
0.30
–1.0
VCC = 5 V; IP = 0 A,
After excursion to 20 A
–3.0
–3.5
0.20
0.15
0.10
–4.0
0.05
–4.5
–5.0
-50
-25
0
25
50
75
100
125
0
–50
150
–25
0
25
75
50
100
125
150
TA (°C)
TA (°C)
Mean Total Output Error versus Ambient Temperature
10
Sensitivity versus Ambient Temperature
188
8
187
6
Sens (mV/A)
4
ETOT (%)
5.3
Nonlinearity versus Ambient Temperature
–0.5
2
0
–2
–4
186
185
184
183
–6
–8
–50
182
–25
0
25
75
50
100
125
150
–50
–25
0
25
TA (°C)
Output Voltage versus Sensed Current
4.5
4.0
3.0
Sens (mV/A)
VCC = 5 V
3.5
TA (°C)
–40
–20
25
85
125
2.5
2.0
1.5
1.0
0.5
0
0
5
10
15
20
25
200.00
198.00
196.00
194.00
192.00
190.00
188.00
186.00
184.00
182.00
180.00
178.00
176.00
174.00
525
125
150
TA (°C)
–40
25
85
150
0
5
10
15
Ip (A)
20
25
0 A Output Voltage Current versus Ambient Temperature
0.140
0.120
520
0.100
IP = 0 A
IP = 0 A
0.080
IOUT(Q) (A)
515
510
505
500
0.060
0.040
0.020
0
495
490
-50
100
Sensitivity versus Sensed Current
IP (A)
0 A Output Voltage versus Ambient Temperature
75
50
TA (°C)
5.0
VIOUT (V)
5.2
0.35
0
VIOUT(Q) (mV)
5.0 5.1
VCC (V)
-0.020
-25
0
25
50
TA (°C)
75
100
125
150
-0.040
-50
-25
0
25
50
75
100
125
150
TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
8
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
CHARACTERISTIC PERFORMANCE
IP = 30 A, unless otherwise specified
Mean Supply Current versus Ambient Temperature
10.1
10.8
10.0
10.6
ICC (mA)
Mean ICC (mA)
9.9
VCC = 5 V
90.8
9.7
10.4
10.2
10.0
9.6
9.8
9.5
9.6
9.4
-50
-25
0
25
50
75
100
125
Supply Current versus Supply Voltage
9.4
4.5
150
4.6
4.7
4.8
4.9
TA (°C)
–0.5
IOM (mA)
5.5
0.25
–1.5
–2.5
ELIN (%)
–2.0
VCC = 5 V; IP = 0 A,
After excursion to 20 A
–3.0
–3.5
–4.0
0.20
VCC = 5 V
0.15
0.10
0.05
–4.5
–5.0
-50
-25
0
25
50
75
100
125
0
–50
150
Mean Total Output Error versus Ambient Temperature
133.5
6
133.0
Sens (mV/A)
8
4
2
0
130.5
–6
130.0
25
75
50
100
125
129.5
–50
150
Output Voltage versus Sensed Current
4.5
Sens (mV/A)
4.0
VCC = 5 V
3.0
TA (°C)
–40
–20
25
85
125
2.5
2.0
1.5
1.0
0.5
5
10
15
20
25
30
35
IP (A)
0 A Output Voltage versus Ambient Temperature
514
150
–25
0
25
75
50
100
125
150
140
139
138
137
136
135
134
133
132
131
130
129
128
127
126
125
Sensitivity versus Sensed Current
TA (°C)
–40
25
85
150
0
5
10
15
25
20
Ip (A)
30
35
0 A Output Voltage Current versus Ambient Temperature
0.080
512
0.060
510
IP = 0 A
508
IOUT(Q) (A)
506
504
502
500
498
IP = 0 A
0.040
0.020
0
-0.020
496
494
-50
125
TA (°C)
5.0
0
100
Sensitivity versus Ambient Temperature
TA (°C)
3.5
75
50
131.5
131.0
0
25
132.0
–4
–25
0
132.5
–2
–8
–50
–25
TA (°C)
TA (°C)
VIOUT (V)
5.4
0.30
–1.0
VIOUT(Q) (mV)
5.3
0.35
0
0
5.2
Nonlinearity versus Ambient Temperature
Magnetic Offset versus Ambient Temperature
ETOT (%)
5.0 5.1
VCC (V)
-25
0
25
50
TA (°C)
75
100
125
150
-0.040
-50
-25
0
25
50
75
100
125
150
TA (°C)
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
9
ACS715
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
DEFINITIONS OF ACCURACY CHARACTERISTICS
Sensitivity (Sens). The change in device output in response to a
1 A change through the primary conductor. The sensitivity is the
product of the magnetic circuit sensitivity (G / A) and the linear
IC amplifier gain (mV/G). The linear IC amplifier gain is programmed at the factory to optimize the sensitivity (mV/A) for the
full-scale current of the device.
Noise (VNOISE). The product of the linear IC amplifier gain
(mV/G) and the noise floor for the Allegro Hall effect linear IC
(≈1 G). The noise floor is derived from the thermal and shot
noise observed in Hall elements. Dividing the noise (mV) by the
sensitivity (mV/A) provides the smallest current that the device is
able to resolve.
Linearity (ELIN). The degree to which the voltage output from
the IC varies in direct proportion to the primary current through
its full-scale amplitude. Nonlinearity in the output can be attributed to the saturation of the flux concentrator approaching the
full-scale current. The following equation is used to derive the
linearity:
{ [
100 1–
(VIOUT_full-scale amperes –VIOUT(Q) )
2 (VIOUT_half-scale amperes – VIOUT(Q))
[{
Accuracy is divided into four areas:
• 0 A at 25°C. Accuracy at the zero current flow at 25°C,
without the effects of temperature.
• 0 A over Δ temperature. Accuracy at the zero current flow
including temperature effects.
• Full-scale current at 25°C. Accuracy at the the full-scale current
at 25°C, without the effects of temperature.
• Full-scale current over Δ temperature. Accuracy at the fullscale current flow including temperature effects.
Ratiometry. The ratiometric feature means that its 0 A output,
VIOUT(Q), (nominally equal to VCC × 0.1) and sensitivity, Sens, are
proportional to its supply voltage, VCC . The following formula is
used to derive the ratiometric change in 0 A output voltage,
ΔVIOUT(Q)RAT (%).
100
VIOUT(Q)VCC / VIOUT(Q)5V
VCC / 5 V
The ratiometric change in sensitivity, ΔSensRAT (%), is defined as:
100
where VIOUT_full-scale amperes = the output voltage (V) when the
sampled current approximates full-scale ±IP .
Quiescent output voltage (VIOUT(Q)). The output of the device
when the primary current is zero. For a unipolar supply voltage,
it nominally remains at VCC × 0.1 . Thus, VCC = 5 V translates
into VIOUT(Q) = 0.5 V. Variation in VIOUT(Q) can be attributed to
the resolution of the Allegro linear IC quiescent voltage trim and
thermal drift.
Electrical offset voltage (VOE). The deviation of the device
output from its ideal quiescent value of VCC × 0.1 due to nonmagnetic causes. To convert this voltage to amperes, divide by the
device sensitivity, Sens.
Accuracy (ETOT). The accuracy represents the maximum deviation of the actual output from its ideal value. This is also known
as the total output error. The accuracy is illustrated graphically in
the output voltage versus current chart at right.
SensVCC / Sens5V
VCC / 5 V
Increasing VIOUT(V)
Accuracy
Over ∆Temp erature
Accuracy
25°C Only
Average
VIOUT
Accuracy
Over ∆Temp erature
Accuracy
25°C Only
30 A
–IP (A)
+IP (A)
Full Scale
0A
Decreasing VIOUT(V)
Figure 1: Output Voltage versus Sampled Current
Accuracy at 0 A and at Full-Scale Current
10
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISITCS
Power-On Time (tPO). When the supply is ramped to its operating voltage, the device requires a finite time to power its internal
components before responding to an input magnetic field.
Power-On Time, tPO , 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, VCC(min), as shown in the
chart at right.
Figure 2: Power-On Time
Rise time (tr). The time interval between a) when the device
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 device, in which ƒ(–3 dB) = 0.35 / tr.
Both tr and tRESPONSE are detrimentally affected by eddy current
losses observed in the conductive IC ground plane.
Primary Current
I (%)
90
Transducer Output
10
0
t
Rise Time, tr
Noise vs. Filter Cap
Power on Time versus External Filter Capacitance
10000
IP = 5 A
IP = 0 A
0
1200
10
20
CF (nF)
30
40
Rise Time versus External Filter Capacitance
CF (nF)
Open
1
4.7
22
47
100
220
470
Expanded in chart at right
}
tr(µs)
800
400
200
0
0.1
1
10
CF (nF)
100
1000
100
10
1
0.01
50
1000
600
Noise versus External Filter Capacitance
1000
Noise(p-p) (mA)
200
180
160
140
120
100
80
60
40
20
0
tr (µs)
3.5
5.8
17.5
73.5
88.2
291.3
623
1120
tr(µs)
tPO (µs)
Figure 3: Rise Time
180
160
140
120
100
80
60
40
20
0
0.1
0.1
1
CF (nF)
10
100
1000
Rise Time versus External Filter Capacitance
1
CF (nF)
10
100
Figure 4: Power-On and Rise Time Characteristics
11
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
CHOPPER STABILIZATION TECHNIQUE
Sample and
Hold
This technique is made possible through the use of a BiCMOS
Chopper Stabilization is an innovative circuit technique that is
used to minimize the offset voltage of a Hall element and an asso- process that allows the use of low-offset and low-noise amplifiers
ciated on-chip amplifier. Allegro patented a Chopper Stabilizain combination with high-density logic integration and sample
tion technique that nearly eliminates Hall IC output drift induced
and hold circuits.
by temperature or package stress effects. This offset reduction
+5 V
VS1
Regulator
technique is based on a signal modulation-demodulation process.
Modulation is used to separate the undesired DC offset signal
CBYP
0.1 µF
Clock/Logic
from the magnetically induced signal in the frequency domain.
8
1
VCC
IP+
Low-Pass
U1
Then, using a low-pass filter, the modulated DC offset is sup7 VElement
Hall
+
OUT
2
LMC6772
Filter
IP+ VIOUT
pressed while the magnetically induced signal passes through
VREF –
ACS715
IP1 the
Amp
the filter. As a result of this chopper stabilization approach,
6
3
FILTER
output voltage from the Hall IC is desensitized to the effects4 IP–
CF
IP–
of temperature and mechanical stress. This technique produces GND 5
Q3
devices that have an extremely stable Electrical Offset Voltage,
2N7002
are immune to thermal stress, and have precise recoverability
R3
Q1
10 kΩ
FDS6675a
after temperature cycling.
R1
100 kΩ
Figure 5: Concept of Chopper Stabilization Technique
VS2
+5 V
CBYP
0.1 µF
1
2
IP
IP+
R1
33 kΩ
VCC
IP+ VIOUT
ACS715
3
4
IP– FILTER
IP–
GND
8
7
1
VOUT
IP2
4
3
6
5
CF
2
RPU
100 kΩ
R2
100 kΩ
–
+
5
+5 V
VCC
IP+
IP+ VIOUT
IP– FILTER
Fault 4 IP–
1
GND
2 U1
LMV7235
6
–
8
5
IP
Q4
6
2N7002
IP– FILTER
4R4
10IP–
kΩ GND 5
R2
100 kΩ
Application 2. 10 A Overcurrent Fault Latch. Fault threshold set by R1
and R2. This circuit latches an overcurrent fault and holds it until the
5 V rail is powered down.
2
IP1
VCC
IP+ VIOUT
ACS715
3
4
IP– FILTER
IP–
GND
3
–
LM321
5
VOUT
4
2
C1
1000 pF
R3
3.3 kΩ
CF
0.01 µF
+5 V
IP+
+
Application 3. This configuration increases gain to 610 mV/A (tested
using the ACS712ELC-05A).
VS1
1
1
RF
1 kΩ
ACS715
3
D1
1N914
R2
100 kΩ
1
VCC
IP+
CF
7
2
IP+ VIOUT
Q2
FDS6675a
Application 4. Control circuit for MOSFET ORing.
R1
100 kΩ
U2
LMC6772
+
7 VOUT
VREF
ACS715
3
CBYP
CBYP 0.1 µF
0.1 µF
8
LOAD
+5 V
CBYP
0.1 µF
8
VREF
1
U1
LMC6772
+
7 VOUT
–
2
IP2
6
5
+5 V
VS2
CF
IP+
VCC
IP+ VIOUT
ACS715
3
4
IP– FILTER
IP–
GND
CBYP
0.1 µF
8
+
7 VOUT
VREF
–
6
5
CF
Q3
2N7002
Q1
FDS6675a
U2
LMC6772
Q4
2N7002
Q2
FDS6675a
R3
10 kΩ
R4
10 kΩ
R2
100 kΩ
R1
100 kΩ
LOAD
Figure 6: Typical Applications
12
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
IMPROVING SENSING SYSTEM ACCURACY USING THE FILTER PIN
In low-frequency sensing applications, it is often advantageous
to add a simple RC filter to the output of the device. Such a lowpass filter improves the signal-to-noise ratio, and therefore the
resolution, of the device output signal. However, the addition of
an RC filter to the output of a sensor IC can result in undesirable
device output attenuation — even for DC signals.
Signal attenuation, ∆VATT , is a result of the resistive divider
effect between the resistance of the external filter, RF (see Application 5), and the input impedance and resistance of the customer
interface circuit, RINTFC. The transfer function of this resistive
divider is given by:
RINTFC
RF + RINTFC
∆VATT = VIOUT
.
Even if RF and RINTFC are designed to match, the two individual
resistance values will most likely drift by different amounts over
temperature. Therefore, signal attenuation will vary as a function
of temperature. Note that, in many cases, the input impedance,
RINTFC , of a typical analog-to-digital converter (ADC) can be as
low as 10 kΩ.
The ACS715 contains an internal resistor, a FILTER pin connection to the printed circuit board, and an internal buffer amplifier. With this circuit architecture, users can implement a simple
RC filter via the addition of a capacitor, CF (see Application 6)
from the FILTER pin to ground. The buffer amplifier inside of
the ACS715 (located after the internal resistor and FILTER pin
connection) eliminates the attenuation caused by the resistive
divider effect described in the equation for ∆VATT. Therefore, the
ACS715 device is ideal for use in high-accuracy applications that
cannot afford the signal attenuation associated with the use of an
external RC low-pass filter.
+5 V
Pin 3 Pin 4
IP–
IP–
VCC
Pin 8
Allegro ACS706
Voltage
Regulator
To all subcircuits
Filter
0.1 µF
Resistive Divider
VIOUT
Pin 7
Dynamic Offset
Cancellation
Application 5. When a low pass filter is constructed externally to a standard Hall effect
device, a resistive divider may exist between
the filter resistor, RF, and the resistance of the
customer interface circuit, RINTFC. This resistive divider will cause excessive attenuation,
as given by the transfer function for ∆VATT.
Amp
Out
N.C.
Pin 6
Input
RF
Application
Interface
Circuit
Low Pass Filter
Temperature
Coefficient
Gain
Offset
CF
RINTFC
Trim Control
GND
Pin 5
IP+
IP+
Pin 1 Pin 2
+5 V
VCC
Pin 8
Allegro ACS715
IP+
Pin 1
IP+
Pin 2
IP–
Pin 3
IP–
Pin 4
Sense Temperature
Coefficient Trim
Buffer Amplifier
and Resistor
Dynamic Offset
Cancellation
Application 6. Using the FILTER
pin provided on the ACS715 eliminates the attenuation effects of the
resistor divider between RF and
RINTFC, shown in Application 5.
Hall Current
Drive
Signal
Recovery
VIOUT
Pin 7
Input
Application
Interface
Circuit
Sense
Trim
0 Ampere
Offset Adjust
RINTFC
GND
Pin 5
FILTER
Pin 6
CF
Figure 7: Typical Applications
13
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
PACKAGE OUTLINE DRAWING
For Reference Only – Not for Tooling Use
(Reference MS-012AA)
Dimensions in millimeters – NOT TO SCALE
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
8°
0°
4.90 ±0.10
1.27
0.65
8
8
0.25
0.17
3.90 ±0.10
5.60
6.00 ±0.20
A
1.04 REF
1
1.75
2
1
1.27
0.40
C
2
PCB Layout Reference View
0.25 BSC
SEATING PLANE
Branded Face
GAUGE PLANE
C
8X
0.10
1.75 MAX
C
NNNNNNN
SEATING
PLANE
PPT-AAA
LLLLL
0.51
0.31
0.25
0.10
1.27 BSC
1
A
Terminal #1 mark area
B
Branding scale and appearance at supplier discretion
C
Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M);
all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances.
B
Standard Branding Reference View
N = Device part number
P = Package Designator
T = Device temperature range
A = Amperage
L = Lot number
Belly Brand = Country of Origin
Figure 8: Package LC, 8-pin SOIC
14
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
Automotive Grade, Fully Integrated, Hall Effect-Based Linear Current Sensor IC
with 2.1 kVRMS Voltage Isolation and a Low-Resistance Current Conductor
ACS715
Revision History
Revision
Revision Date
9
November 16, 2014
10
June 24, 2015
Description of Revision
Update rise time and isolation, IOUT reference data, patents
Revised performance characteristics
Copyright ©2006-2015, Allegro MicroSystems, LLC
The products described herein are protected by U.S. patents: 5,621,319; 7,598,601; and 7,709,754.
Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to
permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that
the information being relied upon is current.
Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the
failure of that life support device or system, or to affect the safety or effectiveness of that device or system.
The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its
use; nor for any infringement of patents or other rights of third parties which may result from its use.
For the latest version of this document, go to our website at:
www.allegromicro.com
15
Allegro MicroSystems, LLC
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com