ACS709
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
Features and Benefits
▪ Industry-leading noise performance with 120 kHz
bandwidth through proprietary amplifier and filter
design techniques
▪ Integrated shield greatly reduces capacitive coupling
from current conductor to die due to high dV/dt, and
prevents offset drift in high-side applications
▪ Small footprint surface-mount QSOP24 package
▪ High isolation voltage, suitable for line-powered
applications
▪ 1.1 mΩ primary conductor resistance for low power loss
▪ User-settable Overcurrent Fault level
▪ Overcurrent Fault signal typically responds to an
overcurrent condition in < 2 μs
▪ Filter pin capacitor sets analog signal bandwidth
▪ ±2% typical output error
▪ 3 to 5.5 V, single supply operation
▪ Factory trimmed sensitivity, quiescent output voltage,
and associated temperature coefficients
▪ Chopper stabilization results in extremely stable
quiescent output voltage
▪ Ratiometric output from supply voltage
Package: 24 pin QSOP (suffix LF)
Description
The Allegro™ ACS709 current sensor IC provides economical
and precise means for current sensing applications in industrial,
automotive, commercial, and communications systems. The
device is offered in a small footprint surface mount package
that allows easy implementation in customer applications.
The ACS709 consists of a precision linear Hall sensor integrated
circuit with a copper conduction path located near the surface
of the silicon die. Applied current flows through the copper
conduction path, and the analog output voltage from the Hall
sensor IC linearly tracks the magnetic field generated by the
applied current. The accuracy of the ACS709 is maximized
with this patented packaging configuration because the Hall
element is situated in extremely close proximity to the current
to be measured.
High level immunity to current conductor dV/dt and stray
electric fields, offered by Allegro proprietary integrated shield
technology, provides low output ripple and low offset drift in
high-side applications.
The voltage on the Overcurrent Input (VOC pin) allows
customers to define an overcurrent fault threshold for the
device. When the current flowing through the copper conduction
path (between the IP+ and IP– pins) exceeds this threshold,
Continued on the next page…
Approximate Scale
Typical Application
1
2
3
4
5
6
IP
7
8
9
10
11
12
ACS709A-DS, Rev. 4
NC 24
IP+
NC 23
Fault_EN
22
IP+
IP+
IP+
IP+
FAULT_EN
ACS709
VOC
VCC
IP+
FAULT
IP–
VIOUT
IP–
FILTER
IP–
VZCR
IP–
GND
RH
VCC
RH, RL
21
19
18
17
330 kΩ
COC
VIOUT
16
15
IP–
NC 14
IP–
NC 13
CF
RL
20
1 nF
A
0.1 µF
B
CF
COC
Sets resistor divider reference for VOC
Noise and bandwidth limiting filter capacitor
Fault delay setting capacitor, 22 nF maximum
A
Use of capacitor required
B
Use of resistor optional
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Description (continued)
the open drain Overcurrent Fault pin will transition to a logic low
state. Factory programming of the linear Hall sensor IC inside of
the ACS709 results in exceptional accuracy in both analog and
digital output signals.
The internal resistance of the copper path used for current sensing is
typically 1.1 mΩ, for low power loss. Also, the current conduction
path is electrically isolated from the low voltage device inputs and
outputs. This allows the ACS709 family of sensor ICs to be used
in applications requiring electrical isolation, without the use of
opto-isolators or other costly isolation techniques.
Applications include:
• Motor control and protection
• Load management and overcurrent detection
• Power conversion and battery monitoring / UPS systems
Selection Guide
IP(LIN)
(A)
Sens (Typ)
(mV/A)
ACS709LLFTR-35BB-T
75
28 (VCC = 5 V)
ACS709LLFTR-20BB-T
37.5
56 (VCC = 5 V)
ACS709LLFTR-10BB-T
24
85 (VCC = 5 V)
ACS709LLFTR-6BB-T
15
90 (VCC = 3.3 V)
Part Number
TA
(°C)
Packing*
–40 to 150
Tape and Reel, 2500 pieces per reel
*Contact Allegro for packing options.
Absolute Maximum Ratings
Characteristic
Rating
Units
VCC
8
V
Filter Pin
VFILTER
8
V
Analog Output Pin
VIOUT
32
V
VOC
8
V
Supply Voltage
Overcurrent Input Pin
¯U¯¯L
¯ ¯T¯ Pin
¯ ¯A
Overcurrent ¯F
Symbol
Notes
V ¯F¯ ¯A
¯U¯¯L¯ ¯T¯
8
V
Fault Enable (FAULT_EN) Pin
VFAULTEN
8
V
Voltage Reference Output Pin
VZCR
8
V
DC Reverse Voltage: Supply Voltage, Filter, Analog
Output, Overcurrent Input, Overcurrent Fault, Fault
Enable, and Voltage Reference Output Pins
VRdcx
–0.5
V
IIOUT(Source)
3
mA
Output Current Source
Output Current Sink
Operating Ambient Temperature
IIOUT(Sink)
TA
Range L
1
mA
–40 to 150
°C
Junction Temperature
TJ(max)
165
°C
Storage Temperature
Tstg
–65 to 170
°C
Isolation Characteristics
Characteristic
Symbol
Notes
Dielectric Strength Test Voltage*
VISO
Agency type-tested for 60 seconds per
UL standard 1577
Working Voltage for Basic Isolation
VWFSI
For basic (single) isolation per UL standard 1577;
for higher continuous voltage ratings, please contact
Allegro
Rating
Unit
2100
VAC
277
VAC
* Allegro does not conduct 60-second testing. It is done only during the UL certification process.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Functional Block Diagram
VCC
Hall
Bias
FAULT_EN
D
Q
CLK
R
POR
POR
FAULT Reset
Drain
–
VOC
+
2VREF
Control
Logic
FAULT
3 mA
Fault
Comparator
–
Sensitivity
Trim
IP+
VZCR
+
VIOUT
Signal
Recovery
RF(INT)
Hall
Amplifier
IP–
VOUT(Q)
Trim
GND
FILTER
Terminal List Table
Number
Pinout Diagram
Name
Description
1 through 6
IP+
Sensed current copper conduction path pins. Terminals for current being sensed;
fused internally, loop to IP– pins; unidirectional or bidirectional current flow.
7 through 12
IP–
Sensed current copper conduction path pins. Terminals for current being sensed;
fused internally, loop to IP+ pins; unidirectional or bidirectional current flow.
IP+ 1
24 NC
13, 14, 23, 24
NC
IP+ 2
23 NC
15
GND
Device ground connection.
IP+ 3
22 FAULT_EN
IP+ 4
21 VOC
16
VZCR
IP+ 5
20 VCC
Voltage Reference Output pin. Zero current (0 A) reference; output voltage on this
pin scales with VCC .
IP+ 6
19 FAULT
17
FILTER
IP– 7
18 VIOUT
Filter pin. Terminal for an external capacitor connected from this pin to GND to set
the device bandwidth.
IP– 8
17 FILTER
18
VIOUT
IP– 9
16 VZCR
Analog Output pin. Output voltage on this pin is proportional to current flowing
through the loop between the IP+ pins and IP– pins.
IP– 10
15 GND
19
¯F¯ ¯A
¯U¯¯
L¯ ¯T¯
IP– 11
14 NC
Overcurrent Fault pin. When current flowing between IP+ pins and IP– pins
exceeds the overcurrent fault threshold, this pin transitions to a logic low state.
IP– 12
13 NC
20
VCC
Supply voltage.
VOC
Overcurrent Input pin. Analog input voltage on this pin sets the overcurrent fault
threshold.
21
22
No connection
¯U¯¯L¯ ¯T¯ when low.
FAULT_EN Enables overcurrent faulting when high. Resets ¯F¯ ¯A
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
ACS709
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
COMMON OPERATING CHARACTERISTICS: Valid at TA = –40°C to 150°C, VCC = 5 V (3.3 V for -6BB version), unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
3
–
5.5
V
ELECTRICAL CHARACTERISTICS
Supply Voltage1
VCC
Nominal Supply Voltage
VCCN
Supply Current
ICC
–
5
–
V
VIOUT open, FAULT pin high, VCC = 5 V
(all versions but -6BB)
–
11
14.5
mA
VIOUT open, FAULT pin high, VCC = 3.3 V
(-6BB version)
–
9
11
mA
Output Capacitance Load
CLOAD
VIOUT pin to GND
–
–
10
nF
Output Resistive Load
RLOAD
VIOUT pin to GND
10
–
–
kΩ
Current flowing from IP+ to IP– pins
–
9.5
–
G/A
Magnetic Coupling from Device Conductor
to Hall Element
MCHALL
RF(INT)
Internal Filter Resistance2
Primary Conductor Resistance
RPRIMARY
–
1.7
–
kΩ
TA = 25°C
–
1.1
–
mΩ
ANALOG OUTPUT SIGNAL CHARACTERISTICS
Full Range Linearity3
ELIN
IP = ±IP0A
–0.75
±0.25
0.75
%
Symmetry4
ESYM
IP = ±IP0A
99.1
100
100.9
%
IP = 0 A, TA = 25°C
–
VCC×0.5
–
V
TA = 25°C, Swing IP from 0 A to IP0A,
no capacitor on FILTER pin, 100 pF from
VIOUT to GND
–
3
–
μs
TA = 25°C, no capacitor on FILTER pin,
100 pF from VIOUT to GND
–
1
–
μs
tRESPONSE
TA = 25°C, Swing IP from 0 A to IP0A,
no capacitor on FILTER pin, 100 pF from
VIOUT to GND
–
4
–
μs
VIOUT Large Signal Bandwidth5
f3dB
–3 dB, TA = 25°C, no capacitor on FILTER
pin, 100 pF from VIOUT to GND
–
120
–
kHz
Power-On Time
tPO
Output reaches 90% of steady-state level,
no capacitor on FILTER pin, TA = 25°C
–
35
–
μs
VOC
VCC×0.25
–
VCC×0.4
V
INCOMP
–
±1
–
A
Switchpoint in VOC safe operating area;
assumes INCOMP = 0 A
–
±5
–
%
¯U¯¯L¯ ¯T¯ pin
1 mA sink current at ¯F¯ ¯A
–
–
0.4
V
Bidirectional Quiescent Output
VOUT(QBI)
TIMING PERFORMANCE CHARACTERISTICS
VIOUT Signal Rise Time
VIOUT Signal Propagation Time
VIOUT Signal Response Time
tr
tPROP
OVERCURRENT CHARACTERISTICS
Setting Voltage for Overcurrent Switchpoint6
Signal Noise at Overcurrent
Comparator Input
Overcurrent Fault Switchpoint Error7,8
EOC
¯U¯¯L
¯ ¯T¯ Pin Output Voltage
Overcurrent ¯F¯ ¯A
V ¯F¯ ¯A
¯U¯¯
L¯ ¯T¯
Fault Enable (FAULT_EN Pin) Input Low
Voltage Threshold
VIL
–
–
0.1 × VCC
V
Fault Enable (FAULT_EN Pin) Input High
Voltage Threshold
VIH
0.8 × VCC
–
–
V
Fault Enable (FAULT_EN Pin) Input
Resistance
RFEI
–
1
–
MΩ
Continued on the next page…
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
ACS709
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
COMMON OPERATING CHARACTERISTICS (continued): Valid at TA = –40°C to 150°C, VCC = 5 V (3.3 V for -6BB version), unless
otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
tFED
Set FAULT_EN to low, VOC = 0.25 × VCC ,
COC = 0 F; then run a DC IP exceeding the
corresponding overcurrent threshold; then
reset FAULT_EN from low to high and
measure the delay from the rising edge of
¯U¯¯L¯ ¯T¯
FAULT_EN to the falling edge of ¯F¯ ¯A
–
15
–
µs
Overcurrent Fault Response Time
tOC
FAULT_EN set to high for a minimum
of 20 µs before the overcurrent event;
switchpoint set at VOC = 0.25 × VCC ;
delay from IP exceeding overcurrent
fault threshold to V ¯F¯ ¯A
¯U¯¯L¯ ¯T¯ 0.8 × VCC , RPU = 330 kΩ
–
500
–
ns
Overcurrent Fault Reset Hold Time
tOCH
Time from VFAULTEN pin < VIL to reset of
fault latch; see Functional Block Diagram
–
250
–
ns
Overcurrent Input Pin Resistance
ROC
TA = 25°C, VOC pin to GND
2
–
–
MΩ
Voltage Reference Output
VZCR
TA = 25 °C
–
0.5 × VCC
–
V
Voltage Reference Output Load Current
IZCR
OVERCURRENT CHARACTERISTICS (continued)
Fault Enable (FAULT_EN Pin) Delay9
VOLTAGE REFERENCE CHARACTERISTICS
Voltage Reference Output Drift
∆VZCR
Source current
3
–
–
mA
Sink current
50
–
–
µA
–
±10
–
mV
1 Devices
are trimmed for maximum accuracy at VCC = 5 V. The ratiometry feature of the device allows operation over the full VCC range; however, accuracy
may be slightly degraded for VCC values other than 5 V. Contact the Allegro factory for applications that require maximum accuracy for VCC = 3.3 V.
2R
F(INT) forms an RC circuit via the FILTER pin.
3 This parameter can drift by as much as 0.25% over the lifetime of this product.
4 This parameter can drift by as much as 0.3% over the lifetime of this product.
5 Calculated using the formula f
3dB = 0.35 / tr .
6 See page 8 on how to set overcurrent fault switchpoint.
7 Switchpoint can be lower at the expense of switchpoint accuracy.
8 This error specification does not include the effect of noise. See the I
NCOMP specification in order to factor in the additional influence of noise on the
fault switchpoint.
9 Fault Enable Delay is designed to avoid false tripping of an Overcurrent (OC) fault at power-up. A 15 µs (typical) delay will always be needed, every
time FAULT_EN is raised from low to high, before the device is ready for responding to any overcurrent event.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
X6BB PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Optimized Accuracy Range
IP(OA)
–6.5
–
6.5
A
Linear Sensing Range
IP(LIN)
–15
–
15
A
–
2.5
–
mV
Performance Characteristics at VCC = 3.3 V
Noise1
VNOISE(rms) TA = 25°C, Sens = 90 mV/A, Cf = 0, CLOAD = 4.7 nF, RLOAD open
IP = 6.5 A, TA = 25°C
Sensitivity2,3
Sens
–
90
–
mV/A
IP = 6.5 A, TA = 25°C to 150°C
85
–
95
mV/A
IP = 6.5 A, TA = – 40°C to 25°C
83
–
97
mV/A
–
±5
–
mV
IP = 0 A, TA = 25°C
Electrical Offset
Voltage2
Total Output Error2,4
VOE
ETOT
IP = 0 A, TA = 25°C to 150°C
–30
–
30
mV
IP = 0 A, TA = – 40°C to 25°C
–45
–
45
mV
Tested at IP = 6.5 A , IP applied for 5 ms, TA = 25°C to 150°C
–
±2
–
%
Tested at IP = 6.5 A , IP applied for 5 ms, TA = – 40°C to 25°C
–
±4
–
%
1V
pk-pk noise (6 sigma noise) is equal to 6 × VNOISE(rms). Lower noise levels than this can be achieved by using Cf for applications requiring narrower
bandwidth. See Characteristic Performance page for graphs of noise versus Cf and bandwidth versus Cf.
2 See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3 This parameter can drift by as much as 1.75% over lifetime of the product.
4 This parameter can drift by as much as 2.5% over lifetime of the product.
X10BB PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless otherwise specified
Min.
Typ.
Max.
Units
Optimized Accuracy Range
Characteristic
Symbol
IP(OA)
Test Conditions
–10
–
10
A
Linear Sensing Range
IP(LIN)
–24
–
24
A
–
2.3
–
mV
–
85
–
mV/A
IP = 10 A, TA = 25°C to 150°C
82
85
88
mV/A
IP = 10 A, TA = – 40°C to 25°C
80
85
90
mV/A
–
±5
–
mV
Performance Characteristics at VCC = 5 V
Noise1
VNOISE(rms) TA = 25°C, Sens = 85 mV/A, Cf = 0, CLOAD = 4.7 nF, RLOAD open
IP = 10 A, TA = 25°C
Sensitivity2,3
Sens
IP = 0 A, TA = 25°C
Electrical Offset
Voltage2
Total Output Error2,4
VOE
ETOT
IP = 0 A, TA = 25°C to 150°C
–30
–
30
mV
IP = 0 A, TA = – 40°C to 25°C
–45
–
45
mV
Tested at IP =10 A , IP applied for 5 ms, TA = 25°C to 150°C
–
±2
–
%
Tested at IP =10 A , IP applied for 5 ms, TA = – 40°C to 25°C
–
±4
–
%
1V
pk-pk noise (6 sigma noise) is equal to 6 × VNOISE(rms). Lower noise levels than this can be achieved by using Cf for applications requiring narrower
bandwidth. See Characteristic Performance page for graphs of noise versus Cf and bandwidth versus Cf.
2 See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3 This parameter can drift by as much as 1.75% over lifetime of the product.
4This parameter can drift by as much as 2.5% over lifetime of the product.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
X20BB PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Optimized Accuracy Range
IP(OA)
–20
–
20
A
Linear Sensing Range
IP(LIN)
–37.5
–
37.5
A
–
1.50
–
mV
Performance Characteristics at VCC = 5 V
Noise1
VNOISE(rms) TA = 25°C, Sens = 56 mV/A, Cf = 0, CLOAD = 4.7 nF, RLOAD open
IP = 12.5 A, TA = 25°C
Sensitivity2,3
Sens
–
56
–
mV/A
IP = 12.5 A, TA = 25°C to 150°C
54.5
–
58
mV/A
IP = 12.5 A, TA = – 40°C to 25°C
54.5
–
58.5
mV/A
–
±5
–
mV
IP = 0 A, TA = 25°C
Electrical Offset
Voltage2
Total Output Error2,4
VOE
ETOT
IP = 0 A, TA = 25°C to 150°C
–25
–
25
mV
IP = 0 A, TA = – 40°C to 25°C
–40
–
40
mV
Tested at IP =12.5 A , IP applied for 5 ms, TA = 25°C to 150°C
–
±2
–
%
Tested at IP =12.5 A , IP applied for 5 ms, TA = – 40°C to 25°C
–
±3
–
%
1V
pk-pk noise (6 sigma noise) is equal to 6 × VNOISE(rms). Lower noise levels than this can be achieved by using Cf for applications requiring narrower
bandwidth. See Characteristic Performance page for graphs of noise versus Cf and bandwidth versus Cf.
2 See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3 This parameter can drift by as much as 1.75% over lifetime of the product.
4 This parameter can drift by as much as 2.5% over lifetime of the product.
X35BB PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless otherwise specified
Min.
Typ.
Max.
Units
Optimized Accuracy Range
Characteristic
Symbol
IP(OA)
Test Conditions
–37.5
–
37.5
A
Linear Sensing Range
IP(LIN)
–75
–
75
A
–
1
–
mV
–
28
–
mV/A
IP = 25 A, TA = 25°C to 150°C
27
–
29.5
mV/A
IP = 25 A, TA = – 40°C to 25°C
27
–
29.5
mV/A
–
±5
–
mV
IP = 0 A, TA = 25°C to 150°C
–25
–
25
mV
IP = 0 A, TA = – 40°C to 25°C
–40
–
40
mV
Tested at IP = 25 A , IP applied for 5 ms, TA = 25°C to 150°C
–
±3
–
%
Tested at IP = 25 A , IP applied for 5 ms, TA = – 40°C to 25°C
–
±3
–
%
Performance Characteristics at VCC = 5 V
Noise1
VNOISE(rms) TA = 25°C, Sens = 28 mV/A, Cf = 0, CLOAD = 4.7 nF, RLOAD open
IP = 25 A, TA = 25°C
Sensitivity2,3
Sens
IP = 0 A, TA = 25°C
Electrical Offset
Voltage2
Total Output Error2,4
VOE
ETOT
1V
pk-pk
noise (6 sigma noise) is equal to 6 × VNOISE(rms). Lower noise levels than this can be achieved by using Cf for applications requiring narrower
bandwidth. See Characteristic Performance page for graphs of noise versus Cf and bandwidth versus Cf.
2 See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3 This parameter can drift by as much as 1.75% over lifetime of the product.
4 This parameter can drift by as much as 2.5% over lifetime of the product.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Thermal Characteristics
Characteristic
Symbol
Steady State Package Thermal Resistance
Transient Package Thermal Resistance
Test Conditions
Value
Units
RθJA
Tested with 30 A DC current and based on ACS709 demo
board in 1 cu. ft. of still air. Please refer to product FAQs
page on Allegro web site for detailed information on
ACS709 demo board.
21
ºC/W
RTθJA
Tested with 30 A DC current and based on ACS709 demo
board in 1 cu. ft. of still air. Please refer to product FAQs
page on Allegro web site for detailed information on
ACS709 demo board.
See graph
ºC/W
ACS709 Transient Package Thermal Resistance
On 85--0444 Demo Board (No Al Plate)
22
20
Thermal Resistance (°C/W)
18
16
14
12
10
8
6
4
2
0
0.01
0.1
1
10
100
1000
Time (Sec)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Characteristic Performance
ACS709 Bandwidth versus External Capacitor Value, CF
Capacitor connected between FILTER pin and GND
1000
Bandwidth (kHz)
100
10
1
0.1
0.01
0.1
1
10
100
1000
Capacitance (nF)
ACS709 Noise versus External Capacitor Value, CF
Capacitor connected between FILTER pin and GND
1000
900
900
800
RMS Noise (µV)
RMS Noise (µV)
ACS709x-35B
V CC = 5 V
800
700
600
700
600
500
400
500
400
ACS709x-35B
V CC = 3.3 V
0
10
20
30
40
300
50
0
10
Capacitance (nF)
ACS709x-20B
V CC = 5 V
1400
1400
1200
1200
1000
800
600
400
200
0
30
40
50
40
50
ACS709x-20B
V CC = 3.3 V
1600
RMS Noise (µV)
RMS Noise (µV)
1600
20
Capacitance (nF)
1000
800
600
400
200
0
10
20
30
Capacitance (nF)
40
50
0
0
10
20
30
Capacitance (nF)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Characteristic Performance Data
Data taken using the ACS709-6BB, VCC = 3.3 V
Accuracy Data
Electrical Offset Voltage versus Ambient Temperature
Sensitivity versus Ambient Temperature
93.0
20
92.0
Sens (mV/A)
30
VOE (mV)
10
0
-10
91.0
90.0
89.0
88.0
-20
87.0
-30
86.0
-40
–50
-25
0
25
50
75
100
125
85.0
–50
150
-25
0
25
TA (°C)
Nonlinearity versus Ambient Temperature
100
125
150
Symmetry versus Ambient Temperature
0.40
100.3
0.30
100.2
0.20
100.1
ESYM (%)
100.4
0.10
0
100.0
99.9
-0.10
99.8
-0.20
99.7
-0.30
99.6
99.5
-25
0
25
50
75
100
125
150
–50
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Total Output Error versus Ambient Temperature
4
2
0
ETOT (%)
ELIN (%)
75
TA (°C)
0.50
-0.40
–50
50
-2
-4
-6
-8
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Mean
Typical Minimum Limit
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10
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Characteristic Performance Data
Data taken using the ACS709-10BB, VCC = 5 V
Accuracy Data
Electrical Offset Voltage versus Ambient Temperature
Sensitivity versus Ambient Temperature
86.5
30
86.0
Sens (mV/A)
20
VOE (mV)
10
0
-10
-20
85.0
84.5
84.0
83.5
83.0
-30
-40
–50
85.5
82.5
-25
0
25
50
75
100
125
82.0
–50
150
-25
0
25
TA (°C)
Nonlinearity versus Ambient Temperature
100
125
150
Symmetry versus Ambient Temperature
100.5
0.20
100.4
100.3
0.10
ESYM (%)
0
-0.10
-0.20
100.2
100.1
100.0
99.9
99.8
-0.30
99.7
-0.40
99.6
-25
0
25
50
75
100
125
99.5
–50
150
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Total Output Error versus Ambient Temperature
3.00
2.00
1.00
0
ETOT (%)
ELIN (%)
75
TA (°C)
0.30
-0.50
–50
50
-1.00
-2.00
-3.00
-4.00
-5.00
-6.00
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Mean
Typical Minimum Limit
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11
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Characteristic Performance Data
Data taken using the ACS709-20BB, VCC = 5 V
Accuracy Data
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
–50
Sensitivity versus Ambient Temperature
58.0
57.5
Sens (mV/A)
VOE (mV)
Electrical Offset Voltage versus Ambient Temperature
57.0
56.5
56.0
55.5
-25
0
25
50
75
100
125
55.0
–50
150
-25
0
25
TA (°C)
Nonlinearity versus Ambient Temperature
100
125
150
Symmetry versus Ambient Temperature
100.8
0.15
100.6
0.10
ESYM (%)
0.05
0
-0.05
-0.10
-0.15
100.4
100.2
100.0
99.8
-0.20
99.6
-0.25
99.4
-25
0
25
50
75
100
125
150
–50
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Total Output Error versus Ambient Temperature
4
3
2
ETOT (%)
ELIN (%)
75
TA (°C)
0.20
-0.30
–50
50
1
0
-1
-2
-3
-4
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Mean
Typical Minimum Limit
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12
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Characteristic Performance Data
Data taken using the ACS709-35BB, VCC = 5 V
Accuracy Data
Sensitivity versus Ambient Temperature
20
29.0
15
28.8
10
28.6
Sens (mV/A)
VOE (mV)
Electrical Offset Voltage versus Ambient Temperature
5
0
-5
-10
28.4
28.2
28.0
-15
27.8
-20
27.6
-25
–50
-25
0
25
50
75
100
125
27.4
–50
150
-25
0
25
TA (°C)
Nonlinearity versus Ambient Temperature
100
125
150
Symmetry versus Ambient Temperature
101.0
100.8
0.20
100.6
ESYM (%)
0.10
0
-0.10
100.4
100.2
100.0
99.8
99.6
99.4
-0.20
99.2
-25
0
25
50
75
100
125
99.0
–50
150
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Total Output Error versus Ambient Temperature
4
3
2
ETOT (%)
ELIN (%)
75
TA (°C)
0.30
-0.30
–50
50
1
0
-1
-2
-3
-4
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Mean
Typical Minimum Limit
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13
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Setting Overcurrent Fault Switchpoint
Setting 20BB and 35BB Versions
The VOC needed for setting the overcurrent fault
switchpoint can be calculated as follows:
VOC = Sens × | IOC | ,
where VOC is in mV, Sens in mV/A, and IOC (overcurrent fault switchpoint) in A.
| Ioc | is the overcurrent fault switchpoint for a bidirectional (AC) current, which means a bi-directional
device will have two symmetrical overcurrent fault
switchpoints, +IOC and –IOC .
See the following graph for IOC and VOC ranges.
IOC versus VOC
(20BB and 35BB Versions)
IOC
0.4 VCC / Sens
Not in Valid Range
In Valid Range
0.25 VCC / Sens
0
0. 25 VCC
– 0.25 VCC / Sens
0. 4 VCC
VOC
– 0.4 VCC / Sens
Example: For ACS709LLFTR-35BB-T, if required overcurrent fault switchpoint is 50 A, and VCC = 5 V, then the
required VOC can be calculated as follows:
VOC = Sens × IOC = 28 × 50 = 1400 (mV)
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14
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Setting 10BB and 6BB Versions
The VOC needed for setting the overcurrent fault
switchpoint can be calculated as follows:
VOC = 1.17 × Sens × | IOC | ,
where VOC is in mV, Sens in mV/A, and IOC (overcurrent fault switchpoint) in A.
| Ioc | is the overcurrent fault switchpoint for a bidirectional (AC) current, which means a bi-directional
sensor will have two symmetrical overcurrent fault
switchpoints, +IOC and –IOC .
See the following graph for IOC and VOC ranges.
IOC versus VOC
(10BB and 6BB Versions)
IOC
0.4 VCC / (1.17 × Sens)
Not Valid Range
Valid Range
0.25 VCC / (1.17 × Sens)
0
0.25 VCC
– 0.25 VCC / (1.17 × Sens)
0.4 VCC
VOC
– 0.4 VCC / (1.17 × Sens)
Example: For ACS709LLFTR-6BB-T, if required overcurrent fault switchpoint is 10 A, and VCC = 3.3 V, then the
required VOC can be calculated as follows:
VOC = 1.17 × Sens × IOC = 1.17 × 90 × 10 = 1053 (mV)
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15
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Functional Description
Overcurrent Fault Operation
The primary concern with high-speed fault detection is that noise
may cause false tripping. Various applications have or need to
be able to ignore certain faults that are due to switching noise
or other parasitic phenomena, which are application dependant.
The problem with simply trying to filter out this noise up front is
that in high-speed applications, with asymmetric noise, the act of
filtering introduces an error into the measurement. To get around
this issue, and allow the user to prevent the fault signal from
¯¯U¯¯L¯¯T¯
being latched by noise, a circuit was designed to slew the ¯F¯A
pin voltage based on the value of the capacitor from that pin to
ground. Once the voltage on the pin falls below 2 V, as established by an internal reference, the fault output is latched and
pulled to ground quickly with an internal N-channel MOSFET.
Fault Walk-through
The following walk-through references various sections and
attributes in the figure below. This figure shows different
fault set/reset scenarios and how they relate to the voltages on
the ¯F¯A¯¯U¯¯L¯¯T¯ pin, FAULT_EN pin, and the internal Overcurrent
(OC) Fault node, which is invisible to the customer.
1. Because the device is enabled (FAULT_EN is high for a minimum period of time, the Fault Enable Delay, tFED , 15 µs typical)
¯¯U¯¯L
¯¯T¯ pin starts
and there is an OC fault condition, the device ¯F¯A
discharging.
VCC
FAULT
(Output)
2V
1
¯¯U
¯¯L¯¯T¯ pin voltage reaches approximately 2 V, the
2. When the ¯F¯A
¯
fault is latched, and an internal NMOS device pulls the ¯F¯A¯¯U¯¯L¯¯T
pin voltage to approximately 0 V. The rate at which the ¯F¯A¯¯U¯¯L¯¯T¯
pin slews downward (see [4] in the figure) is dependent on the
¯¯T¯ pin.
external capacitor, COC, on the ¯F¯A¯¯U¯¯L
¯ pin starts
3. When the FAULT_EN pin is brought low, the ¯F¯A¯¯U¯¯L¯¯T
resetting if no OC Fault condition exists. The internal NMOS
pull-down turns off and an internal PMOS pull-up turns on (see
[7] if the OC Fault condition still exists).
4. The slope, and thus the delay, on the fault is controlled by the
¯¯L¯¯T¯ pin to ground. During this
capacitor, COC, placed on the ¯F¯A¯¯U
portion of the fault (when the ¯F¯A¯¯U¯¯L¯¯T¯ pin is between VCC and
2 V), there is a 3 mA constant current sink, which discharges
COC. The length of the fault delay, t, is equal to:
t=
where VCC is the device power supply voltage.
tFED
6
1
6
4
8
4
5
2
(1)
¯¯L¯¯T¯ pin did not reach the 2 V latch point before the
5. The ¯F¯A¯¯U
OC fault condition cleared. Because of this, the fixed 3 mA
current sink turns off, and the internal PMOS pull-up turns on to
¯¯T¯ pin.
recharge COC through the ¯F¯A¯¯U¯¯L
1
4
COC ( VCC – 2 V )
3 mA
4
2
6
2
7
0V
3
Time
FAULT_EN
(Input)
OC Fault
Condition
(Active High)
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High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
6. This curve shows VCC charging external capacitor COC
through the internal PMOS pull-up. The slope is determined
by COC.
7. When the FAULT_EN pin is brought low, if the fault condi¯¯L¯¯T¯ pin will stay low until
tion still exists, the latched ¯F¯A¯¯U
the fault condition is removed, then it will start resetting.
8. At this point there is a fault condition, and the part is enabled
¯ pin can charge to VCC. This shortens the
before the ¯F¯A¯¯U¯¯L¯¯T
user-set delay, so the fault is latched earlier. The new delay
time can be calculated by equation 1, after substituting the
voltage seen on the ¯F¯A¯¯U¯¯L¯¯T¯ pin for VCC.
Chopper Stabilization Technique
Chopper Stabilization is an innovative circuit technique that is
used to minimize the offset voltage of a Hall element and an associated on-chip amplifier. Allegro patented a Chopper Stabilization technique that nearly eliminates Hall IC output drift induced
by temperature or package stress effects. This offset reduction
technique is based on a signal modulation-demodulation process.
Modulation is used to separate the undesired dc offset signal from
the magnetically induced signal in the frequency domain. Then,
using a low-pass filter, the modulated DC offset is suppressed
while the magnetically induced signal passes through the filter.
As a result of this chopper stabilization approach, the output
voltage from the Hall IC is desensitized to the effects of temperature and mechanical stress. This technique produces devices that
have an extremely stable Electrical Offset Voltage, are immune to
thermal stress, and have precise recoverability after temperature
cycling.
This technique is made possible through the use of a BiCMOS
process that allows the use of low-offset and low-noise amplifiers
in combination with high-density logic integration and sample
and hold circuits.
Regulator
Clock/Logic
Amp
Sample and
Hold
Hall Element
Low-Pass
Filter
Concept of Chopper Stabilization Technique
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ACS709
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
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 device 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_1/2 full-scale amperes – VIOUT(Q) )
[{
Accuracy is divided into four areas:
• 0 A at 25°C. Accuracy of sensing zero current flow at 25°C,
without the effects of temperature.
• 0 A over Δ temperature. Accuracy of sensing zero current
flow including temperature effects.
• Full-scale current at 25°C. Accuracy of sensing the full-scale
current at 25°C, without the effects of temperature.
• Full-scale current over Δ temperature. Accuracy of sensing fullscale current flow including temperature effects.
Ratiometry. The ratiometric feature means that its 0 A output,
VIOUT(Q), (nominally equal to VCC/2) 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
VCC / 5 V
The ratiometric change in sensitivity, ΔSensRAT (%), is defined as:
where VIOUT_full-scale amperes = the output voltage (V) when the
sensed current approximates full-scale ±IP .
100
Symmetry (ESYM). The degree to which the absolute voltage
output from the device varies in proportion to either a positive
or negative full-scale primary current. The following formula is
used to derive symmetry:
100
VIOUT(Q)VCC / VIOUT(Q)5V
SensVCC / Sens5V
VCC / 5 V
Output Voltage versus Sensed Current
Accuracy at 0 A and at Full-Scale Current
Increasing VIOUT(V)
Accuracy
Over ∆Temp erature
VIOUT_+ full-scale amperes – VIOUT(Q)
VIOUT(Q) – VIOUT_–full-scale amperes
Accuracy
25°C Only
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 0.5×VCC. For example, in the case of a
bidirectional output device, VCC = 5 V translates into VIOUT(Q) =
2.5 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 voltage 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 ouput error. The accuracy is illustrated graphically in
the output voltage versus current chart at right. Note that error is
directly measured during final test at Allegro.
Average
VIOUT
Accuracy
Over ∆Temp erature
IP(min)
Accuracy
25°C Only
–IP (A)
+IP (A)
Full Scale
IP(max)
0A
Accuracy
25°C Only
Accuracy
Over ∆Temp erature
Decreasing VIOUT(V)
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18
ACS709
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
Definitions of Dynamic Response Characteristics
I (%)
Propagation delay (tPROP). The time required for the device
output to reflect a change in the primary current signal. Propagation delay is attributed to inductive loading within the linear IC
package, as well as in the inductive loop formed by the primary
conductor geometry. Propagation delay can be considered as a
fixed time offset and may be compensated.
Primary Current
90
Transducer Output
0
Propagation Time, tPROP
I (%)
Response time (tRESPONSE). The time interval between a) when
the primary current signal reaches 90% of its final value, and b)
when the device reaches 90% of its output corresponding to the
applied current.
Primary Current
90
Transducer Output
0
Response Time, tRESPONSE
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 current sensor IC, 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.
t
I (%)
t
Primary Current
90
Transducer Output
10
0
Rise Time, tr
t
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19
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Package LF, 24-pin QSOP
8º
0º
8.66 ±0.10
24
0.25
0.15
3.91 ±0.10
2.30
5.00
5.99 ±0.20
A
1
1.27
0.41
2
0.25 BSC
Branded Face
24X
1.75 MAX
0.20 C
0.30
0.20
0.635 BSC
1.04 REF
SEATING
PLANE
C
0.40
B
SEATING PLANE
GAUGE PLANE
0.25 MAX
TLF-AAA
LLLLLLLLLLL
A Terminal #1 mark area
All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances
C Branding scale and appearance at supplier discretion
PCB Layout Reference View
NNNNNNNNNNNNN
For Reference Only, not for tooling use (reference JEDEC MO-137 AE)
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
B Reference pad layout (reference IPC7351 SOP63P600X175-24M)
0.635
C
Standard Branding Reference View
N = Device part number
T = Temperature code
LF = (Literal) Package type
A = Amperage
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20
High-Bandwidth, Fast Fault Response Current Sensor IC
in Thermally Enhanced Package
ACS709
Revision History
Revision
Revision Date
3
June 6, 2014
4
February 8, 2016
Description of Revision
Added 10BB and 6BB parts
Updated Common Operating Characteristics and Supply Current in electrical characteristics table
Copyright ©2008-2016, Allegro MicroSystems, LLC
The products described herein are protected by U.S. patents: 7,166,807; 7,425,821; 7,573,393; and 7,598,601.
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 any devices or systems, including but not limited to life support devices or systems, in which a failure of
Allegro’s product can reasonably be expected to cause bodily harm.
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, visit our website:
www.allegromicro.com
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