ACS709LLFTR-20BB-T [ALLEGRO]
High Bandwidth, Fast Fault Response Current Sensor IC In Thermally Enhanced Package; 高带宽，快速故障响应电流传感器IC采用散热增强型封装
| 型号： | ACS709LLFTR-20BB-T |
| 厂家： | 
ALLEGRO MICROSYSTEMS |
| 描述： | High Bandwidth, Fast Fault Response Current Sensor IC In Thermally Enhanced Package |
| 文件： | 总16页 (文件大小：467K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ACS709
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
Features and Benefits
Description
▪ Industry-leading noise performance with 120 kHz
bandwidth through proprietary amplifier and filter
design techniques
TheAllegro® ACS709 current sensor IC provides economical
andprecisemeansforcurrentsensingapplicationsinindustrial,
automotive, commercial, and communications systems. The
device is offered in a small footprint surface mount package
that allows easy implementation in customer applications.
▪ 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
▪ 2100 VRMS isolation voltage between primary current
path and sensor IC electronics
▪ 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
TheACS709consistsofaprecisionlinearHallsensorintegrated
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.
▪ 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
High level immunity to current conductor dV/dt and stray
electric fields, offered byAllegro proprietary integrated shield
technology, guarantees 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.Whenthecurrentflowingthroughthecopperconduction
path (between the IP+ and IP– pins) exceeds this threshold,
Package: 24 pin QSOP (suffix LF)
Continued on the next page…
Approximate Scale
Typical Application
1
2
24
IP+
IP+
IP+
IP+
IP+
IP+
IP–
IP–
IP–
IP–
IP–
IP–
NC
NC
VCC
23
22
Fault_EN
RH
3
FAULT_EN
VOC
RH, RL Sets resistor divider reference for VOC
4
21
20
19
18
17
16
15
5
ACS709
RL
CF
COC
A
Noise and bandwidth limiting filter capacitor
Fault delay setting capacitor, 22 nF maximum
Use of capacitor required
VCC
FAULT
VIOUT
FILTER
VZCR
GND
6
330 kΩ
IP
C
7
OC
0.1 μF
B
VIOUT
8
9
C
Use of resistor optional
B
F
10
11
12
1 nF
A
14
13
NC
NC
ACS709-DS
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Description (continued)
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.
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.
Applications include:
• Motor control and protection
• Load management and overcurrent detection
• Power conversion and battery monitoring / UPS systems
Theinternalresistanceofthecopperpathusedforcurrentsensingis
typically 1.1 mꢀ, for low power loss. Also, the current conduction
path is electrically isolated from the low voltage device inputs and
Selection Guide
Sens
(Typ at VCC = 5 V)
(mV/A)
IP(LIN)
(A)
TA
(°C)
Part Number
Packing*
ACS709LLFTR-35BB-T
ACS709LLFTR-20BB-T
75
28
56
–40 to 150
Tape and Reel, 2500 pieces per reel
37.5
*Contact Allegro for packing options.
Absolute Maximum Ratings
Characteristic
Symbol
VCC
Notes
Rating
Units
Supply Voltage
8
8
V
V
V
V
V
V
V
Filter Pin
VFILTER
VIOUT
VOC
Analog Output Pin
Overcurrent Input Pin
32
8
¯¯¯¯¯¯¯¯¯
Overcurrent FAULT Pin
V¯¯¯¯¯¯¯¯¯
8
FAULT
Fault Enable (FAULT_EN) Pin
Voltage Reference Output Pin
VFAULTEN
VZCR
8
8
DC Reverse Voltage: Supply Voltage, Filter, Analog
Output, Overcurrent Input, Overcurrent Fault, Fault
Enable, and Voltage Reference Output Pins
VRdcx
–0.5
V
Isolation Voltage
VISO
IIOUT(Source)
IIOUT(Sink)
TA
60 Hz AC, TA = 25°C, 1 minute
2100
VAC
mA
mA
°C
Output Current Source
Output Current Sink
3
1
Operating Ambient Temperature
Junction Temperature
Range L
–40 to 150
165
TJ(max)
°C
Storage Temperature
Tstg
–65 to 170
°C
Allegro MicroSystems, Inc.
115 Northeast Cutoff
2
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Functional Block Diagram
VCC
D
Q
CLK
R
POR
Hall
Bias
POR
FAULT Reset
FAULT_EN
VOC
Drain
–
+
FAULT
2VREF
Control
Logic
3 mA
Fault
Comparator
VZCR
–
+
Sensitivity
Trim
IP+
VIOUT
Signal
Recovery
RF(INT)
Hall
Amplifier
IP–
VOUT(Q)
Trim
GND
FILTER
Terminal List Table
Number
Name
Description
Sensed current copper conduction path pins. Terminals for current being sensed;
fused internally, loop to IP– pins; unidirectional or bidirectional current flow.
1 through 6
IP+
Pin-out Diagram
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–
13, 14, 23, 24
15
NC
No connection
24 NC
IP+
IP+
IP+
IP+
IP+
IP+
IP–
IP–
IP–
1
2
3
4
5
6
7
8
9
23 NC
GND
Device ground connection.
22 FAULT_EN
21 VOC
20 VCC
19 FAULT
18 VIOUT
17 FILTER
16 VZCR
15 GND
14 NC
Voltage Reference Output pin. Zero current (0 A) reference; output voltage on this
pin scales with VCC
16
17
18
VZCR
FILTER
VIOUT
.
Filter pin. Terminal for an external capacitor connected from this pin to GND to set
the device bandwidth.
Analog Output pin. Output voltage on this pin is proportional to current flowing
through the loop between the IP+ pins and IP– pins.
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.
¯¯¯¯¯¯¯¯¯
FAULT
19
20
21
IP– 10
IP– 11
IP– 12
VCC
VOC
Supply voltage.
13 NC
Overcurrent Input pin. Analog input voltage on this pin sets the overcurrent fault
threshold.
¯¯¯¯¯¯¯¯¯
22
FAULT_EN Enables overcurrent faulting when high. Resets FAULT when low.
Allegro MicroSystems, Inc.
115 Northeast Cutoff
3
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
COMMON OPERATING CHARACTERISTICS Valid at TA = –40°C to 150°C, VCC= 5 V, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
ELECTRICAL CHARACTERISTICS
Supply Voltage1
VCC
3
–
–
5
5.5
–
V
V
Nominal Supply Voltage
VCCN
¯¯¯¯¯¯¯¯¯
Supply Current
ICC
VIOUT open, FAULT pin high
–
–
11
–
14.5
10
–
mA
nF
Output Capacitance Load
Output Resistive Load
CLOAD
RLOAD
VIOUT pin to GND
VIOUT pin to GND
10
–
kꢀ
Magnetic Coupling from Device Conductor
to Hall Element
MCHALL
Current flowing from IP+ to IP– pins
–
9.5
–
G/A
Internal Filter Resistance2
RF(INT)
–
–
1.7
1.1
–
–
kΩ
Primary Conductor Resistance
RPRIMARY
TA = 25°C
mꢀ
ANALOG OUTPUT SIGNAL CHARACTERISTICS
Full Range Linearity3
Symmetry4
ELIN
IP = ±IP0A
–0.75
99.1
–
±0.25
100
0.75
100.9
–
%
%
V
ESYM
IP = ±IP0A
Bidirectional Quiescent Output
VOUT(QBI)
IP = 0 A, TA = 25°C
VCC×0.5
TIMING PERFORMANCE CHARACTERISTICS
TA = 25°C, Swing IP from 0 A to IP0A
no capacitor on FILTER pin, 100 pF from
VIOUT to GND
,
VIOUT Signal Rise Time
tr
–
–
–
3
1
4
–
–
–
ꢁs
ꢁs
ꢁs
TA = 25°C, no capacitor on FILTER pin,
100 pF from VIOUT to GND
VIOUT Signal Propagation Time
VIOUT Signal Response Time
tPROP
TA = 25°C, Swing IP from 0 A to IP0A
,
tRESPONSE
no capacitor on FILTER pin, 100 pF from
VIOUT to GND
–3 dB, TA = 25°C, no capacitor on FILTER
pin, 100 pF from VIOUT to GND
VIOUT Large Signal Bandwidth5
Power-On Time
f3dB
tPO
–
–
120
35
–
–
kHz
Output reaches 90% of steady-state level,
no capacitor on FILTER pin, TA = 25°C
ꢁs
OVERCURRENT CHARACTERISTICS
Setting Voltage for Overcurrent Switchpoint6
VOC
VCC×0.25
–
–
VCC×0.4
–
V
A
Signal Noise at Overcurrent
Comparator Input
INCOMP
±1
Switchpoint in VOC safe operating area;
assumes INCOMP = 0 A
Overcurrent Fault Switchpoint Error7,8
EOC
–
–
±5
–
–
%
V
¯¯¯¯¯¯¯¯¯
Overcurrent FAULT Pin Output Voltage
V¯¯¯¯¯¯¯¯¯
0.4
¯¯¯¯¯¯¯¯¯
1 mA sink current at FAULT pin
FAULT
Fault Enable (FAULT_EN Pin) Input Low
Voltage Threshold
VIL
VIH
–
0.8 × VCC
–
–
–
1
0.1×VCC
V
V
Fault Enable (FAULT_EN Pin) Input High
Voltage Threshold
–
–
Fault Enable (FAULT_EN Pin) Input
Resistance
RFEI
MΩ
Continued on the next page…
Allegro MicroSystems, Inc.
115 Northeast Cutoff
4
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
COMMON OPERATING CHARACTERISTICS (continued) Valid at TA = –40°C to 150°C, VCC= 5 V, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
OVERCURRENT CHARACTERISTICS (continued)
Switchpoint set at 90% of IPOA
,
delay from IP exceeding overcurrent
Overcurrent Fault Response Time
tOC
–
–
1.9
–
–
μs
fault threshold to V¯¯¯¯¯¯¯¯¯ < 0.4 V, without
FAULT
external COC capacitor
Time from VFAULTEN < VIL to
Overcurrent Fault Reset Delay
tOCR
500
ns
VFAULT > 0.8 × VCC , RPU = 330 kꢀ
Time from VFAULTEN pin < VIL to reset of
fault latch; see Functional Block Diagram
Overcurrent Fault Reset Hold Time
tOCH
ROC
–
2
250
–
–
–
ns
Overcurrent Input Pin Resistance
VOLTAGE REFERENCE CHARACTERISTICS
Voltage Reference Output
TA = 25°C, VOC pin to GND
Mꢀ
VZCR
IZCR
TA = 25 °C
–
3
0.5 × VCC
–
–
–
–
V
Source current
Sink current
–
–
mA
μA
mV
Voltage Reference Output Load Current
Voltage Reference Output Drift
50
–
∆VZCR
±10
1Devices 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.
2RF(INT) forms an RC circuit via the FILTER pin.
3This parameter can drift by as much as 0.25% over the lifetime of this product.
4This parameter can drift by as much as 0.3% over the lifetime of this product.
5Calculated using the formula f3dB = 0.35 / tr.
6See page 8 on how to set overcurrent fault switchpoint.
7Switchpoint can be lower at the expense of switchpoint accuracy.
8This error specification does not include the effect of noise. See the INCOMP specification in order to factor in the additional influence of noise on the
fault switchpoint.
Allegro MicroSystems, Inc.
115 Northeast Cutoff
5
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
X20B PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = –40°C to 150°C, VCC = 5 V, unless otherwise specified
Characteristic
Optimized Accuracy Range
Linear Sensing Range
Symbol
IP(OA)
Test Conditions
Min.
–20
Typ.
Max.
20
Units
–
–
A
A
IP(LIN)
–37.5
37.5
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
–
–
1.50
56
–
–
–
mV
mV/A
mV/A
mV/A
mV
Sensitivity2,3
Sens
IP = 12.5 A, TA = 25°C to 150°C
54.5
54.5
–
58
58.5
–
IP = 12.5 A, TA = –40°C to 25°C
–
IP = 0 A, TA = 25°C
±5
–
Electrical Offset Voltage2
Total Output Error2,4
VOE
IP = 0 A, TA = 25°C to 150°C
–25
–40
–
25
40
–
mV
IP = 0 A, TA = –40°C to 25°C
–
mV
Tested at IP =12.5 A, IP applied for 5 ms, TA = 25°C to 150°C
Tested at IP =12.5 A, IP applied for 5 ms, TA = –40°C to 25°C
±2
±3
%
ETOT
–
–
%
1Vpk-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.
2See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3This 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.
X35B PERFORMANCE CHARACTERISTICS, TA Range L, valid at TA = –40°C to 150°C, VCC = 5 V, unless otherwise specified
Characteristic
Optimized Accuracy Range
Linear Sensing Range
Symbol
IP(OA)
Test Conditions
Min.
–37.5
–75
Typ.
Max.
37.5
75
Units
–
–
A
A
IP(LIN)
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
–
–
1
28
–
–
–
mV
mV/A
mV/A
mV/A
mV
Sensitivity2,3
Sens
IP = 25 A, TA = 25°C to 150°C
27
27
–
29.5
29.5
–
IP = 25 A, TA = –40°C to 25°C
–
IP = 0 A, TA = 25°C
±5
–
Electrical Offset Voltage2
Total Output Error2,4
VOE
IP = 0 A, TA = 25°C to 150°C
–25
–40
–
25
40
–
mV
IP = 0 A, TA = –40°C to 25°C
–
mV
Tested at IP = 25 A, IP applied for 5 ms, TA = 25°C to 150°C
Tested at IP = 25 A, IP applied for 5 ms, TA = –40°C to 25°C
±3
±3
%
ETOT
–
–
%
1Vpk-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.
2See Characteristic Performance Data graphs for parameter distribution over ambient temperature range.
3This 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, Inc.
115 Northeast Cutoff
6
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Thermal Characteristics
Characteristic
Symbol
Test Conditions
Value
Units
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.
Steady State Package Thermal Resistance
RθJA
21
ºC/W
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.
Transient Package Thermal Resistance
RTθJA
See graph
ºC/W
ACS709 Transient Package Thermal Resistance
On 85--0444 Demo Board (No Al Plate)
22
20
18
16
14
12
10
8
6
4
2
0
0.01
0.1
1
10
100
1000
Time (Sec)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
7
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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
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
ACS709x-35B
ACS709x-35B
= 3.3 V
V
= 5 V
V
CC
CC
900
800
700
600
500
400
300
1000
900
800
700
600
500
400
0
10
20
30
40
50
0
10
20
30
40
50
Capacitance (nF)
Capacitance (nF)
ACS709x-20B
ACS709x-20B
V
= 5 V
V
= 3.3 V
CC
CC
1600
1400
1200
1000
800
600
400
200
0
1600
1400
1200
1000
800
600
400
200
0
0
10
20
30
40
50
0
10
20
30
40
50
Capacitance (nF)
Capacitance (nF)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
8
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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
Electrical Offset Voltage versus Ambient Temperature
Sensitivity versus Ambient Temperature
58.0
57.5
57.0
56.5
56.0
55.5
55.0
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
–50
-25
0
25
50
75
100
125
150
–50
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Nonlinearity versus Ambient Temperature
Symmetry versus Ambient Temperature
0.20
100.8
100.6
100.4
100.2
100.0
99.8
0.15
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
-0.25
-0.30
99.6
99.4
–50
-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
1
0
-1
-2
-3
-4
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Typical Minimum Limit
Mean
Allegro MicroSystems, Inc.
115 Northeast Cutoff
9
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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
Electrical Offset Voltage versus Ambient Temperature
Sensitivity versus Ambient Temperature
29.0
28.8
28.6
28.4
28.2
28.0
27.8
27.6
27.4
20
15
10
5
0
-5
-10
-15
-20
-25
–50
-25
0
25
50
75
100
125
150
–50
-25
0
25
50
75
100
125
150
TA (°C)
TA (°C)
Nonlinearity versus Ambient Temperature
Symmetry versus Ambient Temperature
0.30
101.0
100.8
100.6
100.4
100.2
100.0
99.8
0.20
0.10
0
-0.10
-0.20
-0.30
99.6
99.4
99.2
99.0
–50
-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
1
0
-1
-2
-3
-4
–50
-25
0
25
50
75
100
125
150
TA (°C)
Typical Maximum Limit
Typical Minimum Limit
Mean
Allegro MicroSystems, Inc.
115 Northeast Cutoff
10
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Setting Overcurrent Fault Switchpoint
The VOC needed for setting the overcurrent fault
switchpoint can be calculated as follows:
|Ioc | is the overcurrent fault switchpoint for a bi-
directional (AC) current, which means a bi-directional
device will have two symmetrical overcurrent fault
VOC = Sens × |IOC | ,
switchpoints, +IOC and –IOC
.
where VOC is in mV, Sens in mV/A, and IOC (overcur-
rent fault switchpoint) in A.
See the following graph for IOC and VOC ranges.
IOC versus VOC
IOC
0.4 VCC / Sens
Not in Valid Range
In Valid Range
0.25 VCC / Sens
0
VOC
0. 25 VCC
0. 4 VCC
– 0.25 VCC / Sens
– 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)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
11
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Functional Description
¯¯¯¯¯¯¯¯¯
2. When the FAULT pin voltage reaches approximately 2 V, the
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
fault is latched, and an internal NMOS device pulls the FAULT
¯¯¯¯¯¯¯¯¯
pin voltage to approximately 0 V. The rate at which the FAULT
pin slews downward (see [4] in the figure) is dependent on the
¯¯¯¯¯¯¯¯¯
external capacitor, COC, on the FAULT pin.
¯¯¯¯¯¯¯¯¯
3.When the FAULT_EN pin is brought low, the FAULT pin starts
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).
¯¯¯¯¯¯¯¯¯
being latched by noise, a circuit was designed to slew the FAULT
4. The slope, and thus the delay, on the fault is controlled by the
¯¯¯¯¯¯¯¯¯
capacitor, COC, placed on the FAULT pin to ground. During this
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 estab-
lished by an internal reference, the fault output is latched and
pulled to ground quickly with an internal N-channel MOSFET.
¯¯¯¯¯¯¯¯¯
portion of the fault (when the FAULT 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:
Fault Walk-through
COC ( VCC – 2 V )
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
t
=
(1)
3 mA
where VCC is the device power supply voltage.
¯¯¯¯¯¯¯¯¯
¯¯¯¯¯¯¯¯¯
the FAULT pin, FAULT_EN pin, and the internal Overcurrent
5. The FAULT pin did not reach the 2 V latch point before
(OC) Fault node, which is invisible to the customer.
the OC fault condition cleared. Because of this, the fixed 3 mA
current sink turns off, and the internal PMOS pull-up turns on to
1.Because the device is enabled (FAULT_EN is high) and there is
¯¯¯¯¯¯¯¯¯
¯¯¯¯¯¯¯¯¯
recharge COC through the FAULT pin.
an OC fault condition, the device FAULT pin starts discharging.
1
1
1
VCC
4
6
8
4
4
FAULT
(Output)
6
5
4
2
2
2
6
2 V
7
3
0 V
Time
FAULT_EN
(Input)
OC Fault
Condition
(Active High)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
12
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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
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 tempera-
ture 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.
by COC
.
7. When the FAULT_EN pin is brought low, if the fault condi-
¯¯¯¯¯¯¯¯¯
tion still exists, the latched FAULT pin will stay low until
the fault condition is removed, then it will start resetting.
8. At this point there is a fault condition, and the part is enabled
¯¯¯¯¯¯¯¯¯
before the FAULT pin can charge to VCC. This shortens the
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 FAULT 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 asso-
ciated on-chip amplifier. Allegro patented a Chopper Stabiliza-
tion technique that nearly eliminates Hall IC output drift induced
by temperature or package stress effects. This offset reduction
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
Low-Pass
Filter
Hall Element
Amp
Concept of Chopper Stabilization Technique
Allegro MicroSystems, Inc.
115 Northeast Cutoff
13
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Definitions of Accuracy Characteristics
Sensitivity (Sens). The change in device output in response to a
1A 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 pro-
grammed at the factory to optimize the sensitivity (mV/A) for the
full-scale current of the device.
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.
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.
Full-scale current over Δ temperature. Accuracy of sensing full-
scale 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
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:
proportional to its supply voltage, VCC.The following formula is
used to derive the ratiometric change in 0 A output voltage,
VIOUT(Q)RAT (%).
V
IOUT(Q)VCC / VIOUT(Q)5V
100
VCC
/
5 V
VIOUT_full-scale amperes – VIOUT(Q)
2 (VIOUT_1/2 full-scale amperes – VIOUT(Q)
100
1–
The ratiometric change in sensitivity, SensRAT (%), is defined as:
{
[
) [ {
SensVCC / Sens5V
where VIOUT_full-scale amperes = the output voltage (V) when the
sensed current approximates full-scale ±IP .
100
VCC
/
5 V
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:
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)
100
V
IOUT(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
Average
V
IOUT
Accuracy
Over $Temp erature
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.
Accuracy
25°C Only
IP(min)
Electrical offset voltage (VOE). The deviation of the device out-
put from its ideal quiescent voltage due to nonmagnetic causes. To
convert this voltage to amperes, divide by the device sensitivity,
Sens.
–IP (A)
+IP (A)
Full Scale
IP(max)
0 A
Accuracy (ETOT). The accuracy represents the maximum devia-
tion 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.
Accuracy
25°C Only
Accuracy
Over $Temp erature
Decreasing VIOUT(V)
Allegro MicroSystems, Inc.
115 Northeast Cutoff
14
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
High Bandwidth, Fast Fault Response Current Sensor IC
In Thermally Enhanced Package
ACS709
Definitions of Dynamic Response Characteristics
Primary Current
I (%)
90
Propagation delay (tPROP). The time required for the device
output to reflect a change in the primary current signal. Propaga-
tion 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.
Transducer Output
0
t
t
t
Propagation Time, tPROP
Primary Current
I (%)
90
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.
Transducer Output
0
Response Time, t
RESPONSE
Primary Current
I (%)
90
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.
Transducer Output
10
0
Rise Time, t
r
Allegro MicroSystems, Inc.
115 Northeast Cutoff
15
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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
2.30
5.00
3.91 ±0.10
5.99 ±0.20
A
1.27
0.41
1.04 REF
1
2
0.25 BSC
Branded Face
0.40
0.635
PCB Layout Reference View
B
SEATING PLANE
GAUGE PLANE
24X
C
1.75 MAX
0.25 MAX
SEATING
PLANE
0.20
C
0.30
0.20
0.635 BSC
NNNNNNNNNNNNN
TLF-AAA
For Reference Only, not for tooling use (reference JEDEC MO-137 AE)
Dimensions in millimeters
LLLLLLLLLLL
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown
A
Terminal #1 mark area
Standard Branding Reference View
C
B
Reference pad layout (reference IPC7351 SOP63P600X175-24M)
All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances
N = Device part number
T = Temperature code
LF = (Literal) Package type
A = Amperage
Branding scale and appearance at supplier discretion
C
Copyright ©2008-2009, Allegro MicroSystems, Inc.
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, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to per-
mit 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, Inc. 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
Allegro MicroSystems, Inc.
115 Northeast Cutoff
16
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
相关型号：
ACS709LLFTR-35BB-T
High Bandwidth, Fast Fault Response Current Sensor IC In Thermally Enhanced Package
ALLEGRO
ACS709_V
High Bandwidth, Fast Fault Response Current Sensor IC In Thermally Enhanced Package
ALLEGRO
ACS710
120 kHz Bandwidth, High Voltage Isolation Current Sensor with Integrated Overcurrent Detection
ALLEGRO
ACS710KLATR-12CB-T
120 kHz Bandwidth, High Voltage Isolation Current Sensor with Integrated Overcurrent Detection
AVAGO
©2020 ICPDF网 联系我们和版权申明