ACPL-C87AT [BOARDCOM]
Automotive High Precision DC Voltage Isolation Sensor;
| 型号： | ACPL-C87AT |
| 厂家： | 
Broadcom Corporation. |
| 描述： | Automotive High Precision DC Voltage Isolation Sensor |
| 文件： | 总16页 (文件大小：1743K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Data Sheet
ACPL-C87AT/ACPL-C87BT
Automotive High Precision DC Voltage Isolation
Sensor
Description
Features
®
The Broadcom ACPL-C87AT/C87BT isolation sensors
Unity gain
utilize superior optical coupling technology, with sigma-delta
(-) analog-to-digital converter, chopper stabilized
amplifiers, and a fully differential circuit topology to provide
unequaled isolation-mode noise rejection, low offset, high
gain accuracy and stability.
± 0.5% (ACPL-C87BT) and ± 1% (ACPL-C87AT) gain
tolerance @ 25°C
–0.3 mV Input offset voltage
0.05% non linearity
25 ppm/°C gain drift vs. temperature
100 kHz bandwidth
ACPL-C87AT (±1% gain tolerance) and ACPL-C87BT
(±0.5% gain tolerance) are designed for high precision DC
voltage sensing in electronic motor drives, DC/DC and
AC/DC converter and battery monitoring system. The
ACPL-C87AT/C87BT features high input impedance and
operate with full span of analog input voltage up to 2.46V.
The shutdown feature provides power saving and can be
controlled from external source, such as microprocessor.
0 to 2V nominal input range
Qualified to AEC-Q100 Grade 1 test guidelines
Operating temperature: –40°C to +125°C
Shutdown feature (active high)
15 kV/µs common-mode rejection at V
= 1 kV
CM
Working voltage, V
= 1414 V
peak
IORM
Compact, surface mount stretched SO8 package
Worldwide safety approval:
The high common-mode transient immunity (15 kV/µs) of
the ACPL-C87AT/C87BT maintains the precision and
stability needed to accurately monitor DC rail voltage in high
noise motor control environments. This galvanic safe
isolation solution is delivered in a compact, surface mount
stretched SO-8 (SSO-8) package that meets worldwide
regulatory safety standards.
– UL 1577 (5000 V
– CSA
/1 minute)
RMS
– IEC/EN/DIN EN 60747-5-5
Applications
Automotive BMS battery pack voltage sensing
Automotive DC/DC converter voltage sensing
Automotive motor inverter DC bus voltage sensing
2
®
Broadcom R Coupler isolation products provide the
reinforced insulation and reliability needed for critical
automotive and high temperature industrial applications.
Automotive AC/DC (charger) DC output voltage
sensing
Isolation interface for temperature sensing
General-purpose voltage sensing and monitoring
CAUTION! Take normal static precautions in handling and assembly of this component to prevent damage and/or
degradation which may be induced by ESD.
Broadcom
AV02-3564EN
July 24, 2018
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Functional Diagram
Figure 1: Functional Diagram
VDD1
VDD2
8
7
6
1
2
VIN
VOUT+
VOUT-
0.1 PF
0.1 PF
SHDN
3
4
5
SHIELD
GND1
GND2
A 0.1-µF bypass capacitor must be connected between pin 1 and pin 4, and pin 5 and pin 8 as shown.
Figure 2: Functional Diagram 2
VDD1
VDD2
VIN
VOUT = VOUT+ − VOUT-
0 − 2 V
VOUT+
VOUT-
0 − 2 V
VIN
SHDN
Isolation
GND1
GND2
Figure 3: Typical Voltage Sensing Circuit
5 V
15 V
V+
MEV1S1505DC
IN OUT
5 V
Gate
Driver
1 nF
R1
M
0.1 PF
20 k:
39 :
Gate
Driver
0.1 PF
R4 20 k:
R5 20 k:
VOUT
R2
10 nF
V-
1 nF
20 k:
ACPL-C87AT/BT
Broadcom
AV02-3564EN
2
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Figure 4: Package Pinout
1
2
8
7
VDD1
VIN
VDD2
VOUT+
SHDN
GND1
VOUT-
3
4
6
5
GND2
Pin Description
Pin Number Pin Name
Description
Pin Number Pin Name
Description
1
VDD1
Input power supply
8
VDD2
Output power supply
When VDD1 = 0, then VOUT+ = 0V, VOUT- = 2.6V
Voltage input, full scale range = 2.46V
2
3
VIN
7
6
VOUT+
VOUT-
Positive output voltage
Negative output voltage
SHDN
Shutdown (active high)
When active, then VOUT+ = 0V, VOUT- = 2.6V
4
GND1
Input side ground
5
GND2
Output side ground
Ordering Information
Option
(RoHS
UL 5000 Vrms
/
Surface
Mount
IEC/EN/DIN
Part Number
ACPL-C87AT
ACPL-C87BT
Compliant)
Package
Tape and Reel 1 Minute rating EN 60747-5-5
Quantity
-000E
-500E
Stretched
SO-8
X
X
X
X
X
X
80 per tube
X
1000 per reel
To order, choose a part number from the part number column and combine with the desired option from the option column
to form an order entry.
Example:
ACPL-C87AT-500E to order product of SSO-8 Surface Mount package in Tape and Reel packaging with RoHS compliant.
Contact your Broadcom sales representative or authorized distributor for information.
Broadcom
AV02-3564EN
3
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Package Outline Drawing (Stretched SO8)
Figure 5: Package Outline Drawing
RECOMMENDED LAND PATTERN
5.850 0.254
(0.230 0.010ꢀ
PART NUMBER
DATE CODE
8
7
6
5
12.650
(0.498ꢀ
C87BT
YWW
EE
6.807 0.127
(0.268 0.005ꢀ
RoHS-COMPLIANCE
INDICATOR
1.905
(0.075ꢀ
1
2
3
4
EXTENDED DATECODE
FOR LOT TRACKING
0.64
(0.025ꢀ
1.590 0.127
(0.063 0.005ꢀ
7°
45°
0.450
(0.018ꢀ
3.180 0.127
(0.125 0.005ꢀ
0.750 0.250
0.254 0.100
(0.010 0.004ꢀ
0.200 0.100
(0.008 0.004ꢀ
(0.0295 0.010ꢀ
0.381 0.127
(0.015 0.005ꢀ
11.50 0.250
(0.453 0.010ꢀ
1.270
(0.050ꢀ BSG
Dimensions in millimeters and (inches).
Note:
Lead coplanarity = 0.1 mm (0.004 inches).
Floating lead protrusion = 0.25mm (10mils) max.
Recommended Pb-Free IR Profile
Recommended reflow condition as per JEDEC Standard, J-STD-020 (latest revision).
NOTE: Use non-halide flux.
Regulatory Information
The ACPL-C87AT and ACPL-C87BT are approved by the following organizations.
UL
CSA
IEC/EN/DIN EN 60747-5-5
IEC 60747-5-5
UL1577, component recognition program up Approved under CSA Component
to VISO = 5kVRMS
Acceptance Notice #5.
EN 60747-5-5
DIN EN 60747-5-5
Broadcom
AV02-3564EN
4
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
IEC/EN/DIN EN 60747-5-5 Insulation Characteristics
Description
Symbol
Units
Installation classification per DIN VDE 0110/1.89, Table 1
for rated mains voltage ≤ 150 Vrms
for rated mains voltage ≤ 300 Vrms
for rated mains voltage ≤ 450 Vrms
for rated mains voltage ≤ 600 Vrms
for rated mains voltage ≤ 1000 Vrms
Climatic Classification
I – IV
I – IV
I – IV
I – IV
I – III
40/125/21
2
Pollution Degree (DIN VDE 0110/1.89)
Maximum Working Insulation Voltage
VIORM
VPR
1414
Vpeak
Vpeak
Input to Output Test Voltage, Method b
2651
2262
8000
VIORM × 1.875 = VPR, 100% Production Test with tm = 1 sec, Partial discharge <
5 pC
Input to Output Test Voltage, Method a
VPR
Vpeak
VIORM × 1.6 = VPR, Type and Sample Test with tm = 10 sec, Partial discharge <
5 pC
Highest Allowable Overvoltage (Transient Overvoltage tini = 60 sec)
VIOTM
Vpeak
Safety-limiting values – maximum values allowed in the event of a failure, also see
Figure 6.
Case Temperature
Input Current
TS
IS,INPUT
PS,OUTPUT
RS
175
230
600
°C
mA
mW
Ω
Output Power
> 109
Insulation Resistance at TS, VIO = 500V
Figure 6: Dependence of Safety-Limiting Values on Temperature
700
PS (mWꢀ
IS (mWꢀ
600
500
400
300
200
100
0
0
25
50
75
100
125 150 175 200
TS – CASE TEMPERATURE – °C
Broadcom
AV02-3564EN
5
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Insulation and Safety-Related Specifications
Parameter
Symbol
Value
Units
Conditions
Minimum External Air Gap
(External Clearance)
L(101)
8.0
mm
Measured from input terminals to output terminals,
shortest distance through air.
Minimum External Tracking
(External Creepage)
L(102)
CTI
8.0
0.5
mm
mm
Measured from input terminals to output terminals,
shortest distance path along body.
Minimum Internal Plastic Gap
(Internal Clearance)
Through insulation distance conductor to conductor,
usually the straight line distance thickness between the
emitter and detector.
Tracking Resistance (Comparative
Tracking Index)
> 175
IIIa
Volts
DIN IEC 112/VDE 0303 Part 1
Isolation Group (DIN BDE0109)
Material Group (DIN VDE 0110)
Absolute Maximum Ratings
Parameter
Storage Temperature
Symbol
TS
Min.
Max.
150
Units
°C
Note
–55
–40
Ambient Operating Temperature
Supply Voltages
TA
125
°C
VDD1, VDD2
VIN
–0.5
–2.0
–0.5
–0.5
6.0
Volts
Volts
Volts
Volts
Input Voltage
VDD1 + 0.5
VDD1 + 0.5
VDD2 + 0.5
Shutdown Voltage
Output Voltages
VSD
V
OUT+, VOUT-
Recommended Operating Conditions
Parameter
Ambient Operating Temperature
Input Supply Voltage
Output Supply Voltage
Input Voltage
Symbol
TA
Min.
Max.
125
5.5
Units
°C
Notes
-40
VDD1
VDD2
VIN
4.5
Volts
Volts
Volts
Volts
3.0
0
5.5
2.0
Shutdown Voltage
VSD
VDD1 – 0.5
VDD1
Broadcom
AV02-3564EN
6
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Electrical Specifications
Unless otherwise noted, all typical values at T = 25°C, V
= V
= 5V, V = 0 to 2V, V = 0V; all Minimum/Maximum
DD2 IN SD
A
DD1
specifications are at recommended voltage supply conditions: 4.5V ≤ V
≤ 5.5V, 4.5V ≤ V
≤ 5.5V.
DD2
DD1
Parameter
Power Supplies
Symbol
Min.
Typ.
Max.
Units
Test Conditions
Figure Note
Input Supply Current
IDD1
—
—
10.5
20
15
—
mA VSD = 0V
18, 19
Input Supply Current
(Shutdown Mode)
IDD1(SD)
µA
VSD = 5V
Output Supply Current
IDD2
—
6.5
12
mA
18, 20
DC Characteristics
a
Gain (ACPL-C87BT, ± 0.5%)
G0
G1
0.995
0.99
1
1
1.005
1.01
V/V TA = 25°C, VIN = 0 to 2 V,
VDD1 = VDD2 = 5.0V
8
a
Gain (ACPL-C87AT, ± 1%)
V/V TA = 25°C, VIN = 0 to 2 V, 8, 11
VDD1 = VDD2 = 5.0V
Magnitude of Gain Change vs.
Temperature
|dG/dTA|
—
—
25
—
—
ppm/°C TA = -40°C to +125°C
11
Magnitude of Gain Change vs.
VDD1
|dG/dVDD1
|
|
0.05
%/V TA = 25°C
12
Magnitude of Gain Change vs.
VDD2
|dG/dVDD2
NL
—
—
0.02
0.05
—
%/V TA = 25 °C
12, 13
15, 16
Nonlinearity
0.12
%
VIN = 0 to 2V,
TA = –40°C to +125°C
Input Offset Voltage
VOS
–10
—
-0.3
21
10
—
mV VIN is shorted to GND1,
TA = 25°C
7, 9, 10
7, 9
Magnitude of Input Offset Change |dVOS/dTA|
vs. Temperature
µV/°C VIN is shorted to GND1,
TA = –40°C to +125°C
Inputs and Outputs
Full-Scale Differential Voltage Input
Range
FSR
—
2.46
—
V
Referenced to GND1
VIN = 0V
Input Bias Current
IIN
–0.1
—
-0.001
1000
0.1
—
—
—
—
—
µA
MΩ
V
22
22
Equivalent Input Impedance
Output Common-Mode Voltage
VOUT+ Range
RIN
VOCM
VOUT+
VOUT-
—
1.23
VIN = 0V, VSD = 0V
VIN = 2.5V
—
VOCM+1.23
VOCM – 1.23
30
V
VOUT - Range
—
V
VIN = 2.5V
Output Short-Circuit Current
|IOSC
|
—
mA VOUT+ or VOUT-,
shorted to GND2 or VDD2
Output Resistance
ROUT
—
36
—
Ω
VIN = 0V
a. Gain is defined as the slope of the best-fit line of differential output voltage (VOUT+ – VOUT-) versus input voltage over the nominal range, with
offset error adjusted. A 0.5% gain tolerance for ACPL-C87BT, and a 1% tolerance for ACPL-C87AT.
Broadcom
AV02-3564EN
7
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Electrical Specifications (Continued)
Unless otherwise noted, all typical values at T = 25°C, V
= V
= 5V, V = 0 to 2V, V = 0V; all Minimum/Maximum
DD2 IN SD
A
DD1
specifications are at recommended voltage supply conditions: 4.5V ≤ V
≤ 5.5V, 4.5V ≤ V
≤ 5.5V.
DD2
DD1
Parameter
AC Characteristics
Small-Signal Bandwidth (–3 dB)
OUT Noise
Symbol
Min.
Typ.
Max.
Unit
Test Conditions
Figure Note
f–3 dB
NOUT
tPD10
—
—
—
100
1.3
2.2
—
—
kHz
a
V
mVRMS VIN = 2V; BW = 1 kHz
23
Input to Output Propagation Delay
(10% to 10%)
3.5
µs
µs
µs
µs
VIN = 0 to 2V Step
VIN = 0 to 2V Step
VIN = 0 to 2V Step
Step Input
21, 26
21, 26
21, 26
Input to Output Propagation Delay
(50% to 50%)
tPD50
tPD90
tR/F
—
—
—
3.7
5.3
2.7
6.0
7.0
4.0
Input to Output Propagation Delay
(90% to 90%)
Output Rise/Fall Time
(10% to 90%)
Shutdown Time
tSD
tON
—
—
—
25
—
—
—
µs
µs
dB
25
25
Shutdown Recovery Time
Power Supply Rejection
150
–78
PSR
1 Vp-p, 1 kHz sine wave
ripple on VDD1, differential
output
b
Common Mode Transient Immunity
CMTI
10
15
—
kV/µs VCM = 1 kV, TA = 25°C
24
a. Noise is measured at the output of the differential to single ended post amplifier.
b. Common mode transient immunity (CMTI) is tested by applying a fast rising/falling voltage pulse across GND1 (pin 4) and GND2 (pin 5). The
output glitch observed is less than 0.2V from the average output voltage for less than 1 µs.
Package Characteristics
Unless otherwise noted, all typical values are at T = 25°C; all Minimum/Maximum specifications are at Recommended
A
Operating Conditions.
Parameter
Symbol
Min.
Typ.
Max.
Units
Test Conditions
Figure Note
b, c
Input-Output Momentary Withstand
Voltagea
VISO
5000
—
—
VRMS RH < 50%, t = 1 minute,
TA = 25°C
b
b
1014
0.5
Input-Output Resistance
RI-O
CI-O
—
—
—
—
Ω
VI-O = 500 VDC
f =1 MHz
Input-Output Capacitance
pF
a. The Input-Output Momentary Withstand Voltage is a dielectric voltage rating that should not be interpreted as an input-output continuous
voltage rating.
b. Device considered a two terminal device: pins 1, 2, 3, and 4 shorted together, and pins 5, 6, 7, and 8 shorted together.
c. In accordance with UL 1577, each optocoupler is proof tested by applying an insulation test voltage ≥ 6000 VRMS for 1 second.
Broadcom
AV02-3564EN
8
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Typical Characteristic Plots and Test Conditions
All ±3 plots are based on characterization test result at the point of product release. For guaranteed specification, refer to
the respective Electrical Specifications section.
Figure 7: Input Offset Voltage Test Circuit
Figure 8: Gain and Nonlinearity Test Circuit
VDD1 VDD2
VDD1 VDD2
8
8
1
2
1
2
0.1 PF
0.1 PF
0.1 PF
7
6
5
7
6
5
VIN
ACPL-C87AT/BT
ACPL-C87AT/BT
V
VOLTMETER
3
4
0.1 PF
3
4
V
VOLTMETER
GND1
GND2
GND1
GND2
Figure 9: Input Offset Voltage vs. Temperature
Figure 10: Input Offset vs. Supply Voltage
10
0
-1
-2
-3
-4
-5
-6
-7
vs Vdd1
vs Vdd2
8
6
+3 SIGMA
MEAN
-3 SIGMA
4
2
0
-2
-4
-6
-8
-10
-40 -20
0
20
40
60
80 100 120 140
4.5
4.75
5
5.25
5.5
TA - TEMPERATURE - °C
VDD - SUPPLY VOLTAGE - V
Figure 11: Gain vs. Temperature
Figure 12: Gain vs. Supply Voltage
1.003
1.002
1.001
1.000
0.999
0.998
0.997
1.006
1.004
1.002
1.000
0.998
0.996
0.994
vs Vdd1
vs Vdd2
MEAN
0.992
0.990
0.988
+3 SIGMA
-
3 SIGMA
-40 -20
0
20
40 60
TA - TEMPERATURE - °C
80 100 120 140
4.5
4.75
5
5.25
5.5
VDD - SUPPLY VOLTAGE - V
Broadcom
AV02-3564EN
9
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Figure 13: Gain vs Temperature at Different VDD2
Figure 14: Nonlinearity vs. Supply Voltage
1.006
0.08
0.07
0.06
0.05
0.04
VDD2 = 3.3 V
VDD2 = 5 V
VDD2 = 5.5 V
vs Vdd1
vs Vdd2
1.004
1.002
1.000
0.998
0.996
0.994
0.992
0.990
0.988
-40 -20
0
20 40 60 80 100 120 140
TA - TEMPERATURE - °C
4.5
4.75
5
5.25
5.5
VDD - SUPPLY VOLTAGE - V
Figure 15: Nonlinearity vs. Temperature
Figure 16: Nonlinearity vs. Temperature at Different VDD2
0.12
0.10
0.08
0.06
0.04
0.02
0.00
0.12
VDD2 = 3.3 V
VDD2 = 5.0 V
VDD2 = 5.5 V
0.10
0.08
0.06
0.04
0.02
0.00
MEAN
+3 SIGMA
-3 SIGMA
-40 -20
0
20
40
60
80 100 120 140
-40 -20
0
20
40
60
80 100 120 140
TA - TEMPERATURE - °C
TA - TEMPERATURE - °C
Figure 17: Output Voltage vs. Input Voltage
Figure 18: Typical Supply Current vs. Input Voltage
12
2.5
VOUT+
VOUT-
IDD1
IDD2
2
1.5
1
10
8
6
0.5
0
4
0
1
2
3
4
5
6
0
0.5
1
1.5
2
2.5
VIN - INPUT VOLTAGE - V
VIN - INPUT VOLTAGE - V
Broadcom
AV02-3564EN
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ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Figure 19: Typical Input Supply Current vs. Temperature at
Different VDD1
Figure 20: Typical Output Supply Current vs. Temperature at
Different VDD2
9
8
7
6
14
13
12
11
10
9
8
V
V
V
= 4.5 V
= 5.0 V
= 5.5 V
V
V
V
= 3.3 V
= 5.0 V
= 5.5 V
DD1
DD1
DD1
DD2
DD2
DD2
5
4
7
6
-40 -20
0
20
40
60
80 100 120 140
-40 -20
0
20
40
60
80 100 120 140
TA - TEMPERATURE - °C
TA - TEMPERATURE - °C
Figure 21: Typical Propagation Delay vs. Temperature
Figure 22: Input Current vs. Input Voltage
6
5
4
3
2
0.5
0
-0.5
-1
T
T
T
50-10
50-50
50-90
PD
PD
PD
-1.5
-2
1
0
-40 -20
0
20
40
60
80 100 120 140
0
0.5
1
1.5
2
2.5
TA - TEMPERATURE - °C
VIN - INPUT VOLTAGE - V
Figure 23: AC Noise vs. Filter Bandwidth
Figure 24: Phase vs. Frequency
16
0
-20
-40
-60
-80
V
= 2.0 V
IN
14
12
10
8
-100
-120
-140
-160
-180
-200
6
4
2
0
1000
10000
100000
Frequency (Hzꢀ
1000000
0
20
40
60
80
100
FILTER BANDWIDTH - kHz
Broadcom
AV02-3564EN
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ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Figure 25: Common Mode Transient Immunity Test Circuit
5 V
5 V
1 nF
20 k:
39 :
0.1 PF
0.1 PF
20 k:
20 k:
VOUT
10 nF
1 nF
20 k:
ACPL-C87AT/BT
+
–
VCM
Figure 26: Shutdown Timing Diagram
5 V
VSHDN
0 V
2 V
VIN
tSD
tON
0 V
2.4 V
VOUT+ – VOUT-
0 V
-2.4 V
Figure 27: Propagation Delay Diagram
2 V
VIN
0 V
2 V
90%
50%
1 V
VO+ – VO-
10%
0 V
TPD10
TPD50
TPD90
Broadcom
AV02-3564EN
12
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Application Information
The circuit shown in the Figure 28 is a high voltage sensing application using ACPL-C87AT/BT (isolation amplifier) and
ACPL-M49T (optocoupler). The high voltage input is sensed by the precision voltage divider resistors R1 and sensing
resistor R2. The ratio of the voltage divider is determined by the allowable input range of the isolation amplifier (0 to 2 V).
This small analog input goes through a 39Ω and 10 nF anti aliasing filter (ACPL-C87AT/BT use - modulation).
Inside the isolation amplifier: the analog input signal is digitized and optically transmitted to the output side of the amplifier.
The detector will then decode the signal and converted back to analog signal. The output differential signals of
ACPL-C87AT/BT go through an op-amp to convert the differential signals to a single ended output.
Figure 28: Typical Application Circuit for Battery Voltage Sensing
SWITCH
MODE
POWER
SUPPLY
R12
R13
10 k:
V+
Battery Cells
C7 1 nF
20 :
ACPL-M49T
R1
R2
R7 20 k:
C4
0.1 PF
C2
0.1 PF
M
C
R4 20 k:
U
V
OUT
R3 39 :
V-
R5 20 k:
C6
1 nF
R6 20 k:
C1
10 nF
ACPL-C87AT/BT
Vref
0.1 PF
Bypass Capacitor
A 0.1-µF bypass capacitor must be connected as near as possible between V
to GND1 and V
to GND2 (Figure 29).
DD2
DD1
Figure 29: Bypass Capacitors C2, C4
C2
0.1 PF
C4
0.1 PF
ACPL-C87AT/BT
Broadcom
AV02-3564EN
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ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
To reduce the voltage stress of a sole resistor, R1 can be a
series of several resistors.
Anti-aliasing Filter
A 39Ω resistor and a 10-nF capacitor are recommended to
be connected to the input (V ) as anti-aliasing filter
IN
Post Amplifier Circuit
because ACPL-C87AT/BT uses sigma data modulation
(Figure 30). The value of the capacitor must be greater than
1 nF and bandwidth must be less than 410 kHz.
The output of ACPL-C87AT/BT is a differential output
(V
and V
pins). A post amplifier circuit is needed to
OUT-
OUT+
convert the differential output to single ended output with a
reference ground. The post amplifier circuit can also be
configured to establish a desired gain if needed. It also
functions as filter to high frequency chopper noise. The
bandwidth can be adjusted by changing the feedback
resistor and capacitor (R7 and C7). Adjusting this bandwidth
to a minimum level helps minimize the output noise.
Figure 30: Anti-aliasing Filter C1, R3
Post op-amp resistive loading (R4, R5) should be equal or
greater than 20 kΩ (Figure 31). Resistor values lower than
this can affect the overall system error due to output
impedance of isolation amplifier.
Figure 31: Loading Resistors R4, F5
The application circuit in Figure 28 features two op-amps to
improve the linearity at voltage near 0V caused by the
limited headroom of the amplifier. The second op-amp can
set the reference voltage to above 0V.
R4
20 k:
R5
20 k:
Shutdown Function
ACPL-C87AT/BT
ACPL-C87AT/BT has a shutdown function to disable the
device and make the output (V
– V
) low. A voltage
OUT-
OUT+
Designing the Input Resistor Divider
of 5V on SHDN pin will shutdown the device producing an
output (V – V ) of –2.6V. To be able to control the
OUT+
OUT-
1. Choose the sensing current (Isense) for bus voltage; for
example, 1 mA.
SHDN function (example, from microprocessor), an
optocoupler (ACPL-M49T) is used.
2. Determine R2,
Total System Error
Voltage input range
ISENSE
2 V
1 mA
R2 =
=
= 2 k:
Total system error is the sum of the resistor divider error,
isolation amplifier error and post amplifier error. The resistor
divider error is due to the accuracy of the resistors used. It
is recommended to use high accuracy resistor of 0.1%. Post
amplifier error is due to the resistor matching and the
voltage offset characteristic which can be found on the
supplier data sheet.
3. Determine R1 using voltage divider formula:
R2
R1 + R2
(V+ – V-) x
= Voltage input range, or
(V+ – V-) xꢀR2
Voltage input range
R1 =
– R2
Isolation Amplifier Error is shown in the following table.
where (V+ – V-) is the high voltage input; for example,
0 to 600V,
(600 V – 0 V) xꢀ2 k:
R1 =
– 2 k:ꢀ= 598 k:
2 V
Broadcom
AV02-3564EN
14
ACPL-C87AT/ACPL-C87BT Data Sheet
Automotive High Precision DC Voltage Isolation Sensor
Isolation Amplifier Error Calculation
3Distribution or
Specificationa
Typical
ACPL-C87AT ACPL-C87BT
Figure
A
B
Error due to offset voltage (25°C)
0.015%
0.5%
0.5%
Offset Voltage /Recommended specs
input voltage range (2.0V)
Error due to offset voltage drift (across
temperature)
0.1%
0.4%
0.4%
Offset Voltage /Recommended
input voltage range (2.0V)
C
D
E
F
Error due to gain tolerance (25°C)
0%
1%
1%
specs
specs
Error due to gain drift (across temperature)
Error due to Nonlinearity (across temperature)
Total uncalibrated error (A+B+C+D+E)
Total offset calibrated error (F – A)
0.25%
0.05%
0.415%
0.4%
0.8%
0.8%
0.12%
2.82%
2.32%
1.32%
0.12%
2.82%
2.32%
1.32%
G
H
Total gain and offset calibrated error (G – C) 0.4%
a. 3 distribution is based on corner wafers.
GND1 and GND2 must be totally isolated in the PCB layout
(Figure 33). Distance of separation depends on the high
voltage level of the equipment. The higher the voltage level,
the larger the distance of separation needed. Designers can
refer to specific IEC standard of their equipment for the
creepage/clearance requirements.
PCB Layout Recommendations
Bypass capacitor C2 and C4 must be located close to
ACPL-C87xT Pins 1 and Pin 8 respectively. Grounded pins
of C4 and C5 can be connected by vias through the
respective ground layers. If the design has multiple layers,
a dedicated layer for ground is recommended for flexibility
in component placement.
R1, which is directly connected to the high voltage input,
must have sufficient clearance with the low voltage
components. Clearance depends on the high voltage level
of the input. Designers can refer to specific IEC standards of
their equipment for the clearance requirements.
Anti aliasing filters R3 and C1 also need to be connected as
close as possible to Pin 2 of ACPL-C87AT/BT. See
Figure 32 for actual component placement of the
anti-aliasing filter and bypass capacitors.
Figure 33: Bottom Layer Layout Recommendation
Figure 32: Component Placement Recommendation
R1 (Series Resistorsꢀ
Isolation
BYPASS CAPACITORS
Clearance
GND1
GND2
ANTI ALIASING FILTER
ACPL-C87AT/BT
Broadcom
AV02-3564EN
15
2
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