ACPL-C87AT-500E

Data Sheet ACPL-C87AT/ACPL-C87BT Automotive High Precision DC Voltage Isolation Sensor Description The Broadcom® ACPL-C87AT/C87BT isolation sensors 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. Features      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.  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.  Broadcom R2Coupler® isolation products provide the reinforced insulation and reliability needed for critical automotive and high temperature industrial applications.        Unity gain ± 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 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 VCM = 1 kV Working voltage, VIORM = 1414 Vpeak Compact, surface mount stretched SO8 package Worldwide safety approval: – UL 1577 (5000 VRMS/1 minute) – CSA – 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 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 October 29, 2018 ACPL-C87AT/ACPL-C87BT Data Sheet Automotive High Precision DC Voltage Isolation Sensor Functional Diagram Figure 1: Functional Diagram VDD1 8 1 VDD2 VIN 2 7 VOUT+ SHDN 3 6 VOUT- 0.1 PF 0.1 PF GND1 4 SHIELD 5 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+ − VOUTVOUT+ VIN 0−2V Isolation GND1 0−2V VOUT- SHDN GND2 Figure 3: Typical Voltage Sensing Circuit 5V 15 V V+ MEV1S1505DC IN OUT Gate Driver 5V 1 nF R1 M 0.1 PF 20 k: 39 : Gate Driver R2 0.1 PF R4 20 k: VOUT R5 20 k: 10 nF V1 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 VDD1 VDD2 8 2 VIN VOUT+ 7 3 SHDN VOUT- 6 4 GND1 GND2 5 Pin Description Pin Number Pin Name Description Pin Number Pin Name Description Input power supply When VDD1 = 0, then VOUT+ = 0V, VOUT- = 2.6V 8 VDD2 Output power supply Voltage input, full scale range = 2.46V 7 VOUT+ Positive output voltage SHDN Shutdown (active high) When active, then VOUT+ = 0V, VOUT- = 2.6V 6 VOUT- Negative output voltage GND1 Input side ground 5 GND2 Output side ground 1 VDD1 2 VIN 3 4 Ordering Information Option Part Number ACPL-C87AT ACPL-C87BT (RoHS Compliant) -000E -500E Package Stretched SO-8 Surface Mount Tape and Reel X X X UL 5000 Vrms / IEC/EN/DIN 1 Minute rating EN 60747-5-5 Quantity X X 80 per tube X 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 ± 0.010) PART NUMBER DATE CODE 8 RoHS-COMPLIANCE INDICATOR 7 6 5 C87BT YWW EE 12.650 (0.498) 6.807 ± 0.127 (0.268 ± 0.005) 1.905 (0.075) 1 2 3 4 EXTENDED DATECODE FOR LOT TRACKING 0.64 (0.025) 7° 1.590 ± 0.127 (0.063 ± 0.005) 45° 0.450 (0.018) 3.180 ± 0.127 (0.125 ± 0.005) 0.750 ± 0.250 (0.0295 ± 0.010) 11.50 ± 0.250 (0.453 ± 0.010) 0.200 ± 0.100 (0.008 ± 0.004) 0.381 ± 0.127 (0.015 ± 0.005) 1.270 (0.050) BSG 0.254 ± 0.100 (0.010 ± 0.004) 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 UL 1577, component recognition program up Approved under CSA Component to VISO = 5kVRMS Acceptance Notice #5. Broadcom IEC/EN/DIN EN 60747-5-5 IEC 60747-5-5 EN 60747-5-5 DIN EN 60747-5-5 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 I – IV for rated mains voltage ≤ 300 Vrms I – IV for rated mains voltage ≤ 450 Vrms I – IV for rated mains voltage ≤ 600 Vrms I – IV for rated mains voltage ≤ 1000 Vrms I – III Climatic Classification 40/125/21 Pollution Degree (DIN VDE 0110/1.89) 2 Maximum Working Insulation Voltage VIORM 1414 Vpeak Input to Output Test Voltage, Method b VIORM × 1.875 = VPR, 100% Production Test with tm = 1 sec, Partial discharge < 5 pC VPR 2651 Vpeak Input to Output Test Voltage, Method a VIORM × 1.6 = VPR, Type and Sample Test with tm = 10 sec, Partial discharge < 5 pC VPR 2262 Vpeak VIOTM 8000 Vpeak TS 175 °C Input Current IS,INPUT 230 mA Output Power PS,OUTPUT 600 mW RS > 109 Ω Highest Allowable Overvoltage (Transient Overvoltage tini = 60 sec) Safety-limiting values – maximum values allowed in the event of a failure, also see Figure 6. Case Temperature Insulation Resistance at TS, VIO = 500V OUTPUT POWER – PS, INPUT CURRENT - IS Figure 6: Dependence of Safety-Limiting Values on Temperature 700 PS (mW) IS (mW) 600 500 400 300 200 100 0 0 Broadcom 25 50 75 100 125 150 TS – CASE TEMPERATURE – °C 175 200 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 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) 8.0 mm Measured from input terminals to output terminals, shortest distance path along body. 0.5 mm Through insulation distance conductor to conductor, usually the straight line distance thickness between the emitter and detector. > 175 Volts DIN IEC 112/VDE 0303 Part 1 Minimum Internal Plastic Gap (Internal Clearance) Tracking Resistance (Comparative Tracking Index) CTI Isolation Group (DIN BDE0109) IIIa Conditions Material Group (DIN VDE 0110) Absolute Maximum Ratings Parameter Symbol Min. Max. Units Storage Temperature TS –55 150 °C Ambient Operating Temperature TA –40 125 °C Supply Voltages VDD1, VDD2 –0.5 6.0 Volts Input Voltage VIN –2.0 VDD1 + 0.5 Volts Shutdown Voltage VSD –0.5 VDD1 + 0.5 Volts VOUT+, VOUT- –0.5 VDD2 + 0.5 Volts Output Voltages Note Recommended Operating Conditions Parameter Symbol Min. Max. Units TA -40 125 °C Input Supply Voltage VDD1 4.5 5.5 Volts Output Supply Voltage VDD2 3.0 5.5 Volts Input Voltage VIN 0 2.0 Volts Shutdown Voltage VSD VDD1 – 0.5 VDD1 Volts Ambient Operating Temperature Broadcom Notes 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 TA = 25°C, VDD1 = VDD2 = 5V, VIN = 0 to 2V, VSD = 0V; all Minimum/Maximum specifications are at recommended voltage supply conditions: 4.5V ≤ VDD1 ≤ 5.5V, 4.5V ≤ VDD2 ≤ 5.5V. Parameter Symbol Min. Typ. Max. Units Test Conditions Figure Note Input Supply Current IDD1 — 10.5 15 mA VSD = 0V Input Supply Current (Shutdown Mode) IDD1(SD) — 20 — µA VSD = 5V IDD2 — 6.5 12 mA Gain (ACPL-C87BT, ± 0.5%) G0 0.995 1 1.005 V/V TA = 25°C, VIN = 0 to 2 V, VDD1 = VDD2 = 5.0V 8 a Gain (ACPL-C87AT, ± 1%) G1 0.99 1 1.01 V/V TA = 25°C, VIN = 0 to 2 V, VDD1 = VDD2 = 5.0V 8, 11 a Magnitude of Gain Change vs. Temperature |dG/dTA| — 25 — Magnitude of Gain Change vs. VDD1 |dG/dVDD1| — 0.05 — %/V TA = 25°C 12 Magnitude of Gain Change vs. VDD2 |dG/dVDD2| — 0.02 — %/V TA = 25 °C 12, 13 Nonlinearity NL — 0.05 0.12 % VIN = 0 to 2V, TA = –40°C to +125°C 15, 16 Input Offset Voltage VOS –10 -0.3 10 mV VIN is shorted to GND1, TA = 25°C 7, 9, 10 |dVOS/dTA| — 21 — FSR — 2.46 — V Referenced to GND1 Input Bias Current IIN –0.1 -0.001 0.1 µA VIN = 0V Equivalent Input Impedance RIN — 1000 — MΩ Output Common-Mode Voltage VOCM — 1.23 — V VIN = 0V, VSD = 0V VOUT+ Range VOUT+ — VOCM+1.23 — V VIN = 2.5V VOUT - Range VOUT- — VOCM – 1.23 — V VIN = 2.5V Output Short-Circuit Current |IOSC| — 30 — mA Output Resistance ROUT — 36 — Ω Power Supplies Output Supply Current 18, 19 18, 20 DC Characteristics Magnitude of Input Offset Change vs. Temperature ppm/°C TA = -40°C to +125°C µV/°C VIN is shorted to GND1, TA = –40°C to +125°C 11 7, 9 Inputs and Outputs Full-Scale Differential Voltage Input Range 22 22 VOUT+ or VOUT-, shorted to GND2 or VDD2 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 TA = 25°C, VDD1 = VDD2 = 5V, VIN = 0 to 2V, VSD = 0V; all Minimum/Maximum specifications are at recommended voltage supply conditions: 4.5V ≤ VDD1 ≤ 5.5V, 4.5V ≤ VDD2 ≤ 5.5V. Parameter Symbol Min. Typ. Max. Unit Test Conditions Figure Note Small-Signal Bandwidth (–3 dB) f–3 dB — 100 — kHz VOUT Noise NOUT — 1.3 — 23 a Input to Output Propagation Delay (10% to 10%) tPD10 — 2.2 3.5 µs VIN = 0 to 2V Step 21, 26 Input to Output Propagation Delay (50% to 50%) tPD50 — 3.7 6.0 µs VIN = 0 to 2V Step 21, 26 Input to Output Propagation Delay (90% to 90%) tPD90 — 5.3 7.0 µs VIN = 0 to 2V Step 21, 26 Output Rise/Fall Time (10% to 90%) tR/F — 2.7 4.0 µs Step Input Shutdown Time tSD — 25 — µs 25 Shutdown Recovery Time tON — 150 — µs 25 Power Supply Rejection PSR — –78 — dB Common Mode Transient Immunity CMTI 10 15 — AC Characteristics mVRMS VIN = 2V; BW = 1 kHz 1 Vp-p, 1 kHz sine wave ripple on VDD1, differential output kV/µs VCM = 1 kV, TA = 25°C 24 b 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 TA = 25°C; all Minimum/Maximum specifications are at Recommended Operating Conditions. Parameter Symbol Min. Typ. Max. Units Test Conditions Figure Input-Output Momentary Withstand Voltagea VISO 5000 — — Input-Output Resistance RI-O — 1014 — Ω VI-O = 500 VDC b Input-Output Capacitance CI-O — 0.5 — pF f =1 MHz b VRMS RH < 50%, t = 1 minute, TA = 25°C Note b, c 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 VDD1 Figure 8: Gain and Nonlinearity Test Circuit VDD1 VDD2 8 1 7 2 0.1 PF 3 0.1 PF ACPL-C87AT/BT 0.1 PF VIN 6 GND1 2 7 ACPL-C87AT/BT 0.1 PF 6 V VOLTMETER 5 GND1 GND2 GND2 Figure 10: Input Offset vs. Supply Voltage 0 +3 SIGMA MEAN -3 SIGMA -20 0 20 40 60 80 TA - TEMPERATURE - °C 100 Vos - INPUT OFFSET VOLTAGE - mV Vos - INPUT OFFSET VOLTAGE - mV 8 4 Figure 9: Input Offset Voltage vs. Temperature 10 8 6 4 2 0 -2 -4 -6 -8 -10 -40 1 3 V VOLTMETER 5 4 VDD2 120 -2 -3 -4 -5 -6 -7 4.5 140 Figure 11: Gain vs. Temperature vs Vdd1 vs Vdd2 -1 4.75 5 5.25 VDD - SUPPLY VOLTAGE - V 5.5 Figure 12: Gain vs. Supply Voltage 1.003 1.006 1.004 vs Vdd1 vs Vdd2 1.002 1.000 G - GAIN - V/V G - GAIN - V/V 1.002 0.998 0.996 0.994 MEAN +3 SIGMA - 3 SIGMA 0.992 0.990 0.988 -40 Broadcom -20 0 20 40 60 80 TA - TEMPERATURE - °C 1.001 1.000 0.999 0.998 100 120 140 0.997 4.5 4.75 5 5.25 VDD - SUPPLY VOLTAGE - V 5.5 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 VDD2 = 3.3 V VDD2 = 5 V VDD2 = 5.5 V G - GAIN - V/V 1.002 vs Vdd1 vs Vdd2 NL - NON LINEARITY - % 1.004 1.000 0.998 0.996 0.994 0.992 0.07 0.06 0.05 0.990 0.988 -40 0.04 -20 0 20 40 60 80 TA - TEMPERATURE - °C 100 120 Figure 15: Nonlinearity vs. Temperature 0.12 0.12 0.10 0.10 0.08 0.06 0.04 MEAN +3 SIGMA -3 SIGMA 0.02 -20 0 20 40 60 80 TA - TEMPERATURE - °C 100 120 5.5 VDD2 = 3.3 V VDD2 = 5.0 V VDD2 = 5.5 V 0.08 0.06 0.04 0.00 -40 140 Figure 17: Output Voltage vs. Input Voltage -20 0 20 40 60 80 TA - TEMPERATURE - °C 100 120 140 Figure 18: Typical Supply Current vs. Input Voltage 12 2.5 VOUT+ VOUT- 2 IDD - SUPPLY CURRENT - mA Vo - OUTPUT VOLTAGE - V 5 5.25 VDD - SUPPLY VOLTAGE - V 0.02 0.00 -40 4.75 Figure 16: Nonlinearity vs. Temperature at Different VDD2 NL - NON LINEARITY - % NL - NON LINEARITY - % 4.5 140 1.5 1 0.5 0 IDD1 IDD2 10 8 6 4 0 Broadcom 1 2 3 4 VIN - INPUT VOLTAGE - V 5 6 0 0.5 1 1.5 VIN - INPUT VOLTAGE - V 2 2.5 AV02-3564EN 10 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 IDD2 - OUTPUT SUPPLY CURRENT - mA IDD1 - INPUT SUPPLY CURRENT - mA 14 13 12 11 10 9 8 VDD1 = 4.5 V VDD1 = 5.0 V VDD1 = 5.5 V 7 6 -40 0 20 40 60 80 TA - TEMPERATURE - °C 100 120 140 6 VDD2 = 3.3 V VDD2 = 5.0 V VDD2 = 5.5 V 5 -40 6 0.5 5 0 4 3 2 TPD 50-10 TPD 50-50 TPD 50-90 1 0 -40 0 20 40 60 80 TA - TEMPERATURE - °C 100 120 100 120 140 -1 -1.5 12 Phase (deg) 10 8 6 4 2 0 20 40 60 FILTER BANDWIDTH - kHz 0.5 1 1.5 VIN - INPUT VOLTAGE - V 2 2.5 Figure 24: Phase vs. Frequency VIN = 2.0 V Broadcom 20 40 60 80 TA - TEMPERATURE - °C -0.5 0 140 16 0 0 -2 -20 Figure 23: AC Noise vs. Filter Bandwidth 14 -20 Figure 22: Input Current vs. Input Voltage IIN - INPUT CURRENT - nA Tp - PROPAGATION DELAY - Ps 7 4 -20 Figure 21: Typical Propagation Delay vs. Temperature AC NOISE - mVRMS 8 80 100 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 -200 1000 10000 100000 Frequency (Hz) 1000000 AV02-3564EN 11 ACPL-C87AT/ACPL-C87BT Data Sheet Automotive High Precision DC Voltage Isolation Sensor Figure 25: Common Mode Transient Immunity Test Circuit 5V 5V 1 nF 20 k: 39 : 0.1 PF 0.1 PF 20 k: VOUT 20 k: 10 nF 1 nF 20 k: ACPL-C87AT/BT + – VCM Figure 26: Shutdown Timing Diagram 5V VSHDN 0V 2V VIN 0V 2.4 V VOUT+ – VOUT- tSD tON 0V -2.4 V Figure 27: Propagation Delay Diagram 2V VIN 0V 2V 90% 1V VO+ – VO- 50% 10% 0V 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 V+ 10 k: Battery Cells R12 C7 1 nF R13 20 : ACPL-M49T R1 C4 0.1 PF C2 0.1 PF R2 R7 20 k: R4 20 k: VOUT R3 39 : VC1 10 nF ACPL-C87AT/BT M C U R5 20 k: C6 R6 20 k: 1 nF Vref 0.1 PF Bypass Capacitor A 0.1-µF bypass capacitor must be connected as near as possible between VDD1 to GND1 and VDD2 to GND2 (Figure 29). Figure 29: Bypass Capacitors C2, C4 C2 0.1 PF C4 0.1 PF ACPL-C87AT/BT Broadcom AV02-3564EN 13 ACPL-C87AT/ACPL-C87BT Data Sheet Anti-aliasing Filter A 39Ω resistor and a 10-nF capacitor are recommended to be connected to the input (VIN) as anti-aliasing filter 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. Figure 30: Anti-aliasing Filter C1, R3 Automotive High Precision DC Voltage Isolation Sensor To reduce the voltage stress of a sole resistor, R1 can be a series of several resistors. Post Amplifier Circuit The output of ACPL-C87AT/BT is a differential output (VOUT+ and VOUT- pins). A post amplifier circuit is needed to 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. 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 R4 20 k: R5 20 k: ACPL-C87AT/BT Designing the Input Resistor Divider 1. Choose the sensing current (Isense) for bus voltage; for example, 1 mA. 2. Determine R2, R2 = Voltage input range 2V = = 2 k: ISENSE 1 mA 3. Determine R1 using voltage divider formula: (V+ – V-) x R1 = R2 = Voltage input range, or R1 + R2 (V+ – V-) xR2 – R2 Voltage input range where (V+ – V-) is the high voltage input; for example, 0 to 600V, R1 = 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. Shutdown Function ACPL-C87AT/BT has a shutdown function to disable the device and make the output (VOUT+ – VOUT-) low. A voltage of 5V on SHDN pin will shutdown the device producing an output (VOUT+ – VOUT-) of –2.6V. To be able to control the SHDN function (example, from microprocessor), an optocoupler (ACPL-M49T) is used. Total System Error 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. Isolation Amplifier Error is shown in the following table. (600 V – 0 V) x2 k: – 2 k:= 598 k: 2V Broadcom AV02-3564EN 14 ACPL-C87AT/ACPL-C87BT Data Sheet Automotive High Precision DC Voltage Isolation Sensor Isolation Amplifier Error Calculation 3Distribution or Specificationa Typical ACPL-C87AT ACPL-C87BT Figure A Error due to offset voltage (25°C) 0.015% 0.5% 0.5% Offset Voltage /Recommended specs input voltage range (2.0V) B Error due to offset voltage drift (across temperature) 0.1% 0.4% 0.4% Offset Voltage /Recommended input voltage range (2.0V) C Error due to gain tolerance (25°C) 0% 1% 0.5% D Error due to gain drift (across temperature) 0.25% 0.8% 0.8% E Error due to Nonlinearity (across temperature) 0.05% 0.12% 0.12% F Total uncalibrated error (A+B+C+D+E) 0.415% 2.82% 2.32% G Total offset calibrated error (F – A) 0.4% 2.32% 1.82% Total gain and offset calibrated error (G – C) 0.4% 1.32% 1.32% H specs specs a. 3 distribution is based on corner wafers. 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. 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 32: Component Placement Recommendation 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. 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. Figure 33: Bottom Layer Layout Recommendation R1 (Series Resistors) BYPASS CAPACITORS Isolation Clearance GND1 ANTI ALIASING FILTER Broadcom GND2 ACPL-C87AT/BT AV02-3564EN 15 Broadcom, the pulse logo, Connecting everything, Avago Technologies, Avago, the A logo, and R2Coupler are among the trademarks of Broadcom and/or its affiliates in the United States, certain other countries, and/or the EU. Copyright © 2013–2018 Broadcom. All Rights Reserved. The term “Broadcom” refers to Broadcom Inc. and/or its subsidiaries. For more information, please visit www.broadcom.com. Broadcom reserves the right to make changes without further notice to any products or data herein to improve reliability, function, or design. 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