HCNR201#550

Data Sheet HCNR200 and HCNR201 High-Linearity Analog Optocouplers Description The Broadcom® HCNR200/201 high-linearity analog optocoupler consists of a high-performance AlGaAs LED that illuminates two closely matched photodiodes. The input photodiode monitors, and therefore stabilizes, the light output of the LED. As a result, the nonlinearity and drift characteristics of the LED can be virtually eliminated. The output photodiode produces a photocurrent that is linearly related to the light output of the LED. The close matching of the photodiodes and advanced design of the package ensure the high linearity and stable gain characteristics of the optocoupler. The HCNR200/201 isolates analog signals in a wide variety of applications that require good stability, linearity, bandwidth, and low cost. The HCNR200/201 is flexible and, by appropriate design of the application circuit, is capable of operating in many different modes, including unipolar/ bipolar, AC/DC and inverting/noninverting. The HCNR200/201 is an excellent solution for many analog isolation problems. Features   Low nonlinearity: 0.01% K3 (IPD2/IPD1) transfer gain HCNR200: ±15% HCNR201: ±5%       Low gain temperature coefficient: 65 ppm/°C Wide bandwidth – DC to >1 MHz Worldwide safety approval – UL 1577 recognized (5 kV rms/1 min. rating) – CSA approved – IEC/EN/DIN EN 60747-5-5 approved VIORM = 1414 Vpeak (option -050E/-350E/-550E) Surface mount option available (Option #300) 8-pin DIP package – 0.400-in. spacing Allows flexible circuit design Applications    Low cost analog isolation Telecom: Modem, PBX Industrial process control: Transducer isolator Isolator for thermocouples 4 mA to 20 mA loop isolation    SMPS feedback loop, SMPS feedforward Monitor motor supply voltage Medical CAUTION! Take normal static precautions in handling and assembly of this component to prevent damage and/or degradation which may be induced by ESD. The components featured in this data sheet are not to be used in military or aerospace applications or environments. The components are not AEC-Q100 qualified and not recommended for automotive applications. Broadcom AV02-0886EN June 25, 2021 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Schematic 1 8 LED CATHODE NC VF IF + LED ANODE NC 2 7 3 6 PD1 CATHODE IPD1 PD2 CATHODE I PD2 PD1 ANODE PD2 ANODE 4 5 Ordering Information HCNR200/HCNR201 is UL Recognized with 5000 Vrms for 1 minute per UL1577. Option Part Number HCNR200 HCNR201 RoHS Compliant Non-RoHS Compliant -000E no option -300E #300 -500E #500 -050E #050 -350E -550E Package 400-mil Widebody DIP-8 Surface Mount Gull Wing X X X X #350 X X #550 X X UL 5000 Vrms/ Tape and 1 Minute Reel rating X X IEC/EN/DIN EN 60747-5-5 VIORM = 1414 Vpeak Quantity X 42 per tube X 42 per tube X 750 per reel X X 42 per tube X X 42 per tube X X 750 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 1: HCNR200-550E to order product of Gull Wing Surface Mount package in Tape and Reel packaging with IEC/EN/ DIN EN 60747-5-5 VIORM = 1414 Vpeak Safety Approval and UL 5000 Vrms for 1 minute rating and RoHS compliant. Example 2: HCNR201 to order product of 8-Pin Widebody DIP package in Tube packaging with UL 5000 Vrms for 1 minute rating and non RoHS compliant. Option data sheets are available. Contact your Broacom sales representative or authorized distributor for information. NOTE: Broadcom The notation ‘#XXX’ is used for existing products, while (new) products launched since July 15, 2001 and RoHS compliant will use ‘-XXXE’. AV02-0886EN 2 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Package Outline Drawings Figure 1: 8-Pin DIP 0.20 (0.008) 0.30 (0.012) 11.30 (0.445) MAX. 8 7 6 5 MARKING A HCNR200 z yyww EEE * PIN ONE 1 2 3 LOT ID 9.00 (0.354) TYP. 10.16 (0.400) TYP. 11.00 (0.433) MAX. 0° 15° 4 1.50 (0.059) MAX. 1 5.10 (0.201) MAX. LED 2 0.51 (0.021) MIN. 1.70 (0.067) 1.80 (0.071) 3.10 (0.122) 3.90 (0.154) 0.40 (0.016) 0.56 (0.022) 2.54 (0.100) TYP. K2 K1 3 4 NC 8 NC 7 6 PD1 PD2 5 DIMENSIONS IN MILLIMETERS AND (INCHES). MARKING : yy - Year ww - Work Week Marked with black dot - Designates Lead Free option E XXX = 050 ONLY if option #050,#350,#550 (or -050,-350,-550) ordered (otherwise blank) * - Designates pin 1 NOTE: FLOATING LEAD PROTRUSION IS 0.25 mm (10 mils) MAX. Broadcom AV02-0886EN 3 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Gull Wing Surface Mount Option #300 Figure 2: 8-Pin Gull Wing Surface Mount Option #300 11.15 ± 0.15 (0.442 ± 0.006) 8 7 6 LAND PATTERN RECOMMENDATION 5 9.00 ± 0.15 (0.354 ± 0.006) 1 2 3 13.56 (0.534) 4 1.3 (0.051) 2.29 (0.09) 12.30 ± 0.30 (0.484 ± 0.012) 1.55 (0.061) MAX. 11.00 MAX. (0.433) 4.00 MAX. (0.158) 1.78 ± 0.15 (0.070 ± 0.006) 2.54 (0.100) BSC 0.75 ± 0.25 (0.030 ± 0.010) DIMENSIONS IN MILLIMETERS (INCHES). LEAD COPLANARITY = 0.10 mm (0.004 INCHES). 1.00 ± 0.15 (0.039 ± 0.006) + 0.076 0.254 - 0.0051 + 0.003) (0.010 - 0.002) 7° NOM. NOTE: FLOATING LEAD PROTRUSION IS 0.25 mm (10 mils) MAX. Broadcom AV02-0886EN 4 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Solder Reflow Profile The recommended reflow soldering conditions are per JEDEC Standard J-STD-020 (latest revision). Non-halide flux should be used. Regulatory Information The HCNR200/201 optocoupler features a 0.400-in. wide, eight-pin DIP package. This package was specifically designed to meet worldwide regulatory requirements. The HCNR200/201 has been approved by the following organizations. Recognized under UL 1577, Component Recognition Program, FILE E55361. UL IEC/EN/DIN EN 60747-5-5 Approved under CSA Component Acceptance Notice #5, File CA 88324 CSA Insulation and Safety-Related Specifications Parameter Symbol Value Units Min. External Clearance (External Air Gap) L(IO1) 9.6 mm Measured from input terminals to output terminals, shortest distance through air Min. External Creepage (External Tracking Path) L(IO2) 10.0 mm Measured from input terminals to output terminals, shortest distance path along body Min. Internal Clearance (Internal Plastic Gap) 1.0 mm Through insulation distance conductor to conductor, usually the direct distance between the photoemitter and photodetector inside the optocoupler cavity Min. Internal Creepage (Internal Tracking Path) 4.0 mm The shortest distance around the border between two different insulating materials measured between the emitter and detector 200 V Comparative Tracking Index Isolation Group CTI IIIa Conditions DIN IEC 112/VDE 0303 PART 1 Material group (DIN VDE 0110) NOTE: Option 300 – surface mount classification is Class A in accordance with CECC 00802. Broadcom AV02-0886EN 5 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers IEC/EN/DIN EN 60747-5-5 Insulation Characteristics (Option -050E/-350E/-550E Only) Description Symbol Characteristic Units Installation classification per DIN VDE 0110, Table 1 For rated mains voltage ≤ 600 V rms I-IV For rated mains voltage ≤1000 V rms I-III Climatic Classification 40/85/21 Pollution Degree (DIN VDE 0110/39) 2 Maximum Working Insulation Voltage VIORM 1414 Vpeak Input to Output Test Voltage, Method b VPR = 1.875 × VIORM, 100% Production Test with tm = 1s, Partial Discharge < 5 pC VPR 2651 Vpeak Input to Output Test Voltage, Method aa VPR = 1.6 × VIORM, Type and sample test, tm = 10s, Partial Discharge < 5 pC VPR 2262 Vpeak VIOTM 8000 Vpeak Case Temperature TS 150 °C Current (Input Current IF, PS = 0) IS 400 mA PS,OUTPUT 700 mW RS > 109 Ω a Highest Allowable Overvoltagea (Transient Overvoltage, tini = 60s) Safety-Limiting Values (Maximum values allowed in the event of a failure) Output Power Insulation Resistance at TS, VIO = 500V a. Refer to the front of the Optocoupler section of the current catalog for a more detailed description of IEC/EN/DIN EN 60747-5-5 and other product safety regulations. NOTE: Optocouplers providing safe electrical separation per IEC/EN/DIN EN 60747-5-5 do so only within the safety-limiting values to which they are qualified. Protective cut-out switches must be used to ensure that the safety limits are not exceeded. Absolute Maximum Ratings Description Rating Storage Temperature –55°C to +125°C Operating Temperature (TA) –55°C to +100°C Junction Temperature (TJ) 125°C Reflow Temperature Profile See Package Outline Drawings Lead Solder Temperature (up to seating plane) 260°C for 10s Average Input Current – IF 25 mA Peak Input Current – IF (50 ns maximum pulse width) 40 mA Reverse Input Voltage – VR (IR = 100 µA, Pins 1 to 2) 2.5V Input Power Dissipation (Derate at 2.2 mW/°C for operating temperatures above 85°C) 60 mW at TA = 85°C Reverse Output Photodiode Voltage (Pins 6 to 5) 30V Reverse Input Photodiode Voltage (Pins 3 to 4) 30V Broadcom AV02-0886EN 6 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Recommended Operating Conditions Description Condition Storage Temperature –40°C to +85°C Operating Temperature –40°C to +85°C Average Input Current – IF 1 mA to 20 mA Peak Input Current – IF (50% duty cycle, 1-ms pulse width) 35 mA Reverse Output Photodiode Voltage (Pins 6 to 5) 0 to 15V Reverse Input Photodiode Voltage (Pins 3 to 4) 0 to 15V Electrical Specifications TA = 25°C unless otherwise specified. Parameter Transfer Gain Symbol Device Min. Typ. Max. K3 HCNR200 0.85 1.00 1.15 5 nA < IPD < 50 µA, 0V < VPD < 15V HCNR201 0.95 1.00 1.05 5 nA < IPD < 50 µA, 0V < VPD < 15V a HCNR201 0.93 1.00 1.07 –40°C < TA < 85°C, 5 nA < IPD < 50 µA, 0V < VPD < 15V a — –65 — HCNR200 — 0.01 0.25 HCNR201 — 0.01 0.05 5 nA < IPD < 50 µA, 0V < VPD < 15V b HCNR201 — 0.01 0.07 –40°C < TA < 85°C, 5 nA < IPD < 50 µA, 0V < VPD < 15V b — 0.016 — % 5 nA < IPD < 50 µA, 0V < VPD < 15V c HCNR200 0.25 0.50 0.75 % 0.36 0.48 0.72 IF = 10 mA, 0V < VPD1 < 15V 8 HCNR201 –40°C < TA < 85°C, IF = 10 mA, 0V < VPD1 < 15V 8 9 Temperature Coefficient of Transfer Gain K3/TA DC Nonlinearity (Best Fit) NLBF DC Nonlinearity (Ends Fit) NLEF Input Photodiode Current Transfer Ratio (IPD1/IF) K1 Units Test Conditions ppm/°C –40°C < TA < 85°C, 5 nA < IPD < 50 µA, 0V < VPD < 15V % 5 nA < IPD < 50 µA, 0V < VPD < 15V Temperature Coefficient of K1 K1/TA — –0.3 — %/°C Photodiode Leakage Current ILK — 0.5 25 nA IF = 0 mA, 0V < VPD < 15V BVRPD 30 150 — V IR = 100 µA CPD — 22 — pF VPD = 0V Photodiode Reverse Breakdown Voltage Photodiode Capacitance Broadcom Figure Note 3, 4 a 3, 4 5, 6, 7 b AV02-0886EN 7 HCNR200 and HCNR201 Data Sheet Parameter LED Forward Voltage High-Linearity Analog Optocouplers Symbol Device VF Min. Typ. Max. Units 1.3 1.6 1.85 V 1.2 1.6 1.95 LED Reverse Breakdown Voltage BVR 2.5 9 — Temperature Coefficient of Forward Voltage VF/TA — –1.7 — LED Junction Capacitance CLED — 80 — Test Conditions IF = 10 mA Figure Note 10, 11 IF = 10 mA, –40°C < TA < 85°C V IF = 100 µA mV/°C IF = 10 mA pF f = 1 MHz, VF = 0V a. K3 is calculated from the slope of the best fit line of IPD2 vs. IPD1 with eleven equally distributed data points from 5 nA to 50 µA. This is approximately equal to IPD2/IPD1 at IF = 10 mA. b. BEST FIT DC NONLINEARITY (NLBF) is the maximum deviation expressed as a percentage of the full scale output of a “best fit” straight line from a graph of IPD2 vs. IPD1 with eleven equally distributed data points from 5 nA to 50 µA. IPD2 error to best fit line is the deviation below and above the best fit line, expressed as a percentage of the full scale output. c. ENDS FIT DC NONLINEARITY (NLEF) is the maximum deviation expressed as a percentage of full scale output of a straight line from the 5 nA to the 50 µA data point on the graph of IPD2 vs. IPD1. AC Electrical Specifications TA = 25°C unless otherwise specified. Parameter Min. Typ. Max. Units Test Conditions Figure — 9 — MHz IF = 10 mA High Speed — 1.5 — MHz 17 a High Precision — 10 — kHz 18 a — 95 17 a, b LED Bandwidth Symbol f – 3 dB Device Note Application Circuit Bandwidth Application Circuit: IMRR High Speed dB freq = 60 Hz a. Specific performance will depend on circuit topology and components. b. IMRR is defined as the ratio of the signal gain (with signal applied to VIN of Figure 17) to the isolation mode gain (with VIN connected to input common and the signal applied between the input and output commons) at 60 Hz, expressed in dB. Broadcom AV02-0886EN 8 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Package Characteristics TA = 25°C unless otherwise specified. Parameter Symbol Device Min. Typ. Max. Input-Output Momentary-Withstand Voltagea VISO 5000 — — Resistance (Input-Output) RI-O 1012 1013 — 1011 — — — 0.4 0.6 Capacitance (Input-Output) CI-O Units Test Conditions Figure V rms RH ≤ 50%, t = 1 min. Ω pF Note b c , VO = 500 VDC b TA = 100°C, VIO = 500 VDC b f = 1 MHz b a. The Input-Output Momentary-Withstand Voltage is a dielectric voltage rating that should not be interpreted as an input-output continuous voltage rating. For the continuous voltage rating, refer to the VDE 0884 Insulation Characteristics Table (if applicable), your equipment level safety specification, or Application Note 1074, Optocoupler Input-Output Endurance Voltage. b. The 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 of ≥.6000 V rms for ≥.1 second (leakage detection current limit, II-O of 5 µA max.). This test is performed before the 100% production test for partial discharge (method b) shown in the IEC/EN/DIN EN 60747-5-5 Insulation Characteristics Table (for Option -050E/-350E/-550E only). Broadcom AV02-0886EN 9 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 3: Normalized K3 vs. Input IPD 0.02 = NORM K3 MEAN = NORM K3 MEAN ± 2 • STD DEV DELTA K3 – DRIFT OF K3 TRANSFER GAIN NORMALIZED K3 – TRANSFER GAIN 1.06 Figure 4: K3 Drift vs. Temperature 1.04 1.02 1.00 0.98 0.96 0.94 0.0 NORMALIZED TO BEST-FIT K3 AT TA = 25°C, 0 V < VPD < 15 V 10.0 20.0 30.0 40.0 50.0 60.0 0.015 0 V < VPD < 15 V 0.01 0.005 0.0 -0.005 -0.01 = DELTA K3 MEAN = DELTA K3 MEAN ± 2 • STD DEV -0.015 -0.02 -55 -25 IPD1 – INPUT PHOTODIODE CURRENT – μA 0.035 = ERROR MEAN = ERROR MEAN ± 2 • STD DEV 0.02 0.01 0.00 -0.01 -0.02 -0.03 0.0 TA = 25 °C, 0 V < VPD < 15 V 10.0 20.0 30.0 40.0 50.0 0.02 0.015 0.01 0 V < VPD < 15 V 5 nA < IPD < 50 μA 0.005 0.00 -55 -25 0.005 0.0 -0.005 -0.01 = DELTA NLBF MEAN = DELTA NLBF MEAN ± 2 • STD DEV 35 65 TA – TEMPERATURE – °C Broadcom 95 125 NORMALIZED K1 – INPUT PHOTODIODE CTR DELTA NLBF – DRIFT OF BEST-FIT NL – % PTS 0.01 5 5 35 65 95 125 Figure 8: Input Photodiode CTR vs. LED Input Current 0 V < VPD < 15 V 5 nA < IPD < 50 μA -25 125 TA – TEMPERATURE – °C 0.02 -0.02 -55 95 0.025 60.0 Figure 7: NLBF Drift vs. Temperature -0.015 65 = NLBF 50TH PERCENTILE = NLBF 90TH PERCENTILE 0.03 IPD1 – INPUT PHOTODIODE CURRENT – μA 0.015 35 Figure 6: NLBF vs. Temperature NLBF – BEST-FIT NON-LINEARITY – % IPD2 ERROR FROM BEST-FIT LINE (% OF FS) Figure 5: IPD2 Error vs. Input IPD (see note b) 0.03 5 TA – TEMPERATURE – °C 1.2 -55°C 1.1 -40°C 1.0 0.9 25°C 85°C 100°C 0.8 0.7 0.6 0.5 NORMALIZED TO K1 CTR AT IF = 10 mA, TA = 25°C 0 V < VPD1 < 15 V 0.4 0.3 0.2 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 IF – LED INPUT CURRENT – mA AV02-0886EN 10 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 9: Typical Photodiode Leakage vs. Temperature Figure 10: LED Input Current vs. Forward Voltage 100 TA = 25°C VPD = 15 V IF – FORWARD CURRENT – mA ILK – PHOTODIODE LEAKAGE – nA 10.0 8.0 6.0 4.0 2.0 0.0 -55 -25 5 35 65 95 125 10 1 0.1 0.01 0.001 0.0001 1.20 TA – TEMPERATURE – °C 1.40 1.60 1.50 VF – FORWARD VOLTAGE – VOLTS Figure 11: LED Forward Voltage vs. Temperature Figure 12: Thermal Derating Curve Dependence of Safety-Limiting Value with Case Temperature per IEC/EN/DIN EN 60747-5-5 1000 1.8 VF – LED FORWARD VOLTAGE – V 1.30 1.7 PS OUTPUT POWER – mV IS INPUT CURRENT – mA 900 IF = 10 mA 800 700 1.6 600 500 1.5 400 1.4 300 200 1.3 1.2 -55 100 0 -25 5 35 65 TA – TEMPERATURE – °C Broadcom 95 125 0 25 50 75 100 125 150 175 TS – CASE TEMPERATURE – °C AV02-0886EN 11 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 13: Basic Isolation Amplifier R2 VIN R1 IPD1 PD1 + A1 LED IPD2 A2 + PD2 VOUT IF A) BASIC TOPOLOGY VCC VIN C1 R1 PD1 A1 + R2 C2 LED - R3 PD2 PD2 A2 + VOUT B) PRACTICAL CIRCUIT Figure 14: Unipolar Circuit Topologies VCC VIN - - + + A) POSITIVE INPUT VOUT B) POSITIVE OUTPUT VIN - - + + C) NEGATIVE INPUT Broadcom VOUT D) NEGATIVE OUTPUT AV02-0886EN 12 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 15: Bipolar Circuit Topologies VCC1 VCC2 VCC1 IOS1 IOS2 VIN - - + + VOUT A) SINGLE OPTOCOUPLER VCC + VIN - VOUT + + B) DUAL OPTOCOUPLER Figure 16: Loop-Powered 4 mA to 20 mA Current Loop Circuits R2 +IIN R1 D1 PD1 + PD2 LED VOUT + R3 -IIN A) RECEIVER VCC VIN R1 LED R2 PD1 + D1 +IOUT Q1 + PD2 R3 -IOUT B) TRANSMITTER Broadcom AV02-0886EN 13 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 17: High-Speed Low-Cost Analog Isolator VCC2 +5 V VCC1 +5 V LED R3 10 K VIN R1 68 K R2 68 K Q2 2N3904 Q1 2N3906 R4 10 PD1 R5 10 K R7 470 VOUT Q3 2N3906 PD2 Q4 2N3904 R6 10 Figure 18: Precision Analog Isolation Amplifier VCC1 +15 V VCC2 +15 V C3 0.1μ C5 0.1μ R4 2.2 K R5 270 Q1 2N3906 INPUT BNC 1% PD1 2 3 C2 33 P 7 6 A1 LT1097 + 4 C4 0.1μ VEE1 -15 V Broadcom R6 6.8 K C1 47 P R1 200 K 6 LT1097 174 K 7 - 2 A2 3 + 4 1% R2 50 K OUTPUT BNC PD2 C6 0.1μ R3 33 K LED D1 1N4150 VEE2 -15 V AV02-0886EN 14 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 19: Bipolar Isolation Amplifier C3 C1 R6 180 K R2 180 K D1 R4 680 + OC1 PD1 R1 50 K BALANCE VIN - 10 pf 10 pf R7 50 K GAIN OC1 PD2 OC1 LED - VMAG + OC2 PD1 OC2 LED + - R3 180 K C2 VCC1 = +15 V VEE1 = -15 V OC2 PD2 R5 680 D2 10 pf Figure 20: Magnitude/Sign Isolation Amplifier C3 C1 R5 180 K D1 GAIN + VIN OC1 PD1 R2 10 K R4 680 R3 4.7 K OC1 PD2 - VMAG + OC1 LED + D2 R6 50 K D3 - R1 220 K 10 pf 10 pf D4 + C2 VCC 10 pf + - R7 6.8 K R8 2.2 K VSIGN VCC1 = +15 V VEE1 = -15 V Broadcom OC2 6N139 AV02-0886EN 15 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 21: SPICE Model Listing Broadcom AV02-0886EN 16 HCNR200 and HCNR201 Data Sheet High-Linearity Analog Optocouplers Figure 22: 4 mA to 20 mA HCNR200 Receiver Circuit 0.001 μF +ILOOP HCNR200 LED R1 10 k: R4 100 : HCNR200 PD1 + R2 10 k: -ILOOP R5 80 k: Z1 5.1 V VCC 5.5 V 0.1 μF LM158 - 2N3906 - + LM158 VOUT HCNR200 PD2 0.001 μF R3 25 : 2 Design Equations: (VOUT / ILOOP) = K3 (R5 R3) / (R1 + R3) K3 = K2 / K1 = Constant = 1 The two OP-AMPS shown are two separate LM158 ICs, and not two channels in a dual package; otherwise, the LOOP side and the output side will not be properly isolated. NOTE: Figure 23: 4 mA to 20 mA HCNR200 Transmitter Circuit VCC 5.5 V 0.001 μF VCC R1 80 k: VIN + +ILOOP R2 150 : R8 100 k: HCNR200 LED 2N3906 LM158 HCNR200 PD1 R3 10 k: 2N3904 Z1 5.1 V 0.001 μF 2N3904 LM158 2N3904 0.1 μF R7 3.2 k: R6 140 : HCNR200 PD2 + R4 10 k: 1 -ILOOP R5 25 : Design Equations: (ILOOP / Vin) = K3 (R5 + R3) / (R5 R1) K3 = K2 / K1 = Constant ≈ 1 NOTE: Broadcom The two OP-AMPS shown are two separate LM158 ICs, and not dual channels in a single package; otherwise, the LOOP side and input side will not be properly isolated. The 5V1 Zener should be properly selected to ensure that it conducts at 187 µA. AV02-0886EN 17 HCNR200 and HCNR201 Data Sheet Theory of Operation Figure 1 shows how the HCNR200/201 high-linearity optocoupler is configured. The basic optocoupler consists of an LED and two photodiodes. The LED and one of the photodiodes (PD1) is on the input leadframe and the other photodiode (PD2) is on the output leadframe. The package of the optocoupler is constructed so that each photodiode receives approximately the same amount of light from the LED. An external feedback amplifier can be used with PD1 to monitor the light output of the LED and automatically adjust the LED current to compensate for any nonlinearities or changes in light output of the LED. The feedback amplifier acts to stabilize and linearize the light output of the LED. The output photodiode then converts the stable, linear light output of the LED into a current, which can then be converted back into a voltage by another amplifier. Figure 13a illustrates the basic circuit topology for implementing a simple isolation amplifier using the HCNR200/201 optocoupler. Besides the optocoupler, two external op-amps and two resistors are required. This circuit is actually a bit too simple to function properly in an actual circuit, but it is quite useful for explaining how the basic isolation amplifier circuit works (a few more components and a circuit change are required to make a practical circuit, like the one shown in Figure 13b). The operation of the basic circuit may not be immediately obvious just from inspecting Figure 13a, particularly the input part of the circuit. Stated briefly, amplifier A1 adjusts the LED current (IF), and therefore the current in PD1 (IPD1), to maintain its “+” input terminal at 0V. For example, increasing the input voltage would tend to increase the voltage of the “+” input terminal of A1 above 0V. A1 amplifies that increase, causing IF to increase, as well as IPD1. Because of the way that PD1 is connected, IPD1 pulls the “+” terminal of the op-amp back toward ground. A1 continues to increase IF until its “+” terminal is back at 0V. Assuming that A1 is a perfect op-amp, no current flows into the inputs of A1; therefore, all of the current flowing through R1 will flow through PD1. Because the “+” input of A1 is at 0V, the current through R1, and therefore IPD1 as well, is equal to VIN / R1. Essentially, amplifier A1 adjusts IF so that High-Linearity Analog Optocouplers Notice that IPD1 depends only on the input voltage and the value of R1 and is independent of the light output characteristics of the LED. As the light output of the LED changes with temperature, amplifier A1 adjusts IF to compensate and maintain a constant current in PD1. Also notice that IPD1 is exactly proportional to VIN, giving a very linear relationship between the input voltage and the photodiode current. The relationship between the input optical power and the output current of a photodiode is very linear. Therefore, by stabilizing and linearizing IPD1, the light output of the LED is also stabilized and linearized. And because light from the LED falls on both of the photodiodes, IPD2 will be stabilized as well. The physical construction of the package determines the relative amounts of light that fall on the two photodiodes and, therefore, the ratio of the photodiode currents. This results in very stable operation over time and temperature. The photodiode current ratio can be expressed as a constant, K, where K = IPD2 / IPD1 Amplifier A2 and resistor R2 form a trans-resistance amplifier that converts IPD2 back into a voltage, VOUT, where VOUT = IPD2 × R2 Combining the above three equations yields an overall expression relating the output voltage to the input voltage: VOUT / VIN = K × (R2 / R1) Therefore the relationship between VIN and VOUT is constant, linear, and independent of the light output characteristics of the LED. The gain of the basic isolation amplifier circuit can be adjusted simply by adjusting the ratio of R2 to R1. The parameter K (called K3 in the electrical specifications) can be thought of as the gain of the optocoupler and is specified in the data sheet. Remember, the circuit in Figure 13a is simplified to explain the basic circuit operation. A practical circuit, more like Figure 13b, will require a few additional components to stabilize the input part of the circuit, to limit the LED current, or to optimize circuit performance. Example application circuits will be described later in the data sheet. IPD1 = VIN / R1. Broadcom AV02-0886EN 18 HCNR200 and HCNR201 Data Sheet Circuit Design Flexibility Circuit design with the HCNR200/201 is very flexible because the LED and both photodiodes are accessible to the designer. This allows the designer to make performance trade-offs that would otherwise be difficult to make with commercially available isolation amplifiers (for example, bandwidth vs. accuracy vs. cost). Analog isolation circuits can be designed for applications that have either unipolar (for example, 0V to 10V) or bipolar (for example, ±10V) signals, with positive or negative input or output voltages. Several simplified circuit topologies illustrating the design flexibility of the HCNR200/201 are in this section. The circuit in Figure 13a is configured to be non-inverting with positive input and output voltages. By changing the polarity of one or both of the photodiodes, the LED, or the op-amp inputs, it is possible to implement other circuit configurations as well. Figure 14 shows how to change the basic circuit to accommodate both positive and negative input and output voltages. The input and output circuits can be matched to achieve any combination of positive and negative voltages, allowing for both inverting and noninverting circuits. All of the configurations described previously are unipolar (single polarity); the circuits cannot accommodate a signal that might swing both positive and negative. It is possible, however, to use the HCNR200/201 optocoupler to implement a bipolar isolation amplifier. Two topologies that allow for bipolar operation are shown in Figure 15. The circuit in Figure 15a uses two current sources to offset the signal so that it appears to be unipolar to the optocoupler. Current source IOS1 provides enough offset to ensure that IPD1 is always positive. The second current source, IOS2, provides an offset of opposite polarity to obtain a net circuit offset of zero. Current sources IOS1 and IOS2 can be implemented simply as resistors connected to suitable voltage sources. The circuit in Figure 15b uses two optocouplers to obtain bipolar operation. The first optocoupler handles the positive voltage excursions, while the second optocoupler handles the negative ones. The output photodiodes are connected in an antiparallel configuration so that they produce output signals of opposite polarity. High-Linearity Analog Optocouplers The first circuit has the obvious advantage of requiring only one optocoupler; however, the offset performance of the circuit is dependent on the matching of IOS1 and IOS2 and is also dependent on the gain of the optocoupler. Changes in the gain of the optocoupler directly affect the offset of the circuit. The offset performance of the second circuit, on the other hand, is much more stable; it is independent of optocoupler gain and has no matched current sources to worry about. However, the second circuit requires two optocouplers, separate gain adjustments for the positive and negative portions of the signal, and can exhibit crossover distortion near 0V. The correct circuit to choose for an application would depend on the requirements of that particular application. As with the basic isolation amplifier circuit in Figure 13a, the circuits in Figure 15 are simplified and would require a few additional components to function properly. Two example circuits that operate with bipolar input signals are described in the next section. As a final example of circuit design flexibility, the simplified schematics in Figure 16 illustrate how to implement 4 mA to 20 mA analog current-loop transmitter and receiver circuits using the HCNR200/201 optocoupler. In these circuits, the loop side of the circuit is powered entirely by the loop current, eliminating the need for an isolated power supply. The input and output circuits in Figure 16a are the same as the negative input and positive output circuits shown in Figure 14c and Figure 14b, except for the addition of R3 and zener diode D1 on the input side of the circuit. D1 regulates the supply voltage for the input amplifier, while R3 forms a current divider with R1 to scale the loop current down from 20 mA to an appropriate level for the input circuit (