® ISO213 13 O2 IS Two-Port Isolated, Low Profile ISOLATED INSTRUMENTATION AMPLIFIER FEATURES APPLICATIONS ● GAIN RANGE: 0.5 - 5000 ● ±10V INPUT SIGNAL RANGE ● INSTRUMENTATION AMPLIFIER INPUTS ● INDUSTRIAL PROCESS CONTROL: Transducer Channel Isolator for Thermocouples, RTDs, Pressure Bridges, Flow Meters ● 4mA TO 20mA LOOP ISOLATION ● MOTOR AND SCR CONTROL ● ±40V INPUT OVER VOLTAGE PROTECTION ● 12-BIT ACCURACY ● LOW PROFILE (Less Than 0.5" High) ● SMALL FOOTPRINT ● EXTERNAL POWER CAPABILITY (±14V at 3mA) ● SYNCHRONIZATION CAPABILITY ● SINGLE 12V TO 15V SUPPLY OPERATION ● LOW POWER (45mW) ● ● ● ● GROUND LOOP ELIMINATION ANALYTICAL MEASUREMENTS POWER PLANT MONITORING DATA ACQUISITION/TEST EQUIPMENT ISOLATION ● MULTIPLEXED SYSTEMS WITH CHANNEL TO CHANNEL ISOLATION Isolation Barrier DESCRIPTION 8 ISO213 signal isolation amplifier is a member of a series of low-cost isolation products from Burr-Brown. The low-profile ZIP plastic package allows PCB spacings of 0.5" to be achieved, and the small footprint results in efficient use of board space. To provide isolation, the design uses high-efficiency, miniature toroidal transformers in both the signal and power paths. An uncommitted instrumentation amplifier on the input and an isolated external bipolar supply ensure the majority of input interfacing or conditioning needs can be met. Gain Set –VIN 7 3 38 +VIN FB +VSS Out Com 1 –VSS Out 1 37 VOUT ACom 2 4 6 DC/DC Converter 31 2 5 32 +VCC Com 2 34 35 Clock Out Clock In International Airport Industrial Park • Mailing Address: PO Box 11400 Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • © 1995 Burr-Brown Corporation • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706 Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 PDS-881E PDS-1281A Printed in U.S.A. April, 1995 SPECIFICATIONS At TA = +25°C, VCC = +15V, unless otherwise noted. ISO213P PARAMETER CONDITIONS ISOLATION Voltage Rated Continuous AC, 50/60Hz DC Rated 1 min AC, 50/60Hz 100% Test (AC, 50Hz) Isolation-Mode Rejection(1) AC DC Barrier Resistance Barrier Capacitance Leakage Current(2) GAIN Equation Initial Error Gain vs Temperature Non-Linearity(3) INPUT OFFSET VOLTAGE Offset Voltage RTI vs Temperature vs Power Supply(4) MIN Partial Discharge 1s <5pC VISO = Rated Continuous 50/60Hz TYP Vrms VDC 2500 2500 Vrms Vrms 115 160 1010 15 VISO = 240Vrms, 60Hz VISO = 240Vrms, 50Hz G = 0.5 G = 0.5 VO = –5V to +5V, G = 0.5 G = (1 + 50k/RG)/2 ±0.2 10 0.01 G = 0.5,VCC = 14V to 16V ±5 ±35/G ±3 ±1 ±1 G = 0.5 VCM = ±10V, ∆RS = 1kΩ G = 0.5 G=5 G = 50 G = 500 Full Signal Bandwidth ISOLATED POWER OUTPUTS Voltage Outputs (±VSS)(7) vs Temperature vs Load Current Output(7) (Both Loaded) (One Loaded) POWER SUPPLIES Rated Voltage Voltage Range(5, 9) Quiescent Current ±3 50 0.025 % FSR(8) ppm of FSR/°C %FSR ±0.5 ±25/G mV µV/°C mV/V ±10 ±10 nA nA ±12 V 73 89 98 100 90 110 120 125 dB dB dB dB 1010 || 3 1010 || 6 Ω || pF Ω || pF 3 1 20 kΩ V mVp-p µV/√Hz 1 kHz 200 Hz ±5 Load = 1MΩ f = clk f = 0 to 5kHz FREQUENCY RESPONSE Small Signal Bandwidth 3 2.4 dB dB Ω pF µArms µArms ±10 Impedance Differential Common-Mode OUTPUT Output Impedance Voltage Ripple Voltage(6) Output Noise UNITS 1500 2120 INPUT CURRENT Bias Offset INPUT Linear Input Range(5) Common-Mode Rejection MAX VIN = 1Vp-p, –3dB, G = 0.5 VIN = 10Vp-p, –3dB, G = 0.5 3mA ±13 ±14 7 180 VDC mV/°C mV/mA VSS = ±13V VSS = ±13V 3 4 6 6 mA mA 15 11.4 to 16 3 6 V V mA +70 +85 °C °C Rated Performance No Load TEMPERATURE RANGE Specification Operating 0 –25 NOTES: (1) Isolation-mode rejection is the ratio of the change in output voltage to a change in isolation barrier voltage. (2) Tested at 2500Vrms 50Hz limit 25µA (barrier is essentially capacitive). (3) Nonlinearity is the peak deviation of the output voltage from the best-fit straight line. It is expressed as the ratio of deviation to FSR. (4) Power Supply Rejection is the change in VOS /Supply Change. (5) See max VOUT and VIN vs Supply Voltage in typical performance curves. (6) Ripple is the residual component of the barrier carrier frequency generated internally. (7) Derated at VCC < 15V. (8) FSR = Full Scale Output Range = 10V. (9) Minimum supply voltage is given as 11.4V. This is the minimum supply to ensure a ±5V output swing can be achieved. The ISO213 actually works down to a minimum supply of 4V as shown in the typical performance curve “Max VOUT and VIN vs Supply Voltage.” ® ISO213 2 PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS Supply Voltage Without Damage ......................................................... 18V Continuous Isolation Voltage Across Barrier: ............................ 2500Vr ms Storage Temperature Range ............................................ –25°C to 100°C Lead Temperature (soldering, 10s) ............................................... +300°C Amplifier Output Short-Circuit Duration ............... Continuous to Common Output Voltage to Com 2 ............................................................... ±VCC /2 Bottom View 1 +VIN Com 1 2 3 –VIN FB 4 5 –VSS +VSS 6 7 GSB GSA 8 ELECTROSTATIC DISCHARGE SENSITIVITY This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. 31 +VCC Com 2 32 Clock Out 34 ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 35 Clock In 37 ACom 2 VOUT 38 PACKAGE INFORMATION MODEL PACKAGE PACKAGE DRAWING NUMBER(1) ISO213P 38-Pin Plastic ZIP 326 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. ORDERING INFORMATION MODEL PACKAGE ISO213P 38-Pin Plastic ZIP OPERATING TEMPERATURE RANGE –25°C to +85°C ISOLATION RATING 1 MIN 2500Vr ms The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® 3 ISO213 TYPICAL PERFORMANCE CURVES At TA = +25°C, VCC = +15V, unless otherwise noted. SINE RESPONSE (f = 2kHz) SINE RESPONSE (f = 200Hz) +5 Output Voltage (V) Output Voltage (mV) +500 0 0 –500 –5 VIN = ±10V, G = 0.5 VIN = ±1V, G = 0.5 0 500 0 1000 STEP RESPONSE (f = 2kHz) STEP RESPONSE (f = 200Hz) Output Voltage (V) +5 0 –500 0 –5 V IN = ±10V, G = 0.5 V IN = ±1V, G = 0.5 0 500 1000 0 5 Time (µs) 10 Time (ms) MAX VOUT AND VIN vs SUPPLY VOLTAGE IMR vs FREQUENCY 10 15 85 80 +VOUT 5 5 +VIN 0 0 –VIN –5 –5 + –10 6 8 10 60 55 50 12 –10 14 40 1k Supply Voltage 10k 100k 1M Frequency (Hz) ® ISO213 65 45 –VOUT –15 4 70 ±VOUT – 2 75 IMR (dB) 10 Maximum Output Voltage Maximum Input Voltage 10 Time (ms) +500 Output Voltage (mV) 5 Time (µs) 4 10M 100M TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VCC = +15V, unless otherwise noted. NON-LINEARITY vs CLOCK RATE GAIN ERROR vs CLOCK RATE 0.4 0.3 20 Gain Error (%) Non-Linearity (m%) 30 10 0.2 0.1 0 0 20 40 60 80 100 30 40 60 Clock (kHz) INPUT COMMON-MODE RANGE vs OUTPUT VOLTAGE 15 10 Common-Mode Voltage (V) Input Bias Current (mA) 8 6 G = 500 2 0 G = 0.5 G = 0.5 –2 G = 500 –4 –6 0 40 G≥5 G = 0.5 5 G = 0.5 VD/2 0 VD/2 –5 –10 –15 –7.5 –10 G≥5 10 –8 –40 100 Clock (kHz) INPUT BIAS CURRENT vs INPUT OVERLOAD VOLTAGE 4 80 – VOUT + – ISO213P + VCM All Gains –5 All Gains –2.5 0 2.5 5 7.5 Output Voltage (V) Overload Voltage (V) ® 5 ISO213 ficient for most applications at low frequencies with no external networks connected. DISCUSSION OF SPECIFICATIONS The ripple on ±VSS will typically be 100mVp-p at 25kHz. Loading the supplies will increase the ripple unless extra filtering is added externally; a capacitor of 1µF is normally sufficient for most applications, although in some cases 10µF may be required. Noise introduced onto ±VSS should be decoupled to prevent degraded performance. ISO213 is intended for applications where isolation and input signal conditioning are required. The best signal-tonoise performance is obtained when the input amplifier gain setting is such that FB pin has a full scale range of ±10V. The bandwidth is internally limited to typically 1kHz, making the device ideal for use in conjunction with sensors that monitor slowly varying processes. To power external functions or networks, 3mA at ±14V typical is available at the isolated port. THEORY OF OPERATION ISO213 has no galvanic connection between the input and output. The analog input signal is multiplied by the gain of the input amplifier and accurately reproduced at the output. A simplified diagram of ISO213 is shown in Figure 2. The design consists of a DC/DC converter, an uncommitted input instrumentation amplifier, a modulator circuit and a demodulator circuit with a gain of 0.5. Magnetic isolation is provided by separate transformers in the power and signal paths. LINEARITY PERFORMANCE ISO213 offers non-linearity performance compatible with 12-bit resolution systems (0.025%). Note that the specification is based on a best-fit straight line. INPUT PROTECTION The inputs of ISO213 are individually protected for voltages up to ±40V. For example, a condition of –40V on one input and +40V on the other input will not cause damage. Internal circuitry on each input provides low series impedance under normal signal conditions. To provide equivalent protection, series input resistors would contribute excessive noise. If the input is overloaded, the protection circuitry limits the input current to a safe value of approximately 1.5mA to 5mA. The typical performance curve “Input Bias Current vs Input Overload Voltage” shows this input current limit behavior. The inputs are protected even if the power supplies are disconnected or turned off. The DC/DC converter provides power and synchronization signals across the isolation barrier to operate the instrumentation amplifier and modulator circuitry. It also has sufficient capacity to power external input signal conditioning networks. The uncommitted instrumentation amplifier may be configured for signal buffering or amplification, depending on the application. The modulator converts the input signal to an amplitudemodulated AC signal that is magnetically coupled to the demodulator by a miniature transformer providing the signal-path isolation. The demodulator recovers the input signal from the modulated signal using a synchronous technique to minimize noise and interference. USING ±VSS TO POWER EXTERNAL CIRCUITRY The DC/DC converter in ISO213 runs at a switching frequency of 25kHz. Internal rectification and filtering is sufIsolation Barrier 50kΩ ∆VIN =1+ ∆FB RG 4 1 VIN 3 +VIN 35 FB 34 Clock Clock In Out –VIN 2 Com 1 VOUT 38 ACom 2 37 ∆VIN 50kΩ = 1+ /2 ∆VOUT RG VOUT Com 2 32 +V SS 6 (1) 10µF + –V SS 5 7 Gain Set +V CC RG 31 8 0.1µF (1) + 10µF Tantalum + 10µF Input Ground Plane 100µH +15V Output Ground Plane NOTE: (1) 10µF decoupling to be used with external loads connected FIGURE 1. Power Supply and Signal Connections Shown for Non-Inverting, Unity Gain Configuration. ® ISO213 6 ABOUT THE BARRIER For any isolation product, barrier integrity is of paramount importance in achieving high reliability. ISO213 uses miniature toroidal transformers designed to give maximum isolation performance when encapsulated with a high dielectric-strength material. The internal component layout is designed so that circuitry associated with each side of the barrier is positioned at opposite ends of the package. Areas where high electric fields can exist are positioned in the center of the package. The result is that the dielectric strength of the barrier typically exceeds 3kVrms. ISOLATION VOLTAGE RATINGS Because a long term test is impractical in a manufacturing situation, the generally accepted practice is to perform a production test at a high voltage for some shorter time. The relationship between actual test voltage and the continuous derated maximum specification is an important one. Historically, Burr-Brown has chosen a deliberately conservative one: VTEST = (2 x ACrms continuous rating) + 1000V for ten seconds, followed by a test at rated ACrms voltage for one minute. zation requires a higher applied voltage to start the discharge and a lower voltage to extinguish it once started. The higher start voltage is known as the inception voltage and the lower voltage is called the extinction voltage. Just as the total insulation system has an inception voltage, so do the individual voids. A voltage will build up across a void until its inception voltage is reached. At this point, the void will ionize, effectively shorting itself out. This action redistributes electrical charge within the dielectric and is known as partial discharge. If the applied voltage gradient across the device continues to rise, another partial discharge cycle begins. The importance of this phenomenon is that if the discharge does not occur, the insulation system retains its integrity. If the discharge begins and is allowed to continue, the action of the ions and electrons within the defect will eventually degrade any organic insulation system in which they occur. The measurement of partial discharge is both useful in rating the devices and in providing quality control of the manufacturing process. The inception voltage of these voids tend to be constant, so that the measurement of total charge being redistributed within the dielectric is a very good indicator of the size of the voids and their likelihood of becoming an incipient failure. Recent improvements in high voltage stress testing have produced a more meaningful test for determining maximum permissible voltage ratings, and Burr-Brown has chosen to apply this new technology to the manufacture and testing of ISO213. The bulk inception voltage, on the other hand, varies with the insulation system and the number of ionization defects. This directly establishes the absolute maximum voltage (transient) that can be applied across the test device before destructive partial discharge can begin. PARTIAL DISCHARGE When an insulation defect such as a void occurs within an insulation system, the defect will display localized corona or ionization during exposure to high voltage stress. This ioni- Measuring the bulk extinction voltage provides a lower, more conservative, voltage from which to derive a safe continuous rating. In production, it’s acceptable to measure at a level somewhat below the expected inception voltage and then de-rate by a factor related to expectations about the FB 4 GSB 7 –VIN 3 +VIN 1 Signal – 38 Modulator GSA + 37 8 31 +14V +VSS –VSS 50kHz Power 34 6 Oscillator 0.47µF VOUT Demodulator –14V 25kHz Rectifier 35 32 5 ACom 2 +VCC Clock Out Clock In Com 2 0.47µF Com 1 2 FIGURE 2. Simplified Diagram of Isolation Amplifier. ® 7 ISO213 system transients. The isolation barrier has been extensively evaluated under a combination of high temperatures and high voltage to confirm its performance in this respect. ISO213 is free from partial discharges at rated voltages. CEXT 1 has minimal effect on total IMR. FB PARTIAL DISCHARGE TESTING IN PRODUCTION This test method provides far more qualitative information about stress withstand levels than did previous stress tests. It also provides quantitative measurements from which quality assurance and control measures can be based. Tests similar to this test have been used by some manufacturers such as those of high voltage power distribution equipment for some time. They employed a simple measurement of RF noise to detect ionization. This method was not quantitative with regard to energy of the discharge and was not sensitive enough for small components such as isolation amplifiers. Now, however, manufacturers of HV test equipment have developed means to measure partial discharge, and VDE, the German standards group, has adopted use of this method for the testing of opto-couplers. To accommodate poorly defined transients, the part under test is exposed to a voltage that is 1.6 times the continuous rated voltage and must display <5pC partial discharge level in a 100% production test. Where transients are not present on an applied voltage and the bulk inception voltage is not exceeded, degradation will not take place. This is the case where OEM production testing is performed to satisfy regulatory requirements. The normal test is to apply a relatively slow ramp to a defined test voltage. Maintain that voltage for 1 minute and then ramp to zero. Where this test voltage is less than or equal to the partial discharge test voltage it can be seen that degradation will not occur. Hence ISO213 is guaranteed to withstand a continuous test voltage for 1 minute at the partial discharge test voltage. – VOUT CINT R Load Circuit + ACom 2 CEXT 2 Com 2 –VCC +VCC CEXT 1 Power Supply Com 1 Input Common VISO FIGURE 3. Technique for Connecting Com 1 and Com 2. reference leads, must be minimized. Any capacitance across the barrier will increase AC leakage and, in conjunction with ground line resistance, may degrade high frequency IMR. VOLTAGE GAIN MODIFICATIONS The uncommitted instrumentation amplifier at the input can be used to provide gain, signal inversion, or current to voltage conversion. The standard design approach for any instrumentation amplifier stage can be used, provided that the full scale voltage appearing on FB does not exceed ±10V. Also, it should be noted that the current required to drive the equivalent impedance of any feedback network is supplied by the internal DC/DC converter and must be taken into account when calculating the loading added to ±VSS. INSTALLATION AND OPERATING INSTRUCTIONS POWER SUPPLY AND SIGNAL CONNECTIONS As with any mixed analog and digital signal component, correct decoupling and signal routing precautions must be used to optimize performance. Figure 1 shows the proper power supply and signal connections. VCC should be bypassed to Com 2 with a 0.1µF ceramic capacitor and 100µH inductor as close to the device as possible. Short leads will minimize lead inductance. A ground plane will also reduce noise problems. If a low impedance ground plane is not used, signal common lines, and ACom 2 should be tied directly to the ground at the supply and Com 2 returned via a separate trace to the supply ground. ISOLATED POWER OUTPUT DRIVE CAPABILITY On the input side of ISO213, there are two power supplies capable of delivering 3mA at ±14V typical to power external circuitry. When using these supplies with external loads, it is recommended that additional decoupling in the form of 10µF tantalum bead capacitors, is added to improve the voltage regulation. Loss of linearity will result if additional filtering is not used with an output load. Again, power dissipated in a feedback network must be subtracted from the available power output at ±VSS. If ISO213 is to be used in multiple applications, care should be taken in the design of the power distribution network, especially when all ISO213s are synchronized. It is best to use a well decoupled distribution point and to take power to each ISO213 from this point in a star arrangement as shown in Figure 4. To avoid gain and isolation mode (IMR) errors introduced by the external circuit, connect grounds as indicated in Figure 3. Layout practices associated with isolation amplifiers are very important. In particular, the capacitance associated with the barrier, and series resistance in the signal and ® ISO213 CEXT 2 and R have a direct effect. 8 number of ISO213s. See Figure 6, 7, and 8 for connections in multiple ISO213 installations. Power In Track Resistance/Inductance 0.1µF 10µF 0.1µF 10µF 0.1µF ISO213P 10µF 0.1µF ISO213P 100µF ISO213P +VCC Clock In 39kΩ 220pF Ground Plane Clamp Clock Out Diodes FIGURE 4. Recommended Decoupling and Power Distribution. Com 2 NOISE Output noise is generated by residual components of the 25kHz carrier that have not been removed from the signal. This noise may be reduced by adding an output low-pass filter (see Figure 9). The filter time constant should be set below the carrier frequency. The output from ISO213 is a switched capacitor and requires a high impedance load to prevent degradation of linearity. Loads of less than 1MΩ will cause an increase in noise at the carrier frequency and will appear as ripple in the output waveform. Since the output signal power is generated from the input side of the barrier, decoupling of the ±VSS outputs will improve the signal to noise ratio. FIGURE 5. Equivalent Circuit, Clock Input/Output. Inverters are CMOS. ISO213P/Master +V CC Clk Out Clk In Com 2 ISO213P/Slave +V CC Clk Out Clk In Com 2 ISO213P/Slave SYNCHRONIZATION OF THE INTERNAL OSCILLATOR +V CC Clk Out Clk In Com 2 ISO213 has an internal oscillator and associated timing components, which can be synchronized. This alleviates the requirement for an external high-power clock driver. The typical frequency of oscillation is 50kHz. The internal clock will start when power is applied to ISO213 and Clk In is not connected. 0V +15V Sync FIGURE 6. Oscillator Connections for Synchronous Operation in Multiple ISO213P Installations. Clk In Clk In Clk In Clk In 22k Ω Slave 22k Ω Slave 22k Ω Slave 22k Ω Slave Master Clk Out 22k Ω Slave Because the oscillator frequency of each ISO213 can be marginally different, “beat” frequencies ranging from a few Hz to a few kHz can exist in multiple amplifier applications. The design of ISO213 accommodates “internal synchronous” noise, but a synchronous beat frequency noise will not be strongly attenuated, especially at very low frequencies if it is introduced via the power, signal, or potential grounding paths. To overcome this problem in systems where several ISO213s are used, the design allows synchronization of each oscillator in a system to one frequency. Do this by forcing the timing node on the internal oscillator with an external driver connected to Clk In (Figure 5). The driver may be an external component with Series 4000 CMOS characteristics, or one ISO213 in the system can be used as the master clock for the system. An alternative where a specific frequency is not required is to lock all ISO213s together by joining all Clk Ins. This method can be used to lock an unlimited RS Slave N Clk In Slave 4 Clk In Slave 3 Clk In Slave 2 Clk In Slave 1 Master Clk Out FIGURE 7. Isolating the Clk Out Node. ® 9 ISO213 CHARGE ISOLATION When more than one ISO213 is used in synchronous mode, the charge which is returned from the timing capacitor (220pF in Figure 5) on each transition of the clock becomes significant. Figure 7 illustrates a method of isolating the “Clk Out” clamp diodes (Figure 5) from this charge. two isolated power supplies capable of supplying 3mA at ±14V typical are available to power external circuitry. APPLICATIONS FLEXIBILITY In Figure 9, ISO213 +Vss isolated supply powers a REF200 to provide an accurate 200µA current source. This current is used via the 1.5kΩ resistor to set the output to –5V at 4mA input. A 22kΩ resistor (recommended maximum) together with the 39kΩ internal oscillator timing resistor (Figure 5) forms a potential divider. The ratio of these resistors should be greater than 0.6 which ensures that the input voltage triggers the inverter connected to “Clk In”. If using a single resistor, then account must be taken of the paralleled timing resistors. This means that the 22kΩ resistor must be halved to drive two ISO213s, or divided by 8 if driving 8 ISO213s to insure that the ratio of greater than 0.6 is maintained. The series resistors shown in Figure 7 reduce the high frequency content of the power supply current. Figure 8 can be used where a specific frequency of operation is not required. The primary function of the output circuitry is to add gain, to produce a ±10V output and to reduce output impedance. The addition of a few resistors and capacitors provides a low pass filter with a cutoff frequency equal to the full signal bandwidth of ISO213, typically 200Hz. The filter response is flat to 1dB and rolls off from cut off at –12dB per octave. The accuracy of REF200 and external resistors eliminates the need for expensive trim pots and adjustments. The errors introduced by the external circuitry only add about 10% of ISO213 specified gain and offset voltage error. ISO213 operates from a single +15V supply and offers low power consumption and 12-bit accuracy. On the input side, Clk In Clk In Dev 3 Clk In Dev N Clk In Dev 2 ISO213 isolation amplifier, together with a few low cost components, can isolate and accurately convert a 4-to-20mA input to a ±10V output with no external adjustment. Its low height (0.43" (11mm) ) and small footprint (2.5" x 0.33" (57mm x 8mm) ) make it the solution of choice in 0.5" board spacing systems and in all applications where board area savings are critical. Dev 1 APPLICATIONS FIGURE 8. Recommended Synchronizing Scheme. –VSS 10µF REF200 200µA 6.8nF (10%) +15V +15V 5 1 0.1µF + 31 100kΩ 38 4-20mA 100kΩ 25Ω 1.5kΩ 37 3 (5%) (5%) – 6.8nF (10%) 8 4mA to 20mA –10V to +10V + OPA27 2 – 32 2 3 6 0.1µF 4mA to 20mA –5V to +5V –15V 7 RG 1.02kΩ NOTE: All resistors are 0.1% unless otherwise stated. G = 1 + 50kΩ /2 RG FIGURE 9. Isolated 4-20mA Current Receiver with Output Filter. ® ISO213 10 22kΩ 22kΩ RG +VSS REF03 +15V 7 +2.5V 3 0.1µF 8 – 31 1kΩ 1kΩ 32 + 5 1kΩ(1) 1kΩ VOUT 37 1 +VSS 38 ISO213P 6 2 OPA1013 –2.5V 10µF 10µF –VSS +VSS –VSS NOTE: (1) e.g., strain gauge, pressure transducer, RTD, gas detection and analysis. FIGURE 10. Instrument Bridge Isolation Amplifier. 2.8kΩ LA RA RG/2 VOUT ISO213P 2.8kΩ G=5 390kΩ 1/2 OPA1013 1/2 OPA1013 RL 10kΩ 390kΩ FIGURE 11. ECG Amplifier With Right-Leg Drive. 10.0V 6 REF102 R1 2 +VSS R2 1MΩ 4 Pt100 ISA TYPE Cu K Cu RG ISO213P VOUT R3 100Ω = RTD at 0°C MATERIAL SEEBECK COEFFICIENT (µV/°C) R1, R2 E + Chromel – Constantan 58.5 66.5kΩ J + Iron – Constantan 50.2 76.8kΩ K + Chromel – Alumel 39.4 97.6kΩ T + Copper – Constantan 38.0 102kΩ FIGURE 12. Thermocouple Amplifier With Cold Junction Compensation and Down-Scale Burn-Out. ® 11 ISO213 +500VDC ISO213P 1kΩ 3 – VD +15V 1 V D = 50mV (FS) + 6.8nF 0.1µF 2 DC Motor +15V 31 100kΩ 38 100kΩ 3 37 6.8nF 32 2 6 OPA27 or –15V 22kΩ 22kΩ 120Vrms 100A 3 3-Phase Y-Connected Power Transformer 200kΩ 1 – + 2 4.7V 0.1µF 4.7V 200kΩ FIGURE 13. Isolated Current Monitoring Applications. +VSS 10µF 8 REF200 3 Wire PT100 –200°C to 850°C 1 100µA 7 6 2 100µA +15V 6 3 – 0V at 0°C 31 100Ω at 0°C 0.385Ω/°C 100Ω ISO213P 1 VOUT 37 32 + 8 7 RG FIGURE 14. Isolated Temperature Sensing and Amplification. ® ISO213 38 12 2 G = 1 + 50kΩ /2 RG –10V to +10V ® 13 ISO213 Type K R4 100Ω R3 4.87kΩ CW R2 1MΩ FIGURE 15. Complete Temperature Acquisition System. T1 ISO Thermal Block R5 R1 1.82kΩ 8.25kΩ R10 47Ω R6 80.6Ω R9 47kΩ C2 1nF R8 47kΩ REF 1004 2.5 7 3 1 8 R7 169Ω R11 2.26kΩ C1 10µF 2 6 ISO213 31 37 32 38 R13 13kΩ VS +12V 10nF 10µF 2.2nF R14 88.7kΩ + 100µH 2.2µF 3 2 R15 10kΩ 7 4 In 6 CW OPA1013 R16 9.53kΩ + 3 R18 1kΩ R17 100Ω GND 2 7805 1 Out 1 + 2 ADS7806 U3 28 1µF 19 Out