Programmable, Isolated a Voltage-to-Current Converter 1B22 FEATURES FUNCTIONAL BLOCK DIAGRAM Internal Isolated Loop Supply Drives 1000 Load Pin Programmable Inputs: 0 V to +5 V or 0 V to +10 V IN1 1B22 Pin Programmable Outputs: 4 to 20 mA or 0 to 20 mA OUT IN2 REF HI RESISTOR SIGNAL High CMV Isolation: 1500 V RMS 4mA NETWORK ISOLATION OFFSET Normal-Mode Output Protection: 240 V RMS OUT S. NODE LO High Accuracy MODULATOR DEMODULATOR PROT Low Offset Tempco: 300 nA/ C POWER Low Gain Tempco: 50 ppm/ C SYNC ISOLATION Low Nonlinearity: 0.02% +15V RECTIFIER/ OSCILLATOR 15V High CMR: 90 dB min LOOP SUPPLY A. COM Small Package: 1.0 2.10 0.35 Meets IEEE STD 472: CMV Transient Protection (SWC) P. COM V LOOP APPLICATIONS Multichannel Process Control D/A ConverterCurrent Loop Interface Analog Transmitters and Controllers DESIGN FEATURES AND USER BENEFITS Remote Data Acquisition Systems Isolated Loop Power: Internal loop supply completely isolates the loop from the input terminals (1500 V rms) and provides the capability to drive 0 to 1000 loads. This elimi- GENERAL DESCRIPTION nates the need for an external dc/dc converter. The 1B22 is an isolated voltage-to-current converter that incorporates transformer isolation to achieve high performance Ease of Use: The 1B22 offers complete isolated voltage-to- and automated surface mount manufacturing for low cost current conversion with minimum external parts required to get and increased reliability. Designed for industrial applications, a conditioned current signal. No external buffers or drivers are it is especially suited for harsh environments with extremely required. high common-mode interference. With programmable inputs High CMV Isolation: The 1B22 features high input to output and outputs, the 1B22 provides an unbeatable combination of galvanic isolation to eliminate ground loops and offer protection versatility and performance in a compact plastic package. against damage from transients and fault voltages. The isolation Functionally, the V/I converter consists of four basic sections: barrier will withstand continuous CMV of 1500 V rms and meets input conditioning, modulator/demodulator, isolated loop the IEEE Standard for Common-Mode Voltage Transient Pro- supply and current source (Figure 1). The 1B22 is pin program- tection (STD 472-SWC). mable for 0 V to +5 V or 0 V to +10 V inputs and 0 to 20 mA Small Size: The 1B22 package size (1.0 2.1 DIP) makes it or 4 to 20 mA outputs using an internal resistor network. It can an excellent choice in multichannel systems for maximum chan- also be set by an external resistor to accept 0 V to +1 V to 0 V nel density. The 0.35 height also facilitates applications with to +10 V inputs. Transformer coupling provides 1500 V rms limited board clearance. galvanic isolation between the inputs and the current loop. Nonlinearity is an excellent 0.05% max. Loop power is generated internally through a dc/dc converter and is also isolated from the input side (1500 V rms). Loop compliance voltage is dependent on the voltage supplied to the 1B22, and with V = 28 V, it is sufficient to drive a 1000 LOOP load. The 1B22 is fully specified over 25C to +85C and operates over the industrial (40C to +85C) temperature range. REV. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or Tel: 781/329-4700 World Wide Web Site: (typical +25 C and V = 15 V, V = +24 V, unless otherwise noted) 1B22SPECIFICATIONS S LOOP Model 1B22AN OUTLINE DIMENSIONS Dimensions shown in inches and (mm). INPUT SPECIFICATIONS Factory Calibrated, User Selectable 0 V to +5 V, 0 V to +10 V Input Impedance 0 V to +10 V Input Range 50 k 0 V to +5 V Input Range 25 k OUTPUT SPECIFICATIONS Current Output Range, User Selectable 4 to 20 mA, 0 to 20 mA Load Compliance Range, V = +15 V 8 V min LOOP Load Compliance Range, V = +28 V 20 V min LOOP Maximum Output Current Input Overload 30 mA Output Noise, 100 Hz Bandwidth 300 nA p-p NONLINEARITY (% of Span) 0.02% (0.05% max) ISOLATION CMV, Input to Output Continuous 1500 V rms max CMR, 60 Hz 90 dB min Normal-Mode Output Protection 240 V rms Continuous CMV Transient Protection IEEE-STD 472 (SWC) ACCURACY Warm-Up Time to Rated Performance 5 min Total Output Error +25C Offset (V = 0 V) 60 A IN Span (V = +10 V) 0.7% Full Scale IN vs. Temperature (25C to +85C) Offset 300 nA/C AC1225 MATING SOCKET Span 50 ppm/C DYNAMIC RESPONSE Settling Time to 0.1% of FS for 10 V Step 9 ms Small Signal Bandwidth 400 Hz POWER SUPPLY Bipolar Input Supplies Operating Voltage 15 V 5% Quiescent Current 7.5 mA Power Supply Rejection 0.01%/V Loop Supply Operating Voltage +14 V to +30 V Operating Current, at Full-Scale Output 25 mA PIN DESIGNATIONS Loop Supply Rejection 0.005%/V Pin Function ENVIRONMENTAL Temperature Range 11 OUT HI Rated Performance 25C to +85C 16 IN2 Operating 40C to +85C 17 IN1 Storage 40C to +85C 18 S. NODE Relative Humidity, Noncondensing 0 to 95% 60C 19 4 mA OFFSET CASE SIZE 1.0 2.1 0.35 20 +15 V Specifications subject to change without notice. 21 ANA COM 22 15 V 23 SYNC 24 V LOOP 25 POWER COM 38 OUT LO 2 REV. B