® 722 FPO FPO50% FPO 41% DUAL ISOLATED DC/DC CONVERTER FEATURES APPLICATIONS ● DUAL ISOLATED ±5V TO ±16V OUTPUTS ● HIGH BREAKDOWN VOLTAGE: 8000V Test ● ● ● ● ● LOW LEAKAGE CURRENT: <1µA at 240V/60Hz ● LOW COST PER ISOLATED CHANNEL ● SMALL SIZE: 27.9mm x 27.9mm x 7.6mm (1.1" x 1.1" x 0.3") MEDICAL EQUIPMENT INDUSTRIAL PROCESS CONTROL TEST EQUIPMENT DATA ACQUISITION SYSTEMS ● NUCLEAR INSTRUMENTATION DESCRIPTION The 722 converts a single 5VDC to 16VDC input into a pair of bipolar output voltages of the same value as the input voltage. The converter is capable of providing a total output current of 64mA at rated voltage accuracy and up to 200mA without damage. The two output channels are isolated from the input and from each other. They may be connected independently, in series for higher output voltage or in parallel for higher output current, as a single channel isolated DC/DC converter. Integrated circuit construction of the 722 reduces size and cost. High isolation breakdown voltages and low leakage currents are assured by special design and construction which includes use of a high dielectric strength, low leakage coating used on the internal assembly. A self-contained 900kHz oscillator drives switching circuitry, which is designed to eliminate the common problem of input current spiking due to transformer saturation or crossover switching. P+ 11 Rectifiers and Filters V+ 20 E 18 Oscillator and Switch Drivers Rectifiers and Filters V– 16 International Airport Industrial Park • Mailing Address: PO Box 11400 Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • ©1978 Burr-Brown Corporation 1 +VO1 2 C1 3 –VO1 10 +VO2 9 C2 8 –VO2 • 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-398F Printed in U.S.A. September, 1991 SPECIFICATIONS ELECTRICAL TA = +25°C, VIN = 15VDC, C = 0.47µF, R1 selected per Typical Performance Curve. 722 PARAMETER CONDITIONS INPUT Rated Input Voltage Input Voltage Range(1) Input Current MIN TYP 722BG MAX MIN 16 * 15 Input Ripple(2) ISOLATION Test Voltages 50 105 120 — 3 6 — Input-to-Output, 5 seconds, min Input-to-Output, 1 minute, min Channel-to-Channel, 5 seconds, min Input-to-Output, continuous Channel-to-Channel, continuous Input-to-Output Input-to-Output, 240V, 60Hz Rated Voltages Isolation Impedance Leakage Current(3) OUTPUT Rated Output Voltages(4) ILOAD = 3mA per Output ILOAD = 16mA per Output ILOAD = 40mA per Output Total of All Outputs Any One Output(5) Output Current Tracking Error between Dual Outputs Sensitivity to Input Voltage Changes Output Voltage Temperature Coefficient TEMPERATURE Specification 16.2 16.2 — 200 100 — 3 15 35 — ±100 TA = TSPECIFICATION RANGE 1.13 ±0.02 Storage Junction Temperature * — * * — 275 — * 2500 * * * * * * 50 * * * 16.2 * * * * — * * * * * mA mA mA, pk mA, pk mA, pk — * * — * * VDC VDC VDC mA mA * * * * * * * * * * * * VDC VDC mA mA * * * UNITS Vpk Vrms Vpk V V GΩ || pF µA * 14.2 * 100 +85 +60 +125 +125 * * * * 13.7 MAX * * * * 1 –25 –25 –55 * TYP * — * * * * 10 || 6 ILOAD = 3mA per Output ILOAD = 16mA per Output ILOAD = 40mA per Output Balanced Loads ILOAD ≤ 16mA per Output ILOAD ≤ 40mA per Output * * * 225 * * 12 — (5) Load Regulation Ripple Voltage MIN * * * 120 8000 — 5000 3500 2000 15.4 14.3 — 722MG MAX * 5 Total Output Current = 12mA Total Output Current = 64mA Total Output Current = 64mA at TA = +85°C Total Output Current = 160mA Total Output Current = 12mA Total Output Current = 64mA Total Output Current = 160mA TYP mVpk mVpk mVpk mVDC V/V %/°C * * * * * * * °C °C °C °C *Specifications same as 722. NOTES: (1) For ambient temperature above +70°C the input voltage is 12.5V (max). The input voltage remains 16V (max) if case temperature is kept below +85°C. (2) External capacitor across “P+” to “V–” pins and 12" of #24 wire to VIN. (3) Reference UL544, paragraph 27.5, Leakage Current. (4) See “Typical Performance Curves.” (5) A minimum output current of 3mA at each output is recommended to maintain output voltage accuracy. PACKAGE INFORMATION(1) MODEL 722 ORDERING INFORMATION PACKAGE PACKAGE DRAWING NUMBER 20-Pin 102A NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. MODEL PACKAGE TEMPERATURE RANGE(1) 722 722BG 722MG 20-Pin 20-Pin 20-Pin –25°C to +85°C –25°C to +85°C –25°C to +85°C NOTE: (1) –25°C to +60°C for ILOAD ≤ 40mA per Output. 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. ® 722 2 TYPICAL PERFORMANCE CURVES TA = +25°C, VIN = 15VDC, C = 0.47µF, R1 selected per Typical Performance Curve. MAXIMUM SAFE OPERATING TEMPERATURE vs TOTAL OUTPUT CURRENT SELECTION OF R1 OR EXTERNAL VOLTAGE V+ FOR MINIMUM INTERNAL POWER DISSIPATION V+EXT 820Ω 510Ω 200Ω 510Ω 200Ω 0Ω 200Ω 0Ω 0Ω — — — 6.5V 7.5V 9.0V Maximum Ambient Temperature °C 100 75 75 Ambient 50 50 25 25 0 0 0 50 100 150 (2) Total Output Current OUTPUT VOLTAGE vs INPUT VOLTAGE Output Load Voltage, |VLOAD| (V) 13 Total Output Current = 64mA 8 Total Output Current = 200mA 3 IF IF = 3mA IF = 16mA 15 IF + VO – + + Load 16 Total Output Current = 12mA V – + VO – V – IL IL 14 IF = 50mA 13 4 8 12 16 0 20 Input Voltage (V) 15 IF 14 VO – + + V – + VO VO – – Opposite Channel, Output Voltage, |VN| (V) IF = 16mA + Load IF IF = 3mA IL IF IF = 50mA 13 0 20 40 60 80 100 CHANNEL-TO-CHANNEL INTERACTION SINGLE OUTPUT LOAD REGULATION 16 40 Output Load Current |IL| (mA) 60 80 16 IF = 3mA 15 IF = 16mA IF = 50mA 14 + + VN V – + – + IF VN IL IF V – – 13 0 100 IF Load Output Voltage (V) (mA) SINGLE-CHANNEL LOAD REGULATION 18 Output Load Voltage, |VLOAD| (V) 200 Load Input Voltage (V) >13 11 to 13 9 to 11 8 to 9 <8 Case 100 Maximum Case Temperature(1) (°C) 125 125 MAXIMUM OUTPUT CURRENT FROM ANY SINGLE OUTPUT 16mA to <16mA 30mA 30mA 1.3kΩ 820Ω 510Ω 20 40 60 80 100 Output Load Current |IL| (mA) Output Load Current |IL| (mA) NOTES: (1) Using a 104mm x 19mm x 1.6mm aluminum strip mounted to the bottom of the case with heat sink compound. (2) Total output current is the sum of the currents for each individual output. ® 3 722 TYPICAL PERFORMANCE CURVES (CONT) TA = +25°C, VIN = 15VDC, C = 0.47µF. R1 selected per Typical Performance Curve. PARALLEL OUTPUT BALANCED LOAD REGULATION PARALLEL OUTPUT UNBALANCED LOAD REGULATION V 14 Load 15 V V V IL IL 13 V V VO VO IF = 6mA Load Output Load Voltage, |VLOAD| (V) 16 Load Output Load Voltage, |VLOAD| (V) 16 IL IF 15 IF = 100mA 14 IF = 32mA 13 0 20 40 60 80 0 100 40 Output Load Current |IL| (mA) 80 120 160 200 Output Load Current |IL| (mA) IF = 6mA V V VN VN Load Opposite Output, Output Voltage, |VN| (V) OUTPUT-TO-OUTPUT INTERACTION 16 IL IF 15 IF = 32mA 14 IF = 100mA 13 0 40 80 120 160 200 Output Load Current |IL| (mA) INSTALLATION AND OPERATING INSTRUCTIONS Typical application connections for the 722 are shown in Figures 1 and 3. Primary power (VIN) is applied at the “P+” and “V–” terminals. The common or ground for VIN may be connected to either “P+” or “V–”; the only requirement is that “P+” and “V+” must be positive with respects to “V–”. The “E” pin enables the converter when connected to “V+” and disables it when connected to “V–.” An external capacitor, “C” (0.47µF ceramic), is used to reduce input ripple. It should be connected as close to the “P+” and “V–” pins as practical. Input leads to these terminals should also be kept as short as possible. Since the 722 is not internally shielded, external shielding may be appropriate in applications where RFI at the 900kHz nominal oscillator frequency is a problem. Power for the internal oscillator and switch drivers is derived from the primary power by a voltage dropping resistor, R1. The value of R1 as a function of VIN is shown in the Typical Performance Curves section. Alternately, voltage for the “V+” terminal may be obtained from a separate source. “V+” should be +5V to +7.5V positive with respect to “V–.” If a separate source is used, the “V+” input must be applied before the “P+” input to avoid possible damage to the unit. “P+” and “V+” must remain positive with respect to “V–” at all times (including transients). If necessary, diode clamps should be put across these inputs. Each output is filtered with an internal 0.22µF capacitor. Output ripple voltage can be reduced below the specified value by adding external capacitors up to 10µF between each output and its common. ® 722 4 DISCUSSION SHORT CIRCUIT PROTECTION The circuit in Figure 2 may be added to the input of the 722 to protect it from damage in situations where too much current is demanded from the outputs—such as a short circuit from an output to its common. The circuit limits input current to approximately 150mA for an input voltage of 15VDC (for ß of 2N2219 of 50). OUTPUT CURRENT RATINGS At rated output voltage accuracy, the 722 is capable of providing 64mA divided among its four outputs(1). A minimum average output current of 3mA is recommended at each output to maintain voltage accuracy. Output channels(2) may be connected in series or parallel for higher output voltage or current. P+ +VO1 + ISOLATION CONFIGURATIONS The fact that the two outputs of the 722 are isolated from the input and from each other allows both two-port and threeport isolation connections. C1 R1 3.6kΩ V+ –VO1 VIN Figure 1 shows Burr-Brown’s 3650 optically coupled isolation amplifier connected in three-port configuration. One of the 722 channels provides power to the 3650’s input. The other channel supplies power to the 3650’s output. The amplifier’s input and output are isolated from each other and the system’s power supply common. In this configuration, the 722’s channel-to-channel isolation specification applies to the amplifier input-to-output voltage. 2N2219 E +VO2 IN4148 C2 100Ω V– –VO2 1Ω – 722 FIGURE 2. Short Circuit Protection. 3650 +15V –15V +15V +VO1 P+ 3650 C1 C R1 O/P Com –VO1 V+ +VO2 E VIN I/P Com Com I/P Com #1 722 R1 –VO1 V+ Com –VO2 V– C C1 C2 O/P +15V +VO1 P+ +VO2 E VIN C2 Power Supply Common Com –VO2 V– I/P Com #2 722 +15V –15V O/P Com FIGURE 1. Three-Port Isolation. 3650 –15V Figure 3 illustrates how the 722 may provide isolated input power to the input stage of two 3650’s connected in the twoport configuration. Power for the output stage is provided by the system +15V and –15V supplies. Input stages are isolated from each other and from the system supply. In this situation, the 722’s input-to-output isolation specification applies to the amplifier’s input-to-output voltages, while the channel-to-channel 722 specification applies to the voltage existing between “I/P Com #1” and “I/P Com #2.” O/P Com FIGURE 3. Two-Port Isolation with Two 3650’s. NOTES: (1) “Output” denotes a single output terminal (+V or –V) and its associated common. (2) “Channel” denotes a pair of outputs (+V and –V) and their associated common. ® 5 722