PWS725A

PWS725A BURR-BROWN | Alldatasheet

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Isolated, Unregulated DC/DC CONVERTERS International Airport Industrial Park • Mailing Address: PO Box 11400 • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706 Tel: (520) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 FEA TURES l ISOLATED ±7 TO ±18VDC OUTPUT FROM SINGLE 7 TO 18VDC SUPPLY l ±15mA OUTPUT AT RATED VOLTAGE ACCURACY l HIGH ISOLATION VOLTAGE PWS725A, 1500Vrms PWS726A, 3500Vrms l LOW LEAKAGE CAPACITANCE: 9pF l LOW LEAKAGE CURRENT: 2 µA max, at 240VAC 50/60Hz l HIGH RELIABILITY DESIGN l AVAILABLE WITH OUTPUT SYNCHRONIZATION SIGNAL FOR USE WITH ISO120 AND ISO121 oscillator before either MOSFET driver turns on, protects the switches, and eliminates high inrush cur- rents during turn-on. Input current sensing protects both the converter and the load from possible thermal damage during a fault condition. Special design features make these converters especially easy to apply. The compact size allows dense circuit layout while maintaining critical isola- tion requirements. The Input Sync connection allows frequency synchronization of multiple converters. The Output Sync is available to synchronize ISO120 and ISO121 isolation amplifiers. The Enable input allows control over output power in instances where shutdown is desired to conserve power, such as in battery-powered equipment, or where sequencing of power turn-on/turn-off is desired.

DESCRIPTION

The PWS725A and PWS726A convert a single 7 to 18VDC input to bipolar voltages of the same value as the input voltage. The converters are capable of providing ±15mA at rated voltage accuracy and up to ±40mA without damage. (See Output Current Rating.) The PWS725A and PWS726A converters provide reliable, engineered solutions where isolated power is required in critical applications. The high isolation voltage rating is achieved through use of a specially- designed transformer and physical spacing. An addi- tional high dielectric-strength, low leakage transformer coating increases the isolation rating of the PWS726A. Reliability and performance are designed in. The bifilar wound, wirebonded transformer simultaneously provides lower output ripple than competing designs, and a higher performance/cost ratio. The soft-start oscillator/driver design assures full operation of the l PROTECTED AGAINST OUTPUT FAULTS l COMPACT l LOW COST l EASY TO APPLY—FEW EXTERNAL PARTS APPLICA TIONS l MEDICAL EQUIPMENT l INDUSTRIAL PROCESS EQUIPMENT l TEST EQUIPMENT l DATA ACQUISITION © 1987 Burr-Brown Corporation PDS-736D Printed in U.S.A. October, 1993

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS INPUT Rated Voltage 15 * VDC Input Voltage Range 7 18 * * VDC Input Current I O = ±15mA 77 * mA Input Current Ripple No External Filtering 150 * mAp-p L-C Input Filter, LIN = 100µH, CIN = 1µF(1) 5 * mAp-p C Only, CIN = 1µF 60 mAp-p ISOLATION Test Voltages Input to Output, 10 seconds 4000 8000 VDC Input to Output, 60 seconds, min 1500 3500 Vrms Rated Voltage Input to Output, Continuous, AC 60Hz 1500 3500 Vrms Input to Output, Continuous DC 2121 4950 VDC Isolation Impedance Input to Output 10 12 || 9 * Ω || pF Leakage Current Input to Output, 240Vrms, 60Hz 1.2 2.0 * * µA OUTPUT Rated Output Voltage 14.25 15 15.75 * * * VDC Output Current Balanced Loads 15 40 * * mA Single-Ended 80 * mA Load Regulation Balanced Loads, ±10mA < IOUT < ±40mA 0.4 * %/mA Ripple Voltage (400kHz) No External Capacitor 60 * mVp-p LO = 10µH, CO = 1µF (Figure 1) 10 * mVp-p LO = 0µH, CO Filter Only Output Switching Noise L O = 10µH, CO = 1µF 1 * mVp-p Output Capacitive Load L O = 100µH, C Filter 10 * µF C Filter Only 1 * µF Voltage Balance, V+, V– 0.04 % Sensitivity to ΔVIN 1.15 V/V Output Voltage Temp. Coefficient 10 mV/ °C Output Sync Signal Square Wave, 50% Duty Cycle 30 * Vp-p TEMPERATURE Specification –25 +85 * * °C Operating –25 +85 * * °C Storage –25 +125 * * °C SPECIFICATIONS ELECTRICAL TA = +25°C, CL = 1µF ceramic, VIN = 15VDC, operating frequency = 800kHz, VOUT = ±15VDC, CIN = 1µF ceramic, IOUT = ±15mA, unless otherwise specified. PSW726APWS725A * Specification same as PWS725A. See Performance Curves 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. PIN CONFIGURATION PACKAGE INFORMATION (1) PACKAGE DRAWING MODEL PACKAGE NUMBER PWS725A 32-Pin Ceramic DIP 210 PWS726A 32-Pin Ceramic DIP 210 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. Top View DIP +V O NC Output Ground Output Sync Frequency Adjust Frequency Adjust Enable NC O NC NC Output Ground NC Input Ground Input Sync V IN

Output Voltage (V) Balanced Loads 10 20 30 40 Output Current (mA) 20 40 60 80 Balanced Single Single-ended Loads VIN = +15V OUTPUT VOLTAGE DRIFT Temperature (°C) Output Voltage (%) –50 100 05 0 TYPICAL PERFORMANCE CURVES TA = +25°C, VCC = ±15VDC unless otherwise noted. Capacitance (µF) OUTPUT CAPACITANCE vs RIPPLE VOLTAGE Output Ripple Voltage (mVp-p) 01 0.3 100 Peak-to-Peak Capacitor Only DC < f < 20MHz L-C Filter, L = 100µH IO = ±15mA VIN = ±15V MAXIMUM POWER DISSIPATION Temperature (°C) Output Power (W) –25 0 2 55 07 5 1 0 0 85 1.44 LINE REGULATION Input Voltage (V) Output Voltage (V) 8 1 01 21 41 61 8 IO = ±15mA INPUT CURRENT vs OUTPUT CURRENT IO (mA) IIN (mA) 140 ±15 ±30 ±45

TA = +25°C, VCC = ±15VDC unless otherwise noted. FIGURE 1. PWS725A/726A Functional Diagram. (1) Frequency Adjust is optional, with pins 19 and 20 left open. The normal switching frequency is 800kHz. (2) Leave INPUT SYNC pin open if unused; limit stray capacitance on INPUT SYNC pin to less than 50pF. (5) Optional input filtering, see Performance Curves for LIN = 0. (6) CAUTION: Do not connect pin 29 to low impedance loads. See Figure 5.