LT1424-9 Isolated Flyback Switching Regulator with 9V Output FEATURES DESCRIPTIO n No Transformer Third Winding or Optoisolator The LT 1424-9 is a monolithic high power switching Required regulator specifically designed for the isolated flyback n Application Circuit Meets PCMCIA Type II topology. No third winding or optoisolator is required Height Requirement the integrated circuit senses the isolated output voltage n Fixed, Application Specific 9V Output Voltage directly from the primary side flyback waveform. A high n Regulation Maintained Well into Discontinuous current, high efficiency switch is included on the die along Mode (Light Load) with all oscillator, control and protection circuitry. n Load Compensation Provides Excellent The LT1424-9 operates with input supply voltages from Load Regulation 3V to 20V and draws only 7mA quiescent current. It can n Available in 8-Pin PDIP and SO Packages deliver up to 200mA at 9V with no external power devices. n Operating Frequency: 285kHz By utilizing current mode switching techniques, it pro- U vides excellent AC and DC line regulation. APPLICATIO S The LT1424-9 has a number of features not found on other n Ethernet Isolated 5V to 9V Converter switching regulator ICs. Its unique control circuitry can maintain regulation well into discontinuous mode. Load compensation circuitry allows for improved load regula- tion. An externally activated shutdown mode reduces total supply current to 20m A typical for standby operation. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO 9V PCMCIA Type II Isolated LAN Supply (2.41mm Maximum Component Height) C6 ISOLATION R2 220pF BARRIER 75W 5V MBRS130LT3 C1 R1 C2 D1 OUT 10m F 75W 10m F 0.1m F 1N5248 COM 25V 25V 1 C5 3 LT1424-9 220pF C3 C4 1.8k 2 8 10m F 10m F T1 D2 V R C CCOMP 25V 25V 1 7 MBR0540T4 SHDN V IN 2 4 100k 3 6 9V SYNC V 47pF SW 200mA 4 5 1424 TA01 1:1 1000pF SGND PGND 0.1m F C1, C2, C3, C4: MARCON THCS50E1E106Z CERAMIC INPUT CAPACITOR, SIZE 1812. (847) 696-2000 COM T1: COILTRONICS CTX02-13483 sn14249 14249fs 1 U ULT1424-9 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) ORDER PART Supply Voltage ........................................................ 20V TOP VIEW NUMBER Switch Voltage ......................................................... 35V SHDN 1 8 R CCOMP SHDN, SYNC Pin Voltage........................................... 7V LT1424CN8-9 V 2 7 V C IN Operating Junction Temperature Range LT1424CS8-9 SYNC 3 6 V SW Commercial .......................................... 0 C to 125 C LT1424IN8-9 SGND 4 5 PGND Industrial ......................................... 40 C to 125 C LT1424IS8-9 Storage Temperature Range ................. 65 C to 150 C N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO S8 PART MARKING Lead Temperature (Soldering, 10 sec).................. 300 C T = 145 C, q = 130 C/ W (N) JMAX JA 14249 T = 145 C, q = 110 C/ W (S) JMAX JA 1424I9 Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 5V, V Open, V = 1.4V, unless otherwise specified. A IN SW C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply V Minimum Input Voltage l 2.8 3.1 V IN(MIN) I Supply Current l 7.0 9.5 mA CC Shutdown Mode Supply Current l 15 40 m A Shutdown Mode Threshold l 0.3 0.9 1.3 V Feedback Amplifier V Reference Voltage Measured at V Pin (Note 2) 9.00 9.15 9.30 V REF SW l 8.90 9.15 9.40 V g Feedback Amplifier Transconductance D I = 10m A (Note 2) l 400 1000 1600 m mho m C I , I Feedback Amplifier Source or Sink Current l 30 50 80 m A SOURCE SINK V Feedback Amplifier Clamp Voltage 1.9 V CL Reference Voltage/Current Line Regulation 5V V 18V l 0.01 0.04 %/V IN Voltage Gain (Note 3) 500 V/V Output Switch BV Output Switch Breakdown Voltage I = 5mA l 35 50 V C V(V ) Output Switch ON Voltage I = 1A l 0.55 0.85 V SW SW I Switch Current Limit Duty Cycle = 50%, 0 C T 125 C l 1.35 1.6 1.95 A LIM J Duty Cycle = 50%, 40 C T 125 C l 1.20 1.6 1.95 A J Duty Cycle = 80% 1.3 A Current Amplifier Control Pin Threshold Duty Cycle = Minimum 0.95 1.2 1.3 V l 0.85 1.2 1.4 V Control Voltage to Switch Transconductance 2 A/V sn14249 14249fs 2 U W U W U WW