LT1339 High Power Synchronous DC/DC Controller DESCRIPTION FEATURES n High Voltage: Operation Up to 60V The LT 1339 is a high power synchronous current mode n High Current: Dual N-Channel Synchronous Drive switching regulator controller. The IC drives dual Handles Up to 10,000pF Gate Capacitance N-channel MOSFETs to create a single IC solution for high n Programmable Average Load Current Limiting power DC/DC converters in applications up to 60V. n 5V Reference Output with 10mA External The LT1339 incorporates programmable average current Loading Capability limiting, allowing accurate limiting of DC load current n Programmable Fixed Frequency Synchronizable independent of inductor ripple current. The IC also incor- Current Mode Operation Up to 150kHz porates user-adjustable slope compensation for minimi- n Undervoltage Lockout with Hysteresis zation of magnetics at duty cycles up to 90%. n Programmable Start Inhibit for Power Supply The LT1339 timing oscillator operating frequency is pro- Sequencing and Protection n grammable and can be synchronized up to 150kHz. Mini- Adaptive Nonoverlapping Gate Drive Prevents mum off-time operation provides main switch protection. Shoot-Through The IC also incorporates a soft start feature that is gated by U both shutdown and undervoltage lockout conditions. APPLICATIONS An output phase reversal pin allows flexibility in configu- n 48V Telecom Power Supplies ration of converter types, including inverting and negative n Personal Computers and Peripherals topologies. n Distributed Power Converters n Industrial Control Systems n Lead-Acid Battery Backup Systems n Automotive and Heavy Equipment , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION 28V to 5V 20A Buck Converter V 28V to 5V Efficiency IN DBST 28V IN5819 100 12V SYNC V C BOOST IN C 1500F 12VIN CBST 47F 63V 1F 5V REF 3 90 IRL3803 TG R CT D1 10k MBR0520 C 5VREF 80 CT TS 1F C C SL/ADJ CT AVG 12V IN 2200pF IRL3103D2 2200pF LT1339 BG 70 2 D2 L1 I AVG MBR0520 10H C , 1F SS PGND SS R 60 RUN PHASE R , 10k VC 100k C , 1nF VC V C RUN/SHDN + 50 SENSE SGND 0 5 10 15 20 C REF R S 0.1F OUTPUT CURRENT (A) V FB 0.005 V 1339 TA03a OUT V SENSE REF 5V AT 20A C OUT 2200F R R FB2 FB1 6.3V 1k 3k L1 = CTX02-13400-X2 2 1339 TA03 sn1339 1339fas 1 EFFICIENCY (%) + + + + + + U ULT1339 O ABS LUTEXAI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART Supply Voltages TOP VIEW NUMBER Power Supply Voltage (12V )...............0.3V to 20V IN SYNC 1 20 V BOOST Topside Supply Voltage (V ) BOOST 5V 2 19 TG REF LT1339CN V 0.3V to V + 20V (V = 75V) CT 3 18 TS TS TS MAX LT1339CSW Topside Reference Pin Voltage (TS) ......0.3V to 60V SL/ADJ 4 17 12V IN LT1339IN I 5 16 BG Input Voltages AVG SS 6 15 PGND LT1339ISW Sense Amplifier Input Common Mode...0.3V to 60V V 7 14 PHASE C RUN/SHDN Pin Voltage ...................... 0.3V to 12V IN SGND 8 13 RUN/SHDN All Other Inputs .......................................0.3V to 7V V 9 12 SENSE FB Maximum Currents + 11 V 10 SENSE REF 5V Reference Output Current............................ 65mA Maximum Temperatures N PACKAGE SW PACKAGE 20-LEAD PDIP 20-LEAD PLASTIC SO WIDE Operating Ambient Temperature Range LT1339C ............................................ 0 C to 70 C T = 125 C, q = 70 C/W (N) JMAX JA T = 125 C, q = 85 C/W (SW) LT1339I......................................... 40 C to 85 C JMAX JA Storage Temperature Range ................. 65 C to 150 C Lead Temperature (Soldering, 10 sec).................. 300 C Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS 12V = V = 12V, V = 2V, TS = 0V, V = V = 1.25V, C = C = 3000pF, T = 25 C unless otherwise noted. IN BOOST C FB REF TG BG A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Supply and Protection I DC Active Supply Current (Note 2) l 14 20 mA 12VIN DC Standby Supply Current V < 0.5V l 150 250 m A RUN/SHDN I DC Active Supply Current (Note 2) 2.2 mA BOOST DC Standby Supply Current V < 0.5V 0 m A RUN/SHDN V Shutdown Rising Threshold l 1.15 1.25 1.35 V RUN/SHDN V Shutdown Threshold Hysteresis 25 mV SSHYST I Soft Start Charge Current l 48 14 m A SS V Undervoltage Lockout Threshold - Falling l 8.20 9.00 9.75 V UVLO Undervoltage Lockout Threshold - Rising l 9.35 9.95 V Undervoltage Lockout Hysteresis l 200 350 mV 5V Reference V 5V Reference Voltage Line, Load and Temperature l 4.75 5.00 5.25 V REF5 5V Reference Line Regulation 10V 12V 15V l 3 5 mV/V IN I 5V Reference Load Range - DC l 10 mA REF5 Pulse l 20 mA 5V Reference Load Regulation 0 I 20mA l 1.25 2 V/A REF5 I 5V Reference Short-Circuit Current 45 mA SC sn1339 1339fas 2 U WU U W W W