LT1765EFE#PBF Analog Devices

LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 Monolithic 3A, 1.25MHz Step-Down Switching Regulator FEATURES DESCRIPTION n 3A Switch in a Thermally Enhanced 16-Lead The LT 1765 is a 1.25MHz monolithic buck switching TSSOP or 8-Lead SO Package regulator. A high ef ciency 3A, 0.09 switch is included n Constant 1.25MHz Switching Frequency on the die together with all the control circuitry required n Wide Operating Voltage Range: 3V to 25V to construct a high frequency, current mode switching n High Ef ciency 0.09 Switch regulator. Current mode control provides fast transient n 1.2V Feedback Reference Voltage response and excellent loop stability. n Uses Low Pro le Surface Mount Components New design techniques achieve high ef ciency at high n Low Shutdown Current: 15A switching frequencies over a wide operating voltage n Synchronizable to 2MHz range. A low dropout internal regulator maintains con- n Current Mode Loop Control sistent performance over a wide range of inputs from n Constant Maximum Switch Current Rating at 24V systems to Li-Ion batteries. An operating supply All Duty Cycles* current of 1mA improves ef ciency, especially at lower n Available in 8-Lead SO and 16-Lead Thermally output currents. Shutdown reduces quiescent current to Enhanced TSSOP Packages 15A. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator into the range of APPLICATIONS 1.6MHz to 2MHz. n DSL Modems Full cycle-by-cycle current control and thermal shutdown n Portable Computers are provided. High frequency operation allows the reduc- n Regulated Wall Adapters tion of input and output ltering components and permits n Battery-Powered Systems the use of chip inductors. n Distributed Power L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. *Patent Pending TYPICAL APPLICATION 5V to 3.3V Step-Down Converter Ef ciency vs Load Current 90 CMDSH-3 V = 10V IN V = 5V OUT 0.18F 85 1.5H BOOST OUTPUT INPUT V V 3.3V 5V IN SW 2.5A 2.2F LT1765-3.3 80 CERAMIC OFF ON SHDN FB SYNC V GND C 4.7F 75 2.2nF UPS120 CERAMIC 1765 TA01 70 1.0 0 0.5 1.5 2.0 SWITCH CURRENT (A) 1765 TAO1a 1765fd 1 EFFICIENCY (%)LT1765/LT1765-1.8/LT1765-2.5/ LT1765-3.3/LT1765-5 (Note 1) ABSOLUTE MAXIMUM RATINGS Input Voltage ........................................................... 25V SYNC Pin Current ................................................... 1mA BOOST Pin Above SW ............................................. 20V Operating Junction Temperature Range Max BOOST Pin Voltage ............................................35V (Note 2) ................................................. 40C to 125C SHDN Pin ................................................................. 25V Storage Temperature Range ................. 65C to 150C FB Pin Current ......................................................... 1mA Lead Temperature (Soldering, 10 sec) ................ 300C PIN CONFIGURATION TOP VIEW GND 1 16 GND TOP VIEW BOOST 2 15 NC BOOST 1 8 SYNC V 3 14 SYNC IN V 4 13 V V 2 7 V IN C IN C 17 SW 5 12 FB SW 3 6 FB SW 6 11 SHDN GND 4 5 SHDN NC 7 10 NC S8 PACKAGE GND 8 9 GND 8-LEAD PLASTIC SO T = 125C, = 90C/W, = 30C/W JMAX JA JC(PIN 4) FE PACKAGE GROUND PIN CONNECTED TO LARGE COPPER AREA 16-LEAD PLASTIC TSSOP = 45C/W, = 10C/W JA JC(PAD) EXPOSED PAD (PIN 17) SOLDERED TO LARGE COPPER PLANE ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1765EFE PBF LT1765EFE TRPBF 1765EFE 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-1.8 PBF LT1765EFE-1.8 TRPBF 1765EFE-1.8 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-2.5 PBF LT1765EFE-2.5 TRPBF 1765EFE-2.5 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-3.3 PBF LT1765EFE-3.3 TRPBF 1765EFE-3.3 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-5 PBF LT1765EFE-5 TRPBF 1765EFE-5 16-Lead Plastic TSSOP 40C to 125C LT1765ES8 PBF LT1765ES8 TRPBF 1765 8-Lead Plastic SO 40C to 125C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1765EFE LT1765EFE TR 1765EFE 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-1.8 LT1765EFE-1.8 TR 1765EFE-1.8 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-2.5 LT1765EFE-2.5 TR 1765EFE-2.5 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-3.3 LT1765EFE-3.3 TR 1765EFE-3.3 16-Lead Plastic TSSOP 40C to 125C LT1765EFE-5 LT1765EFE-5 TR 1765EFE-5 16-Lead Plastic TSSOP 40C to 125C LT1765ES8 LT1765ES8 TR 1765 8-Lead Plastic SO 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. For more information on lead free part marking, go to: