LTC1430A High Power Step-Down Switching Regulator Controller DESCRIPTIO FEATURES n High Power 5V to 1.xV-3.xV Switching Controller: The LTC 1430A is a high power, high efficiency switching Can Exceed 10A Output regulator controller optimized for 5V to 1.xV-3.xV applica- n Maximum Duty Cycle > 90% Permits 3.3V to 2.xV tions. It includes a precision internal reference and an inter- Conversion Using a Low Power 5V Supply nal feedback system that can provide output regulation of n All N-Channel External MOSFETs 1% over temperature, load current and line voltage shifts. n Fixed Frequency OperationSmall L The LTC1430A uses a synchronous switching architecture n Excellent Output Regulation: 1% Over Line, Load with two N-channel output devices, eliminating the need for and Temperature Variations a high power, high cost P-channel device. Additionally, it n High Efficiency: Over 95% Possible senses output current across the drain-source resistance n No Low Value Sense Resistor Needed of the upper N-channel FET, providing an adjustable cur- n Outputs Can Drive External FETs with Up to rent limit without an external low value sense resistor. 10,000pF Gate Capacitance The LTC1430A includes a fixed frequency PWM oscillator n Quiescent Current: 350m A Typ, 1m A in Shutdown for low output ripple under virtually all operating condi- n Fast Transient Response tions. The 200kHz free-running clock frequency can be n Adjustable or Fixed 3.3V Output externally adjusted from 100kHz to above 500kHz. The n Available in 8-Lead SO and 16-Lead GN LTC1430As maximum duty cycle is typically 93.5% com- and SO Packages pared to 88% for the LTC1430. This permits 3.3V to 2.xV conversion using a low power 5V supply. The LTC1430A features low 350m A quiescent current, allowing greater APPLICATI S than 90% efficiency operation in converter designs from n 1A to greater than 50A output current. Shutdown mode Power Supply for Pentium II and AMD-K6 drops the LTC1430A supply current to 1m A. For new Microprocessors n designs, refer to the LTC3830. High Power 5V to 3.xV Regulators n , LTC and LT are registered trademarks of Linear Technology Corporation. Local Regulation for Dual Voltage Logic Boards Pentium is a registered trademark of Intel Corporation. n Low Voltage, High Current Battery Regulation AMD-K6 is a registered trademark of Advanced Micro Devices, Inc. TYPICAL APPLICATI Typical 5V to 3.3V, 10A Application Efficiency 100 5V T = 25C A PV = 5V + C CC IN 90 MBR0530T1 + V = 3.3V 220m F OUT 100W 1m F 4 80 PV PV 16k 0.1m F CC2 CC1 Q1A, Q1B 2 IN PARALLEL + V G1 CC 70 4.7m F 0.1m F 0.1m F SS I 2.7m H/15A MAX 1k 0.01m F 3.3V LTC1430A I FB 60 10A + C OUT NC FREQSET G2 Q2 330m F 6 50 SHUTDOWN SHDN PGND COMP GND 40 C1 + 0.1 1 10 R SENSE 220pF C 1430 TA01 7.5k LOAD CURRENT (A) FB NC C C SENSE 1430 TA02 Q1A, Q1B, Q2: MOTOROLA MTD20N03HL 4700pF C : AVX-TPSE227M010R0100 IN C : AVX-TPSE337M006R0100 OUT 1 EFFICIENCY (%) UO UO ULTC1430A (Note 1) ABSOLUTEXAI U RATI GS Supply Voltage Junction Temperature........................................... 150 C V ....................................................................... 9V Operating Temperature Range CC PV .............................................................. 13V LTC1430AC ............................................. 0 C to 70 C CC1, 2 Input Voltage LTC1430AI ........................................ 40 C to 85 C I ......................................................... 0.3V to 18V Storage Temperature Range ................ 65 C to 150 C FB All Other Inputs ...................... 0.3V to (V + 0.3V) Lead Temperature (Soldering, 10 sec)................. 300 C CC PACKAGE/ORDER I FOR ATIO ORDER ORDER TOP VIEW PART NUMBER PART NUMBER G1 1 16 G2 TOP VIEW PV 2 15 PV CC2 CC1 LTC1430ACGN LTC1430ACS8 G1 1 8 G2 PGND 3 14 V CC LTC1430AIGN PV V /PV 2 7 CC1 CC CC2 GND 4 13 I FB LTC1430ACS GND 3 6 COMP SENSE 5 12 I MAX FB 4 5 SHDN FB 6 11 FREQSET + SENSE 7 10 COMP S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO SHDN 8 9 SS T = 150 C, q = 150 C/W JMAX JA 1430A GN PACKAGE S PACKAGE 16-LEAD PLASTIC SSOP 16-LEAD PLASTIC SO T = 150 C, q = 130 C/W (GN) JMAX JA T = 150 C, q = 110 C/W (S) JMAX JA Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS V = 5V, T = 25 C (Note 2) unless otherwise noted. CC A LTC1430AC LTC1430AI SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS V Supply Voltage l 48 4 8 V CC PV PV , PV Voltage l 313 3 13 V CC CC1 CC2 V Output Voltage Figure 1 3.30 3.30 V OUT + V Feedback Voltage SENSE and SENSE Floating , l 1.25 1.265 1.28 1.23 1.265 1.29 V FB V = 2.5V COMP D V Output Load Regulation Figure 1, I = 0A to 10A 5 5 mV OUT OUT Output Line Regulation Figure 1, V = 4.75V to 5.25V 1 1 mV CC I Supply Current (V Only) Figure 2, V = V l 350 700 350 700 m A VCC CC SHDN CC V = 0V 1 10 1 10 m A SHDN I Supply Current (PV ) Figure 2, PV = 5V, V = V (Note 3) 1.5 1.5 mA PVCC CC CC SHDN CC V = 0V 0.1 0.1 m A SHDN f Internal Oscillator Frequency FREQSET Floating l 140 200 260 130 200 300 kHz OSC 2 U WU U W W W