DEMO MANUAL DC164 DESIGN READY SWITCHER DEMO MANUAL DC164 LTC1624 Constant Frequency, 8-Pin N-Channel DC/DC Converter U DESCRIPTIO Demonstration Circuit 164 is a constant-frequency step- This results in a power supply that has very high down (buck) regulator implemented entirely in surface efficiency, low ripple and fast transient response. At mount, using the LTC 1624 switching regulator controller. low output currents the LTC1624 automatically switches TM DC164 is usable in a wide range of portable, industrial, to Burst Mode operation to reduce switching losses computer and communications applications. The output and maintain high operating efficiencies. Additionally, voltage is programmable to 2.5V, 3.3V or 5V via a jumper. the supply current can be shut down to less than The input voltage can range from 4.8V to 28V (limited by the 20A (V = 10V). This feature is an absolute necessity to IN external MOSFET). The circuit highlights the capabilities of maximize battery life in portable applications. Gerber files the LTC1624, which uses a current mode, constant-fre- for this circuit board are available. Call the LTC factory. quency architecture to switch an N-channel power MOSFET , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. while providing 95% maximum duty cycle. Operating effi- ciencies exceeding 90% are obtained. PERFORMANCE SUMM ARY Operating Temperature Range 0C to 50C. Input Voltage Range (Maximum Input Voltage Limited by External MOSFET and Input Capacitor) 4.8V to 28V Output Output Voltage (Jumper Selectable) 2.5V, 3.3V, 5V Max Output Current (Continuous) 3.0A Max Output Current (Peak) 3.5A Typical Output Ripple at 10MHz Bandwidth (Burst Mode Operation) I = 100mA 50mV O P-P Typical Output Ripple at 10MHz Bandwidth (Continuous) I = 1A 35mV O P-P V Line Regulation 4.5V to 20V 0.002%/V IN I Load Regulation No Load to Full Rated Output 1% OUT I Supply Current with No Load (Typical), V = 10V 550A Q IN Supply Current in Shutdown (Typical), V = 10V 16A IN V Run Pin Threshold (Typical) 0.8V ITH/RUN Frequency Operating Frequency (Typical) 200kHz WUU TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTO Efficiency 100 V = 10V IN 90 V = 5V OUT 80 V = 2.5V OUT 70 60 V = 3.3V OUT 50 1 10 100 1000 3000 LOAD CURRENT (mA) DC164 TPC01 1 EFFICIENCY (%) WW UWDEMO MANUAL DC164 U W W PACKAGE AND SCHEMATIC DIAGRAMS TOP VIEW SENSE 1 8 V IN I /RUN 2 7 BOOST TH LTC1624CS8 V 3 6 TG FB GND 4 5 SW S8 PACKAGE 8-LEAD PLASTIC SO C2 1000pF 1 8 SENSE V V (E1) IN IN C C R S C C C1 R IN1 IN2 C C 470pF IN3 0.033 22F 22F 0.1F 6.8k GND (E2) OPTION 2 7 1% 35V 35V I /RUN BOOST TH 1/2W U1 J1 LTC1624 3 6 M1 V TG I /RUN FB TH Si4412DY C B C3 0.1F 100pF 4 5 GND SW V (E3) OUT L1 C C OUT1 OUT2 R6 C OUT3 10H D1 100F 100F 10 OPTION MBRS340T3 10V 10V V (E4) OSENSE R1 35.7k RX 1% R2 R3 R4 R5 C4 11k 20k 32.4k OPEN 100pF GND (E5) 1% 1% 1% USER J2A J2B J2C PGM 5V 3.3V 2.5V 164 SCHEMATIC J2D Figure 1. Demo Board Schematic PARTS LIST REFERENCE DESIGNATOR QUANTITY PART NUMBER DESCRIPTION VENDOR TELEPHONE C 1 08055A471MAT1A 470pF 50V 10% Chip Capacitor NPO AVX (803) 448-9411 C 08055A681MAT1A (5A) 680pF 50V 10% Chip Capacitor NPO AVX (803) 448-9411 C , C , (C ) 2 (3, 5A) TPSE226M035R0300 22F 35V 20% Tantalum Capacitor AVX (803) 448-9411 IN1 IN2 IN3 C , C , (C ) 2 (3, 5A) TPSD107M010R0065 100F 10V 20% Tantalum Capacitor AVX (803) 448-9411 OUT1 OUT2 OUT3 C3, C4 2 08055A101KAT1A 100pF 50V 10% Chip Capacitor NPO AVX (803) 448-9411 C8, C1 2 08055C104MAT2A 0.1F 50V 20% Chip Capacitor X7R AVX (803) 448-9411 C2 1 08055A102MAT2A 1000pF 50V 20% Chip Capacitor NPO AVX (803) 448-9411 D1 1 MBRS340T3 BVR = 40V Schottky Diode Motorola (602) 244-3576 MBRD835L (5A) BVR = 35V Schottky Diode Motorola (602) 244-3576 E1, E2, E3, E4, E5 5 2502-2 Turret Terminal Keystone (718) 956-8900 JP1, JP2A, 5 2802S-03-G2 2mm Pin Header COMM CON (818) 301-4200 JP2B, JP2C, JP2D J1, J2A, J2B, J2C, J2D 2 CCIJ2MM-138-G Jumper COMM CON (818) 301-4200 L1 1 CDRH125-10 10H Inductor Sumida (847) 956-0666 CDRH127-10 (5A) 10H Inductor (Alternate) Sumida (847) 956-0666 2 + + + + + +