DC355A Analog Devices

DEMO MANUAL DC355/DC356 NO-DESIGN SWITCHER LT1959 Monolithic 4A Switcher 5V to 15V Input 1.8V Output DESCRIPTIO Demonstration circuits DC355 and DC356 are complete handheld devices and, in larger systems, as local onboard DC/DC step-down regulators using the LT 1959 constant regulators. High frequency switching allows the use of frequency, high efficiency converter in 7-pin DD (DC356) small inductors, making this all surface mount solution and SO-8 (DC355) packages. These circuits are primarily ideal for space conscious systems. used in personal computers, disk drives, portable , LTC and LT are registered trademarks of Linear Technology Corporation. PERFOR A CE SU ARY T = 25 C, V = 5V, I = 2A, V = 1.8V, SHDN and SYNC pins open, unless otherwise specified. A IN LOAD OUT PARAMETER CONDITIONS MIN TYP MAX UNITS Output Voltage (Note 1) 1.75 1.8 1.85 V Maximum I (Note 2) 4.3 A LOAD Input Voltage Range 4.5 15 V Switching Frequency 460 500 540 kHz Output Ripple Voltage 25 mV P-P Line Regulation 5V to 15V 4 mV Load Regulation I = 10mA to 4A 10 mV LOAD SHDN Lockout Threshold 2.3 2.38 2.46 V SHDN Shutdown Threshold 0.15 0.37 0.6 V Synchronization Range DC355 Only 580 1000 kHz Supply Current SHDN = 0V 20 m A Note 1: Output voltage variations include 1% tolerance of feedback divider network. Note 2: For DC355, additional thermal restrictions apply. BOARD PHOTOS DC355 Component Side DC356 Component Side 1 WW UW UDEMO MANUAL DC355/DC356 NO-DESIGN SWITCHER TYPICAL PERFOR A CE CHARACTERISTICS 1.8V Output Efficiency Temperature Rise vs Load Current 90 120 V = 5V IN V = 1.8V OUT 85 100 5V DC355 IN 80 80 DC356 60 75 12V IN 40 70 65 20 60 0 0 12 3 4 0 12 3 4 LOAD CURRENT (A) LOAD CURRENT (A) DC355/356 TA01 DC355/356 TA02 PACKAGE A D SCHE ATIC DIAGRA SM DC355 D2* OPTIONAL C4 1F D3* L1 10V MMBD914LT1 6.8H E1 E5 V V IN OUT TOP VIEW 5V TO 15V + + + + 3.3V/4A C3 C5 C6 2 C7 D1 10F 100F 0.47F V 1 8 V OPTIONAL IN SW MBRD835L 25V BOOST 10V 10V 1 8 E4 V SW BOOST 2 7 SYNC IN U1 GND R2 LT1959CS8 FB 3 6 SHDN 1.21k E2 6 7 E6 SHDN SYNC 1% SHDN SYNC 3 GND 4 5 V C FB GND V R3 C E3 S8 PACKAGE 2.49k GND 4 5 8-LEAD PLASTIC SO 1% DC355 SCHEM R1 LT1959CS8 C1 3.3k *MOVE D3 TO POSITION D2 OPTIONAL FOR OUTPUT VOLTAGES >3.3V C2 3.3nF DC356 D2* OPTIONAL C4 1F D3* L1 10V MMBD914LT1 6.8H E1 E5 V V IN OUT 5V TO 15V + C5 + 3.3V/4A + C3 + C6 C7 6 D1 100F 10F 0.47F OPTIONAL MBRD835L 25V 10V BOOST 10V 5 3 E4 V SW R2 IN GND U1 1.21k FRONT VIEW LT1959CR 1% 2 E2 7 7 FB SHDN FB SHDN 6 BOOST R3 GND V C TAB 5 V IN E3 2.49k IS 4 GND 4 1 GND 1% 3 V GND SW DC356 SCHEM 2 SYNC OR SHDN R1 1 V C 3.3k C1 *MOVE D3 TO POSITION D2 OPTIONAL C2 FOR OUTPUT VOLTAGES >3.3V R PACKAGE 3.3nF 7-LEAD PLASTIC DD PAK LT1959CR 2 EFFICIENCY (%) DIE TEMPERATURE RISE (C) W WU UW