DEMO MANUAL DC053A DEMO MANUAL DC053ANO-DESIGN SWITCHER LT1372/LT1377 5V to 12V Step-Up Converters U DESCRIPTIO Demonstration board DC053A is a complete DC/DC step- very small inductors, making this all surface mount solu- up switching regulator using the LT 1372 or the LT1377 tion ideal for space conscious systems. constant frequency, high efficiency converter in an 8-pin , LTC and LT are registered trademarks of Linear Technology Corporation. SOIC package. High frequency switching allows the use of WWU W T = 25C, V = 5V, S/S pin open, unless otherwise specified. PERFOR A CE SU ARY A IN PARAMETER CONDITIONS MIN TYP MAX UNITS Output Voltage R2 = R3 = 1% (Note 1) 11.60 12.04 12.50 V Output Current V = 5V 250 mA IN Input Voltage Range (Note 2) 2.7 11 V Switching Frequency LT1372 500 kHz LT1377 1 MHz Output Ripple Voltage I = 250mA 150 mV LOAD P-P I = 250mA (Note 3) 80 mV LOAD P-P V , I = 250mA 3 mV OUT2 LOAD P-P Supply Current I = 0A 4.5 mA LOAD Shutdown Supply Current I = 0A, V = 0V (Note 4) 100 A LOAD S/S Note 1: The reference voltage tolerance of the LT1372/LT1377 is 1.6% Note 3: To reduce output ripple voltage, change C7 to a 2.2F ceramic over temperature. Output voltage is a worst-case summation of R2, R3 chip capacitor (Tokin 1E225ZY5U-C203). and reference tolerances, plus feedback input current times R3. For a Note 4: Single inductor step-up converters have a direct path from the tighter output voltage range, use lower tolerance feedback resistors, or a input supply to the output, and therefore draw some supply current even fixed voltage version of the LT1372/LT1377 (consult Linear Technology when the LT1372/LT1377 is in shutdown. Shutdown supply current will Marketing). also increase with the addition of an output load. Applications are available which remove this direct path and reduce shutdown supply Note 2: Increase L1 to 10H for V < 4.75V or to 15H for V < 3.3V. IN IN current to 30A maximum, independent of loading. W U U TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTO 12V Output Efficiency Maximum Output Current vs Input Voltage* Component Side 100 1.0 V = 5V IN V = 12V OUT 0.9 90 0.8 0.7 80 0.6 0.5 70 0.4 0.3 60 0.2 0.1 50 0 DC053A BP 0.01 0.1 1 2354 67189 101 OUTPUT CURRENT (A) DC053A G01 INPUT VOLTAGE (V) DC053A G02 *INCREASE L1 TO 10H FOR V < 4.75V IN OR TO 15H FOR V < 3.3V IN 1 EFFICIENCY (%) MAXIMUM OUTPUT CURRENT (A)DEMO MANUAL DC053A PACKAGE A D SCHE ATIC DIAGRA SM L1* 4.7H OPTIONAL E2 OUTPUT FILTER V IN L2** 5V + C3 1H TOP VIEW E6 V 22F OUT2 25V 12V V 1 V 8 C SW + C6 0.25A E1 4.7F FB 2 7 GND S/S 25V 4 5 D1 NFB GNDS 3 6 MBRS130 S/S V IN E4 V 8 OUT 3 S/S 4 5 V IN V NFB NC SW 12V 0.25A U1 R3 S8 PACKAGE LT1372/LT1377 53.6k, 1% 8-LEAD PLASTIC SO 1 2 FB V C C1 LT1372CS8 GNDS GND 0.047F R2 LT1377CS8 C2 67 + + C7 C4 6.19k C5 0.0047F R1 0.1F 22F 1% OMIT 2k (NOTE 4) 25V E3 E5 GND GND *SUMIDA CD43-4R7KC **MILLER PM20-1R0K NOTES: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTOR VALUES OHMS, 1/8W, 5% 2. ALL CAPACITOR VALUES F, 50V, 20% 3. ALL POLARIZED CAPACITOR AVX TPS SERIES OR EQUIVALENT DC053A F01 4. PLACE C7 AT THE LOAD Figure 1. Switching Regulator 5V to 12V, 0.25A 500kHz for the LT1372 and 1MHz for the LT1377 PARTS LIST REFERENCE DESIGNATOR QUANTITY PART NUMBER DESCRIPTION VENDOR TELEPHONE C1 1 AVX 12065C473MAT2A 0.047F, 50V, 20%, X7R Capacitor AVX (803) 946-0362 C2 1 AVX 12065C472MAT2A 0.0047F, 50V, 20%, X7R Capacitor AVX (803) 946-0362 C3, C4 2 AVX TPSD226M025R0200 22F, 25V, 20%, Tantalum Capacitor AVX (207) 282-5111 C5, C6 0 Capacitor, Optional (See Text) C7 1 AVX 12065C104MAT2A 0.1F, 50V, 20%, X7R Capacitor AVX (803) 946-0362 D1 1 MBRS130LT3 30V, 1A, Schottky Diode Motorola (602) 244-5768 E1 to E5 5 1502-2 2-Turret, 0.092 Terminal Keystone (718) 956-8900 E6 0 Terminal, Optional (See Text) L1 1 CD43-4R7KC 4.7H, SMT Inductor Sumida (708) 956-0666 L2 0 Inductor, Optional (See Text) R1 1 AVX CR32-202J-T 2k, 5%, SMT1206 Resistor AVX (803) 946-0524 R2 1 AVX CR32-6191F-T 6.19k, 1%, SMT 1206 Resistor AVX (803) 946-0524 R3 1 AVX CR32-5362F-T 53.6k, 1%, SMT-1206 Resistor AVX (803) 946-0524 U1* 1 LT1372CS8 SO-8, LT1372, Switching Regulator IC LTC (408) 432-1900 U1* 1 LT1377CS8 SO-8, LT1377, Switching Regulator IC LTC (408) 432-1900 *The two demo board versions are: DC53A-A: U1 = LT1372CS8 DC53A-B: U1 = LT1377CS8 2 W W U