LT1616 UUWUAPPLICATIO S I FOR ATIO 5 V 1 IN VIN BOOST 10V LT1616 4 6 10µH V SHDN SW OUT 3.3V GND FB 22Ω 2 3 33Ω C C OUT = 4.7µF CERAMIC, CASE SIZE 0805 OUT 1616 F04 Figure 4. Circuit Used for Transient Load Test Shown in Figure 3 Regardless of which capacitor or combination of capaci- tors you choose, you should do transient load tests to COUT = 10µF CERAMIC, CASE SIZE 1206 evaluate the circuit’s stability. Avoid capacitors or combi- nations that result in a ringing response. Problems may occur if the output capacitance is very low or if a high value inductor is used in combination with a large value, low ESR capacitor. The high performance (low ESR), small size and robust- C ness of ceramic capacitors make them the preferred type OUT = 47µF, ESR ≅ 0.080Ω (SANYO POSCAP 6TPA47M) C CASE for LT1616 applications. However, all ceramic capacitors are not the same. Many of the higher value capacitors use poor dielectrics with high temperature and voltage coefficients. In particular, Y5V types should be regarded with suspicion. Stick with X7R and X5R types. Don’t be afraid to run them at their rated voltage. Table 2 lists several capacitor manufacturers. COUT = 100µF, ESR ≅ 0.150Ω (TANTALUM AVX TPSC107M006R0150) C CASE Catch Diode V A 0.5A Schottky diode is recommended for the catch diode OUT 20mV/DIV D1. The ON Semiconductor MBR0530 is a good choice; it is rated for 0.5A forward current and a maximum reverse voltage of 30V. For circuits with VIN less than 20V, the ILOAD 100mA/DIV MBR0520L can be used. Other suitable diodes are the Zetex ZHCS500TR and ZHCS750TR, and various versions 0 of the 1N5818. COUT = 100µF TANTALUM AND 2.2µF CERAMIC Figure 3. Transient Load Response of the LT1616 9