Datasheet LTC3539, LTC3539-2 (Analog Devices) - 10

LTC3539/LTC3539-2
APPLICATIONS INFORMATION Table 1. Representative Inductors
An output capacitor of up to 100µF is required at lower
VENDOR PART/STYLE
output voltages. Even with VOUT greater than 3V, larger Coilcraft MSS5131 values up to 100µF may be used to obtain extremely low (847) 639-6400 LPS4018-222 output voltage ripple and improve transient response. X5R www.coilcraft.com MSS6132 and X7R dielectric materials are preferred for their ability MOS6020 to maintain capacitance over wide voltage and temperature Murata LQH55D www.murata.com LQH66S ranges. Y5V types should not be used. Sumida CDRH4D22 A small ceramic capacitor in parallel with a larger tantalum (847) 956-0666 CDRH4D28C www.sumida.com CDRH5D28 capacitor may be used in demanding applications which CDR6D23 have large load transients. A feedforward capacitor across TDK VLF5014ST the top resistor of the feedback divider (from VOUT to FB) (847) 803-6100 is usually required to improve transient response. A typical www.component.tdk.com value of 33pF will generally suffice. Toko D53LC (408) 432-8282 D63LCB Low ESR input capacitors reduce input switching noise www.tokoam.com and reduce the peak current drawn from the battery. It Würth WE-TPC Type LH, X (201) 785-8800 WE-PD Type XS follows that ceramic capacitors are also a good choice www.we-online.com for input decoupling and should be located as close as possible to the device. A 2.2µF input capacitor is sufficient for most applications. Larger values may be used without
Output and Input Capacitor Selection
limitations. Table 2 shows a list of several ceramic capaci- The internal loop compensation of the LTC3539 is designed tor manufacturers. Consult the manufacturers directly for to be stable with output capacitor values of 22µF or greater. detailed information on their selection of ceramic parts. Although ceramic capacitors are recommended, low ESR (equivalent series resistance) tantalum capacitors may be
Table 2. Capacitor Vendor Information
used as well.
SUPPLIER PHONE WEBSITE
AVX (803) 448-9411 www.avxcorp.com Low ESR capacitors should be used to minimize the Murata (714) 852-2001 www.murata.com output voltage ripple. Multilayer ceramic capacitors are Taiyo-Yuden (408) 573-4150 www.t-yuden.com an excellent choice as they have extremely low ESR and are available in small footprints. A 22µF to 47µF output TDK (847) 803-6100 www.component.tdk.com capacitor is sufficient for output voltages of 3V or greater. 35392fc 10 For more information www.linear.com/3539/3539-2 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts