Datasheet LTC3525D-3.3 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | 400mA Micropower Synchronous Step-Up DC/DC Converter with Pass Through Mode |
| Pages / Page | 14 / 10 — operaTion Component Selection. Table 1. Inductor Vendor Information … |
| File Format / Size | PDF / 498 Kb |
| Document Language | English |
operaTion Component Selection. Table 1. Inductor Vendor Information SUPPLIER. PHONE. FAX. WEBSITE
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LTC3525D-3.3
operaTion Component Selection
A ceramic input bypass capacitor should be located as Inductor values between 4.7µH and 15µH are recom- close as possible to the VIN and GND pins of the IC. A mended. In most applications 10µH will yield the best minimum value of 1µF is recommended. If the battery is compromise between size and efficiency. The inductor more than a few inches away, a bulk tantalum decoupling should be a low loss ferrite design and must be rated cap of at least 10µF is recommended on VIN. for peak currents of at least 400mA without saturating. The output capacitor should also be a ceramic, located close Inductors with lower DC resistance will improve efficiency. to the VOUT and GND pins. A minimum value of 10µF is Note that the inductor value does not have a significant recommended. Increasing the value of the output capacitor effect on ripple current, so while lower values will increase to 22µF will result in lower output ripple. Higher capacitor the operating frequency, they do not reduce output volt- values will only offer a small reduction in output ripple, age ripple. while reducing light load efficiency by causing the peak Some recommended inductor examples are Murata inductor current to increase above its minimum value of LQH32C, Coilcraft LPO4812, LPO3310, DO3314, DS1608 150mA. The input and output capacitors should be X5R and MSS4020, Sumida CDRH2D14 and Taiyo Yuden or X7R types, not Y5V. NR3015T.
Table 1. Inductor Vendor Information SUPPLIER PHONE FAX WEBSITE
Murata USA: (814) 237-1431 USA: (814) 238-0490 www.murata.com Coilcraft (847) 639-6400 (847) 639-1469 www.coilcraft.com Sumida USA: (847) 956-0666 USA: (847) 956-0702 www.sumida.com Taiyo Yuden (408) 573-4150 (408) 573-4159 www.t-yuden.com TOKO (847) 297-0070 (847) 699-7864 www.toko.co.jp/products/en TDK (847) 699-2299 (847) 803-6296 www.tdk.com Würth (605) 886-4385 (605) 886-4486 www.we-online.com
Table 2. Capacitor Vendor Information SUPPLIER PHONE FAX WEBSITE
Murata USA: (814) 237-1431 USA: (814) 238-0490 www.murata.com Taiyo Yuden (408) 573-4150 (408) 573-4159 www.t-yuden.com TDK (847) 803-6100 (847) 803-6296 www.component.tdk.com AVX (803) 448-9411 (803) 448-1943 www.avxcorp.com SHDN SHDN SW LTC3525D-3.3 GND GND VIN VIN VOUT VOUT 3525d33 F03
Figure 3. Recommended Component Placement
3525d33fb 10 For more information www.linear.com/LTC3525D3.3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Applications Package Description Revision History Related Parts
operaTion Component Selection
A ceramic input bypass capacitor should be located as Inductor values between 4.7µH and 15µH are recom- close as possible to the VIN and GND pins of the IC. A mended. In most applications 10µH will yield the best minimum value of 1µF is recommended. If the battery is compromise between size and efficiency. The inductor more than a few inches away, a bulk tantalum decoupling should be a low loss ferrite design and must be rated cap of at least 10µF is recommended on VIN. for peak currents of at least 400mA without saturating. The output capacitor should also be a ceramic, located close Inductors with lower DC resistance will improve efficiency. to the VOUT and GND pins. A minimum value of 10µF is Note that the inductor value does not have a significant recommended. Increasing the value of the output capacitor effect on ripple current, so while lower values will increase to 22µF will result in lower output ripple. Higher capacitor the operating frequency, they do not reduce output volt- values will only offer a small reduction in output ripple, age ripple. while reducing light load efficiency by causing the peak Some recommended inductor examples are Murata inductor current to increase above its minimum value of LQH32C, Coilcraft LPO4812, LPO3310, DO3314, DS1608 150mA. The input and output capacitors should be X5R and MSS4020, Sumida CDRH2D14 and Taiyo Yuden or X7R types, not Y5V. NR3015T.
Table 1. Inductor Vendor Information SUPPLIER PHONE FAX WEBSITE
Murata USA: (814) 237-1431 USA: (814) 238-0490 www.murata.com Coilcraft (847) 639-6400 (847) 639-1469 www.coilcraft.com Sumida USA: (847) 956-0666 USA: (847) 956-0702 www.sumida.com Taiyo Yuden (408) 573-4150 (408) 573-4159 www.t-yuden.com TOKO (847) 297-0070 (847) 699-7864 www.toko.co.jp/products/en TDK (847) 699-2299 (847) 803-6296 www.tdk.com Würth (605) 886-4385 (605) 886-4486 www.we-online.com
Table 2. Capacitor Vendor Information SUPPLIER PHONE FAX WEBSITE
Murata USA: (814) 237-1431 USA: (814) 238-0490 www.murata.com Taiyo Yuden (408) 573-4150 (408) 573-4159 www.t-yuden.com TDK (847) 803-6100 (847) 803-6296 www.component.tdk.com AVX (803) 448-9411 (803) 448-1943 www.avxcorp.com SHDN SHDN SW LTC3525D-3.3 GND GND VIN VIN VOUT VOUT 3525d33 F03
Figure 3. Recommended Component Placement
3525d33fb 10 For more information www.linear.com/LTC3525D3.3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Typical Applications Package Description Revision History Related Parts
