 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LT1615IS5-1 Datasheet(PDF) 5 Page - Linear Integrated Systems |
|
||||||||||||||||||||||||||||||
LT1615IS5-1 Datasheet(HTML) 5 Page - Linear Integrated Systems |
|
|
5 / 8 page  5 LT1615/LT1615-1 sn16151 16151fas Choosing an Inductor Several recommended inductors that work well with the LT1615 and LT1615-1 are listed in Table 1, although there are many other manufacturers and devices that can be used. Consult each manufacturer for more detailed infor- mation and for their entire selection of related parts. Many different sizes and shapes are available. Use the equations and recommendations in the next few sections to find the correct inductance value for your design. Table 1. Recommended Inductors PART VALUE ( µH) MAX DCR ( Ω) VENDOR LQH3C4R7 4.7 0.26 Murata LQH3C100 10 0.30 (814) 237-1431 LQH3C220 22 0.92 www.murata.com CD43-4R7 4.7 0.11 Sumida CD43-100 10 0.18 (847) 956-0666 CDRH4D18-4R7 4.7 0.16 www.sumida.com CDRH4D18-100 10 0.20 DO1608-472 4.7 0.09 Coilcraft DO1608-103 10 0.16 (847) 639-6400 DO1608-223 22 0.37 www.coilcraft.com Inductor Selection—Boost Regulator The formula below calculates the appropriate inductor value to be used for a boost regulator using the LT1615 or LT1615-1 (or at least provides a good starting point). This value provides a good tradeoff in inductor size and system performance. Pick a standard inductor close to this value. A larger value can be used to slightly increase the available output current, but limit it to around twice the value calculated below, as too large of an inductance will in- crease the output voltage ripple without providing much additional output current. A smaller value can be used (especially for systems with output voltages greater than 12V) to give a smaller physical size. Inductance can be calculated as: L VV V I t OUT IN MIN D LIM OFF = −+ () where VD= 0.4V (Schottky diode voltage), ILIM= 350mA or 100mA, and tOFF = 400ns; for designs with varying VIN such as battery powered applications, use the minimum APPLICATIO S I FOR ATIO VIN value in the above equation. For most systems with output voltages below 7V, a 4.7 µH inductor is the best choice, even though the equation above might specify a smaller value. This is due to the inductor current over- shoot that occurs when very small inductor values are used (see Current Limit Overshoot section). For higher output voltages, the formula above will give large inductance values. For a 2V to 20V converter (typical LCD Bias application), a 21 µH inductor is called for with the above equation, but a 10 µH inductor could be used without excessive reduction in maximum output current. Inductor Selection—SEPIC Regulator The formula below calculates the approximate inductor value to be used for a SEPIC regulator using the LT1615. As for the boost inductor selection, a larger or smaller value can be used. L VV I t OUT D LIM OFF = + 2 Current Limit Overshoot For the constant off-time control scheme of the LT1615, the power switch is turned off only after the 350mA (or 100mA) current limit is reached. There is a 100ns delay between the time when the current limit is reached and when the switch actually turns off. During this delay, the inductor current exceeds the current limit by a small amount. The peak inductor current can be calculated by: II VV L ns PEAK LIM IN MAX SAT =+ − () 100 Where VSAT = 0.25V (switch saturation voltage). The current overshoot will be most evident for systems with high input voltages and for systems where smaller induc- tor values are used. This overshoot can be beneficial as it helps increase the amount of available output current for smaller inductor values. This will be the peak current seen by the inductor (and the diode) during normal operation. For designs using small inductance values (especially at |
Similar Part No. - LT1615IS5-1 |
|
Similar Description - LT1615IS5-1 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
