Electronic Components Datasheet Search |
|
MAX5028EUT-T Datasheet(PDF) 9 Page - Maxim Integrated Products |
|
MAX5028EUT-T Datasheet(HTML) 9 Page - Maxim Integrated Products |
9 / 13 page 500kHz, 36V Output, SOT23, Step-Up DC-DC Converters _______________________________________________________________________________________ 9 where VREF is 1.25V Determining Peak Inductor Current If the boost converter remains in the discontinuous mode of operation, then the approximate peak inductor current, ILPEAK, is represented by the formula below: where TS is the period, VOUT is the output voltage, VIN is the input voltage, IOUT is the output current, and η is the efficiency of the boost converter. Determining the Inductor Value 47µH is the recommended inductor value when the out- put voltage is 30V and the input voltage is 5V. In gener- al, the inductor should have a current rating greater than the current-limit value. For example, the inductor’s current rating should be greater than 150mA to support a 4mA output current. Equivalent series resistance (ESR) should be below 1Ω for reasonable efficiency. Due to the MAX5025–MAX5028’s high switching fre- quency, inductors with a ferrite core or equivalent are recommended. Powdered iron cores are not recom- mended due to their high losses at frequencies over 500kHz. Table 1 shows a list of vendors and 47µH inductor parts. For 4mA output current and output voltages other than 30V, the inductor can be simply scaled in value according to the following formula: Use the following formula to calculate the upper bound of the inductor value at different output voltages and output currents. This is the maximum inductance value for discontinuous mode operation. Calculate the lower bound, LLOWER, for the acceptable inductance value using the following formula, which will allow the maximum output current to be delivered with- out reaching the peak current limit: Notice that the switch current limit, (VIN/5)(260mA), is a function of the input voltage, VIN. The current rating of the inductor should be greater than the switch current limit. L TV V I V mA LOWER S OUT IN OUT IN = − () () ⎛ ⎝⎜ ⎞ ⎠⎟ 2 5 260 2 η L VV V T IV UPPER OUT IN S OUT OUT IN = − () 2 2 2 η L HV V V OUT IN = () − () () 47 25 μ I TV V I L LPEAK S OUT IN OUT = − () 2 η RR V V OUT REF 12 1 = ⎛ ⎝⎜ ⎞ ⎠⎟ - CONTROL LOGIC MAIN PWM COMPARATOR CURRENT- LIMIT COMPARATOR FB REF -A +A +C -C MAX5025 MAX5026 THERMAL SHUTDOWN OSCILLATOR ULVO PGND 3 GND 2 VCC 5 SHDN 4 1 6 LX N Table 1. Inductor Vendors VENDOR PHONE FAX PART NUMBER OF 47µH INDUCTOR Coilcraft 847-639-6400 847-639-1469 DT1608C-473 Sumida 847-545-6700 847-545-6720 CDRH4D28-470 Toko 847-297-0070 847-699-7864 A915BY-470M Figure 1. Functional Diagram |
Similar Part No. - MAX5028EUT-T |
|
Similar Description - MAX5028EUT-T |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | 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 |