Electronic Components Datasheet Search |
|
TPS54073PWP Datasheet(PDF) 11 Page - Texas Instruments |
|
|
TPS54073PWP Datasheet(HTML) 11 Page - Texas Instruments |
11 / 25 page SWITCHING FREQUENCY OUTPUT FILTER COMPONENTS Inductor Selection R4(kW) + 500 kHz ƒs(kHz) 100 kW (1) INPUT CAPACITORS 0.8 x F I K V ) V (V V L SW OUT IND IN(MAX) OUT IN(MAX) OUT MIN ´ ´ ´ - ´ = (4) I LMAX v 2 I LIMIT(MIN) * I (MAX) (5) DVPVIN + I OUT(MAX) 0.25 C BULK ƒsw ) I OUT(MAX) ESR MAX I CIN + I OUT(MAX) 2 (3) I L(RMS) + I2 OUT(MAX) ) 1 12 V OUT V in(MAX) * V OUT V IN(MAX) L OUT Fsw 0.8 2 TPS54073 www.ti.com ............................................................................................................................................................................................ SLVS547 – FEBRUARY 2005 for 16 V, and the ripple current capacity is greater than 3 A at the operating frequency of 700 kHz. Total The switching frequency can be set to either one of ripple current handling is in excess of 10.4 A. It is two internally programmed frequencies or set to a important that the maximum ratings for voltage and externally programmed frequency. With the RT pin current are not exceeded under any circumstance. open, setting the SYNC pin at or above 2.5 V selects 550-kHz operation, while grounding or leaving the SYNC pin open selects 350-kHz operation. For this design, the switching frequency is externally Two components need to be selected for the output programmed using the RT pin. By connecting a filter, L1 and C2. Because the TPS54073 is an resistor (R4) from RT to AGND, any frequency in the externally compensated device, a wide range of filter range of 250 kHz to 700 kHz can be set. Use component types and values can be supported. Equation 1 to determine the proper value of RT. To calculate the minimum value of the output inductor, use Equation 4 In this example circuit, R4 is calculated to be 71.5 k Ω and the switching frequency is set at 700 kHz. The TPS54073 requires an input de-coupling KIND is a coefficient that represents the amount of capacitor and, depending on the application, a bulk inductor ripple current relative to the maximum output input capacitor. The minimum value for the current. For designs using low ESR output capacitors de-coupling capacitor, C9, is 10 µF. A high-quality such as ceramics, use KIND = 0.3. When using higher ceramic type X5R or X7R is recommended. The ESR output capacitors, KIND = 0.2 yields better voltage rating should be greater than the maximum results. If designing for high output currents, the input voltage. Additionally, some bulk capacitance minimum current limit trip point must also be taken may be needed, especially if the TPS54073 circuit is into consideration when choosing the output inductor. not located within approximately 2 inches from the The minimum current limit trip point for the TPS54073 input voltage source. The value for this capacitor is is 14.5 A. The maximum inductor ripple current can not critical but it also should be rated to handle the be calculated using Equation 5: maximum input voltage including ripple voltage, and should filter the output so that input ripple voltage is acceptable. This input ripple voltage can be approximated by For a 14 A maximum output current, the peak-to-peak Equation 2: inductor ripple current must be less than 1 A. This corresponds to a KIND of 0.071 in Equation 4. FSW is the nominal switching frequency. Use 0.8 times the nominal switching frequency to account for (2) internal variations from the set frequency. Where IOUT(MAX) is the maximum load current. ƒsw is The minimum inductor value is calculated to be 1.54 the switching frequency, C(BULK) is the bulk capacitor µH. A 2.2-µH inductor which is slightly larger than the value and ESRMAX is the maximum series resistance minimum is selected. of the bulk capacitor. For the output filter inductor, it is important that the The maximum RMS ripple current also needs to be RMS current and saturation current ratings not be checked. For worst-case conditions, this can be exceeded. The RMS inductor current can be found approximated by Equation 3: from Equation 6: In this case, the input ripple voltage would be 329 mV and the RMS ripple current would be 7 A. The (6) maximum voltage across the input capacitors would be Vin max plus delta Vin/2. The chosen bulk and the peak inductor current can be found from capacitor, a Sanyo POSCAP 6TPD330M is rated for Equation 7 6.3 V and 4.4 A of ripple current; two bypass capacitors, TDK C3225X7R1C226KT are each rated Copyright © 2005, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Link(s): TPS54073 |
Similar Part No. - TPS54073PWP |
|
Similar Description - TPS54073PWP |
|
|
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 |