Electronic Components Datasheet Search |
|
MP2370DJ Datasheet(PDF) 6 Page - Monolithic Power Systems |
|
MP2370DJ Datasheet(HTML) 6 Page - Monolithic Power Systems |
6 / 8 page MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER IN A TSOT23-6 MP2370 Rev. 0.96 www.MonolithicPower.com 6 9/21/2007 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2007 MPS. All Rights Reserved. APPLICATION INFORMATION Setting LED Current The current sense resistor is inserted between the anode of WLED and GND. The current sense resistor value is calculated as: LED I V 15 . 0 1 R = For 1A WLED current, choose R1 = 150mΩ Selecting the Inductor A 1µH to 10µH inductor with a DC current rating of at least 25% percent higher than the maximum load current is recommended for most applications. For highest efficiency, the inductor’s DC resistance should be less than 200mΩ. Refer to Table 2 for suggested surface mount inductors. For most designs, the required inductance value can be derived from the following equation. SW L IN OUT IN OUT f I V ) V V ( V L × Δ × − × = Where ΔIL is the inductor ripple current. Choose the inductor ripple current to be 30% of the maximum load current. The maximum inductor peak current is calculated from: 2 I I I L LOAD ) MAX ( L Δ + = Under light load conditions below 100mA, a larger inductance is recommended to improve efficiency. See Table 2 for suggested inductors. Also note that the maximum recommended load current is 1A if the duty cycle exceeds 35%. Selecting the Input Capacitor The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. The input capacitor impedance at the switching frequency should be less than the output impedance of the input source to prevent high frequency switching current from passing through the input. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 4.7µF capacitor is sufficient. Selecting the Output Capacitor The output capacitor keeps the output current ripple small and ensures feedback loop stability. The output capacitor impedance should be low at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended for their low ESR characteristics. For most applications, a 2.2µF ceramic capacitor will be sufficient. The MP2370 can also work properly without output capacitor by adding a small capacitor in the feedback loop (see Figure 2). The small capacitor is recommended 680pF. PC Board Layout The high current paths (GND, IN and SW) should be placed very close to the device with short, direct and wide traces. The input capacitor needs to be as close as possible to the IN and GND pins. The external feedback resistors should be placed next to the FB pin. Keep the switch node traces short and away from the feedback network. |
Similar Part No. - MP2370DJ |
|
Similar Description - MP2370DJ |
|
|
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 |