Electronic Components Datasheet Search |
|
LTC3900 Datasheet(PDF) 11 Page - Linear Technology |
|
LTC3900 Datasheet(HTML) 11 Page - Linear Technology |
11 / 12 page LTC3900 11 3900i APPLICATIO S I FOR ATIO PACKAGE DESCRIPTIO S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .016 – .050 (0.406 – 1.270) .010 – .020 (0.254 – 0.508) × 45° 0 °– 8° TYP .008 – .010 (0.203 – 0.254) SO8 0303 .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.483) TYP .004 – .010 (0.101 – 0.254) .050 (1.270) BSC 1 2 3 4 .150 – .157 (3.810 – 3.988) NOTE 3 8 7 6 5 .189 – .197 (4.801 – 5.004) NOTE 3 .228 – .244 (5.791 – 6.197) .245 MIN .160 ±.005 RECOMMENDED SOLDER PAD LAYOUT .045 ±.005 .050 BSC .030 ±.005 TYP INCHES (MILLIMETERS) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) quickly. The VCC supply circuit shown in Figure 9 will provide power for the LTC3900 within the first few switch- ing pulses of the primary controller, preventing overheat- ing of the MOSFETs. MOSFET Selection The required MOSFET RDS(ON) should be determined based on allowable power dissipation and maximum re- quired output current. The body diodes conduct during the power-up phase, when the LTC3900 VCC supply is ramping up. The CG and FG signals stay low and the inductor current flows through the body diodes. The body diodes must be able to handle the load current during start-up until VCC reaches 4.1V. The LTC3900 drivers dissipate power when switching MOSFETs. The power dissipation increases with switch- ing frequency, VCC and size of the MOSFETs. To calculate the driver dissipation, the total gate charge QG is used. This parameter is found on the MOSFET manufacturers data sheet. The power dissipated in each LTC3900 MOSFET driver is: PDRIVER = QG • VCC • fSW where fSW is the switching frequency of the converter. PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC3900 for your layout: 1. Connect the 4.7 µFbypasscapacitorascloseaspossible to the VCC and GND pins. 2. Connect the two MOSFET drain terminals directly to the transformer. The two MOSFET sources should be as close together as possible. 3. Keep the timer, SYNC and VCC regulator circuit away from the high current path of Q3, Q4 and T1. 4. Place the timer capacitor, CTMR as close as possible to the LTC3900. 5. Keep the PCB trace from the resistors RCS1, RCS2 and RCS3 to the LTC3900 CS+/CS– pins as short as possible. Connect the other ends of the resistors directly to the drain and source of the MOSFET, Q4. |
Similar Part No. - LTC3900 |
|
Similar Description - LTC3900 |
|
|
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 |