 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC3530EDD-PBF Datasheet(PDF) 9 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC3530EDD-PBF Datasheet(HTML) 9 Page - Linear Technology |
|
|
9 / 16 page  LTC3530 9 3530fb The efficiency below 1mA becomes dominated primarily by the quiescent current. The Burst Mode operation ef- ficiency is given by: EFFICIENCY •ILOAD 40 μA +ILOAD where η is typically 90% during Burst Mode operation. Automatic Burst Mode Operation Control Burst Mode operation can be automatic or manually con- trolled with a single pin. In automatic mode, the IC will enter Burst Mode operation at light load and return to fixed frequency operation at heavier loads. The load current at which the mode transition occurs is programmed using a single external resistor from BURST to ground, according to the following equations: Enter Burst Mode: IBURST = 8.8 RBURST Leave Burst Mode: I BURST = 11.2 RBURST where RBURST is in kΩ and IBURST is the load transition current in Amps. Do not use values of RBURST greater than 500kΩ. For automatic operation, a filter capacitor must also be connected from BURST to ground. The equation for the minimum capacitor value is: CBURST(MIN) COUT •VOUT 60,000 where CBURST(MIN) and COUT are in μF In the event that a load transient causes FB to drop by more than 4% from the regulation value while in Burst Mode operation, the IC will immediately switch to fixed frequency mode and an internal pull-up will be momentarily applied to BURST, rapidly charging CBURST. This prevents the IC from immediately re-entering Burst Mode operation once the output achieves regulation. Manual Burst Mode Operation For manual control of Burst Mode operation, the RC network connected to BURST can be eliminated. To force fixed frequency mode, BURST should be connected to VIN. To force Burst Mode operation, BURST should be grounded. When commanding Burst Mode operation manually, the circuit connected to BURST should be able to sink up to 2mA. For optimum transient response with large dynamic loads, the operating mode should be controlled manually by the host. By commanding fixed frequency operation prior to a sudden increase in load, output voltage droop can be minimized. Note that if the load current applied during forced Burst Mode operation (BURST pin is grounded) exceeds the current that can be supplied, the output voltage will start to droop and the IC will automatically come out of Burst Mode operation and enter fixed frequency mode, raising VOUT. Once regulation is achieved, the IC will then enter Burst Mode operation once again, and the cycle will repeat, resulting in about 4% output ripple. Burst Mode Operation to Fixed Frequency Transient Response In Burst Mode operation, the compensation network is not used and VC is disconnected from the error amplifier. During long periods of Burst Mode operation, leakage currents in the external components or on the PC board could cause the compensation capacitor to charge (or discharge), which could result in a large output transient when returning to fixed frequency mode of operation, even at the same load current. To prevent this, the LTC3530 incorporates an active clamp circuit that holds the voltage on VC at an optimal voltage during Burst Mode operation. This minimizes any output transient when returning to fixed frequency mode operation. For optimum transient response, Type 3 compensation is also recommended to broad band the control loop and roll off past the two pole response of the output LC filter. See Closing the Feedback Loop under Applications Information. OPERATION |
Similar Part No. - LTC3530EDD-PBF |
|
Similar Description - LTC3530EDD-PBF |
|
|
|
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
