 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC3564ES5-TRPBF Datasheet(PDF) 11 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC3564ES5-TRPBF Datasheet(HTML) 11 Page - Linear Technology |
|
|
11 / 20 page  11 LTC3564 3564f Output Voltage Programming In the adjustable version, the output voltage is set by a resistive divider according to the following formula: VV R R OUT =+ ⎛ ⎝⎜ ⎞ ⎠⎟ 06 1 2 1 . (2) The external resistive divider is connected to the output, allowing remote voltage sensing as shown in Figure 2. 1. The VIN quiescent current is due to two components: the DC bias current as given in the electrical character- istics and the internal main switch and synchronous switch gate charge currents. The gate charge current results from switching the gate capacitance of the internal power MOSFET switches. Each time the gate is switched from high to low to high again, a packet of charge, dQ, moves from VIN to ground. The resulting dQ/dt is the current out of VINthat is typically larger than the DC bias current. In continuous mode, IGATECHG = f(QT + QB) where QT and QB are the gate charges of the internal top and bottom switches. Both the DC bias and gate charge losses are proportional to VIN and thus their effects will be more pronounced at higher supply voltages. 2. I2R losses are calculated from the resistances of the internal switches, RSW, and external inductor RL. In continuous mode, the average output current flowing through inductor L is “chopped” between the main switch and the synchronous switch. Thus, the series resistance looking into the SW pin is a function of both top and bottom MOSFET RDS(ON) and the duty cycle (DC) as follows: RSW = (RDS(ON)TOP)(DC) + (RDS(ON)BOT)(1 – DC) Efficiency Considerations The efficiency of a switching regulator is equal to the output power divided by the input power times 100%. It is often useful to analyze individual losses to determine what is limiting the efficiency and which change would produce the most improvement. Efficiency can be expressed as: Efficiency = 100% – (L1 + L2 + L3 + ...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, two main sources usually account for most of the losses in LTC3564 circuits: VIN quiescent current and I2R losses. The VIN quiescent current loss dominates the efficiency loss at very low load currents whereas the I2R loss dominates the efficiency loss at medium to high load currents. In a typical efficiency plot, the efficiency curve at very low load currents can be misleading since the actual power lost is of no consequence as illustrated in Figure 3. APPLICATIO S I FOR ATIO Figure 3. Power Lost vs Load Current Figure 2. Setting the LTC3564 Output Voltage LOAD CURRENT (A) 0.1 0.0001 0.01 1 1 10 100 1000 10000 3564 F03 0.001 0.1 VOUT = 1.2V VOUT = 1.5V VOUT = 1.8V VIN = 3.6V VFB GND LTC3564 0.6V ≤ VOUT ≤ 5.5V R2 R1 3564 F02 |
Similar Part No. - LTC3564ES5-TRPBF |
|
Similar Description - LTC3564ES5-TRPBF |
|
|
|
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
