Electronic Components Datasheet Search |
|
MAX861ISA Datasheet(PDF) 7 Page - Maxim Integrated Products |
|
MAX861ISA Datasheet(HTML) 7 Page - Maxim Integrated Products |
7 / 12 page 50mA, Frequency-Selectable, Switched-Capacitor Voltage Converters _______________________________________________________________________________________ 7 __________Applications Information Capacitor Selection The MAX860/MAX861 are tested using 10µF capacitors for both C1 and C2, although smaller or larger values can be used (Table 3). Smaller C1 values increase the output resistance; larger values reduce the output resistance. Above a certain point, increasing the capacitance of C1 has a negligible effect (because the output resistance becomes dominated by the internal switch resistance and the capacitor ESR). Low-ESR capacitors provide the lowest output resistance and ripple voltage. The output resistance of the entire circuit (inverter or doubler) is approximately: ROUT = RO + 4 x ESRC1 + ESRC2 + 1 / (fS x C1) where RO (the effective resistance of the MAX860/ MAX861’s internal switches) is approximately 8 Ω and fS is the switching frequency. ROUT is typically 12 Ω when using capacitors with 0.2 Ω ESR and fS, C1, and C2 val- ues suggested in Table 3. When C1 and C2 are so large (or the switching frequency is so high) that the internal switch resistance dominates the output resis- tance, estimate the output resistance as follows: ROUT = RO + 4 x ESRC1 + ESRC2 A typical design procedure is as follows: 1) Choose C1 and C2 to be the same, for convenience. 2) Select fS: a) If you want to avoid a specific noise frequency, choose fS appropriately. b) If you want to minimize capacitor cost and size, choose a high fS. c) If you want to minimize current consumption, choose a low fS. 3) Choose a capacitor based on Table 3, although higher or lower values can be used to optimize per- formance. Table 4 lists manufacturers who provide low-ESR capacitors. *In addition to Table 3, four graphs in the Typical Operating Characteristics section show typical output current for C1 and C2 capacitances ranging from 0.33µF to 22µF. Output current is plotted for inputs of 4.5V (5V - 10%) and 3.0V (3.3V - 10%), and also for 10% and 20% output droop from the ideal -VIN value. ATTRIBUTE LOWER FREQUENCY HIGHER FREQUENCY Output Ripple Larger Smaller C1, C2 Values Larger Smaller Supply Current Smaller Larger C1, C2 (µF) NOMINAL FREQUENCY (kHz) 6 68 13 47 50 10 100 4.7 130 4.7 250 2.2 Table 2. Switching-Frequency Trade-Offs Table 3. Suggested Capacitor Values* Table 4. Low-ESR Capacitor Manufacturers MANUFACTURER–Series PHONE FAX COMMENTS AVX TPS Series (803) 946-0629 (803) 626-3123 Low-ESR tantalum, SMT AVX TAG Series (803) 946-0629 (803) 626-3123 Low-cost tantalum, SMT Matsuo 267 Series (714) 969-2491 (714) 960-6492 Low-cost tantalum, SMT Sprague 595 Series (603) 224-1961 (613) 224-1430 Low-ESR tantalum, SMT Sanyo MV-GX Series (619) 661-6835 (619) 661-1055 Aluminum electrolytic, through hole Sanyo CV-GX Series (619) 661-6835 (619) 661-1055 Aluminum electrolytic, SMT Nichicon PL Series (847) 843-7500 (847) 843-2798 Aluminum electrolytic, through hole United Chemicon (Marcon) (847) 696-2000 (847) 696-9278 Ceramic SMT TDK (847) 390-4461 (847) 390-4405 Ceramic SMT |
Similar Part No. - MAX861ISA |
|
Similar Description - MAX861ISA |
|
|
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 |