Electronic Components Datasheet Search |
|
LMC7660IM Datasheet(PDF) 5 Page - National Semiconductor (TI) |
|
|
LMC7660IM Datasheet(HTML) 5 Page - National Semiconductor (TI) |
5 / 12 page Application Information (Continued) Typical Applications Changing Oscillator Frequency It is possible to dramatically reduce the quiescent operating current of the LMC7660 by lowering the oscillator frequency. The oscillator frequency can be lowered from a nominal 10 kHz to several hundred hertz, by adding a slow-down ca- pacitor C osc (Figure 3). As shown in the Typical Performance Curves the supply current can be lowered to the 10 µA range. This low current drain can be extremely useful when used in µPower and battery back-up equipment. It must be understood that the lower operating frequency and supply current cause an increased impedance of C r and Cp. The in- creased impedance, due to a lower switching rate, can be offset by raising C r and Cp until ripple and load current re- quirements are met. Synchronizing to an External Clock Figure 4 shows an LMC7660 synchronized to an external clock. The CMOS gate overrides the internal oscillator when it is necessary to switch faster or reduce power supply inter- ference. The external clock still passes through the ÷2 circuit in the 7660, so the pumping frequency will be 1⁄2 the external clock frequency. Lowering Output Impedance Paralleling two or more LMC7660’s lowers output imped- ance. Each device must have it’s own pumping capacitor C p, but the reservoir capacitor C r is shared as depicted in Figure 5. The composite output resistance is: DS009136-6 FIGURE 2. Idealized Voltage Converter DS009136-7 FIGURE 3. Reduce Supply Current by Lowering Oscillator Frequency DS009136-8 FIGURE 4. Synchronizing to an External Clock 5 www.national.com |
Similar Part No. - LMC7660IM |
|
Similar Description - LMC7660IM |
|
|
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 |