Electronic Components Datasheet Search |
|
MAX877 Datasheet(PDF) 7 Page - Maxim Integrated Products |
|
MAX877 Datasheet(HTML) 7 Page - Maxim Integrated Products |
7 / 12 page With ILIM shorted to IN, the peak switch current of the internal NPN power switch is set to 1A. It can be set to a lower value by connecting a resistor between ILIM and IN (see Current Limit section). This enables the use of physically smaller inductors with lower saturation- current ratings. At 1A, the switch voltage drop (VSW) is about 500mV. VSW decreases to about 250mV at 0.1A. Conventional PWM converters generate constant- frequency switching noise, while this architecture produces variable-frequency switching noise. The out- put ripple is the product of the peak inductor current and the output capacitor's ESR. Unlike conventional pulse-skippers, the MAX877/MAX878/MAX879 peak currents are scaled down at light loads, resulting in lower output ripple. Step-Down Mode and Power Dissipation In battery-powered applications, for example, where the input voltage exceeds the output voltage, the MAX877/MAX878/MAX879 behave as “switched” linear regulators. If the output voltage starts to drop, the switch turns on and energy is stored in the coil, as in normal step-up mode. After the switch turns off, the voltage at LX flies high. The active rectifier turns on when LX rises above VIN. As in a linear regulator, the voltage difference between VIN and VOUT appears across the rectifier (actually a PNP transistor) until the current goes to zero and the rectifier turns off. At high VIN to VOUT differentials, the maximum load current is limited by the maximum allowable power dissipation in the package (see Typical Operating Characteristics). 5V/3.3V/3V/Adjustable-Output, Step-Up/Step-Down DC-DC Converters _______________________________________________________________________________________ 7 MAX878 DELAY TIMER tOFF DELAY TIMER tON VREF 0.2025V SHUTDOWN CONTROL SHDN 7 ACTIVE RECTIFIER RECTIFIER CONTROL OUT PGND AGND 3 SEL 8 4 6 100 µF VOUT 22 µF VIN 22 µH RLIM SWITCH DRIVER LX ILIM IN 21 5 1 : N Figure 1. MAX878 Block Diagram |
Similar Part No. - MAX877 |
|
Similar Description - MAX877 |
|
|
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 |