 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
C3225X5R1C22M Datasheet(PDF) 9 Page - Richtek Technology Corporation |
|
||||||||||||||||||||||||||||||
C3225X5R1C22M Datasheet(HTML) 9 Page - Richtek Technology Corporation |
|
|
9 / 14 page  RT7272A 9 DS7272A-01 January 2013 www.richtek.com Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. © Application Information Output Voltage Setting The resistive divider allows the FB pin to sense the output voltage as shown in Figure 1. Figure 1. Output Voltage Setting The output voltage is set by an external resistive voltage divider according to the following equation : OUT REF R1 V = V 1 R2 ⎛⎞ + ⎜⎟ ⎝⎠ Where VREF is the reference voltage (0.8V typ.). External Bootstrap Diode Connect a 0.1 μF low ESR ceramic capacitor between the BOOT and SW pins. This capacitor provides the gate driver voltage for the high side MOSFET. It is recommended to add an external bootstrap diode between an external 5V and BOOT pin for efficiency improvement when input voltage is lower than 5.5V or duty ratio is higher than 65% .The bootstrap diode can be a low cost one such as IN4148 or BAT54. The external 5V can be a 5V fixed input from system or a 5V output of the RT7272A. Note that the external boot voltage must be lower than 5.5V Figure 2. External Bootstrap Diode Chip Enable Operation The EN pin is the chip enable input. Pulling the EN pin low (<0.4V) will shutdown the device. During shutdown mode, the RT7272A quiescent current drops to lower than 3 μA. Driving the EN pin high (>2.5V, < 18V) will turn on the device again. For external timing control, the EN pin can also be externally pulled high by adding a REN resistor and CEN capacitor from the VIN pin (see Figure 3). An external MOSFET can be added to implement digital control on the EN pin when no system voltage above 2.5V is available, as shown in Figure 4. In this case, a 100k Ω pull-up resistor, REN, is connected between VIN and the EN pin. MOSFET Q1 will be under logic control to pull down the EN pin. Figure 3. Enable Timing Control Figure 4. Digital Enable Control Circuit RT7272A GND FB R1 R2 VOUT SW BOOT 5V RT7272A 100nF RT7272A EN GND VIN REN CEN EN RT7272A EN GND 100k VIN REN Q1 EN Under Voltage Protection Hiccup Mode The RT7272A provides Hiccup Mode Under Voltage Protection (UVP). When the VFB voltage drops below 0.4V, the UVP function will be triggered to shut down switching operation. If the UVP condition remains for a period, the RT7272A will retry automatically. When the UVP condition is removed, the converter will resume operation. The UVP is disabled during soft-start period. |
Similar Part No. - C3225X5R1C22M |
|
Similar Description - C3225X5R1C22M |
|
|
|
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
