Electronic Components Datasheet Search |
|
ACT4088 Datasheet(PDF) 6 Page - Active-Semi, Inc |
|
ACT4088 Datasheet(HTML) 6 Page - Active-Semi, Inc |
6 / 11 page ACT4088 Rev 1, 14-Feb-11 Innovative PowerTM - 6 - www.active-semi.com Copyright © 2011 Active-Semi, Inc. FUNCTIONAL BLOCK DIAGRAM FUNCTIONAL DESCRIPTION The ACT4088 is a current-mode step-down DC/DC converter that provides excellent transient response with no extra external compensation components. This device contains an internal, low-resistance, high-voltage power MOSFET, and operates at a high 1.4MHz operating frequency to ensure a com- pact, high-efficiency design with excellent AC and DC performance. Setting the Output Voltage An external voltage divider is used to set the output voltage, as well as provide a known impedance from VOUT to FB for compensation purposes. Con- nect a 50kΩ resistor from the output to FB to ensure stable compensation, and select the bottom resistor to provide the desired regulation voltage. Figure 1: Output Voltage Setting The feedback resistor (RFB1) interacts with the inter- nal compensation network, and plays an important in setting the ACT4088's transient response and ensuring stability. For most applications, choosing RFB1 = 49.9kΩ provides good results. For applica- tions with output voltages of 1.8V or lower, use a larger RFB1 value such as 80.6kΩ. Once RFB1 is chosen, use the following equation to choose RFB2: Selecting the Inductor The ACT4088 was optimized for use with a 4.7µH inductor. When choosing an inductor, choose one with a DC resistance of less than 250mΩ and a DC current rating that is typically 30% higher than the maximum load current. During typical operation, the inductor maintains a continuous current to output load. The inductor current has a ripple that is dependent on the inductance value. Higher inductance reduces the peak-to-peak ripple current. The trade off for high inductance value is the increase in inductor core size and series resistance, and a reduction in current handling capability. If efficiency at light loads (such as less than 100mA) is critical in the application, a larger inductor is recommended. RFB1 RFB2 VOUT ACT4088 FB IN EN FB G REFERENCE & THERMAL SHUTDOWN CONTROL SOFT-START PWM Comparator ILIM Comparator HICCUP REGULATOR & UVLO OSCILLATOR COMPENSATION DRIVER CSA Q1 BST SW EA ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ − = 1 V 81 . 0 V R R OUT 1 FB 2 FB (1) |
Similar Part No. - ACT4088 |
|
Similar Description - ACT4088 |
|
|
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 |