LXXLD20

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

7 of 7

www.unisonic.com.tw

QW-4502-701.b



APPLICATION INFORMATION

1. Power Sequencing

2. Output Capacitor

A proper output capacitor to maintain stability and improve transient response over temperature and current is

necessary. Proper ESR (equivalent series resistance) and capacitance of the output capacitor should be selected

properly for stability of the normal operation and good load transient response.

Many kinds of capacitors can be used as an output capacitor, such as ultra-low-ESR capacitors (like ceramic

chip capacitors), low-ESR bulk capacitors (like solid Tantalum, POSCap, and Aluminum electrolytic capacitors). And

also the value of the output capacitors’ can be increased without limit.

In the applications with large stepping load current, the low-ESR bulk capacitors are normally recommended.

Decoupling ceramic capacitors are recommended to be placed at the load and ground pins very closely and also

the impedance of the layout must be minimized.

3. Input Capacitor

In order to prevent the input rail from dropping, the proper input capacitor to supply current surge during stepping

load transients is required. Because the limited slew rate of the surge currents, more parasitic inductance needs more

input capacitance.

Ultra-low-ESR capacitors (>100mF, ESR<300mW) is recommended for the input capacitor.

4. Feedback Network

amplifier, the feedback network can provide proper frequency response for the UTC LXXLD20.

R1

R2

ESR

FB

C1

EAMP

UTC assumes no responsibility for equipment failures that result from using products at values that

exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or

other parameters) listed in products specifications of any and all UTC products described or contained

herein. UTC products are not designed for use in life support appliances, devices or systems where

malfunction of these products can be reasonably expected to result in personal injury. Reproduction in

whole or in part is prohibited without the prior written consent of the copyright owner. The information

presented in this document does not form part of any quotation or contract, is believed to be accurate

and reliable and may be changed without notice.