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5D14N-Rev.F004

EC3121

300mA 2CH Low Dropout Voltage

Linear Regulators

Typical Application Circuit

Application Information

The EC3121 requires input and output decoupling capacitors. The device is specifically designed for portable

applications requiring minimum board space and smallest components. These capacitors must be correctly

selected for good performance (see Capacitor Characteristics Section). Please note that linear regulators with

a low dropout voltage have high internal loop gains which require care in guarding against oscillation

caused by insufficient decoupling capacitance.

Input Capacitor

An input capacitance of 1µF is required space between input pin and ground pin directly (the amount of

the capacitance may be increased without limit).The input capacitor must be located less than 1cm from the

device to assure input stability. A lower ESR capacitor allows the use of less capacitance, while higher ESR type

(like aluminum electrolytic)requires more capacitance.Capacitor types (aluminum, ceramic and tantalum) can be

mixed in parallel, but the total equivalent input capacitance ESR must be defined as above to stable operation.

There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be

considered when selecting the capacitor to ensure the capacitance will be 1µF over the entire

operating temperature range.