EUP7910A
Application Note
External Capacitors
Like any low-dropout regulator, the EUP7910A requires
external capacitors for regulator stability. These
capacitors must be correctly selected for good
performance.
Input Capacitor
An input capacitance of 1µF is required between the
EUP7910A input pin and ground (the amount of the
capacitance may be increased without limit).
This capacitor must be located a distance of not more
than 1cm from the input pin and returned to a clean
analog ground. Any good quality ceramic, tantalum, or
film capacitor may be used at the input.
If a tantalum capacitor is used at the input, it must be
guaranteed by the manufacturer to have a surge current
rating sufficient for the application.
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.
Output Capacitor
The EUP7910A is designed specifically to work with
very small ceramic output capacitors. A ceramic
capacitor (temperature characteristics X7R, X5R, Z5U,
or Y5V) in 2.2 to 10µF range with 5mΩ to 200mΩ ESR
range is suitable in the EUP7910A application circuit.
The output capacitor must meet the requirement for
minimum amount of capacitance and also have an ESR
(Equivalent Series Resistance) value which is within a
stable range (5mΩ to 200mΩ)
No-Load Stability
The EUP7910A will remain stable and in regulation with
no external load. This is specially important in CMOS
RAM keep-alive applications.
DS7910A Ver1.0 May 2008
7
EUTECH [ EUTECH MICROELECTRONICS INC ]
