Amstelveen, the Netherlands Ricoh has launch the R1182x single seamless LDO. The low power LDO is enhanced with a circuit which dynamically improves the input and load transient response performance at higher output current demands and consequently results in a behavior such as a low noise LDO. Ricoh developed a unique solution to save power consumption in order to extend the battery life of an application. With basic LDO’s one can only choose between either low power or low noise types. A combination of these features can be obtained by using the so called 3-mode LDO with 2 control terminals (CE and ECO). This allows to switch between fast transient, low power and off mode however this requires additional wiring on the circuit board and software to control all these functions.
With the launch of its new Seamless LDO technology, Ricoh has added another simple option to make use of combined functions as described above. For example at low output current demand, the Seamless LDO behaves like a normal low power LDO, it saves power and has a slow transient response. When high output current is required, in case the application is fully active, the LDO automatically increases the ripple rejection ratio and behaves like a low noise LDO with fast transient response, the supply current increases accordingly. Finally the LDO can be disabled by controlling the chip enable pin for minimum power consumption.
For protection, an embedded fold-back current limit circuit decreases the output current in case of a short circuit to approximately 50 mA, protecting the LDO and other electronic parts of the application for damage. An optional feature is the auto-discharge function, discharging the output capacitor fast once the LDO is disabled, avoiding odd behaviour of the application during the power down sequence such as random graphics on the display or odd sounds from the speaker. For stable operation small ceramic capacitors with a low ESR value and a minimum of 0.1µF can be used. The R1182N is available in a SOT23-5 package and the R1182K in an ultra tiny PLP1616-6 package.
Ricoh Europe B.V., Amstelveen, the Netherlands, www.ricoh.com/LSI/www.ricoh.com/LSI/