UTCL2949E

LINEAR INTEGRATED CIRCUIT

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QW-R102-014,A

FUNCTIONAL DESCRIPTION

The UTC L2949E is a monolithic integrated voltage regulator,based on the STM modular voltage regulator

approch.Several outstanding features and auxiliary functions are implemented to meet the requirements of supplying

microprocessor systems in automotive applications.Nevertheless,It is suitable also in other applications where the

present functions are required.The modular approach of this device allows to get easily also other features and

functions when required.

Voltage Regulator

The voltage regulator uses an lsolated Collector Vertical PNP transistor as a regulating element.

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Figure 1: Foldback Characteristic of Vo

With this structure very low dropout voltage at currents up to 100mA is obtained.The dropout operation of the

standby regulator is maintained down to 3V input supply voltage.The output voltage is regulated up to the transient

input supply voltage of 4V.With this feature no functional interruption due to overvoltage pulses is generated.The

typical cuve showing the standby.output voltage as a function of the input supply voltage is shown in Fig.2. The

current consumption of the device(quiescent current) is less than 300μA.

To reduce the quiescent current peak in the undervoltage region and to improve the transient response inthis

region.the dropout voltage is controlled,the quiescent current as a function of the supply input voltage is shown in

Fig.3.