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Product data sheet

Rev. 05 — 13 June 2005

6 of 17

Philips Semiconductors

TDA3663

Very low dropout voltage/quiescent current 3.3 V voltage regulator

11.3.1 Application circuit with backup function

Sometimes a backup function is needed to supply, for example, a microcontroller for a

short period of time when the supply voltage spikes to 0 V (or even

−1 V).

This function can easily be built with the TDA3663 by using an output capacitor with a

large value. When the supply voltage is 0 V (or

−1 V), only a small current will flow into

pin REG from this output capacitor (a few

µA).

The application circuit is given in Figure 4.

(1) C1 is optional (to minimize supply noise only).

(2) C2

≤ 4700 µF.

Fig 4.

Application circuit with backup function (SO4 version)

mgs587

13

2, 4

TDA3663

C1(1)

C2(2)

1

µF