DESCRIPTION

The ST662 is an IC developed to provide a 12V

regulated output 30mA from voltage input as low

as 4.75 without any inductors. It is useful for a

wide range of applications and its performances

makes it ideal for flash memory programming

supply.

An evaluation kit is provided to facilitate the

application. This include a single-side demo

board

designed

for

surface-mount

components.The operating principle of ST662

(see fig. 1) is to charge C1 and C2 capacitor by

closing the S1 switch (while S2 is opened) at the

closed so that C1 and C2 capacitors are placed

in series one to each other, and both are in series

with Vin.The sum of VC1 and VC2 and Vin is

applied to the capacitor C4. This works as

voltage tripler. An amplifier error checks the

output voltage and blocks the oscillator if the

output voltage is greater than 12V.

When it is held low the output voltage rises to

+12V. Fig.2 shows the transition time of the shut

down pin when the VSHDN goes from 5V to 0V.

Input logic levels of this input are CMOS

compatible.

Figure 1: Operating Principle Circuit

low as 1

µA. The fig.3 shows the transition time

of the shut down pin when the VSHDN goes from

0V to 5V.

Figure 2: Exiting Shutdown

TIME= 20us/DIV, VERTICAL = 5V/DIV

5V

0V

12V

5V

SHDN

Vout

Figure 3: Entering Shutdown

TIME= 1ms/DIV, VERTICAL = 5V/DIV

5V

0V

12V

5V

SHDN

Vout

µA

µA

ST662A

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