ST662AB datasheet(9/19 Pages) STMICROELECTRONICS

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ST662AB - ST662AC

Description

9/19

Description

The ST662 is an IC developed to provide a 12 V regulated output 30 mA 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

Figure 12) is to charge C1 and C2 capacitor by closing the S1 switch (while S2 is opened) at

the VCC voltage. After S1 will be opened and S2 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 VI is applied to the capacitor C4. This works as voltage triple. An amplifier error checks

the output voltage and blocks the oscillator if the output voltage is greater than 12 V. The

shutdown pin is internally pulled to VCC. When it is held low the output voltage rises to

+12 V. Figure 13 shows the transition time of the shut down pin when the VSHDN goes from

5 V to 0 V. Input logic levels of this input are CMOS compatible Applying a logic high at this

input, the VOUT oscillator will be blocked and the VOUT will reach the VI value by D1. In this

condition ICC will be. low as 1 µA. The Figure 14 shows the transition time of the shut down

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

Figure 12.

Operating principle circuit

ST662AB Datasheet(PDF) 9 Page - STMicroelectronics