ST662 STMICROELECTRONICS [STMicroelectronics], ST662 Datasheet - Page 5

• Manufacturer Part Number: ST662
• Description: DC-DC CONVERTER FROM 5V TO 12V, 0.03A FOR FLASH MEMORY PROGRAMMING SUPPLY
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

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
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
V
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.
The shutdown pin is internally pulled to V
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.
Applying a logic high at this input, the V
oscillator will be blocked and the V
theV
Figure 2: Exiting Shutdown
NOTE: V
CC
5V
5V
IN
voltage. After S1 will be opened and S2
CC
TIME= 20us/DIV, VERTICAL = 5V/DIV
value by D1. In this condition I
= 5V, I
designed
0V
OUT
= 200 A
SHDN
Vout
for
surface-mount
OUT
CC
will reach
will be
12V
OUT
CC
.
Figure 1: Operating Principle Circuit
Figure 3: Entering Shutdown
NOTE: V
low as 1 A. The fig.3 shows the transition time
of the shut down pin when the VSHDN goes from
0V to 5V.
12V
0V
CC
TIME= 1ms/DIV, VERTICAL = 5V/DIV
= 5V, I
5V
OUT
= 200 A
SHDN
Vout
ST662A
5V
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