ST662A
DC-DC CONVERTER FROM 5V TO 12V, 0.03A
FOR FLASH MEMORY PROGRAMMING SUPPLY
June 1997
s
OUTPUT VOLTAGE: 12V
5%
s
SUPPLY VOLTAGE RANGE: 4.5V TO 5.5V
s
GUARANTEED OUTPUT CURRENT UP TO
30mA
s
VERY LOW QUIESCENT CURRENT: 100
A
s
LOGIC CONTROLLED ELECTRONIC
SHUTDOWN: 1
A
s
JUST CAPACITORS NEEDED (NO
INDUCTOR)
DESCRIPTION
The ST662A is a regulated charge pump DC-DC
converter. It provides 12V
5% output voltage to
program byte-wide flash memory, and can supply
30mA output current from input as low as 4.75V
A logic controlled shut down pin that interfaces
directly with microprocessor reduces the sypply
current to only 1
A
TYPICAL APPLICATION CIRCUIT
DIP-8
SO-8
1/12
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V
c c
DC Input Voltage to GND
-0.3 to 6
V
SHDN
Shutdown Voltage
-0.3 t o V
CC
+0.3
V
I
o
Output Current Continuous
50
mA
P
t ot
Power Dissipation
500
mW
T
o p
Operating Ambient Temperature Range (for AC SERIES)
(for AB SERIES)
0 t o 70
- 40 t o 85
o
C
o
C
T
stg
Storage Temperature Range
- 40 t o 150
o
C
Absolute Maximum Rating are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
CONNECTION DIAGRAM AND (top view)
PIN CONNECTIONS
Pin No
Symbol
Name and Fun ction
1
C1-
Negative Terminal For The First Charge Pump Capacitor
2
C1+
Positive Terminal For The First Charge Pump Capacitor
3
C2-
Negative Terminal For The Second Charge Pump Capacitor
4
C2+
Positive Terminal For The Second Charge Pump Capacitor
5
V
CC
Supply Voltage
6
V
OUT
12V Output Voltage V
OUT
= V
CC
When in Sshutdown Mode
7
G ND
Ground
8
SHDN
Active High C-MOS logic level Shutdown Input. SHDN is internally pulled up to
V
CC
. Connect to GND for Normal Operation. In Shutdown mode the charge
pumps are turned off and V
OUT
= V
CC
ORDERING NUMBERS
Type
DIP-8
SO-8 (*)
ST662AB
ST662ABN
ST662ABD
ST662AC
ST662ACN
ST662ACD
(*) AVAILABLE IN TAPE AND REEL WITH "-TR" SUFFIX
ST662A
2/12
ELECTRICAL CHARACTERISTICS (Refer to the test circuits, V
CC
= 4.5V to 5.5V T
a
= T
min
to T
max
unless otherwise specified. Typical Value are referred at T
a
= 25
o
C)
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
o
Output Voltage
I
o
= 0 mA to 20 mA
11.4
12
12.6
V
V
o
Output Voltage
I
o
= 0 mA to 30 mA V
CC
= 4.75 to 5.5 V
11.4
12
12.6
V
I
Q1
Quiescent Current
No Load, V
SHDN
= 0
100
500
A
I
Q2
Shutdown Current
No Load, V
SHDN
= V
CC
1
10
A
I
SH
Shutdown Pin Current
V
SHDN
= 0V, V
CC
= 5V
V
SHDN
= V
CC
= 5V
-50
-12
0
-5
A
A
V
il
Shutdown Input Low Threshold
0.4
V
V
ih
Shutdown Input High
Threshold
2.4
V
f
o
Oscillator Frequency
V
CC
= 5V, I
o
= 30 mA
400
KHz
Power Efficecy
V
CC
= 5V, I
o
= 30 mA
72
%
R
sw
V
CC
- V
OUT
Switch Impedance
V
SHDN
= V
CC
= 5V, I
o
= 100
A
1
2
K
Do not overload or short the Output to Ground. If the above conditions are observerd, the device may be damaged.
Output Voltage vs Temperature
Supply Current vs Temperature
Output Voltage vs Temperature
Supply Currernt vs Supply Voltage
ST662A
3/12
Output Voltage vs Shutdown Input Voltage
Test Circuit
Output Voltage vs Shutdown Input Voltage
SHDN Pin Current vs Temperature
Output Voltage vs Shutdown Input Voltage
ST662A
4/12
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
V
CC
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 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
CC
.
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
OUT
oscillator will be blocked and the V
OUT
will reach
theV
IN
value by D1. In this condition I
CC
will be
Figure 1: Operating Principle Circuit
low as 1
A. 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
NOTE: V
CC
= 5V, I
OUT
= 200
A
NOTE: V
CC
= 5V, I
OUT
= 200
A
ST662A
5/12
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