ICL7660ACPAZ Intersil, ICL7660ACPAZ Datasheet - Page 10

• Manufacturer Part Number: ICL7660ACPAZ
• Description: IC VOLTAGE CONVERTER CMOS 8-DIP
• Manufacturer: Intersil
• Type: Switched Capacitor (Charge Pump), Invertingr

Specifications of ICL7660ACPAZ

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: -1.5 ~ -12 V
• Frequency - Switching: 10kHz
• Voltage - Input: 1.5 ~ 12 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Primary Input Voltage: 5V
• No. Of Outputs: 1
• Output Current: 20mA
• No. Of Pins: 8
• Operating Temperature Range: 0°C To +70°C
• Supply Voltage Range: 1.5V To 12V
• Filter Terminals: Through Hole
• Rohs Compliant: Yes
• Digital Ic Case Style: DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Power - Output: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

Positive Voltage Doubling
The ICL7660 and ICL7660A may be employed to achieve
positive voltage doubling using the circuit shown in Figure
19. In this application, the pump inverter switches of the
ICL7660 and ICL7660A are used to charge C
level of V+ -V
forward voltage drop of diode D
voltage on C
diode D
becomes (2V+) - (2VF) or twice the supply voltage minus the
combined forward voltage drops of diodes D
The source impedance of the output (V
the output current, but for V+ = 5V and an output current of
10mA it will be approximately 60Ω.
Combined Negative Voltage Conversion
and Positive Supply Doubling
Figure 20 combines the functions shown in Figures 13 and
Figure 19 to provide negative voltage conversion and
positive voltage doubling simultaneously. This approach
would be, for example, suitable for generating +9V and -5V
from an existing +5V supply. In this instance capacitors C
and C
respectively for the generation of the negative voltage, while
capacitors C
for the doubled positive voltage. There is a penalty in this
configuration which combines both functions, however, in
that the source impedances of the generated supplies will be
somewhat higher due to the finite impedance of the common
charge pump driver at pin 2 of the device.
FIGURE 18. LOWERING OSCILLATOR FREQUENCY
3
C
1
2
perform the pump and reservoir functions
1
2
3
4
to capacitor C
FIGURE 19. POSITIVE VOLT DOUBLER
+
-
1
2
F
ICL7660A
plus the supply voltage (V+) is applied through
ICL7660
and C
(where V+ is the supply voltage and V
1
2
3
4
4
are pump and reservoir respectively
ICL7660A
ICL7660
2
. The voltage thus created on C
8
7
6
5
10
1
). On the transfer cycle, the
8
7
6
5
V+
+
D
D
-
+
1
2
-
OUT
C
V+
1
) will depend on
C
C
1
2
1
OSC
and D
to a voltage
V
(2V+) - (2V
+
-
V
OUT
OUT
C
ICL7660, ICL7660A
2
2
F
=
.
is the
2
F
1
)
Voltage Splitting
The bidirectional characteristics can also be used to split a
higher supply in half, as shown in Figure 21. The combined
load will be evenly shared between the two sides. Because
the switches share the load in parallel, the output impedance
is much lower than in the standard circuits, and higher
currents can be drawn from the device. By using this circuit,
and then the circuit of Figure 16, +15V can be converted (via
+7.5, and -7.5) to a nominal -15V, although with rather high
series output resistance (
Regulated Negative Voltage Supply
In some cases, the output impedance of the ICL7660 and
ICL7660A can be a problem, particularly if the load current
varies substantially. The circuit of Figure 22 can be used to
overcome this by controlling the input voltage, via an ICL7611
low-power CMOS op amp, in such a way as to maintain a
nearly constant output voltage. Direct feedback is inadvisable,
since the ICL7660s and ICL7660As output does not respond
instantaneously to change in input, but only after the switching
delay. The circuit shown supplies enough delay to
accommodate the ICL7660 and ICL7660A, while maintaining
adequate feedback. An increase in pump and storage
capacitors is desirable, and the values shown provides an
output impedance of less than 5Ω to a load of 10mA.
C
FIGURE 20. COMBINED NEGATIVE VOLTAGE CONVERTER
1
V
R
R
+
-
OUT
L1
L2
FIGURE 21. SPLITTING A SUPPLY IN HALF
= V+ - V-
1
2
3
4
50µF
2
AND POSITIVE DOUBLER
50µF
50µF
ICL7660A
ICL7660
-
-
+
C
2
+
-
-
+
+
~
250Ω).
8
7
6
5
1
2
3
4
V+
ICL7660A
ICL7660
D
D
1
2
8
7
6
5
+
-
V
(V
+
-
V
-
OUT
C
October 10, 2005
FD1
OUT
(nV
C
3
4
IN
)
= (2V+)
=
-
- V
FN3072.7
(V
V+
V
FD2
FDX
-
-
)
)