ICL7660CBAZ-T Intersil, ICL7660CBAZ-T Datasheet - Page 8

• Manufacturer Part Number: ICL7660CBAZ-T
• Description: IC VOLTAGE CONVERTER CMOS 8-SOIC
• Manufacturer: Intersil
• Type: Switched Capacitor (Charge Pump), Invertingr

Specifications of ICL7660CBAZ-T

• Package / Case: 8-SOIC (3.9mm Width)
• Mounting Type: Surface Mount
• Voltage - Input: 1.5 ~ 10 V
• Operating Temperature: 0°C ~ 70°C
• Number Of Outputs: 1
• Internal Switch(s): Yes
• Frequency - Switching: 10kHz
• Synchronous Rectifier: No
• Package: 8SOIC N
• Function: Inverting/Step Up
• Output Voltage: -1.5 to -10|18.6(Max) V
• Output Current: 45(Max) mA
• Rohs Compliant: YES
• Peak Reflow Compatible (260 C): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Output: -
• Power - Output: -

Typical Applications
Simple Negative Voltage Converter
The majority of applications will undoubtedly utilize the ICL7660
and ICL7660A for generation of negative supply voltages.
Figure 13 shows typical connections to provide a negative
supply negative (GND) for supply voltages below 3.5V.
The output characteristics of the circuit in Figure 13A can be
approximated by an ideal voltage source in series with a
resistance as shown in Figure 13B. The voltage source has
a value of -V+. The output impedance (R
the ON resistance of the internal MOS switches (shown in
Figure 12), the switching frequency, the value of C
and the ESR (equivalent series resistance) of C1 and C2. A
good first order approximation for R
R
O
≅
2(R
2(R
SW1
SW2
10µF
+ R
+ R
C
SW4
+
SW3
1
-
V
-(V+)
+ ESR
+ ESR
0
8
FIGURE 16. CASCADING DEVICES FOR INCREASED OUTPUT VOLTAGE
C1
C1
) +
) +
O
1
2
3
4
1
2
3
4
is:
O
ICL7660A
ICL7660A
ICL7660
B
ICL7660
) is a function of
“1”
“1”
FIGURE 15. PARALLELING DEVICES
1
A
FIGURE 14. OUTPUT RIPPLE
ICL7660, ICL7660A
and C
8
7
6
5
8
7
6
5
t
2
10µF
V+
2
10µF
,
V+
+
-
C
+
-
1
RSW, the total switch resistance, is a function of supply
voltage and temperature (See the Output Source Resistance
graphs), typically 23Ω at 25°C and 5V. Careful selection of
C
output impedance. High value capacitors will reduce the
1/(f
lower the ESR term. Increasing the oscillator frequency will
reduce the 1/(f
of a net increase in output impedance when C
there is no longer enough time to fully charge the capacitors
(f
Combining the four R
1
PUMP
t
1
1
2
3
4
PUMP
and C
1
2
3
4
R
R
O
O
ICL7660A
=
ICL7660A
ICL7660
ICL7660
≅
≅
2
• C
“n”
“n”
2(R
will reduce the remaining terms, minimizing the
(f
1
PUMP
2 (R
) component, and low ESR capacitors will
SW1
PUMP
f
OSC
SW
1
2
+ R
) (C1)
8
7
6
5
10µF
8
7
6
5
SWX
) +
• C1) term, but may have the side effect
SW3
C
+
-
terms as R
2
+
-
+ ESR
, R
(f
+ ESR
PUMP
SWX
1
V
C2
C1
) (C1)
OUT
= MOSFET switch resistance)
SW
) +
, we see that:
=
R
L
-
nV+
+ 4 (ESR
1
C1
> 10µF and
October 10, 2005
) + ESR
FN3072.7
C2