ICL7660 pdf datasheet

The Intersil ICL7660 and ICL7660A are monolithic CMOS
power supply circuits which offer unique performance
advantages over previously available devices. The ICL7660
performs supply voltage conversions from positive to
negative for an input range of +1.5V to +10.0V resulting in
complementary output voltages of -1.5V to -10.0V and the
ICL7660Adoesthesameconversionswithaninputrangeof
+1.5Vto+12.0Vresultingincomplementaryoutputvoltages
of -1.5V to -12.0V. Only 2 noncritical external capacitors are
neededforthechargepumpandchargereservoirfunctions.
The ICL7660 and ICL7660A can also be connected to
function as voltage doublers and will generate output
voltages up to +18.6V with a +10V input.
Contained on the chip are a series DC supply regulator, RC
oscillator, voltage level translator, and four output power
MOS switches. A unique logic element senses the most
negativevoltageinthedeviceandensuresthattheoutputN-
Channel switch source-substrate junctions are not forward
biased. This assures latchup free operation.
The oscillator, when unloaded, oscillates at a nominal
frequency of 10kHz for an input supply voltage of 5.0V. This
frequency can be lowered by the addition of an external
capacitor to the  OSC   terminal, or the oscillator may
overdriven by an external clock.
The  LV   terminal may be tied to GROUND to bypass t
internal series regulator and improve low voltage (LV)
operation. At medium to high voltages (+3.5V to +10.0V for
the ICL7660 and +3.5V to +12.0V for the ICL7660A), the LV
pin is left ?oating to prevent device latchup.