HT7660_09 Datasheet, PDF (1/10 Pages) Holtek Semiconductor Inc – CMOS Switched-Capacitor Voltage Converter

HT7660
CMOS Switched-Capacitor Voltage Converter
Features
· Simple conversion of V_DD to -V_DD
· Cascade connection (two devices are connected,
V_OUT= -2 V_DD)
· Boost pin for higher switching frequency
· Easy to use
- Requires only two external capacitors
· No external diode required
· Typically with no load voltage conversion, 99.9% effi-
ciency
· Typical power efficiency is 98%
· Wide operating voltage range: 3V to 12V
· 8-pin DIP/SOP package
Applications
· RS-232 power supply
· On board negative supply for dynamic RAMS
· Supply voltage splitter, V_O= ± V_DD/2
· Operation amplifier supply
· Data acquisition systems
· Positive voltage doubler
General Description
HT7660 is a monolithic CMOS switched-capacitor volt-
age converter. HT7660 is designed to complete a volt-
age conversion from positive to negative. The only
required external components are two low cost electro-
lytic capacitors.
HT7660 includes a voltage regulator, an RC oscillator
and four output power MOS switches. The frequency of
Block Diagram
an RC oscillator can be lowered by adding an external
capacitor between V_DD and the OSC pin, or an external
clock can be connected to the OSC pin to replace the
original oscillator. The LV terminal may be tied to VSS to
disable the voltage regulator. By doing this, low voltage
operation can be improved.
OSC
BOOST
RC
Oscillator
Voltage
Level Shifter
LV
Voltage
Regulator
VSS
VDD
CAP+
CAP
VOUT
Logic
Network
Rev. 1.11
1
February 23, 2009