MAX660CSA+T

The MAX660 monolithic, charge-pump voltage inverter converts a +1.5V to +5.5V input to a corresponding -1.5V to -5.5V output. Using only two low-cost capacitors, the charge pump’s 100mA output replaces switching regulators, eliminating inductors and their associated cost, size, and EMI. Greater than 90% efficiency over most of its load-current range combined with a typical operating current of only 120μA provides ideal performance for both battery-powered and board-level voltage conversion applications. The MAX660 can also double the output voltage of an input power supply or battery, providing +9.35V at 100mA from a +5V input. The MAX660 capacitive charge-pump circuit either inverts or doubles the input voltage (see Typical Operating Circuits). For highest performance, low effective series resistance (ESR) capacitors should be used. When using the inverting mode with a supply voltage less than 3V, LV must be connected to GND. This bypasses the internal regulator circuitry and provides best performance in low-voltage applications. When using the inverter mode with a supply voltage above 3V, LV may be connected to GND or left open. The part is typically operated with LV grounded, but since LV may be left open, the substitution of the MAX660 for the ICL7660 is simplified. LV must be grounded when overdriving OSC (see Changing Oscillator Frequency section). Connect LV to OUT (for any supply voltage) when using the doubling mode.

Applications

• Laptop Computers
• Medical Instruments
• Interface Power Supplies
• Hand-Held Instruments
• Operational-Amplifier Power Supplies

Key features

• Small Capacitors
• 0.65V Typ Loss at 100mA Load
• Low 120μA Operating Current
• 6.5Ω Typ Output Impedance
• Guaranteed ROUT <15Ω for C1 = C2 = 10μF
• Pin-Compatible High-Current ICL7660 Upgrade
• Inverts or Doubles Input Supply Voltage
• Selectable Oscillator Frequency: 10kHz/80kHz
• 88% Typ Conversion Efficiency at 100mA (IL to GND)