The TC7660 is a pin-compatible replacement for the industry standard TC7660 charge pump voltage converter. It converts a +1.5V to +10V input to a corresponding -1.5V-10V output, using only two low-cost capacitors, eliminating the inductor and its associated cost, size, and EMI. The on-board oscillator operates at a nominal frequency of 10kHz. Below 10kHz operation (lower power current applications) is to connect an external capacitor from the OSC to ground (pin 1 open). The TC7660 is available in both 8-pin DIP and 8-pin SOIC package ranges in commercial and extended temperature. The TC7660 contains all the necessary circuitry to implement the high voltage inverter, with the exception of two external capacitors, which may be inexpensive 10 MF polarized electrolytic capacitors. The action is best understood considering Figure 2 which shows an idealized voltage inverter. Capacitor C1 charges to voltage, V+half when switches S1 and S3 are closed cycled. (Note: Switches S2 and S4 are open during this half-cycle.) During the second half-cycle operation, switches S2 and S4 are closed, and S1 and S3 are open, thereby bringing the negative V of capacitor C1 + volts. The charge is then transferred so that from C1 to C2 is exactly the voltage V+ on C2, assuming ideal switching and no load on C2. The four switching MOS power switches in Figure 2; S1 is a p-channel device and S2, S3 and S4 are N-channel devices. The main difficulty with this approach is that in integrating switches, the substrates of S3 and S4 must always remain reverse biased to their source, but not so much to reduce their resistance to resistance. In addition, to start the circuit, under output short-circuit conditions (VOUT = V+), the output voltage must be sensed and the substrate bias adjusted accordingly. Failure to do this will result in high power losses and possible device latch-up. The problem is that the TC7660 detects the output voltage (VOUT) with a level shifter in the knockout logic network, switching the substrates of S3 and S4 to the correct levels to maintain the necessary reverse bias. The voltage regulator part of the TC7660 is an integral part of the anti-latch circuit. Its inherent voltage drop, but can degrade at low voltage operation. To improve low voltage operation, the regulator should be disabled by connecting Lvpin to GND. For supply voltages higher than 3.5V, the LV termination must be left open to ensure latch-up type operation and prevent device damage.