资 源 简 介
The TC1142 generates a regulated negaTIve voltagefrom -3V to -5V at 20mA from an input of 2.5V to 5.5V,using only three external capacitors. Other boost/buckswitching regulators must use an inductor, which islarger and radiates EMI. An internal voltagecomparator inhibits the charge pump when VOUT ismore negaTIve than the regulated value (per theordering opTIon). The values of flying capacitors C1 andC2 are chosen to be less than COUT in order to reducethe ripple generated from regulaTIng VOUT in thismanner. The TC1142 also can be used as a -1x buckregulator by omitting C2, and connecting the C2 pin toVOUT.The part goes into shutdown when the CCLK input isdriven low. When in shutdown mode, the part draws amaximum of 1μA. When CCLK is pulled high, the partruns from the internal 200kHz oscillator. The devicemay be run with an external clock, provided thefrequency is greater than 3kHz and less than 500kHz.The TC1142 comes in a space-saving MSOP package.
