The proprietary low-dropout transmitter output stage enables true RS-232 performance from a +3.1V to +5.5V supply with a dual charge pump. The parts reduce the transmitter output levels to RS-232-compatible levels with no increase in supply current for supplies less than +3.1V and greater than +2.35V. The +2.35V to +5.5V operating range is fully compatible with lithium-ion (Li+) batteries. The charge pump requires only four small 0.1F capacitors for operation. The MAX3380E/MAX3381E transceivers use Maxim's revolutionary AutoShutdown PlusTM feature to automatically enter a 1A shutdown mode. These devices shut down the on-board power supply and drivers when they do not sense a valid signal transition for 30 seconds on either the receiver or transmitter inputs. The MAX3380E is capable of transmitting data at rates of 460kbps while maintaining RS-232 output levels, and the MAX3381E operates at data rates up to 250kbps. The MAX3381E offers a slower slew rate for applications where noise and EMI are issues. The MAX3380E/MAX3381E have a unique V L pin that allows interoperation in mixed-logic voltage systems down to +1.65V. Both input and output logic levels are referenced to the VL pin. The MAX3380E/MAX3381E are available in a space-saving TSSOP package.