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MAX3248E：+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers with ±15kV ESD-Protected I/O and Logic Pins

The MAX3238E/MAX3248E transceivers use Maxim's revolutionary AutoShutdown Plus™ feature to achieve 10nA supply current. These devices shut down the on-board power supply and drivers when they do not sense a valid signal transition on either the receiver or transmitter inputs. This occurs if the RS-232 cable is disconnected or if the transmitters of the connected peripheral are turned off. The devices turn on again when a valid transition is applied to any RS-232 receiver or transmitter input. AutoShutdown Plus automatically achieves this power savings through its on-board circuitry, as no changes are required to the existing BIOS or operating system. All RS-232 inputs and outputs, as well as the logic I/O pins, have enhanced ESD protection to ±15kV. The additional ESD protection on the logic I/O pins makes the MAX3238E/MAX3248E ideal for cell phone data cable applications because it eliminates the need for costly external TransZorb™ or protection schemes. The MAX3238E/MAX3248E contain five drivers and three receivers and are 3V-powered EIA/TIA-232 and V.28/V.24 communication interfaces intended for cell phones, data cables, and modem applications. A proprietary, high-efficiency, dual charge-pump power supply and a low-dropout transmitter combine to deliver true RS-232 performance from a single +3.0V to +5.5V supply. A guaranteed data rate of 250kbps provides compatibility with popular software for communicating with personal computers. The MAX3238E and the MAX3248E differ only in their input logic thresholds. The MAX3238E has standard logic thresholds, while the MAX3248E has low-level logic thresholds of 0.6V to 1.2V, which are ideal for 1.8V systems. The transmitter inputs, FORCEON, and active-low FORCEOFF have a 400 kilohms active positive feedback resistor. Once driven to a valid logic level, they will retain this level if the driving signal is removed or goes high impedance. Unused transmitter and logic inputs may be left unconnected. The MAX3238E/MAX3248E can operate with supply voltages ranging from +3.0V to +5.5V.

Key Features Enhanced ESD Protection on RS-232 I/O Pins and All Logic Pins ±15kV—Human Body Model ±8kV—IEC 1000-4-2 Contact Discharge ±15kV—IEC 1000-4-2 Air-Gap Discharge Guaranteed Data Rate: 250kbps 10nA Low-Power Shutdown with Receivers Active Schmitt Triggers on All Inputs Flow-Through Pinout Meets EIA/TIA-232 Specifications Down to 3.0V Guaranteed 6V/µs Slew Rate Low-Level Logic Thresholds (MAX3248E) RS-232-Compatible Outputs to 2.7V

MAX3238E, MAX3248E: Typical Operating Circuit Applications/Uses Battery-Powered Applications Cellular Data Cables Data Cradles Modems Peripherals Printers

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