MAX3318ECAP+

Overview

The MAX3318ECAP+ is a dual RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, housed in a 20-pin SSOP package. It operates on a single +2.25V to +3.0V supply and achieves a typical operating current of 0.3mA. Utilizing AutoShutdown Plus technology, the device reduces supply current to 1µA when inputs remain inactive for over 30 seconds. It supports data rates up to 460kbps with a guaranteed slew rate of 4V/µs. The component includes integrated ESD protection rated at ±15kV (Human Body Model) and ±8kV (IEC Contact Discharge).

Feature Summary

• AutoShutdown Plus functionality automatically enters low-power shutdown mode after 30 seconds of inactivity.
• Integrated high-level electrostatic discharge protection on all RS-232 I/O pins.
• Dual charge pump generates internal voltage rails from a single low-voltage supply.
• Logic-level READY output indicates when the charge pump is regulating and ready for transmission.

Applications

• Palmtop Computers
• Hand-Held Instruments
• Cellular Phones

Procurement Notes

Verify the specific suffix 'CAP+' against official manufacturer documentation to confirm the exact pin configuration and temperature range. Ordering suffixes define physical package dimensions and thermal specifications; ensure the selected variant matches the target PCB footprint and environmental requirements before finalizing procurement.

Selection Notes

Select this component for applications requiring minimal power consumption during idle periods without BIOS modifications. The MAX3318E specifically requires external FORCEON and FORCEOFF control or relies on automatic detection logic. Ensure the design accommodates four 0.1µF capacitors for the charge pump circuitry to maintain signal integrity at maximum data rates.

Part Context

This part belongs to the MAX3316E–MAX3319E family of 2.5V RS-232 transceivers. While sharing core electrical characteristics like the 460kbps data rate and ESD protection levels, variants within the family differ in shutdown control methods. The MAX3318E utilizes AutoShutdown Plus, distinguishing it from the manual SHDN control of the MAX3317E.

Replacement Considerations

Publicly confirmed substitutes include the MAX3318EEAP+ (same function, different temperature grade) and the MAX3318ECUP+ (same function, TSSOP package). Verify that any replacement maintains the required 20-pin SSOP form factor if board space is constrained.

FAQ

How does the AutoShutdown Plus feature determine when to enter low-power mode?

The device enters AutoShutdown Plus mode when FORCEOFF is high, FORCEON is low, and no valid signal transition is detected on any receiver or transmitter input for more than 30 seconds.

What is the function of the INVALID output pin on the MAX3318E?

The INVALID output asserts low when no valid RS-232 voltage levels are detected on all receiver inputs, indicating an invalid connection state independent of the FORCEON/FORCEOFF states.

Can the MAX3318E operate without modifying existing system software?

Yes, the AutoShutdown Plus feature saves power automatically based on hardware sensing of cable disconnection or peripheral inactivity, requiring no changes to the BIOS or operating system.