MAX3218EPP

Overview

The MAX3218EPP+ is a dual-driver, dual-receiver RS-232 transceiver designed for battery-powered EIA/TIA-232E and V.28/V.24 interfaces. It operates from a single +1.8V to +4.25V supply without voltage regulation. The device features AutoShutdown technology, reducing supply current to 1µA when no valid signal is detected. It guarantees a 120kbps data rate and includes on-board DC-DC converters. The component is housed in a 20-pin Plastic DIP package and supports an industrial temperature range of -40°C to +85°C.

Feature Summary

• AutoShutdown functionality reduces power consumption by disabling the onboard power supply and drivers when invalid receiver levels are sensed.
• Integrated switch-mode power supply generates required ±6.5V levels directly from low-voltage single-cell or dual-cell batteries.
• Three-state receiver outputs allow multiple receivers with different interface standards to be connected on the same bus.

Applications

• Battery-powered equipment
• Subnotebook computers
• Personal Digital Assistants (PDAs)
• Hand-held equipment

Procurement Notes

Verify the specific suffix 'EPP' against the manufacturer's official ordering information table. The provided datasheet revision history indicates that the MAX3218EPP+ part number was removed from the production list in May 2018. Confirm current availability status and lead times directly with Analog Devices or authorized distributors before finalizing procurement plans.

Selection Notes

Select this component for applications requiring minimal quiescent current in portable devices. Ensure the design accommodates external passive components, specifically a 15µH inductor and fast recovery diode, for the onboard charge pump. Verify that the system logic levels are compatible with the specified input thresholds across the full operating voltage range.

Part Context

This device belongs to the MAX3218 family of low-power RS-232 transceivers. It shares functional similarities with the MAX218 but offers improved shutdown capabilities. The product line focuses on extending battery life in mobile communication peripherals by eliminating the need for traditional linear regulators.

Replacement Considerations

The MAX3218EPP+ has been removed from the active production list. Consider the MAX3218CAP+ or MAX3218CPP+ as pin-compatible alternatives within the same family, subject to their respective temperature ranges and package types.

FAQ

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

The device enters AutoShutdown after sensing invalid RS-232 voltage levels at both receiver inputs for typically 30µs. It wakes up automatically when a valid signal level is applied to either receiver input.

What external components are required for the onboard DC-DC converter?

The circuit requires a 15µH inductor with at least 350mA saturation current, a fast recovery diode (such as 1N6050), and four capacitors: C1 (0.47µF), C2 (1µF), C3 (1µF), and C4 (at least 1µF).

Can unused transmitter inputs be left floating?

No. Driver inputs do not have internal pull-up resistors. Unused driver inputs should be connected to either GND or VCC to prevent undefined states.