MAX225EWI

Overview

The MAX225EWI+ is a +5V-powered, multichannel RS-232 driver and receiver integrated circuit from the Analog Devices / Maxim Integrated MAX220–MAX249 family. It provides four drivers and five receivers for full-duplex communication without requiring external bipolar power supplies. The device operates on a single +5V supply (4.75V to 5.25V) with an internal charge pump generating ±10V. Key electrical parameters include a data rate of up to 64 kbps, transmitter output voltage swing of ±5V to ±7.5V, and receiver input operating range of ±25V. It features shutdown modes for low-power operation and is housed in a 44-pin PLCC package.

Feature Summary

• Integrated dual charge-pump DC-DC converters eliminate the need for external bipolar power supplies or capacitors typically required for RS-232 level shifting.
• Provides independent enable controls for transmitters and receivers, allowing flexible management of bus states and power consumption.
• Supports standard EIA/TIA-232E and V.28/V.24 communication interfaces with robust input protection and defined logic thresholds.

Applications

• Multidrop RS-232 networks
• Portable diagnostics equipment
• Interface translation between TTL/CMOS logic and RS-232 serial ports

Procurement Notes

Verify the specific suffix 'EWI' against the manufacturer's current ordering guide to confirm the exact package type (PLCC) and temperature grade (Industrial -40°C to +85°C). Ensure that the component matches the pinout and electrical specifications of the MAX225 variant within the MAX220-MAX249 family, as other members may have different driver/receiver counts or control pin configurations.

Selection Notes

Select this component when board space is critical and external charge-pump capacitors must be avoided. It is suitable for applications requiring multiple transmit and receive channels powered solely by a +5V rail. Compare against the MAX245 series if specific control pin arrangements for individual channel enabling are required, noting that the MAX225 shares similar core functionality but may differ in pin assignment.

Part Context

This part belongs to the MAX220–MAX249 family of +5V-powered RS-232 transceivers. These devices are designed to replace traditional dual-supply solutions by integrating voltage conversion directly onto the chip. The MAX225 specifically offers a high channel count (4 drivers, 5 receivers) in a compact form factor, targeting complex serial communication systems where space and single-supply operation are primary constraints.

Replacement Considerations

Direct parameter-equivalent replacements within the same family include the MAX245, MAX246, MAX247, MAX248, and MAX249. Verify compatibility regarding the number of drivers/receivers and the specific control pin logic (ENT, ENR, ENA, ENB) before substitution, as these vary across the family.