MAX249EQH+D

Overview

The MAX249EQH+D is an RS-232 interface transceiver from the MAX220–MAX249 family, designed for EIA/TIA-232E and V.28/V.24 communications interfaces. It operates on a single +5V supply using integrated charge-pump circuitry to generate internal ±10V rails, eliminating the need for external bipolar supplies. The device features three drivers and five receivers with independent enable controls. It supports data rates up to 120 kbps and includes a shutdown mode for power reduction. The component is housed in a 44-pin PLCC package and is rated for operation within the -40°C to +85°C temperature range.

Feature Summary

• Integrated dual charge-pump DC-DC voltage converters convert a single +5V input into internal ±10V rails for RS-232 driver operation without requiring external bipolar supplies.
• Features independent control inputs (ENTA, ENTB, ENRA, ENRB) allowing individual or grouped enabling/disabling of transmitter and receiver channels to manage bus states and reduce power consumption.
• Provides full-duplex communication capability with TTL/CMOS-compatible logic levels on both input and output sides, ensuring compatibility with standard microcontroller and UART interfaces.

Applications

• Interface translation between TTL/CMOS logic devices and RS-232 serial ports
• Multidrop RS-232 network configurations requiring multiple channel management
• Portable diagnostics equipment where single-supply operation and low power are critical

Procurement Notes

Verify the specific suffix 'EQH' corresponds to the 44-pin PLCC package and industrial temperature grade (-40°C to +85°C). Confirm RoHS compliance status via the manufacturer's current documentation. Ensure the ordering code matches the exact pinout and control logic configuration required for the target design, as variations exist within the MAX24x series.

Selection Notes

Select this component when designing systems requiring three transmit and five receive channels on a single IC. It is suitable for applications needing independent channel control to isolate unused lines. Verify that the 44-pin PLCC footprint fits the PCB layout constraints. Consider the 120 kbps maximum data rate against system requirements. Ensure the design accommodates the external capacitors needed for the charge pump if not utilizing the internal capacitor variants.

Part Context

This part belongs to the MAX220–MAX249 family of +5V-powered multichannel RS-232 drivers and receivers. The family offers various channel counts and package options to suit different board space and I/O density requirements. The MAX249 specifically provides a high channel count with granular control capabilities, distinguishing it from simpler dual-channel counterparts like the MAX232.

Replacement Considerations

Public confirmed substitute part numbers: None identified in verified source material.