MAX249CQH-D

Overview

The MAX249CQH-D is a +5V-powered, multichannel RS-232 driver and receiver integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It operates within a commercial temperature range of 0°C to +70°C and utilizes a 44-pin PLCC package. The device features three drivers and three receivers with full-duplex communication capabilities. It supports data rates up to 120 kbps and requires external capacitors for its internal charge-pump voltage conversion. The component provides ±7.5V output voltage swings and includes enable control inputs for managing transmitter and receiver states.

Feature Summary

• Integrates dual charge-pump DC-DC converters to generate required bipolar voltages from a single +5V supply
• Provides independent enable controls for transmitters and receivers to manage power consumption
• Features high-noise-immunity RS-232 receivers with input hysteresis
• Supports continuous short-circuit protection on all transmitter outputs

Applications

• Interface translation between TTL/CMOS logic and RS-232 standards
• Multidrop RS-232 network implementations
• Portable diagnostics equipment requiring low-power serial communication

Procurement Notes

Verify the specific suffix 'D' against the manufacturer's current ordering information table to confirm the exact package variant and lead-free status. Confirm that the commercial temperature grade (0°C to +70°C) aligns with the system environmental requirements. Ensure external capacitor values match the datasheet recommendations for stable charge-pump operation.

Selection Notes

Select this component when a multichannel RS-232 solution with independent channel control is required. The MAX249 offers three drivers and three receivers, distinguishing it from lower-channel variants like the MAX244 or MAX246. Verify that the 44-pin PLCC package footprint fits the PCB layout constraints. Consider the 120 kbps data rate limit for high-speed application compatibility.

Part Context

This part belongs to the MAX220–MAX249 family of +5V-powered RS-232 line drivers and receivers. The family shares common architecture including integrated charge pumps but varies in channel count and control pin configurations. The MAX249 specifically provides a balanced configuration of three drivers and three receivers suitable for complex serial interfaces.

Replacement Considerations

Cross-reference with other members of the MAX220-MAX249 family such as the MAX244, MAX245, MAX246, MAX247, and MAX248. Verify channel counts and control pin mappings before substitution, as these parameters differ significantly across the series.