ADM239LAQ

Overview

The ADM239LAQ is a CMOS RS-232 transceiver from the ADM2xxL family, designed for EIA-232-E and V.28 interfaces. It operates from a single 5 V supply (VCC) and an external positive supply ranging from 7.5 V to 13.2 V (V+). The device integrates three drivers and five receivers with internal charge pump circuitry generating -12 V from the V+ input. Key electrical parameters include a data rate of 120 kbps, ±9 V output voltage swing, and receiver inputs tolerant to ±30 V. It features low power shutdown capability with current consumption ≤1 µA and includes an active-low enable pin for receiver control.

Feature Summary

• Integrates three TTL/CMOS-to-RS-232 drivers and five RS-232-to-TTL/CMOS receivers on a single chip
• Includes internal negative charge pump converter requiring only two external capacitors
• Features low power shutdown mode reducing dissipation to less than 5 µW
• Provides receiver outputs in high impedance state via active-low enable input

Applications

• Battery-powered equipment requiring low standby power
• Computers and peripheral interface connections
• Modems and printers utilizing standard serial communication
• Instruments sharing common data lines or microprocessor buses

Procurement Notes

Verify the specific suffix 'LAQ' against the manufacturer's ordering guide to confirm package type and temperature range. Ensure the design supports the required external V+ supply voltage between 7.5 V and 13.2 V, as this part differs from standard 5 V-only RS-232 transceivers by requiring an additional positive rail for its internal charge pump operation.

Selection Notes

Select this component when a system requires multiple receiver channels alongside driver functionality but lacks a dedicated +12 V supply rail. The ADM239L is distinct within the family because it generates only the negative charge pump voltage, necessitating an external positive supply. Verify that the application can accommodate the necessary external capacitors for the charge pump and the specific voltage requirements for the V+ pin.

Part Context

The ADM239L belongs to the ADM2xxL enhanced upgrade series, succeeding the AD2xx family with lower power consumption and faster slew rates. Unlike other members such as the ADM236L which generate both positive and negative supplies internally, the ADM239L relies on an external V+ source. This configuration makes it suitable for systems where a positive intermediate voltage is already available but a negative RS-232 level generator is needed.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the verified documentation.