ADM241LJR

Overview

The ADM241LJR is a CMOS RS-232 line transceiver from the ADM2xxL family, designed for EIA-232-E and V.28 interfaces using a single 5 V supply. It integrates four drivers and five receivers within a 28-pin SOIC package. The device features internal charge pumps generating ±10 V levels from the 5 V input, utilizing external 1 µF capacitors. It supports data rates up to 120 kbps with an output voltage swing of ±9 V. Key control inputs include an active-high Shutdown (SD) pin for low-power modes and an active-low Enable (EN) pin for receiver tri-stating.

Feature Summary

• Integrates dual charge pump converters to generate required RS-232 voltage levels from a single 5 V digital supply
• Features low power shutdown mode reducing dissipation to less than 5 µW for battery-powered applications
• Includes Schmitt trigger receivers with hysteresis to ensure noise immunity on noisy serial lines
• Provides enable functionality to place receiver outputs in high impedance state for bus sharing

Applications

• Battery-powered computers and portable equipment
• Modems and printers requiring RS-232 connectivity
• Instruments and peripherals interfacing with microprocessor systems

Procurement Notes

Verify the J suffix indicates the commercial temperature range (0°C to +70°C). Confirm the package type matches the required board layout for the 28-pin SOIC variant. Ensure ordering documentation specifies the Rev C datasheet parameters for accurate electrical characterization during integration.

Selection Notes

Select this component when a single 5 V supply is available but RS-232 voltage levels are required without external transformers. The ADM241L is appropriate for designs needing multiple receiver channels (five) and driver channels (four). Consider the shutdown feature if power conservation is critical for the end application.

Part Context

The ADM241L belongs to the ADM2xxL enhanced upgrade series, succeeding the AD2xx family. This generation offers lower power consumption, faster slew rates, and compatibility with smaller 1 µF capacitors compared to previous iterations. It is part of a comprehensive range offering various driver/receiver combinations for diverse communication needs.

Replacement Considerations

ADM236L: Offers similar functionality but with only three receivers instead of five.

FAQ

What is the function of the SD pin?

The SD (Shutdown) pin is active high. When asserted, it disables the charge pump, turns off drivers, and places receivers in a high impedance state to minimize power consumption.

How does the EN pin operate?

The EN (Enable) pin is active low. Driving it low enables the receiver outputs, while driving it high places the receiver outputs in a high impedance state, allowing them to be connected to a microprocessor data bus.

What capacitor values are required?

The device requires four external 1 µF ceramic capacitors to support the internal charge pump voltage doublers and inverters.