ADM222ANZ

Overview

The ADM222ANZ is an 18-lead plastic dual in-line package (N-18) RS-232 transceiver from Analog Devices. It operates on a single 5 V supply with a typical quiescent current of 8 mA and supports data rates up to 200 kB/s. The device integrates two drivers and two receivers, utilizing internal charge pumps to generate ±10 V supplies from four external 0.1 µF capacitors. It features a shutdown function that reduces supply current to 0.1 µA. The component meets EIA-232-E specifications, offers ±9 V output swing, and accepts receiver inputs up to ±30 V.

Feature Summary

• Integrates high-speed CMOS technology with bipolar circuitry for efficient operation.
• Includes an active-low shutdown pin to minimize power consumption when disabled.
• Features internal pull-up resistors on transmitter inputs and pull-down resistors on receiver inputs.
• Provides Schmitt trigger inputs on receivers to ensure noise immunity.

Applications

• Computers
• Peripherals
• Modems
• Printers
• Instruments

Procurement Notes

Verify the specific suffix 'ANZ' corresponds to the 18-lead DIP package and RoHS compliance as listed in the official ordering guide. Confirm the required external capacitor values are 0.1 µF for proper charge pump operation. Ensure the design accommodates the industrial temperature range of -40°C to +85°C.

Selection Notes

Select this component for applications requiring full-duplex RS-232 communication with low standby power. The integrated shutdown feature distinguishes it from similar devices lacking this control pin. Verify compatibility with TTL/CMOS logic levels and ensure sufficient board space for the required four external capacitors.

Part Context

The ADM222ANZ belongs to the ADM222/ADM232A/ADM242 family of high-speed RS-232 line drivers and receivers. This family shares core architecture but differs in control features; specifically, the ADM222 includes a shutdown function absent in the ADM232A. The part is fabricated using BiCMOS technology to balance speed and power efficiency.

Replacement Considerations

The datasheet notes pin compatibility with MAX222, MAX232A, and MAX242. Designers should verify electrical parameter alignment before substituting these equivalents.

FAQ

How does the shutdown function affect the receivers?

When the SHDN pin is activated, all transmit and receive functions are disabled, and the supply current drops to 0.1 µA.

What is the purpose of the internal resistors on the inputs?

Transmitter inputs have internal 400 kΩ pull-up resistors to VCC, while receiver inputs have internal 5 kΩ pull-down resistors to GND to define states when unconnected.

Can unused transmitter inputs be left floating?

Yes, due to the internal 400 kΩ pull-up resistor, leaving an input unconnected forces the corresponding output into a low state.