ADM237LANZ

Overview

The ADM237LANZ is a CMOS RS-232 transceiver designed for single 5 V power supply operation. It integrates five drivers and three receivers within a 24-pin PDIP package. The device supports data rates up to 120 kbps and operates with a supply voltage range of 4.75 V to 5.25 V. Internal charge pumps generate the required ±10 V levels using external 1 µF capacitors. It features Schmitt trigger inputs with 650 mV hysteresis, ±30 V receiver input protection, and meets EIA-232-E specifications.

Feature Summary

• Integrates internal DC-to-DC converters to enable full RS-232 functionality from a single 5 V digital supply without requiring external negative voltage sources.
• Features Schmitt trigger receiver inputs that provide noise immunity and ensure error-free reception for signals with slow transition times or high noise environments.
• Includes internal pull-up resistors on transmitter inputs and pull-down resistors on receiver inputs to define logic states when pins are left unconnected.

Applications

• Computers
• Peripherals
• Modems
• Printers
• Instruments

Procurement Notes

Verify the specific ordering suffix 'L' corresponds to the industrial temperature grade (-40°C to +85°C) as defined in the manufacturer's official documentation. Confirm the package type matches the required PCB footprint, typically 24-pin PDIP. Ensure the design accommodates the necessary external 1 µF capacitors for the internal charge pump circuitry.

Selection Notes

Select this component when a system requires five independent transmit channels and three receive channels. It is suitable for applications needing high noise immunity due to the integrated receiver hysteresis. Verify that the available power supply is strictly regulated at 5 V, as the device does not support dual supplies like some other family members.

Part Context

This part belongs to the ADM2xxL family of low-power RS-232 interface circuits. It serves as an enhanced upgrade to the legacy AD2xx series, offering lower power consumption and faster slew rates. Unlike the ADM236L, it lacks a shutdown pin, making it appropriate for always-on applications where power saving during idle states is not a primary constraint.

Replacement Considerations

Public confirmed substitute part numbers include MAX237CNG+ and MAX237ENG+. These parts share similar functional characteristics and pinouts but may differ in specific electrical parameters or packaging options.

FAQ

Does the ADM237LANZ have a low power shutdown mode?

No, the ADM237LANZ does not feature a shutdown (SD) pin. Only the ADM236L and ADM241L in this family include the low power shutdown capability.

What is the purpose of the internal pull-up resistor on the transmitter inputs?

The internal 400 kΩ pull-up resistor ensures that unused transmitter inputs default to a high logic state, which forces the corresponding RS-232 outputs into a low state if left unconnected.

Can the ADM237LANZ operate with a 12 V supply?

No, the ADM237LANZ is designed specifically for a single 5 V supply. Parts like the ADM231L and ADM239L are intended for applications where a 12 V supply is available.