MAX242CAP+

Overview

The MAX242CAP+ is a dual-channel RS-232 transceiver from the MAX220–MAX249 family, designed for EIA/TIA-232E and V.28/V.24 interfaces. It operates on a single +5V supply using an integrated charge pump to generate ±10V internally. The device features two drivers and two receivers with full-duplex communication capability. Electrical specifications include a typical data rate of 120 kbps, output voltage swings of ±7.5V under load, and propagation delays of 3.5µs (TTL-to-RS-232) and 1µs (RS-232-to-TTL). It includes a shutdown mode reducing supply current to 25µA at +25°C. The component is housed in a 16-pin SOIC package and supports an operating temperature range of 0°C to +70°C.

Feature Summary

• Integrated charge-pump circuitry eliminates the need for external bipolar ±12V supplies, enabling single +5V operation.
• Shutdown mode significantly reduces power consumption by lowering supply current to microampere levels.
• Provides robust receiver inputs capable of withstanding ±30V signals while maintaining TTL/CMOS logic compatibility.

Applications

• Interface translation between TTL/CMOS logic and RS-232 serial ports
• Multidrop RS-232 network connections
• Portable diagnostic equipment requiring low-power serial communication

Procurement Notes

Verify the specific suffix 'C' confirms the commercial temperature range (0°C to +70°C) and the 'P' indicates the plastic SOIC package. Confirm RoHS compliance status as indicated by the '+' suffix. Ensure the datasheet revision matches the design requirements for timing parameters like enable/disable times.

Selection Notes

Select this part when a dual-channel RS-232 interface is required without external charge-pump components. Compare against MAX232 variants if higher data rates or different pinouts are needed. Consider the MAX242's specific enable/shutdown control logic versus simpler auto-shutdown models if precise power management is critical.

Part Context

The MAX242 belongs to the broader MAX220–MAX249 family of +5V-powered multichannel RS-232 drivers and receivers. This family shares common internal architecture but varies in channel count and control features. The MAX242 specifically offers dual channels with dedicated enable controls, distinguishing it from simpler fixed-function transceivers in the series.

Replacement Considerations

Public confirmed substitute part numbers: MAX232CAP+, MAX222CAP+. Verify pinout compatibility and electrical parameter alignment before substitution.

FAQ

What is the maximum data rate supported by the MAX242CAP+?

The typical maximum data rate is 120 kbps under standard operating conditions with a +5V supply and appropriate load capacitance.

How does the shutdown feature affect the internal charge pump voltages?

When the SHDN pin is asserted low, the internal charge pumps stop generating ±10V. The V- pin falls to 0V, and the V+ pin falls to +5V, effectively disabling the RS-232 outputs.

What is the input voltage tolerance for the RS-232 receiver inputs?

The receiver inputs (R1IN, R2IN) can withstand voltages up to ±30V without damage, providing protection against accidental connection to live RS-232 lines.