MAX3221EAE+T

Overview

The MAX3221EAE+T is a single-driver, single-receiver RS-232 transceiver in a 16-pin SSOP package. It operates from a +3.0V to +5.5V supply and achieves 1µA current via AutoShutdown when no valid signal is detected for 30µs. The device supports data rates up to 235kbps with typical propagation delays of 0.3µs. It requires only 0.1µF capacitors for 3.3V operation and includes an INVALID output pin to indicate receiver activity status.

Feature Summary

• AutoShutdown technology reduces power consumption by disabling the onboard power supply and drivers when no valid RS-232 signal is present on receiver inputs.
• Integrated dual charge-pump circuitry generates true RS-232 voltage levels from a single low-voltage supply, eliminating the need for external ±12V sources.
• INVALID output pin provides a logic indication of whether valid RS-232 signal levels are currently present at the receiver inputs.

Applications

• Battery-powered equipment
• Hand-held devices
• Portable diagnostics equipment

Procurement Notes

Verify the component matches the specific E suffix for the -40°C to +85°C temperature range and the AE suffix for the 16-pin SSOP package. Confirm RoHS compliance through the manufacturer's documentation. Ensure the ordering suffix aligns with the required packaging format, as variations exist between tubes and reels.

Selection Notes

Select this part for applications requiring minimal standby current and simplified power management. It serves as a direct replacement for older RS-232 transceivers that require larger capacitors or higher supply voltages. Verify that the system logic levels are compatible with the specified input thresholds for the chosen VCC voltage.

Part Context

This component belongs to the MAX3221/MAX3223/MAX3243 family of +3V to +5.5V RS-232 transceivers. While the MAX3223 offers two drivers and receivers, and the MAX3243 provides three drivers with five receivers, the MAX3221 specifically integrates one driver and one receiver in a compact 16-pin form factor.

Replacement Considerations

MAX3221CAE+T (Commercial grade, 0°C to +70°C)

FAQ

How does the AutoShutdown feature function?

When FORCEON is low and FORCEOFF is high, the device monitors receiver inputs. If no valid RS-232 signal level is detected for 30µs, the internal power supply and drivers shut down, reducing supply current to 1µA.

What capacitor values are required for operation?

For 3.3V operation, four 0.1µF capacitors are required. For 5.0V operation, C1 should be 0.047µF while C2, C3, and C4 should be 0.33µF.

What is the purpose of the INVALID output pin?

The INVALID pin indicates the status of the receiver inputs. It goes high when valid RS-232 levels are present and low when the device enters shutdown mode due to the absence of valid signals.