MAX3320BEAP

Overview

The MAX3320BEAP is a dual RS-232 transceiver integrated with a power-on reset supervisor, manufactured by Analog Devices Inc./Maxim Integrated. It operates on a single +3V to +5.5V supply and supports data rates up to 250kbps using an internal dual charge pump requiring only four 0.1µF capacitors. The device features AutoShutdown Plus technology, reducing supply current to 4µA during inactivity. The RESET output monitors VCC with a threshold of 2.85V (suffix B), asserting for at least 100ms after power-up. It is housed in a 20-pin SSOP package and functions within an operating temperature range of -40°C to +85°C.

Feature Summary

• Integrates a microprocessor supervisory circuit with an RS-232 transceiver for combined power management and serial communication.
• Features AutoShutdown Plus mode that reduces supply current to 4µA when no valid signal levels are detected for 30 seconds.
• Includes a precise power-on reset generator with guaranteed validity down to VCC = 1V and immunity to fast supply transients.
• Utilizes a proprietary low-dropout transmitter stage to achieve true RS-232 performance from a single low-voltage supply.

Applications

• Palmtop Computers
• Portable/Battery-Powered Equipment
• Hand-Held Equipment

Procurement Notes

Verify the specific suffix 'B' corresponds to the required 2.85V reset threshold before procurement. Confirm the 'EAP' designation matches the -40°C to +85°C industrial temperature grade and SSOP package requirements. Ensure compatibility with existing board layouts regarding the 20-pin footprint and external capacitor placement for the charge pump circuit.

Selection Notes

Select this component when a system requires both RS-232 communication and hardware-based power supervision in a compact form factor. The 2.85V reset threshold is suitable for 3.3V logic systems. Consider the 4µA shutdown current for battery-operated designs where standby power consumption is critical. Verify that the 250kbps maximum data rate meets the application's throughput requirements.

Part Context

The MAX3320BEAP belongs to the MAX3320A/B/L/T family of true RS-232 transceivers. The 'B' suffix specifically denotes a reset threshold voltage of 2.85V, distinguishing it from other variants like the MAX3320A (4.25V) or MAX3320T (3.08V). The 'EA' indicates the extended temperature range and SSOP packaging, differentiating it from commercial grade options.

Replacement Considerations

Direct functional replacements within the same family include MAX3320AEAP, MAX3320LEAP, and MAX3320TEAP, provided their respective reset thresholds align with the design requirements. Other Maxim RS-232 transceivers may serve as alternatives if integrated reset functionality is not mandatory.

FAQ

What is the function of the INVALID output pin?

The INVALID output asserts low when no valid RS-232 levels are present on any receiver input for at least 90µs, indicating a disconnected cable or inactive peripheral.

How does AutoShutdown Plus operate?

AutoShutdown Plus automatically shuts off the transmitters and onboard power supply after 30 seconds of inactivity on all receiver and transmitter inputs, reducing supply current to 4µA until activity resumes.

What is the minimum supply voltage for operation?

The MAX3320BEAP operates with a supply voltage (VCC) ranging from +3V to +5.5V.