MAX3218CPP+

Overview

The MAX3218CPP+ is a full-duplex RS-232 transceiver manufactured by Analog Devices Inc./Maxim Integrated, housed in a 20-pin Plastic DIP package. It operates within a supply voltage range of +1.8V to +4.25V and supports data rates up to 120kbps. The device integrates two drivers and two receivers with onboard DC-DC converters that generate ±6.5V from the single low-voltage supply. It features an AutoShutdown function that reduces supply current to 1µA when no valid signal is detected. The component is rated for an operating temperature range of 0°C to +70°C.

Feature Summary

• AutoShutdown technology automatically disables the power supply and drivers upon detecting invalid receiver input levels, significantly reducing power consumption.
• Integrated switch-mode power supply generates required high voltages using minimal external components, eliminating the need for external voltage regulators.
• Three-state receiver outputs allow multiple devices with different interface standards to share the same bus without electrical conflict.
• Direct operation from two alkaline, NiCd, or NiMH cells without additional voltage regulation circuitry.

Applications

• Battery-powered equipment
• Subnotebook computers
• Personal Digital Assistants (PDAs)
• Hand-held equipment
• Peripherals

Procurement Notes

Verify the specific ordering suffix CPP+ confirms the 20-pin Plastic DIP package and commercial temperature range (0°C to +70°C). Ensure compatibility with lead-free/RoHS compliance requirements as indicated by the plus sign. Confirm the manufacturer source is Analog Devices Inc. or Maxim Integrated to guarantee authenticity and correct revision history alignment.

Selection Notes

Select this component for applications requiring low-power RS-232 communication powered directly by two battery cells. The AutoShutdown feature is critical for extending battery life in portable systems where the cable may be disconnected frequently. Verify that the 120kbps data rate meets system timing requirements and that the 20-pin DIP footprint fits the target PCB layout constraints.

Part Context

The MAX3218 series includes variants such as the MAX3218CAP+ (SSOP) and MAX3218EAP+ (Extended Temperature SSOP). The MAX3218CPP+ specifically denotes the commercial grade version in a through-hole DIP package. This part belongs to the broader family of low-voltage RS-232 transceivers designed to replace traditional bipolar counterparts with lower power CMOS solutions.

Replacement Considerations

MAX3218CAP+

FAQ

How does the AutoShutdown feature determine when to enter low-power mode?

The device enters shutdown after sensing no valid RS-232 signal level on either receiver input for typically 30µs. It wakes up when a valid level is applied to either receiver input.

What external components are required for the onboard DC-DC converter?

The circuit requires one 15µH inductor, one fast recovery diode (e.g., 1N6050), and four capacitors: C1 (0.47µF), C2 (1µF), C3 (1µF), and C4 (at least 1µF).

Can the receivers remain active while the transmitters are shut down?

Yes, during AutoShutdown, both receivers can remain active to monitor external devices, or they can be disabled under logic control via the FORCEON pin.