MAX3318EIDBR

Overview

The MAX3318EIDBR is a dual-driver, dual-receiver RS-232 transceiver manufactured by Texas Instruments. It operates from a single 2.25-V to 3-V supply and supports data rates up to 460 kbps. The device integrates a charge pump requiring only four 0.1-μF capacitors. It features ±15-kV ESD protection on RS-232 I/O pins using the IEC 61000-4-2 Air-Gap Discharge method. Supply current is 300 μA during operation and reduces to 1 μA in low-power standby mode with receivers active. It is housed in a 20-pin SSOP package.

Feature Summary

• Integrated auto-power-down plus feature reduces supply current to 1 μA when drivers are inactive for approximately 30 seconds.
• Enhanced electrostatic discharge (ESD) protection rated at ±15 kV (HBM), ±8 kV (IEC Contact Discharge), and ±15 kV (IEC Air-Gap Discharge).
• Proprietary low-dropout driver output stage enables RS-232-compatible operation from a 2.25-V to 3-V supply.
• Logic-level READY output indicates when the charge pump is regulating and the device is ready to transmit.

Applications

• Battery-powered systems
• PDAs
• Cellular phones
• Notebooks
• Hand-held equipment

Procurement Notes

Verify the specific ordering suffix 'IDBR' corresponds to the industrial temperature range (-40°C to +85°C) and the SSOP (DB) package type as defined in the TI Package Option Addendum. Confirm that the RoHS status is compliant and check the lead finish specifications (NIPDAU) against assembly requirements. Ensure the moisture sensitivity level (MSL Level-1) aligns with your board manufacturing process capabilities.

Selection Notes

Select this component when designing serial communication interfaces for low-voltage microcontrollers requiring RS-232 compatibility without external voltage inversion circuits. The integrated charge pump minimizes external component count. Consider the auto-power-down functionality for battery-operated applications where power conservation is critical during periods of inactivity.

Part Context

The MAX3318EIDBR belongs to the MAX3318 family of RS-232 transceivers. This series is designed for portable electronics needing reliable serial communication over short distances. The 'E' designation indicates enhanced ESD protection compared to earlier generations. The device replaces older solutions that required higher supply voltages or multiple external components for charge pumping.

Replacement Considerations

MAX3318EIDB is the tube version of the same electrical specification.

FAQ

How does the auto-power-down plus feature function?

When FORCEON is high and FORCEOFF is low, the device monitors receiver and driver inputs. If no valid signal transitions occur for approximately 30 seconds, the charge pump and drivers power down, reducing supply current to 1 μA. The device reactivates upon detecting a valid transition.

What is the purpose of the INVALID output pin?

The INVALID pin indicates the status of the receiver input signals. It goes high if any receiver input voltage is greater than 2.7 V or less than -2.7 V, indicating a valid RS-232 level. It goes low if all receiver inputs remain between -0.3 V and 0.3 V for more than 30 μs.

Can the auto-power-down feature be disabled?

Yes, auto-power-down plus can be disabled by driving both FORCEON and FORCEOFF high. In this state, the transmitters remain active regardless of input activity, preventing the device from entering the low-power shutdown mode.