Texas Instruments MAX3243EIRHBR

Overview

MAX3243EIRHBR from Texas Instruments is a 3-V to 5.5-V multichannel RS-232 line driver/receiver IC with ±15-kV IEC 61000-4-2 air-gap ESD protection, three drivers and five receivers, and integrated dual charge-pump circuitry enabling single-supply operation. It meets TIA/EIA-232-F and ITU V.28 standards and supports up to 500 kbit/s data rates in notebook serial port interfaces.

For engineers reviewing the MAX3243EIRHBR datasheet, MAX3243EIRHBR pinout, MAX3243EIRHBR application, or MAX3243EIRHBR equivalent, this device delivers robust ESD-hardened RS-232 transceivers for battery-powered portable systems requiring low standby current (1 μA), auto-powerdown control, and always-active ROUT2B for ring-indicator signaling during power-down.

Technical Context

The MAX3243EIRHBR integrates a dual charge-pump circuit generating ±V_CC-derived rails (V+, V−) using four 0.1-μF external capacitors, enabling full RS-232 voltage levels (±5.4 V) from a single 3.3-V or 5-V supply. Its receiver input hysteresis (0.5 V) and threshold ranges (V_IT+ = 1.6–2.4 V, V_IT− = 0.6–1.4 V) ensure noise immunity across supply voltages.

Auto-powerdown is controlled via FORCEON/FORCEOFF pins: when FORCEON = GND and FORCEOFF = V_CC, drivers disable if no valid RS-232 signal (|RIN| > 2.7 V or < −2.7 V) is detected for >30 ms; INVALID output asserts high to indicate valid signal presence. ROUT2B remains active regardless of power state, supporting ring-indicator functionality in powered-down host systems.

Key Specifications

Pinout & Package

VQFN-32 (RHB) package: 5.0 mm × 5.0 mm, 0.5-mm pitch, thermally enhanced bottom-exposed pad. Pin count and function match TI's official RHB pinout for MAX3243E.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RS-232 transceiver applications.

Compared with MAX3232EIRHBR and SP3243EEN-L, the MAX3243EIRHBR uniquely combines five receivers, ROUT2B continuity, and full IEC 61000-4-2 certification in a space-saving VQFN-32 package - making it optimal for portable designs demanding maximum RS-232 channel density and ESD resilience.

Availability

MAX3243EIRHBR is available at Aetrix Electronics and suitable for laptop serial port interfaces, industrial modem communication, medical diagnostic handhelds, and point-of-sale terminal docking stations requiring stable component supply and long-term lifecycle support.

Supply support for MAX3243EIRHBR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The MAX3243E product line targets RS-232 physical-layer interfacing in portable and battery-powered systems, emphasizing single-supply operation, ultra-low standby current, and certified ESD robustness for harsh real-world deployment.

FAQ

What is the maximum data rate supported by the MAX3243EIRHBR?

The MAX3243EIRHBR supports a maximum data rate of 500 kbit/s under specified conditions (CL = 1000 pF, RL = 3 kΩ). This is confirmed in Section 7.10 of the datasheet and exceeds the 250 kbit/s minimum required for TIA/EIA-232-F compliance. The actual achievable rate depends on cable length, termination, and noise environment - shorter cables with proper shielding sustain the full 500 kbit/s reliably. The MAX3243EIRHBR achieves this using optimized driver slew-rate control (4–30 V/μs) to minimize distortion.

How does the auto-powerdown feature work in the MAX3243EIRHBR?

The MAX3243EIRHBR auto-powerdown activates when FORCEON = GND and FORCEOFF = V_CC. In this mode, the device monitors all RIN inputs; if no signal exceeds ±2.7 V (or stays within –0.3 V to +0.3 V for >30 ms), driver outputs disable and supply current drops to 1 μA. The INVALID pin goes low to signal invalid bus state. Drivers re-enable automatically upon detecting a valid RS-232 edge. This behavior is fully documented in Section 9.3 and Table 9-1 of the MAX3243EIRHBR datasheet.

What is the purpose of the ROUT2B pin on the MAX3243EIRHBR?

ROUT2B is an always-active noninverting receiver output tied to RIN2, designed specifically to maintain ring-indicator (RI) signaling capability even when the MAX3243EIRHBR is in auto-powerdown or forced-off state. Unlike other receiver outputs, ROUT2B remains functional regardless of FORCEON/FORCEOFF settings or bus activity - enabling host systems to detect incoming calls or modem handshakes while minimizing overall power consumption. This feature is explicitly defined in Sections 1, 3, and 9.3 of the MAX3243EIRHBR datasheet.

Which external capacitors are required for the MAX3243EIRHBR charge-pump circuit?

The MAX3243EIRHBR requires four 0.1-μF ceramic capacitors: C1+ and C1− form the voltage-doubler stage, while C2+ and C2− form the inverter stage. These values are validated for both 3.3-V (±0.3 V) and 5-V (±0.5 V) supplies per Section 10.2.1 of the datasheet. Using 0.1-μF X7R or better dielectrics ensures stable V+ and V− rail generation (±V_CC scaled) and meets IEC 61000-4-2 ESD test requirements. Larger values (e.g., 0.47 μF) may be used for improved ripple suppression at 5.5-V operation.

Does the MAX3243EIRHBR support 5-V logic inputs when powered from a 3.3-V supply?

Yes, the MAX3243EIRHBR accepts 5-V logic-level inputs on DIN1–DIN3 and FORCEON/FORCEOFF pins even when V_CC = 3.3 V. This 5-V-tolerant input capability is specified in Section 7.4 (Recommended Operating Conditions) and eliminates the need for external level shifters in mixed-voltage systems. The internal input protection structure clamps excess voltage safely, and DC parameters (IIH/IIL) remain within ±1 μA across the full 0–5.5-V input range - ensuring reliable operation in legacy 5-V controller interfaces.