STMicroelectronics ST3243EBTR

Overview

ST3243EBTR from STMicroelectronics is a ±15 kV ESD-protected, 3–5.5 V RS-232 transceiver with 3 drivers and 5 receivers, auto power-down (1 µA shutdown), guaranteed 250 kbps data rate, and TSSOP28 package. It enables true RS-232 signaling in battery-powered portable systems including notebooks and handheld peripherals.

For engineers reviewing the ST3243EBTR datasheet, ST3243EBTR pinout, ST3243EBTR application, or ST3243EBTR equivalent, key selection criteria include ESD robustness (±15 kV HBM), wake-up capability via always-active R2OUTB, auto power-down logic control (FORCEON/FORCEOFF), and guaranteed slew rate (6 V/µs) for noise-immune serial communication.

Technical Context

The ST3243EBTR integrates a dual charge-pump circuit to generate ±5.4 V RS-232 output levels from a single 3–5.5 V supply, supporting full compliance with EIA/TIA-232 and V.28/V.24 standards. Its proprietary low-dropout transmitter stage ensures rail-to-rail output swing under load (±5 V min at 3 kΩ).

Auto power-down is triggered when FORCEON = low and FORCEOFF = high, disabling drivers unless a valid RS-232 signal is detected on any receiver input; R2OUTB remains active during sleep to enable host wake-up. The INVALID output provides real-time detection of valid RS-232 levels with 0.2 µs response time.

Key Specifications

Pinout & Package

TSSOP28 (28-pin Thin Shrink Small Outline Package), 9.7 mm × 6.5 mm body, 0.65 mm pitch, ECOPACK® compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3232ESE+ and SP3232ECA-L, the ST3243EBTR uniquely integrates both an always-active R2OUTB output and an INVALID status pin, enabling zero-software-overhead wake-up in battery-critical systems while maintaining superior ESD robustness and compact capacitor count.

Availability

ST3243EBTR is available at Aetrix Electronics and suitable for notebook computers, handheld terminals, industrial printers, and POS peripheral adapters requiring stable component supply across extended temperature ranges (−40 °C to +85 °C).

Supply support for ST3243EBTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, analog ICs, power management, and interface solutions for industrial, automotive, and consumer markets.

The ST3243EBTR belongs to ST's RS-232 transceiver product line, engineered specifically for ultra-low-power portable and embedded systems requiring robust ESD protection, intelligent power management, and compact packaging.

FAQ

What is the minimum external capacitor value required for ST3243EBTR at 3.3 V supply?

At 3.3 V supply, ST3243EBTR requires 0.1 µF for C1 (V+ pump) and 0.1 µF for C2–C4 (V− pump and bypass), per Table 13 in the datasheet. These values ensure stable ±5.5 V rail generation and meet EIA/TIA-232 output swing specifications under load.

How does the INVALID output behave during auto power-down mode?

The INVALID output remains fully functional during auto power-down: it asserts HIGH when any receiver input detects a valid RS-232 signal (≥±2.7 V), and LOW otherwise. This allows host firmware to monitor serial activity without waking the full transceiver.

Can ST3243EBTR drive a standard RS-232 mouse without external components?

Yes - ST3243EBTR guarantees mouse drive ability per its datasheet. When FORCEON is held high and FORCEOFF is high, all drivers remain active regardless of input signal presence, satisfying the continuous output requirement of RS-232 mouse protocols.

What is the maximum recommended trace length between ST3243EBTR and its external capacitors?

Capacitor placement must minimize loop inductance: C1 and C2 should be placed within 5 mm of their respective pins (C1+, C1−, C2+, C2−), with short, wide traces and direct connection to local GND plane. Longer traces degrade charge-pump efficiency and increase EMI susceptibility.