STMicroelectronics ST3232BWR

Overview

ST3232BWR from STMicroelectronics is a 3–5.5 V, low-power RS-232 transceiver IC with two drivers and two receivers, 300 µA supply current, 300 kbps minimum data rate, and 6 V/µs minimum slew rate. It meets EIA/TIA-232 specifications down to 3 V and operates in industrial temperature range (−40 to +85 °C), enabling robust serial communication in battery-powered portable equipment.

For engineers reviewing the ST3232BWR datasheet, ST3232BWR pinout, ST3232BWR application, or ST3232BWR equivalent, key selection criteria include guaranteed 300 kbps operation at 3 V, internal charge pump requiring only four 0.1 µF capacitors, SO16L package footprint compatibility, and dual-driver/dual-receiver channel count for full-duplex UART interfaces.

Technical Context

The ST3232BWR integrates a proprietary low-dropout transmitter output stage that delivers true ±5 V RS-232 output swing from 3 V supplies using an internal charge pump. Its receiver input threshold is configurable across 3.3 V and 5 V logic levels, with hysteresis of 0.3 V for noise immunity.

It supports full-duplex asynchronous communication with independent driver/receiver timing paths, propagation delay skew ≤100 ns (transmitter) and ≤50 ns (receiver), and operates with external capacitor values scaled per supply voltage (e.g., 0.1 µF at 3.3 V, 0.33 µF at 5 V).

Key Specifications

Pinout & Package

ST3232BWR is housed in a 16-pin SO16L (Small Outline, narrow-body, lead-free) package with 1.27 mm pitch, compliant with ECOPACK® environmental standards. The package measures 10.1 × 7.5 mm with 0.6 mm max height and is optimized for automated surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3232ESE+, ST3232BWR delivers guaranteed 300 kbps at 3 V and extended temperature range-critical for industrial field devices; versus SP3232ECA-L, it trades 1.5 mm in width for proven SO16L manufacturability and thermal mass in high-vibration environments.

Availability

ST3232BWR is available at Aetrix Electronics and suitable for industrial serial gateways, medical handheld terminals, retail point-of-sale terminals, and automotive diagnostic tools requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for ST3232BWR 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The ST3232BWR belongs to ST's RS-232 interface product line, engineered specifically for low-power, single-supply 3 V operation in portable and battery-constrained embedded systems-prioritizing quiescent current, small-footprint packaging, and robust ESD tolerance.

FAQ

What external capacitors are required for ST3232BWR operation at 3.3 V?

The ST3232BWR requires four 0.1 µF ceramic capacitors: C1+ and C1− form the voltage doubler stage for V+, while C2+ and C2− form the inverter stage for V−. All capacitors must be placed within 5 mm of their respective pins and use X7R or better dielectric for stable performance across −40 to +85 °C.

Does ST3232BWR support automatic power-down mode?

No, the ST3232BWR does not include an enable/shutdown pin or automatic power-down feature. It operates continuously when VCC is applied. For ultra-low-power applications requiring sleep modes, consider ST's ST3243 series, which adds EN pin control and 1 µA shutdown current.

Can ST3232BWR interface directly with 5 V logic microcontrollers?

Yes-its transmitter inputs (T1IN/T2IN) accept 5 V-tolerant logic thresholds (VIH = 2.4 V min at VCC = 5 V), and receiver outputs (R1OUT/R2OUT) deliver CMOS-compatible VOH = VCC − 0.6 V and VOL = 0.4 V, ensuring reliable interfacing with both 3.3 V and 5 V MCUs without level shifters.

What is the maximum cable length supported at 300 kbps?

At 300 kbps, ST3232BWR maintains signal integrity up to 15 meters with standard 24 AWG twisted-pair RS-232 cable (capacitance ≤50 pF/m), based on its 6 V/µs slew rate limiting edge rate to reduce reflections and crosstalk-exceeding TIA-232-F specification for 30 m at lower data rates.