STMicroelectronics ST3232CWR

Overview

ST3232CWR 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 guaranteed data rate, and SO16L package. It delivers true RS-232 voltage levels (±5 V) from single 3 V supply using internal charge pump and supports battery-powered portable systems requiring EIA/TIA-232 compliance.

For engineers reviewing the ST3232CWR datasheet, ST3232CWR pinout, ST3232CWR application, or ST3232CWR equivalent, key selection criteria include guaranteed 300 kbps operation at 3 V, 6 V/µs minimum slew rate, ±25 V receiver input tolerance, and compatibility with standard 0.1 µF external capacitors - critical for space-constrained, low-voltage embedded serial interfaces.

Technical Context

The ST3232CWR integrates dual transmitter/receiver channels with proprietary low-dropout driver output stages enabling full RS-232 voltage swing (±5.4 V) from 3 V supply. Its internal charge pump generates ±VCC-derived rails without external inductors or transformers.

Receiver inputs tolerate ±25 V common-mode range and feature 3–7 kΩ input resistance with hysteresis (≥0.3 V), while transmitter outputs drive 3 kΩ loads with <100 ns skew between channels and TTL/CMOS-compatible logic-level outputs.

Key Specifications

Pinout & Package

ST3232CWR is housed in a 16-pin SO16L (Small Outline, Low-profile) package with 1.27 mm pitch, 10.1 × 7.5 mm body size, and ECOPACK® RoHS-compliant finish. The package supports automated surface-mount assembly and offers improved thermal performance over standard SO16.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3232CSE+ and SP3232ECA-L, ST3232CWR provides optimal balance of ultra-low power (300 µA), commercial-temp cost efficiency, and SO16L mechanical compatibility with existing 3.3 V portable designs - making it ideal for consumer and medical handhelds where battery life and board area are primary constraints.

Availability

ST3232CWR is available at Aetrix Electronics and suitable for industrial HMI terminals, medical point-of-care devices, and POS terminal peripherals requiring stable component supply and long-term manufacturability.

Supply support for ST3232CWR 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, power ICs, sensors, and analog/mixed-signal products for automotive, industrial, and consumer markets.

The ST3232 series belongs to ST's RS-232 interface product line, engineered specifically for low-voltage, low-power embedded serial connectivity in portable and battery-operated equipment.

FAQ

What external capacitors are required for ST3232CWR operation at 3.3 V?

The ST3232CWR requires four 0.1 µF ceramic capacitors: C1+ and C1− for voltage doubling, C2+ and C2− for voltage inversion. These enable full ±5 V RS-232 output swing from a single 3.3 V supply. No electrolytic or tantalum capacitors are needed, simplifying BOM and improving reliability.

Does ST3232CWR support automatic power-down mode?

No, ST3232CWR does not include an enable/shutdown pin or automatic power-down mode. It operates continuously when VCC is applied. For systems requiring dynamic power gating, external MOSFET control of VCC or use of ST3232EB (with EN pin) is necessary - ST3232CWR maintains fixed 300 µA quiescent current during active operation.

Can ST3232CWR interface directly with 5 V microcontrollers?

Yes - ST3232CWR's transmitter inputs (T1IN/T2IN) accept 5 V logic levels (VIH = 2.4 V min. at VCC = 5 V), and its receiver outputs (R1OUT/R2OUT) drive 5 V-tolerant CMOS inputs (VOH = VCC − 0.1 V). However, VCC must remain within 3–5.5 V; applying 5 V to VCC fully supports 5 V logic interfacing without level shifters.

What is the maximum cable length supported at 300 kbps?

At 300 kbps, ST3232CWR supports up to 5 meters of standard 24 AWG twisted-pair RS-232 cable under typical noise conditions. This is enabled by its 6 V/µs slew rate (limiting edge ringing) and ±25 V receiver input range (tolerating ground shifts). For longer runs, reduce data rate to 90 kbps or add line termination.