STMicroelectronics ST3222ECTR

Overview

ST3222ECTR from STMicroelectronics is a 3–5.5 V, ±15 kV ESD-protected RS-232 transceiver IC with two drivers and two receivers, 300 µA supply current, 250 Kbps guaranteed data rate, and 6 V/µs minimum slew rate. It operates in notebook computers and battery-powered peripherals requiring robust serial interface performance at low voltage.

For engineers reviewing the ST3222ECTR datasheet, ST3222ECTR pinout, ST3222ECTR application, or ST3222ECTR equivalent, key selection criteria include shutdown current (1 µA), receiver input range (±25 V), true RS-232 output swing (±5 V), and TSSOP20 package compatibility with space-constrained PCB layouts.

Technical Context

The ST3222ECTR integrates a dual charge pump generating ±5.5 V rails from a single 3–5.5 V supply, enabling full RS-232 voltage levels without external high-voltage sources. Its proprietary low-dropout transmitter stage maintains compliance with EIA/TIA-232 down to 3 V.

It supports independent receiver enable (EN) and active-low shutdown (SHDN), allowing receivers to remain operational while transmitters and charge pump are disabled-enabling modem monitoring at only 1 mA total supply current.

Key Specifications

Pinout & Package

TSSOP20 package: 6.4–6.6 mm × 6.2–6.6 mm footprint, 0.65 mm pitch, 1.05 mm max height, lead-free ECOPACK® compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3222CSE+ and SP3222ECA-L, the ST3222ECTR uniquely combines independent receiver enable (EN), 1 µA shutdown, and 6 V/µs slew rate - making it optimal for portable devices requiring both low power and noise-resilient serial communication.

Availability

ST3222ECTR is available at Aetrix Electronics and suitable for industrial serial gateways, medical handheld diagnostics, and point-of-sale peripheral interfaces requiring stable component supply across multi-year production cycles.

Supply support for ST3222ECTR 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 industrial, automotive, and consumer markets.

The ST3222E series belongs to ST's RS-232 interface product line, engineered specifically for low-voltage, low-power, high-ESD robustness serial communication in portable and space-constrained embedded systems.

FAQ

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

The ST3222ECTR requires four 0.1 µF ceramic capacitors (C1+, C1−, C2+, C2−) for reliable charge pump operation at 3.3 V. These must be X7R or better dielectric, placed within 5 mm of the IC pins, with low-ESR (<1 Ω) and rated for ≥10 V DC. Using smaller values risks output voltage droop and data corruption above 115.2 kbps.

Can the ST3222ECTR operate with only one transmitter enabled while the other remains inactive?

Yes - transmitter enable is implicit via input logic state: T1IN/T2IN driven high or low activate their respective outputs (T1OUT/T2OUT). No dedicated per-transmitter enable pin exists, but unused inputs can be tied to GND or VCC to force corresponding outputs to fixed states, minimizing crosstalk and power draw.

Does the receiver remain functional during shutdown mode when SHDN = high?

Yes - when SHDN = high (inactive), the charge pump and transmitters power down, but receivers stay fully operational if EN = low. This allows continuous monitoring of incoming RS-232 signals (e.g., modem ring indicator) while consuming only 1 µA total supply current, enabling wake-on-event functionality.

Is the TSSOP20 package of ST3222ECTR compatible with reflow soldering per JEDEC J-STD-020?

Yes - the ST3222ECTR in TSSOP20 is qualified for standard lead-free reflow per JEDEC J-STD-020D. Peak temperature must not exceed 260 °C for ≤30 seconds, with ramp-up rate ≤3 °C/s. The ECOPACK® marking confirms compliance with RoHS and halogen-free requirements, and the package withstands moisture sensitivity level 1 (MSL1) conditions.