STMicroelectronics ST232ACN

Overview

ST232ACN from STMicroelectronics is a dual-transmitter/dual-receiver RS-232 interface IC operating from a single 5 V supply, compliant with EIA/TIA-232 and V.28 standards. It delivers ±9 V transmitter output swing, 400 kbps data rate, 0.1 µs receiver propagation delay, and draws only 1.5 mA typical supply current-ideal for portable computers and battery-powered RS-232 networks.

For engineers reviewing the ST232ACN datasheet, ST232ACN pinout, ST232ACN application, or ST232ACN equivalent, key selection criteria include its ultra-low power consumption, integrated charge-pump voltage generation requiring only four 0.1 µF capacitors, wide ±30 V receiver input range, and operation across 0 to 70 °C ambient temperature.

Technical Context

The ST232ACN implements on-chip charge-pump circuitry to generate ±VCC-derived voltages (V+ and V−) from a single 5 V rail, enabling full RS-232 voltage-level signaling without external ±12 V supplies. Its dual transmitters drive standard 3 kΩ loads with ±9 V swing and 12 V/µs slew rate, while dual receivers accept ±30 V inputs and deliver TTL/CMOS-compatible outputs with 0.1 µs typical propagation delay.

It supports bidirectional logic-level translation between microcontroller UARTs and legacy RS-232 peripherals, featuring 5 kΩ typical receiver input resistance, 0.5 V hysteresis for noise immunity, and robust ±15 V absolute maximum transmitter output rating. All electrical characteristics are specified over 0 to 70 °C and 4.5–5.5 V supply.

Key Specifications

Pinout & Package

ST232ACN is housed in a 16-pin SOIC (SO-16) package with standard 1.27 mm pitch, RoHS-compliant and ECOPACK® certified.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX232ACPE+ and SP3232EEN, the ST232ACN offers best-in-class combination of speed (400 kbps), low power (1.5 mA), and ruggedness (±30 V input), making it optimal for commercial-grade portable and industrial serial interfaces where all three parameters matter.

Availability

ST232ACN is available at Aetrix Electronics and suitable for portable computer serial interfaces, low-power modem links, and industrial equipment interface translation requiring stable component supply and long-term sourcing continuity.

Supply support for ST232ACN 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 interface solutions for industrial, automotive, and consumer markets.

The ST232 series belongs to ST's legacy RS-232 transceiver product line, engineered specifically for single-supply, low-power, drop-in replacement of industry-standard 232 drivers/receivers in cost- and space-constrained commercial applications.

FAQ

What is the minimum number and value of external capacitors required for ST232ACN operation?

The ST232ACN requires exactly four 0.1 µF ceramic capacitors (C1+ to C2−) for internal charge-pump voltage generation. These must be placed close to the IC pins per Figure 2 in the datasheet. No bypass or additional decoupling capacitors are mandatory, though a 100 nF VCC-to-GND capacitor is recommended for noise suppression.

Can ST232ACN operate with a 3.3 V supply?

No. The ST232ACN is specified only for 4.5–5.5 V operation. At 3.3 V, the internal charge pump cannot generate sufficient ±VCC-derived voltages to meet RS-232 output swing requirements (±5 V min). For 3.3 V systems, consider ST3232 or SP3232EEN, which are explicitly rated for 3.0–5.5 V operation.

Is ST232ACN pin-compatible with MAX232?

No. Although both are dual-transmitter/dual-receiver RS-232 ICs in SO-16 packages, ST232ACN uses a different pinout: its charge-pump capacitor terminals (C1+, C1−, C2+, C2−) occupy pins 1–5 and 6, whereas MAX232 places them on pins 1, 2, 3, and 4 with different assignments. Direct replacement requires PCB layout revision.

Does ST232ACN include ESD protection on RS-232 I/O pins?

The ST232ACN provides inherent robustness via its ±30 V receiver input rating and ±15 V transmitter output absolute maximum ratings, but it does not integrate dedicated on-die ESD clamps per IEC 61000-4-2 Level 4. External 15 kV HBM-rated TVS diodes (e.g., SMAJ5.0A) are recommended for applications exposed to frequent hot-plug or cable discharge events.