STMicroelectronics ST232CN

Overview

ST232CN from STMicroelectronics is a dual-transmitter/dual-receiver RS-232 interface IC operating from a single 5 V supply, delivering ±7.8 V transmitter output swing, 220 kbps data rate, and ±30 V receiver input tolerance. It replaces ±12 V supplies in portable computers, battery-powered modems, and multi-drop RS-232 networks using only four 0.1 µF capacitors.

For engineers reviewing the ST232CN datasheet, ST232CN pinout, ST232CN application, or ST232CN equivalent, key selection criteria include its 5 V single-supply operation, controlled slew rate for EMI reduction, DIP-16 package compatibility with legacy designs, and direct functional equivalence to MAX232 in TTL-to-RS-232 level translation.

Technical Context

The ST232CN integrates two charge-pump voltage doublers and inverters to generate ±V_CC-derived RS-232 voltage levels from 5 V, eliminating need for external ±12 V rails. Its receivers feature 5 kΩ input resistance and 0.5 V hysteresis for noise immunity across ±30 V input range.

Transmitter outputs are slew-rate limited to 7–30 V/µs to reduce electromagnetic interference, while propagation delays (0.3–1 µs) and logic thresholds (V_IL = 0.8 V, V_IH = 2.0 V) ensure reliable TTL/CMOS interfacing at up to 220 kbps under full temperature range (0 °C to 70 °C).

Key Specifications

Pinout & Package

DIP-16 package with 0.3-inch body width and through-hole mounting; compatible with standard 0.1-inch grid PCB layouts and socket-based prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX232CPE, ST232CN offers lower capacitor count and reduced quiescent current; versus SP3223ECA, it provides drop-in DIP-16 replacement capability at the expense of shutdown functionality and wider supply flexibility.

Availability

ST232CN is available at Aetrix Electronics and suitable for portable computing, low-power modem interfaces, and battery-powered RS-232 systems requiring stable component supply across extended production cycles.

Supply support for ST232CN 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, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ST232CN belongs to ST's legacy RS-232 transceiver product line, engineered specifically for cost-sensitive, space-constrained commercial applications requiring robust single-supply level translation.

FAQ

What is the minimum required capacitor value for ST232CN operation?

The ST232CN is fully specified for operation with 0.1 µF ceramic capacitors on all four charge pump terminals (C1+, C1−, C2+, C2−). These values are validated across the full 0 °C to 70 °C temperature range and ensure stable ±7.8 V output swing at 220 kbps. Larger values (e.g., 1 µF) may be used but do not improve performance and increase board area and cost.

Can ST232CN drive standard RS-232 loads over 15-meter cables?

Yes - the ST232CN delivers ±7.8 V output swing into 3 kΩ loads, exceeding the EIA/TIA-232 minimum of ±5 V. At 220 kbps, its controlled 7–30 V/µs slew rate maintains signal integrity on properly terminated 15 m cables with ≤1000 pF total capacitance, as confirmed in Figure 4 and Table 5 of the official datasheet.

Does ST232CN support automatic power-down or shutdown mode?

No - the ST232CN has no enable/shutdown pin or internal power-down circuitry. It operates continuously when VCC is applied. For applications requiring ultra-low standby current, consider alternatives like SP3223ECA (1 µA shutdown) or MAX3221 (1 µA shutdown), though these require package and layout changes.

Is ST232CN pin-compatible with MAX232 in all package variants?

Yes - the ST232CN in DIP-16 is fully pin- and function-compatible with MAX232CPE and MAX232ACPE. All 16 pins match in assignment, electrical behavior, and timing. This allows direct substitution in existing designs without PCB modification, provided 0.1 µF capacitors replace the 1 µF types used with MAX232.