STMicroelectronics ST3237BPR

Overview

ST3237BPR from STMicroelectronics is a 3V–5.5V RS-232 transceiver with five drivers and three receivers, supporting 250Kbps (normal) and 1Mbps (very high speed) data rates, ±5.4V output swing, and 1µA shutdown current. It enables robust serial communication in industrial modems and embedded control systems requiring low-power, flow-through pinout design.

For engineers reviewing the ST3237BPR datasheet, ST3237BPR pinout, ST3237BPR application, or ST3237BPR equivalent, key selection criteria include guaranteed slew rate (6–24 V/µs), dual charge-pump architecture for true RS-232 levels from 3V supply, receiver enable/shutdown control logic, and SSOP-28 package compatibility with legacy EIA/TIA-232 designs.

Technical Context

The ST3237BPR implements a dual-charge-pump voltage converter to generate ±5.5V rails from a single 3V–5.5V supply, enabling compliant RS-232 signaling without external high-voltage sources. Its transmitter output stage uses low-dropout circuitry to maintain ±5V output swing into 3kΩ loads across temperature and supply variation.

It supports two operational modes via the VHSCI pin: GND selects 250Kbps/6V/µs slew rate for noise-sensitive environments; VCC enables 1Mbps/24V/µs mode for high-speed point-to-point links. Receiver inputs tolerate ±25V, with hysteresis (0.3V) and 3–7kΩ input resistance ensuring noise immunity in electrically harsh settings.

Key Specifications

Pinout & Package

ST3237BPR is housed in a 28-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, JEDEC MO-153 compliant, lead-free ECOPACK® construction. The flow-through pinout minimizes PCB trace crossovers and simplifies layout for bidirectional RS-232 interfaces.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX3232ESE+ and SP3232ECA-L, ST3237BPR uniquely delivers five transmitters for multi-peripheral control, programmable slew rate via VHSCI, and sub-µA shutdown with active receivers-making it optimal for space-constrained, multi-interface industrial controllers requiring flexible timing and ultra-low standby power.

Availability

ST3237BPR is available at Aetrix Electronics and suitable for industrial modems, POS terminals, medical diagnostic equipment, and PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ST3237BPR 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, analog ICs, power management, and automotive-grade components since 1987.

The ST3237 belongs to ST's RS-232 interface product line, engineered specifically for low-voltage, high-reliability serial communication in industrial and medical equipment where supply flexibility, EMI resilience, and long-term availability are critical.

FAQ

What is the minimum supply voltage required for guaranteed RS-232 compliance?

The ST3237BPR guarantees full EIA/TIA-232-F compliance-including ±5V output swing and ±25V input tolerance-down to 3.0V supply. At VCC = 3.0V, the dual charge pump maintains V+ ≥ +5.2V and V− ≤ −5.2V under load, verified per Table 5 and Table 6 in the official datasheet.

How does the VHSCI pin affect timing performance?

When VHSCI is tied to VCC, the ST3237BPR enables very high speed mode: maximum data rate increases from 250Kbps to 1Mbps, and transmitter skew improves from 100ns to 60ns. Slew rate rises from 6V/µs to 24V/µs, reducing transition time but increasing EMI risk-requires careful PCB layout and optional RC filtering.

Can ST3237BPR drive standard RS-232 cables up to 50 feet?

Yes. With its ±5.4V output swing into 3kΩ and 150pF load, the ST3237BPR meets the RS-232-F specification for driving 50ft (15m) of standard 24AWG twisted-pair cable at 250Kbps. At 1Mbps, maximum recommended length drops to ~15ft due to rise-time limitations and capacitive loading effects.

Is the SHDN pin compatible with microcontroller GPIOs operating at 1.8V logic levels?

No. The SHDN pin has a VIH(min) of 2.0V at VCC = 3.3V and 2.4V at VCC = 5V per Table 4. A 1.8V GPIO cannot reliably assert active-low shutdown; level translation (e.g., N-channel MOSFET or dedicated buffer) is required to interface with sub-2V logic families.