MAX3232 RS232 to TTL Serial Converter Module

Electrical Specifications

• Supply Voltage: 3.0 V – 5.5 V (works with 3.3 V and 5 V systems)

• Supply Current: Typical no-load current ~0.3 mA (module); driver output short-circuits current max ±35 mA

• RS‑232 Voltage Swing: ± 6 V at 3.3 V VCC, ± 9 V at 5 V VCC

• Maximum Baud Rate: Up to 250 kbps (max tested around 512 kbps at 3.3–5 V)

🔌 Interfaces & Pinout

• DB9 Female Connector for RS‑232 connection

• TTL Header (4-pin):

  • VCC (3–5.5 V)

  • GND

  • TXD (TTL out)

  • RXD (TTL in)

• Some versions include second channel pins (T2I/T2O, R2I/R2O) leveraging the dual transceiver capabilities of the MAX3232

🧩 On‑Chip IC: MAX3232 Overview

• Dual RS‑232 line driver and dual receiver with built-in charge-pump circuits

• Operates from a single 3–5.5 V supply with just 4 small (0.1 µF) external capacitors

• Excellent ESD protection (±15 kV) and meets TIA/EIA‑232‑F and ITU V.28 standards

• Typical current draw ~300 µA; driver slew rate up to 30 V/µs

📏 Physical Specs & Operating Conditions

• Module Size: ~30–40 mm × 20–35 mm, PCB weight ~2–16 g depending on build

• Operating Temp Range: –40 °C to +85 °C (some boards specify –40 °C to +150 °C storage)

🔁 Functional Summary

• Full-duplex RS‑232 ↔ TTL conversion with ±6–9 V signal swing

• TTL side supports both 3.3 V and 5 V logic directly

• DB9 female connector for easy desktop PC interfacing

• Ideal for communicating with RS‑232 devices (e.g. modems, GPS units, industrial controllers)

• Transparent level shifting, requires no drivers — just hook up VCC, GND, TXD/RXD

✔️ Summary Table