Basic Product Information
The MAX232DR is a dual-channel RS-232 line driver/receiver manufactured by Texas Instruments. It includes a capacitive voltage generator (charge pump) that produces TIA/EIA-232-F voltage levels from a single 5V supply, requiring only four external 1µF capacitors. Each device contains two drivers that convert TTL/CMOS logic levels to RS-232 levels, and two receivers that convert RS-232 levels to TTL/CMOS logic levels. The receivers feature a typical threshold of 1.3V with 0.5V hysteresis and can accept ±30V input levels, providing robust noise immunity. The MAX232DR supports data rates up to 120 kbit/s and provides ESD protection exceeding 2000V per the Human Body Model (JESD 22, A114-A). Housed in a SOIC-16 package, the device operates from a 4.5V to 5.5V supply over a temperature range of 0°C to +70°C. The “D” suffix denotes the SOIC package; the “R” suffix denotes tape-and-reel packaging. Note: TI recommends the MAX232IDR (industrial temperature range, -40°C to +85°C) or MAX202 for enhanced ESD protection (15 kV HBM) as alternatives.
Core Electrical Parameters
| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Function | Dual RS-232 Driver/Receiver with Integrated Charge Pump |
| Number of Drivers | 2 |
| Number of Receivers | 2 |
| Data Rate | Up to 120 kbit/s |
| Supply Voltage | 4.5V ~ 5.5V (single 5V supply) |
| Supply Current | 8 mA (typ.), 10 mA (max) |
| Driver Output Voltage Swing | ±9V (typ. with 5V supply) |
| Driver Input Logic | TTL/CMOS compatible |
| Receiver Input Threshold | 1.3V (typ.) |
| Receiver Input Hysteresis | 0.5V (typ.) |
| Receiver Input Voltage Range | ±30V |
| Receiver Open-Circuit Output | High (default) |
| External Capacitors Required | 4 × 1µF |
| ESD Protection | > 2000V HBM (A114-A) |
| Operating Temperature | 0°C ~ +70°C |
| Package | SOIC-16 (9.9mm × 3.91mm × 1.58mm) |
| Packaging | Tape & Reel (2,500 pcs/reel) |
| ECCN | EAR99 |
Core Features & Advantages
The MAX232DR remains one of the most widely deployed RS-232 transceivers for several reasons:
- Single 5V Supply with Integrated Charge Pump: The internal capacitive voltage generator produces ±9V RS-232 output swings from a single 5V rail, eliminating the need for bipolar ±12V supplies that older discrete RS-232 drivers required.
- Minimal External Component Count: Only four 1µF capacitors are needed for charge pump operation, keeping BOM cost and board space to a minimum compared to designs requiring multiple voltage regulators.
- ±30V Receiver Input Tolerance: Receivers withstand ±30V input levels, providing robust protection against voltage spikes common in long RS-232 cables and industrial environments.
- Built-In Hysteresis: 0.5V typical receiver hysteresis improves noise immunity on slow-slew-rate RS-232 signals, preventing false transitions in noisy environments.
- Open-Circuit Fail-Safe: Disconnected or floating receiver inputs default to a high output state, ensuring defined logic levels when the cable is unplugged or the remote transmitter is off.
- Proven Legacy Compatibility: Decades of deployment in PC motherboards, industrial controllers, and instrumentation mean the MAX232 has an enormous installed base and extensive reference design ecosystem, making it a safe choice for maintenance and repair.
Typical Application Scenarios
- MCU-to-PC Serial Communication: Converting 5V TTL UART signals from microcontrollers (AVR, 8051, PIC) to RS-232 levels for connection to PC serial ports or USB-to-RS-232 adapters.
- Industrial Control Interfaces: RS-232 communication links between PLCs, HMI panels, and variable-frequency drives in factory automation systems.
- Point-of-Sale Terminals: Serial communication between POS controllers and peripherals such as barcode scanners, receipt printers, and cash drawers.
- Embedded Debug Consoles: Providing RS-232 debug/programming ports on development boards and embedded Linux systems for serial terminal access.
- Legacy System Maintenance: Direct replacement for MAX232 devices in existing board designs for industrial equipment, medical devices, and telecommunications hardware requiring RS-232 connectivity.
- GPS Receiver Interfaces: Converting TTL-level NMEA output from GPS modules to RS-232 levels for integration with marine navigation systems and vehicle tracking units.
Market Reference Price
| Quantity | Unit Price (USD) |
|---|---|
| 1 ~ 99 pcs | $1.845 |
| 100 ~ 249 pcs | $1.419 |
| 250 ~ 999 pcs | $1.045 |
| 1,000+ pcs | $0.747 |
Source: TI official store pricing, as of 2025. The MAX232D variant is in end-of-life status; MAX232IDR (industrial temp) remains in active production at $0.453/ku.
Related Models Comparison
| Feature | MAX232DR | MAX232IDR | MAX3232CPE | MAX202 |
|---|---|---|---|---|
| Manufacturer | TI | TI | TI | TI |
| Supply Voltage | 4.5V ~ 5.5V | 4.5V ~ 5.5V | 3.0V ~ 5.5V | 4.5V ~ 5.5V |
| Drivers/Receivers | 2/2 | 2/2 | 2/2 | 2/2 |
| Data Rate | 120 kbit/s | 120 kbit/s | 250 kbit/s | 120 kbit/s |
| Ext. Capacitors | 4 × 1µF | 4 × 1µF | 4 × 0.1µF | 4 × 0.1µF |
| ESD Protection | 2 kV HBM | 2 kV HBM | 15 kV HBM | 15 kV HBM |
| Operating Temp. | 0°C ~ +70°C | -40°C ~ +85°C | 0°C ~ +70°C | -40°C ~ +85°C |
| Package | SOIC-16 | SOIC-16 | DIP-16 | SOIC-16 |
| Status | End of Life | Active | Active | Active |