The MAX3238 true RS-232 transceiver achieves a 1µA supply current with Maxim’s revolutionary AutoShutdown Plus feature. When the device does not sense a valid signal transition on either the receiver or transmitter inputs within 30sec, the on-board power supply and drivers shut down. This occurs if the RS-232 cable is disconnected or if the transmitters of the con- nected peripheral are inactive. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input, saving power without changes to the existing BIOS or operating system. The MAX3238 5-driver/3-receiver complete serial port is a 3V-powered EIA/TIA-232 and V.28/V.24 communications interface intended for notebook or subnotebook computer applications. A proprietary, high-efficiency, dual charge-pump power supply and a low-dropout transmitter combine to deliver true RS-232 performance from a single +3.0V to +5.5V supply. A guaranteed data rate of 250kbps provides compatibility with popu- lar software for communicating with personal comput- ers. The MAX3238 requires only 0.1µF capacitors in 3.3V operation. It is ideal for 3.3V-only systems, mixed 3.3V and 5.0V systems, or 5V-only systems that require true RS-232 performance. Receiver R1 has an extra, always-active output (in addi- tion to its standard output), which allows external devices, such as a modem, to be monitored without for- ward biasing the protection diode
The MAX3238 is a true RS‑232 transceiver that operates from a single +3.0 V to +5.5 V supply and features Maxim’s AutoShutdown Plus™ to reduce supply current to 1 µA when no valid signal transitions are detected for 30 seconds. It offers a guaranteed data rate of 250 kbps and includes five drivers and three receivers in a space‑saving 28‑pin SSOP package, making it suitable for notebook, handheld, and battery‑powered equipment.
The datasheet details absolute maximum ratings, electrical characteristics, pin descriptions, typical operating curves, and package dimensions. It also explains the AutoShutdown Plus operation, the INVALID output logic, and capacitor selection guidelines for reliable charge‑pump operation.
| Supply Voltage Range | +3.0 V to +5.5 V |
|---|---|
| Guaranteed Data Rate | 250 kbps |
| Drivers / Receivers | 5 drivers / 3 receivers |
| Package | 28‑pin SSOP |
| Operating Temperature Range | -40 °C to +85 °C (MAX3238E) / 0 °C to +70 °C (MAX3238C) |
The device guarantees a data rate of 250 kbps.
The MAX3238 includes five drivers and three receivers.
It is offered in a 28‑pin SSOP (Shrink Small‑Outline Package).