The MAX3233E/MAX3235E are EIA/TIA-232 and V.28/V.24 communications interfaces with automatic shutdown/wake-up features, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge, to ±8kV using IEC 1000-4-2 Contact Discharge, and to ±15kV using the Human Body Model. The MAX3233E operates from a +3.3V supply; the MAX3235E operates from +5.0V. All devices achieve a 1µA supply current using Maxim's revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when the following two conditions occur: either the RS-232 cable is disconnected or the transmitters of the connected peripherals are inactive, and the UART driving the transmitter inputs is inactive for more than 30 seconds. They turn on again when they sense a valid transition at any transmitter or receiver input. AutoShutdown Plus saves power without changes to the existing BIOS or operating system. The MAX3233E/MAX3235E have internal dual charge pumps requiring no external capacitors. Both transceivers have a proprietary low-dropout transmitter output stage that enables true RS-232 performance from a +3.0V to +3.6V supply for the MAX3233E or a +4.5V to +5.5V supply for the MAX3235E. These devices are guaranteed to operate up to 250kbps. Both are available in space-saving 20-pin wide SO or plastic DIP packages.
The MAX3233E and MAX3235E are dual RS‑232 transceivers that integrate internal charge‑pump capacitors, eliminating the need for external components. They operate from a single supply (3.3 V for MAX3233E, 5.0 V for MAX3235E) and provide up to 250 kbps data rates while consuming only 1 pA of supply current thanks to Maxim’s AutoShutdown Plus feature. The devices are protected against up to +15 kV ESD and are offered in 20‑pin SO and plastic DIP packages.
Typical applications include sub‑notebook and palmtop computers, cellular phones, battery‑powered handheld equipment, and other embedded systems. Ordering information, pin descriptions, electrical and timing characteristics, and detailed functional diagrams are provided throughout the document.
| Supply Voltage (MAX3233E) | 3.0 V to 3.6 V |
|---|---|
| Maximum Data Rate | 250 kbps |
| Supply Current | 1 pA |
| ESD Protection (Human Body Model) | +15 kV |
| ESD Protection (IEC Contact Discharge) | +8 kV |
| ESD Protection (IEC Air‑Gap Discharge) | +15 kV |
| Operating Temperature Range (0 °C to +70 °C packages) | 0 °C to +70 °C |
| Operating Temperature Range (‑40 °C to +85 °C packages) | -40 °C to +85 °C |
| Slew Rate | 6 V/µs |
The devices draw only 1 pA of supply current in normal operation.
The pins are protected to +15 kV Human Body Model, +8 kV IEC contact discharge, and +15 kV IEC air‑gap discharge.