MAX3316-MAX3319 transceivers feature a proprietary low-dropout transmitter output stage that enables RS-232-compatible performance from +2.25V to +3.0V with a dual-charge pump. These devices require only four 0.1µF capacitors, and are guaranteed to operate at data rates up to 460kbps. The MAX3318/MAX3319 achieve a 1µA supply current using Maxim’s revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when the RS-232 cable is disconnected or the transmitters of the connected peripherals are inac- tive 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 MAX3318 is a 2-Tx/2-Rx device while the MAX3319 is a 1-Tx/1-Rx device. These devices also feature a logic-level output (READY) that asserts when the charge pump is regulat- ing and the device is ready to begin transmitting. The MAX3316/MAX3317 are 2-Tx/2-Rx transceivers. The MAX3317 features a 1µA shutdown mode that can be entered by driving SHDN low. The MAX3317’s receivers remain active while in shutdown mode, allowing external devices such as modems to be monitored using only 1µA supply current. These devices are available in space-saving packages: MAX3316 (16-pin SSOP and 20-pin TSSOP), MAX3317/ MAX3318 (20-pin SSOP and 20-pin TSSOP), and MAX3319 (16-pin SSOP).
The MAX3316‑MAX3319 family provides RS‑232‑compatible communication from a low supply voltage of +2.25 V to +3.0 V. The devices use a proprietary dual‑charge‑pump architecture and require only four 0.1 µF capacitors, delivering up to 460 kbps data rates while consuming as little as 1 µA in AutoShutdown Plus mode.
The series includes variants with different numbers of transmitters and receivers (MAX3316/3317 are 2‑Tx/2‑Rx, MAX3318 is 2‑Tx/2‑Rx with shutdown, MAX3319 is 1‑Tx/1‑Rx). Features such as a READY logic output, an INVALID signal for receiver inactivity, and optional FORCEON/FORCEOFF control are described, along with detailed electrical characteristics, timing diagrams, and pin configurations.
| Supply Current (AutoShutdown Plus) | 1 µA |
|---|---|
| Maximum Data Rate | 460 kbps |
| Number of Transmitters/Receivers (MAX3319) | 1‑Tx / 1‑Rx |
| External Capacitors Required | Four 0.1 µF capacitors |
| Slew Rate (typical) | 4 V/µs |
AutoShutdown Plus reduces the supply current to about 1 µA when the RS‑232 cable is disconnected or no valid signal is detected for more than 30 seconds, and the device wakes up automatically when a valid transition occurs.
The transceiver requires four external 0.1 µF capacitors (C1‑C4) to operate the dual charge‑pump.
READY is a logic‑level output that goes high when the charge‑pump is active and the device is ready to transmit; it is low when the device is in shutdown.
The transmitter outputs can swing to ±12 V when the device is powered, providing RS‑232‑compatible voltage levels.