The MAX3222/MAX3232/MAX3237/MAX3241 transceivers have a proprietary low-dropout transmitter output
stage enabling true RS-232 performance from a 3.0V to 5.5V supply with a dual charge pump. The
devices require only four small 0.1μF external chargepump capacitors. The MAX3222, MAX3232, and
MAX3241 are guaranteed to run at data rates of 120kbps while maintaining RS-232 output levels. The
MAX3237 is guaranteed to run at data rates of 250kbps in the normal operating mode and 1Mbps in the
MegaBaud· operating mode, while maintaining RS-232 output levels.
The MAX3222/MAX3232 have 2 receivers and 2 drivers. The MAX3222 features a 1μA shutdown mode
that reduces power consumption and extends battery life in portable systems. Its receivers remain active in
shutdown mode, allowing external devices such as modems to be monitored using only 1μA supply current.
The MAX3222 and MAX3232 are pin, package, and functionally compatible with the industry-standard
MAX242 and MAX232, respectively. The MAX3241 is a complete serial port (3 drivers/
5 receivers) designed for notebook and subnotebook computers. The MAX3237 (5 drivers/3 receivers) is ideal
for fast modem applications. Both these devices feature a shutdown mode in which all receivers can remain
active while using only 1μA supply current. Receivers R1 (MAX3237/MAX3241) and R2 (MAX3241) have extra outputs
in addition to their standard outputs. These extra outputs are always active, allowing external devices
such as a modem to be monitored without forward biasing the protection diodes in circuitry that may have VCC
completely removed. The MAX3222, MAX3237, and MAX3241 are available in space-saving TSSOP and SSOP packages.
