RS-232 transceiver with 3 drivers, 5 receivers — what that means for your serial port count
The MAX239CWG+T is a Maxim Integrated full-duplex RS-232 transceiver that packs three drivers and five receivers into a single 24-SOIC package. The 3/5 ratio is unusual — most RS-232 transceivers offer symmetric driver/receiver counts (e.g., 2/2 or 5/5). Here, the extra two receivers let you monitor more incoming lines than you drive, which suits applications like multi-drop receive buses or equipment where the host transmits on fewer channels than it listens to.
120 kbps data rate — sufficient for legacy UART links, not for high-speed serial
Rated at 120 kbps, this part handles standard UART speeds up to 115.2 kbps with margin. It will not support higher-rate protocols like RS-232 at 460.8 kbps or 921.6 kbps. For those, you would need a faster transceiver such as the MAX3221 family (250 kbps or 1 Mbps variants).
Dual supply rails: 5 V logic and 7.5–13.2 V charge-pump input
The supply scheme is two-part: a 5 V rail for the logic interface, and a separate 7.5 V to 13.2 V input that powers the internal charge pump to generate RS-232 voltage levels. This is not a single-supply 3.3 V or 5 V-only part — the higher-voltage rail must be present. The 500 mV receiver hysteresis provides noise rejection on the incoming RS-232 lines, useful in electrically noisy environments within the 0°C to 70°C commercial temperature range.
Active production, no obsolescence risk
The MAX239CWG+T is listed as Active in production. ROHS3 compliant. For current pricing and availability, submit an RFQ — we source through independent distribution and confirm both at quote time.