Analog Devices Inc./Maxim Integrated

The MAX481E, MAX483E, MAX485E, MAX487E- MAX491E, and MAX1487E are low-power transceivers for RS-485 and RS-422 communications in harsh environments. Each driver output and receiver input is protected against ±15kV electro-static discharge (ESD) shocks, without latchup. These parts contain one driver and one receiver. The MAX483E, MAX487E, MAX488E, and MAX489E feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, thus allowing error-free data transmission up to 250kbps. The driver slew rates of the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E are not limited, allowing them to transmit up to 2.5Mbps.These transceivers draw as little as 120µA supply current when unloaded or when fully loaded with disabled drivers (see Selector Guide). Additionally, the MAX481E, MAX483E, and MAX487E have a low-current shutdown mode in which they consume only 0.5µA. All parts operate from a single +5V supply.Drivers are short-circuit current limited, and are protected against excessive power dissipation by thermal shutdown circuitry that places their outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit.The MAX487E and MAX1487E feature quarter-unit-load receiver input impedance, allowing up to 128 transceivers on the bus. The MAX488E-MAX491E are designed for full-duplex communications, while the MAX481E, MAX483E, MAX485E, MAX487E, and MAX1487E are designed for half-duplex applications. For applications that are not ESD sensitive see the pinand function-compatible MAX481, MAX483, MAX485, MAX487-MAX491, and MAX1487.ApplicationsIndustrial-Control Local Area NetworksLevel TranslatorsLow-Power RS-422 TransceiversLow-Power RS-485 TransceiversTransceivers for EMI-Sensitive Applications

The MAX4838–MAX4842 are overvoltage protection ICs that protect low-voltage systems against voltages of up to 28V. If the input voltage exceeds the overvoltage trip level, the MAX4838–MAX4842 turn off the low-cost external n-channel FET(s) to prevent damage to the protected components. An internal charge pump eliminates the need for external capacitors and drives the FET gate for a simple, robust solution.The MAX4838/MAX4839 have a 7.4V overvoltage threshold, and the MAX4840/MAX4841 have a 5.8V overvoltage threshold. The MAX4842 has a 4.7V overvoltage threshold. The MAX4838–MAX4841 have an undervoltage lockout (UVLO) threshold of 3.25V while the MAX4842 has a UVLO of 3.0V. In addition to the single FET configuration, the devices can be configured with back-to-back external FETs to prevent currents from being back-driven into the adapter.On power-up, the device waits for 50ms before driving GATE high. Active-low FLAG is held low for an additional 50ms after GATE goes high before deasserting. The MAX4838/MAX4840/MAX4842 have an open-drain active-low FLAG output, and the MAX4839/MAX4841 have a pushpull FLAG output. The active-low FLAG output asserts immediately to an overvoltage fault.Additional features include a 15kV ESD-protected input (when bypassed with a 1µF capacitor) and a shutdown pin (active-low EN) to turn off the device (MAX4838/MAX4840/MAX4842).All devices are offered in a small 6-pin SC70 package and are specified for operation from -40°C to +85°C.ApplicationsCell PhonesDigital Still CamerasMP3 PlayersPDAs and Palmtop Devices

The MAX4843–MAX4846 overvoltage protection controllers protect low-voltage systems against high-voltage faults of up to 28V. When the input voltage exceeds the overvoltage threshold, these devices turn off a low-cost, external n-channel FET(s) to prevent damage to the protected components. An internal charge pump eliminates the need for external capacitors and drives the FET gate for a simple, robust solution.The overvoltage trip level is set to 7.4V (MAX4843), 6.35V (MAX4844), 5.8V (MAX4845), or 4.65V (MAX4846). When the input voltage drops below the undervoltage lockout (UVLO) threshold, the devices enter a low standby current mode (10µA). The MAX4843/MAX4844/MAX4845 have a UVLO threshold of 4.15V, the MAX4845C/MAX4845D have a UVLO threshold of 2.2V, and the MAX4846 has a UVLO threshold of 2.5V. In addition to the single FET configuration, the devices can be configured with back-to-back external FETs to prevent currents from being back-driven into the adapter.An additional feature includes a ±15kV ESD-protected input when bypassed with a 1µF capacitor to ground. All devices are offered in small 6-pin µDFN (1.5mm x 1.0mm) and 6-pin ultra-thin LGA (MAX4845EYT+T only) (1.5mm x 1.0mm) packages and are specified for operation over the -40°C to +85°C temperature range.ApplicationsCell PhonesDigital Still CamerasMP3 PlayersPDAs and Palmtop Devices