Smart Grid Solutions Guide - Maxim

CommunicationsFeatured productsHighly integrated RS-485 transceivers simplify power-meter interface designsMAX13412E/MAX13413EThe MAX13412E/MAX13413E are half-duplex RS-485/RS-422 transceiversoptimized for isolated power meters. These devices reduce designcomplexity by integrating a low-dropout regulator (LDO) and asensing circuit for AutoDirection control. The internal LDO allowsthe devices to operate from a wide, unregulated voltage range (6Vto 28V), simplifying power-supply designs. AutoDirection controlreduces cost and board space by eliminating an optocoupler inisolated power-meter applications. Other features include enhancedESD protection, fail-safe circuitry, slew-rate limiting, and full-speedoperation.Benefits••AutoDirection control saves cost andboard space––Reduces the number of optical isolatorsneeded in isolated applications••Built-in LDO offers convenience withoutthe worry of providing a regulatedvoltage level––Operates from an unregulated 6V to 28Vpower supply and provides 5V/20mA ofpower to external circuits••Extended ESD level of ±15kV (HumanBody Model) eliminates external ESDprotection circuitry••1/8-unit load receiver input impedanceenables up to 256 peripheral sensors inthe systemV SYSV REGUNREGULATED ISOLATEDPOWER SUPPLY(6V TO 28V)AutoDirection controleliminates thirdoptocouplerRORLDOV CCMCU AND RELATEDCIRCUITRYREDETECTCIRCUITBIntegrated LDO allowswide supply range(6V to 28V)V REGA5V output V REGsupplies up to 20mAto external circuitryV SYSDIDGNDMAX13412E/MAX13413ESystem block diagram of the MAX13412E/MAX13413E.38 Maxim Smart Grid Solutions