Analog Devices Inc./Maxim Integrated

The LTC1518/LTC1519 are high speed, precision delay differential quad bus/line receivers that can operate at data rates as high as 52Mbps. They are pin compatible with the LTC488/LTC489 RS485 line receivers and operate over the entire –7V to 12V common mode range. A unique architecture provides very stable propagation delays and low skew over wide input common mode, input overdrive and ambient temperature ranges. Propagation delay is 18.5ns ±3.5ns over the commercial temperature range. Typical tPLH/tPHLand channel-to-channel skew is 500ps.Each receiver translates differential input levels (| VID| ≥ 300mV) into valid CMOS and TTL output levels. Its high input resistance (≥22k) allows many receivers to be connected to the same driver. The receiver outputs go into a high impedance state when disabled.The receivers have a fail-safe feature that guarantees a high output state when the inputs are shorted or left floating. Other protection features include thermal shutdown and a controlled maximum short-circuit current (50mA Max). Input resistance remains ≥22k when the device is unpowered or disabled, thus allowing hot swapping without loading the data lines.The LTC1518/LTC1519 operate from a single 5V supply and draw 12mA of supply current.ApplicationsHigh Speed RS485/RS422 ReceiversSTS-1/OC-1 Data ReceiversPECL Line ReceiversLevel TranslatorsFast-20/Fast-40 SCSI Receiver

The LTC1520 is a high speed, precision differential line receiver that can operate at data rates as high as 50Mbps. A unique architecture provides very stable propagation delays and low skew over a wide input common mode, input overdrive and ambient temperature range. Propagation delay is 18ns ±3ns, while typically tPLH/tPHLskew is 500ps and channel-to-channel skew is 400ps.Each receiver translates differential input levels (VID≥ 100mV) into valid CMOS and TTL output levels. Its high input resistance (≥18k) allows many receivers to be connected to the same driver. The receiver outputs go into a high impedance state when disabled.Protection features include thermal shutdown and a controlled maximum short-circuit current (50mA max) that does not oscillate in and out of short-circuit mode. Input resistance remains ≥18k when the device is unpowered or disabled, thus allowing the LTC1520 to be hot swapped into a backplane without loading the data lines.The LTC1520 operates from a single 5V supply and draws 12mA of supply current. The part is available in a 16-lead narrow SO package.ApplicationsHigh Speed Backplane InterfaceLine Collision DetectorPECL and LVDS Line ReceiversLevel TranslatorRing OscillatorTapped Delay Line

The LTC1522 is a micropower charge pump DC/DC converter that produces a regulated 5V output from a 2.7V to 5V input supply. Extremely low supply current (6µA typical with no load, <1µA in shutdown) and low external parts count (one 0.22µF flying capacitor and two 10µF capacitors at VINand VOUT) make the LTC1522 ideally suited for small, light load battery-powered applications. Typical efficiency (VIN= 3V) exceeds 75% with load currents between 50µA and 20mA. Modulating the SHDN pin keeps the typical efficiency above 75% with load currents all the way down to 10µA.The LTC1522 has thermal shutdown and can survive a continuous short from VOUTto GND. In shutdown the load is disconnected from VIN. The part is available in 8-pin MSOP and SO packages. The LTC1522 is pin compatible with the LTC1516 in applications where VIN≥ 2.7V and IOUT≤ 20mA.ApplicationsSIM Interface Supplies for GSM Cellular TelephonesLi-Ion Battery Backup SuppliesLocal 3V to 5V ConversionSmart Card ReadersPCMCIA Local 5V Supplies

The LTC1535 is an isolated RS485 full-duplex differential line transceiver. Isolated RS485 is ideal for systems where the ground loop is broken to allow for much larger common mode voltage ranges. An internal capacitive isolation barrier provides 2500VRMSof isolation between the line transceiver and the logic level interface. The powered side contains a 420kHz push-pull converter to power the isolated RS485 transceiver. Internal full-duplex communication occurs through the capacitive isolation barrier. The transceiver meets RS485 and RS422 requirements.The driver and receiver feature three-state outputs, with the driver maintaining high impedance over the entire common mode range. The drivers have short-circuit current limits in both directions and a slow slew rate select to minimize EMI or reflections. The 68kΩ receiver input allows up to 128 node connections. A fail-safe feature defaults to a high output state when the receiver inputs are open or shorted.ApplicationsIsolated RS485 Receiver/DriverRS485 with Large Common Mode VoltageBreaking RS485 Ground LoopsMultiple Unterminated Line Taps