High Speed, Precision Delay RS485 Quad Line Receivers

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/tPHL and 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.

Applications

* High Speed RS485/RS422 Receivers

* STS-1/OC-1 Data Receivers

* PECL Line Receivers

* Level Translators

* Fast-20/Fast-40 SCSI Receiver

* Precision Propagation Delay: 18.5ns ±3.5ns Over 0°C to 70°C Temperature Range

* Data Rate: 52Mbps

* Low tPLH/tPHL Skew: 500ps Typ

* Low Channel-to-Channel Skew: 500ps Typ

* –7V to 12V RS485 Input Common Mode Range

* Input Resistance ≥22k, Even When Unpowered

* Guaranteed Fail-Safe Operation over the Entire Common Mode Range

* Hot Swap™ Capable

* High Common Mode Rejection to 26MHz

* Short-Circuit Protection: 10mA Typ Output Current for an Indefinite Short

* Three-State Output Capability

* Will Not Oscillate with Slow Moving Input Signals

* Single 5V Supply

* Pin Compatible with LTC488, LTC489