XRT5894 Four-Channel E1 Line Interface (3.3V or 5.0V) March 2000-3 FEATURES D Compliant with ITU G.703 Pulse Mask Template for D Logical Inputs Accept either 3.3V or 5.0V Levels 2.048Mbps (E1) Rates D Ultra-Low Power Dissipation D Four Independent CEPT Transceivers D +3.3V or 5.0V Supply Operations D Supports Differential Transformer Coupled D Individual Transmit Channel Over Temperature Receivers and Transmitters Protection D On Chip Pulse Shaping for Both 75W and 120W Line Drivers APPLICATIONS D Compliant with ITU G.775 LOS Declaration/Clearing Recommendation D SDH Multiplexer D Optional User Selectable LOS Declaration/Clearing Delay D Digital Cross Connects GENERAL DESCRIPTION The XRT5894 is an optimized four channel 3.3V line The device offers two distinct modes of LOS detection. interface unit fabricated using low power CMOS The first method, which does not require an external technology. The device contains four independent E1 clock, provides an LOS output indication signal with channels. Each channel performs the driver and receiver thresholds and delay that comply with the ITU G.775 functions necessary to convert bipolar signals to logical requirements. In the second mode, the user provides an levels and vice versa. The device requires transformers external clock that increases the delay for LOS on both receiver and transmitter sides, and supports both declaration and clearing. This feature provides the user balanced and unbalanced interfaces. with the flexibility to implement LOS specifications that require a delay greater than the G.775 requirements. ORDERING INFORMATION Operating Part No. Package Temperature Range XRT5894IV 64 Lead TQFP (10 x 10 x 1.4mm) -40C to +85C Rev. 1.10 E2000 EXAR Corporation, 48720 Kato Road, Fremont, CA 94538z (510) 668-7000z FAX (510) 668-7017XRT5894 BLOCK DIAGRAM Transceiver 1 Transceiver 2 Transceiver 3 Tranceiver 4 RTIP4 (43) RXPOS4 (47) 1:2 R1 Signal Receive TIP Peak Comparators RX Input Detector RXNEG4 (46) RING R2 RRING4 (42) V CC 1 LOS4 (48) Mux LOS Loss O Delay Detect LOSCNT (45) Counter LOSSEL (25) Transmit Duty TXCLK4 (51) Line Cycle Drivers Adjust TXPOS4 (49) TTIP4 (53) R3 0 NRZ 2:1 TXNEG4 (50) TIP To 0 9.1 Pulse RZ TX OUTPUT Mux Shaping RING TRING4 (55) R4 1 1 9.1 Figure 1. XRT5894 Block Diagram Receiver Notes D The same type 1:2CT ratio transformer may be D LOSCNT (pin 45) is unconnected when LOSSEL is used at the receiver input and transmitter output. logic 1, or connected to an external clock when LOSSEL is logic 0. D R1 and R2 are both 150W for 75W operation, or 240W for 120W operation. Transmitter Notes D Return loss exceeds ITU G.703 specification with D Return loss exceeds ETSI 300 166 specification these resistors and a 1:2CT ratio input transformer. with a 1:2 ratio transformer. LOS (Loss of Signal) Notes D R3 and R4 are always 9.1W for both 75W and 120W applications. D LOSSEL (pin 25) is connected to logic 1 for ITU G.775 compliant LOS delay, or to logic 0 for user programmable additional delay. Rev. 1.10 2