MH89761 Datasheet | Mitel Networks

Features - - - - patible with the MH89760B Transmit equalizer and 6d B loop around circuit 6d B pad for easier loopback testing Programmable for varying degrees of equalization TL TL TI Ri RL RL Tx T EIT EA L1 EB EC L2 RCHT RCLT Tx R EIR SW RCHR RCLR ISSUE 4 May 1995 Pin Connections 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Description The MH89761 is a programmable transmit equalizer for use with a T1 line interface, specifically the MH89760B. The MH89761 contains a three setting transmit equalizer, and a 6 d B pad for external loop around. The input and output impedance of the circuit is 100 Ω. The device is fabricated in thick film hybrid technology and is 2 inches high by 0.5 inches wide. The MH89761 is designed to drive 22 gauge twisted pair from the multiplex equipment to the crossconnect point. Figure 1 shows how the MH89761 is connected to the transmit side of a T1 interface. Ordering Information -40°C to 85°C MH89761 20 Pin SIP Hybrid MH89760B TR1 OUTA +12V L2 C2 1: OUTB - 1: :0.5 - R1 L1 C1 - - S1 S2 EIT EIR Tx T Tx R EA EB EC SW RCLT RCHT RCLR RCHR Ti Ri TL RL - - - - - S3 S4 S5 S6 S7 R1 = 150Ω C1 = .01µF C2 = .47µF L1 = 33µH L2 = 33µH TR2 Rx T 1: 1: 1: Rx R - - Figure 1 - Connection Diagram 4-93 Applications The MH89761 can be connected to the MH89760B as illustrated in Figure 1. All pins on the MH89761 not shown connected in Figure 1 should be left open. The internal circuit of the equalizer is shown in Figure 2. The MH89761 has two separate circuits; a 6d B pad and an equalizer. Ti and Ri are inputs to the 6d B pad on the device. The outputs of the pad are brought out on TL and RL. The 6d B pad is provided to loopback the transmit signal back to the receive without altering the equalizer settings. The 4 pole double throw relay shown in Figure 1 permits connection of the output of the transformer TR1 to either the equalizer or the fixed 6d B pad. For normal operation and transmission out to the line, the transformer...