Document
MH88524
®
Dual 2-4 Wire Circuit Preliminary Information
Features
• • • • • • Full duplex operation Two complete circuits per package Transformerless 2-4 Wire (4-2 Wire) conversion + 5V operation Wide bandwidth (50kHz) Small Package Size MH88524
ISSUE 4
April 1995
Ordering Information 10 Pin SIL Package 0° C to 70° C
Description
The Mitel MH88524 (Dual 2-4 wire Circuit) provides two independent interfaces between4-Wire devices such as the MH88631 COIC (Central Office Interface CIrcuit) and a speech switch such as the MT8814 (Analog Switch Array), requiring only a single bidirectional switch per crosspoint. The MH88524 can accommodate two full duplex audio links. The device is fabricated as a thick film hybrid which incorporates various technologies for optimum circuit design and very high reliability.
Applications
4-2 Wire and 2-4 Wire conversion for: • • • • • • • • • MH88630/631, MH88632, MH88500 & MT8840 PBX Key Telephone System Channel bank Voice Mail Terminal Equipment Digital Loop Carrier Modem Intercom
RX1
Receive Gain Circuit1 2-4 Wire Circuit 1 JUN1
TX1
Transmit Gain Circuit 1
RX2
Receive Gain Circuit 2
2-4 Wire Circuit 2
JUN2
TX2
Transmit Gain Circuit 2
VDD
VEE
AGND
Figure 1 - Functional Block Diagram
2-73
MH88524
Preliminary Information
RX1 JUN1 TX1 VDD AGND VEE IC TX2 JUN2 RX2
1 2 3 4 5 6 7 8 9 10
Figure 2 - Pin Connections
Pin Description
Pin # 1 2 3 4 5 6 7 8 9 10 Name RX1 JUN1 TX1 VDD AGND VEE IC TX2 JUN2 RX2 Description Receive 1 (Input). 4-Wire ground (AGND) referenced audio output. Junctor 1 (Transmit and Receive). Ground referenced transmit and receive speech path. Transmit 1. 4-Wire ground (AGND) referenced audio output. Positive Supply Voltage. Typically +5V. Analog Ground. 2-Wire and 4-Wire ground. Normally connected to System Ground. Negative Supply Voltage. Typically -5V. Internal Connection. This pin is internally connected. Transmit 2 (Output). 4-Wire ground AGND) referenced audio output. Junctor 2 (Transmit and Receive). Ground referenced transmit and receive speech path. Receive 2 (Input). 4-Wire ground (AGND) referenced audio output.
Absolute Maximum Ratings*
Parameter 1 2 DC Supply Voltage Storage Temperature Sym VDD VEE TS Min -0.3 +0.3 -55 Max 15 -15 125 Units V V °C Comments With respect LGND
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions
Parameter 1 2 DC Supply Voltage Operating Temperature Sym VDD VEE TOP Typ* 5.0 -5.0 Min 4.75 -4.75 0 Max 10 -10 70 Units V V °C Comments
* Typical figures are at 25° C with nominal +5V supplies and are for design aid only.
2-74
Preliminary Information
DC Electrical Characteristics ‡
Characteristics 1 2 Supply Current Power Dissipation Sym IDD PEE PC Min Typ* Max 4 4 40 Units mA mW
MH88524
Test Conditions VDD = +5.0 VEE = 5.0 VDD = +5.0 VEE = 5.0
‡ DC Electrical Characteristics are over recommended operating conditions unless otherwise stated. * Typ.