Datasheet

73M1866B/73M1966B Data Sheet DS_1x66B_001
6 Rev. 1.6
1 Introduction
The 73M1966B is a two-device chip set that provides embedded FXO functionality by connecting a PCM
interface to a voice-band PSTN. The device set supports ITU-T Recommendation G.711 µ-law and A-law
companding, and also a 16-bit linear mode. High-voltage isolation is provided by the physical separation
of the Host-Side (73M19106) and Line-Side (73M1916) Devices. The Host-Side and the Line-Side
Devices communicate with each other using a single pulse transformer. A few low-cost components
complete the DAA interface to the network. The pulse transformer transmits encoded digital data rather
than analog signals as with other transformer designs. Data is transmitted and received without the usual
degradation from common mode noise and magnetic coupling typical of other capacitive and voice-band
transformer techniques. The data stream passed between the Host-Side and Line-Side Devices includes
the media stream data, control, status, and clocking information.
This data sheet describes both the 73M1966B and 73M1866B, which will be collectively referred to as the
73M1x66B in this document.
A unique capability of the 73M1x66B Host Side device (73M1906B) is its ability to provide power to the
73M1x66B Line Side device (73M1916) via the pulse transformer.
The 73M1906B exchanges control and status information with the host using the SPI interface, while the
PCM encoded media streams connect with other PCM-enabled devices using the PCM highway bus
interface.
Figure 1 shows a reference block diagram of the 73M1x66B connected by a pulse transformer and
example external line interface circuitry shown for clarification.
PRM SCM
(LSBI)
SinC3
Filter
On-Chip
LIC
(OnLIC)
SPI
Interface
PCM
Interface
Interpolation
Filter
Filter
PCM
SPI
Tip
Ring
PRP SCP
Host -Side Device
73M1906B
Line-Side Device
73M1916
Aux A/D
TxA
RxA
Off-Chip
LIC
(OffLIC)
(HSBI)
Decimation
Transmit
Receive
Host
Interface
Side
Barrier
Interface
Side
Barrier
Line
Digital
Sigma
Delta
Modulator
Transmit
Analog
Front End
Receive
Analog
Front End
(with Sigma
Delta
Modulator)
Call Progress Monitor Audio Out
Figure 1: Simple 73M1x66B Reference Block Diagram
The Host-Side Device (73M1906B) consists of:
1. PCM Interface Block (PCM)
2. SPI Interface Block (SPI)
3. Transmit Interpolation Filter
4. Receive Decimation Filter
5. Host-Side Barrier Interface Circuit (HSBI)