73M1903C
Modem Analog Front End
DATA SHEET
JANUARY 2008
DESCRIPTION
The TERIDIAN 73M1903C Analog Front End
(AFE) IC includes fully differential hybrid driver
outputs, which connect to the telephone line
interface through a transformer-based DAA. The
receive pins are also fully differential for
maximum flexibility and performance. This
arrangement allows for the design of a high
performance hybrid circuit to improve signal to
noise performance under low receive level
conditions, and compatibility with any standard
transformer intended for PSTN communications
applications.
The device incorporates a programmable sample
rate circuit to support soft modem and DSP
based implementations of all speeds up to V.92
(56kbps). The sampling rates supported are from
7.2kHz to 16.0kHz by programming the pre-
scaler NCO and the PLL NCO.
The TERIDIAN 73M1903C device incorporates a
digital host interface that is compatible with the
serial ports found on most commercially available
DSPs and processors and exchanges both
payload and control information with the host.
This interface can be configured as a single
master/slave mode or as a daisy chain mode that
allows the user to connect up to eight 73M1903C
devices to a single host for multi Analog Front
End applications, such as, central server
modems.
Costs saving features of the device include an
input reference frequency circuit, which accepts a
range of crystals from 4.9-27MHz. It also accepts
external reference clock values between 1MHz-
40MHz generated by the host processor. In most
applications, this eliminates the need for a
dedicated crystal oscillator and reduces the bill of
materials (BOM).
The 73M1903C also supports two analog loop
back and one digital loop back test modes.
Features
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Two pairs of software selectable transmit
differential outputs for worldwide impedance
driver implementations.
Up to 56kbps (V.92) performance
Programmable sample rates (7.2-16.0kHz)
Reference clock range of 1-40MHz
Crystal frequency range of 4.9-27MHz
Master or slave mode operation and daisy
chain configurable synchronous serial Host
interface
Low power modes
Fully differential receiver and transmitter
Drivers for transformer interface
3.0V – 3.6V operation
5V tolerant I/O
Industrial temperature range (-40 to +85°C)
JATE compliant transmit spectrum
Package options: 32 pin QFN
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Applications
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Central site server modems
Set Top Boxes
Personal Video Recorders (PVR)
Multifunction Peripherals (MFP)
Fax Machines
Internet Appliances
Game Consoles
Point of Sale Terminals
Automatic Teller Machines
Speaker Phones
Digital Answering Machines
RF Modems
VBG
(HYBRID)
TXAP1
TXAN1
TXAP2
TXAN2
RXAP
RXAN
Transmit
Drivers/
Filters
Receiver
MUX/
Filters
Analog
Sigma
Delta
Ref.
SCLK
Control
Registers
SDIN
Serial
Port
SDOUT
FS
Control
Logic
FSD
DAC
GPIO
HOOK
DAA
controls
Clock
Crystal
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©
2005-2008 TERIDIAN Semiconductor Corporation
Rev 4.3
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
