TDK 73M2901-5V User Manual

73M2901/5V

®

TDK SEMICONDUCTOR CORP.

DESCRIPTION

The 73M2901/5V is a single-chip modem that
combines all the controller (DTE) and data pump
functions necessary to implement an intelligent
V.22bis data modem. This device is based on TDK
Semiconductor’s implementation of the industry
standard 8032 microcontroller core with a proprietary
multiply and accumulate (MAC) coprocessor; Sigma­Delta A/D and D/A converters; and an analog front
end. The ROM and RAM necessary to operate the
modem are contained on the device. Additionally,
the 73M2901/5V provides an on-chip oscillator and
Hybrid driver.

The 73M2901/5V is a high performance, low
voltage, low power, single chip modem capable of
data transmission and reception through 2400bps.
The 73M2901/5V is intended for embedded
applications and battery operation. This device
offers options for a low power conventional 5 volt
design with optional internal hybrid and country
specific call progress support.

Advanced Single

Chip Modem

August 2001

FEATURES

· Low overall system chip count. True one

chip solution for embedded systems

· Low operating power (~250mW @ 5V,

automatic low power standby and power
down options available)

· Internal ROM and RAM for normal operation

· On chip optional hybrid driver

· Designed for +5 volts (+/-10%)

· Data speeds:

V.22bis – 2400bps
V.22, Bell 212 – 1200bps
V.21, Bell 103 – 300bps
V.23 – 1200/75bps (w/ turnaround (PAVI))
Bell 202 – 1200bps
Bell 202 and V23 4-wire operations

· Dynamic Range: -9dBm to –43 dBm

· “AT” command set

· Host access to modem port pins via AT

commands for custom I/O expansion

· DTMF tone generation and detection

· Call progress support with multinational

options (FCC68, CTR21, JATE…)

· Caller ID capability

· Blacklisting capability

· Packaging: 32 pin PLCC or 44 pin TQFP

ASRCH

RING

DTR

TxCLK

TxD

RxD

RxCLK

RI
CTS
DCD
DSR
RTS

BLOCK DIAGRAM

RAM

CPU

AFE

USR10
USR11

RELAY

ROM

HBDEN

MAC

Hybrid

RxA
TxAP
TxAP

73M2901/5V
Advanced Single
Chip Modem

HARDWARE DESCRIPTION

The 73M2901/5V is designed for a single +5 volt
supply with low power consumption (~250mW @ 5
volts). The modem supports automatic standby idle
mode. The modem will also accept a request to
power down from the DTE via hardware control. No
additional major components are required to
complete the modem core logic. The modem
provides direct firmware LED support via port pins.

HARDWARE FEATURES

· Fully self-contained. “AT” Command interpreter
and data pump

· User pin available

· Synchronous serial data I/O available

· Asynchronous serial port

· On-chip hybrid driver.

· Autobaud capability from 300bps to 9600bps

POWER SUPPLY

Power is supplied to the 73M2901/5V via the VPD and
VPA pins. The 73M2901/5V is designed for a single
+5 (+/-10%) volt supply and for low power consumption
(~250mW @ 5 volts). Ground Reference is provided
at the VND and VNA pins.

LOW POWER MODE

The TDK 73M2901/5V supports a low power mode.
If the low power standby option is enabled the
73M2901/5V will go into a power saving mode when
idle. The oscillator will be running, clocks will be
supplied to the UART, timers and interrupt blocks;
but no clocks will be supplied to the CPU. Instruction
processing and activity on the internal busses is
halted. Normal operation is resumed when an
interruption such as DTR, RING or ASRCH (any
character send to the 73M2901/5V) is requested or
when a reset occurs.

ANALOG LINE / HYBRID INTERFACE

The 73M2901/5V provides a differential analog
output (TXAP and TXAN) and a single-ended analog
input (RXA) with internal A/D and D/A converters. A
driver is provided for an internal hybrid function.

The internal hybrid driver is capable of driving an
external load matching impedance and a line­coupling transformer. If an external hybrid is to be
used, the on-chip hybrid drivers can be reconfigured
to drive a minimum load of 50kW and thus reduce
the driver’s power consumption.

The hybrid configuration is controlled by the state of
the HBDEN pin. For driving a line-coupling
transformer, HBDEN should be pulled high. For
driving an external hybrid (load on TXAP and TXAN
is 50kW or larger), HBDEN should be pulled low.

The 73M2901/5V provides firmware control for a
hook relay driver (RELAY) as well as interrupt
support for a ring detect opto-coupler (RING).

INTERRUPT PINS

The external interrupt sources, DTR, ASRCH and RING,
come from dedicated input pins of the same name.

DTR informs the 73M2901/5V that the host has
requested the 73M2901/5V perform a specific
function. The actual particulars of that function can
be changed by “AT” commands (described in full in
the TDK 73M2901 User’s Guide).

ASRCH informs the 73M2901/5V that the host is
passing data to the 73M2901/5V over the DTE
interface. This instructs the 73M2901/5V to begin
looking for valid “AT” commands. This pin needs to
be connected to the TXD pin.

RING informs the 73M2901/5V that the external
DAA circuitry has detected a ring signal.

CRYSTAL OSCILATOR

The TDK 73M2901/5V single chip modem can use
an external 11.0592 MHz reference clock or can
generate such a clock using only a crystal and two
capacitors. If an external clock is used, it should be
applied to OSCIN.

SPECIFYING A CRYSTAL

The manufacturer of a crystal resonator verifies its
frequency of oscillation in a test set-up, but to
ensure that the same frequency is obtained in the
application, the circuit conditions must be the same.
The TDK 73M2901/5V modem requires a parallel
mode (antiresonant) crystal, the important
specifications of which are as follows:

Mode: Parallel (antiresonant)
Frequency: 11.0592 MHz
Frequency tolerance: ±50 ppm at initial

temperature.

Temperature drift: ±50 ppm additional over full

Range.
Load capacitance: 18pF or 20pF
ESR: 75W max.
Drive level: Less than 1mW.

2

Advanced Single

RESET

A reset is accomplished by holding the RESET pin
high. To ensure a proper power-on reset, the reset
pin must be held high for a minimum of 3m s. At
power on, the voltage at VPD, VPA, and RESET
must come up at the same time for a proper reset.

PIN DESCRIPTIONS

POWER PIN DESCRIPTION

PIN NAME 32-PIN 44-PIN TYPE DESCRIPTION

VPA 15 16 I Positive analog voltage (+ Analog Supply)
VNA 21 22 I Negative analog voltage. (Analog Ground)
VPD 6, 25,

29

VND 5, 22,

26

2,12,

27, 33

11, 24,

44, 28

I Positive digital voltage (+ Digital Supply)

I Negative digital voltage. (Digital Ground)

ASYNCHRONOUS AND SYNCHRONOUS SERIAL
DATA INTERFACE

The serial data interface consists of the TXD and
RXD data paths (LSBit shifted in and out first,
respectively); and the TXCLK and RXCLK serial
clock outputs associated with the data pins;
CTS/RTS flow control; DCR, DSR and DTR. In
synchronous mode, the data is passed at the bit rate
(tolerance is +1%, -2.5%).

73M2901/5V

Chip Modem

ANALOG INTERFACE PIN DESCRIPTION

PIN NAME 32-PIN 44-PIN TYPE DESCRIPTION

RXA 20 21 I Receive analog data
TXAN 16 17 O Transmit Analog ­TXAP 17 18 O Transmit Analog +
HBDEN 14 15 I 2w/4w hybrid driver enable pin

0 = Driver configured for 50kW or greater load (Tie to VND)
1 = Driver configured for driving line-coupling transformer (Tie to

VPD)
VBG 19 20 O
VREF 18 19 O

Analog Band Gap voltage reference pin (0.1m F to VNA)

Analog reference voltage pin (0.1m F to VNA)

EXTERNAL INTERRUPTS PIN DESCRIPTIONS

PIN NAME 32-PIN 44-PIN TYPE DESCRIPTION

RING
ASRCH
DTR

2
1

32

39
38
37

I

External interrupt – Line interface ring detection circuitry input

I

External interrupt – Autobaud detection, connected to TXD

I

External interrupt – DTE DTR signal input

3

73M2901/5V
Advanced Single
Chip Modem

PIN DESCRIPTIONS (continued)

OSCILLATOR PIN DESCRIPTION

PIN NAME 32-PIN 44-PIN TYPE DESCRIPTION

OSCIN 24 26 I Crystal input for internal oscillator, also input for external

source.
OSCOUT 23 25 O Crystal oscillator output.

DIGITAL INTERFACE PIN DESCRIPTION
PIN NAME 32-PIN 44-PIN TYPE DESCRIPTION

RESET 13 9 I Resets 73M2901/5V
RXCLK 31 36 O Receive Data Synchronous Clock
RXD 30 35 O Serial output to DTE.
TXCLK 28 31 O Transmit Data Synchronous Clock
TXD 27 30 I Serial data input from DTE.
USR10 12 8 I/O This pin can optionally be configured as an active low detect

pin. This can be used to implement such functions as “parallel-

pick-up”, “line-in-use”, or “seize” detect.

USR11 11 7 I/O Programmable I/O port. This pin can ooptionnaly be used to

control an external switch for Caller ID decoding operations.

RTS (USR12) 10 6 I Request to Send
CTS (USR13) 9 5 O Clear to Send
DSR (USR14) 8 4 O Data Set Ready
DCD (USR15) 7 3 O Data Carrier Detect
RI (USR16) 4 43 O Ring Indicator
RELAY (USR17) 3 40 O Relay driver output

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73M2901/5V

Advanced Single

Chip Modem

ELECTRICAL SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS
Operation above maximum rating may permanently damage the device.

PARAMETER RATING

Supply Voltage -0.5V to +7.0V
Pin Input Voltage -0.5V to VPD + 0.5V
Storage Temperature -55ºC to 150°C

RECOMMENDED OPERATING CONDITIONS

PARAMETER RATING

Supply Voltage +5.0V (+/-10%)
Oscillator Frequency 11.0592MHz +/- 50ppm
Operating Temperature -40C to +85°C

TRANSMITTER

PARAMETER CONDITIONS MIN NOM MAX UNIT

ITU Guard Tone Power 550Hz (relative to carrier)

1800Hz (relative to carrier)
Calling Tone 1300Hz -11 -9.0 dBm01
Answer Tone Power 2225/2100Hz -11 -9.0 dBm01
DTMF Transmit Power High band tones

Low band tones

-5

-8

-8.0

-10

-3.5

-6.5

-6.0

-2

-5

-8.0

dB
dB

dBm01

1

dBm0 refers to the TDK recommended DAA ( 8dB loss from Transmit pins to the line and 5dB loss from the line to the Receive pin). Results

may vary depending on selected DAA. 0dBm = 0.775V

. dBm = 10log {Vrms2/[(1mW)(600O)]}

rms

5

73M2901/5V
Advanced Single
Chip Modem

ELECTRICAL SPECIFICATIONS (continued)

MAXIMUM TRANSMIT LEVELS

Vref=2.25V; VPA=5.0V
Transmit type Maximum differential line

QAM -5.5
DPSK -3.4
FSK -1.2
DTMF (high tone) -6.0
DTMF (low tone) -8.0
DTMF (total) -3.9
Vref=1.25V; VPA=5.0V

level (dBm0)

QAM -9.6
DPSK -7.4
FSK -5.3
DTMF (high tone) -7.9
DTMF (low tone) -9.8
DTMF (total) -5.7

Note: The recommended DAA (see the TDK 73M2901 Reference Manual) will result in approximately 8dB loss from the transmit pins to the
phone line. This includes the loss through the line matching impedance (475W resistor), transformer, and solid state off-hook relay.

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