73M2901/3.3V
Advanced Single
Chip Modem
December 2000
DESCRIPTION
The 73M2901/3.3V 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; Sigma-
Delta 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 73M2901/3.3V provides an on-chip oscillator and
Hybrid driver.
The 73M2901/3.3V is a high performance, low
voltage, low power, single chip modem capable of
data transmission and reception through 2400bps.
The 73M2901/3.3V is intended for embedded
applications and battery operation. This device
offers low power 3.3 volt design with optional
internal hybrid and country specific call progress
support.
FEATURES
•
•
•
•
•
•
Low overall system chip count. True one
chip solution for embedded systems
Low operating power (~120mW @ 3.3V,
automatic low power standby and power
down options available)
Internal ROM and RAM for normal operation
On chip optional hybrid driver
Designed for +3.15 through +3.6 volts
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
•
•
•
•
•
•
•
•
BLOCK DIAGRAM
RAM
ASRCH
RING
DTR
TxCLK
TxD
RxD
RxCLK
ROM
CPU
AFE
MAC
Hybrid
RxA
TxAP
TxAP
RI
CTS
DCD
DSR
RTS
USR10
USR11
RELAY
HBDEN
73M2901/3.3V
Advanced Single
Chip Modem
HARDWARE DESCRIPTION
The 73M2901/3.3V is designed for a single +3.3 volt
supply with low power consumption (~120mW @ 3.3
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
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 50kΩ or larger), HBDEN should be pulled low.
The 73M2901/3.3V 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 73M2901/3.3V that the host has
requested the 73M2901/3.3V 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 73M2901/3.3V that the host is
passing data to the 73M2901/3.3V over the DTE
interface. This instructs the 73M2901/3.3V to begin
looking for valid “AT” commands. This pin needs to
be connected to the TXD pin.
RING
informs the 73M2901/3.3V that the external
DAA circuitry has detected a ring signal.
POWER SUPPLY
Power is supplied to the 73M2901/3.3V via the VPD
and VPA pins. The 73M2901/3.3V is designed for a
single +3.15 through +3.6 volt supply and for low
power consumption (~120mW @ 3.3 volts). Ground
Reference is provided at the VND and VNA pins.
LOW POWER MODE
The TDK 73M2901/3.3V supports a low power
mode. If the low power standby option is enabled
the 73M2901/3.3V 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 73M2901/3.3V) is requested
or when a reset occurs.
ANALOG LINE / HYBRID INTERFACE
The 73M2901/3.3V 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 line-
coupling transformer. If an external hybrid is to be
used, the on-chip hybrid drivers can be reconfigured
to drive a minimum load of 50kΩ and thus reduce
the driver’s power consumption.
2
CRYSTAL OSCILATOR
The TDK 73M2901/3.3V 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 73M2901/3.3V modem requires a parallel
mode
(antiresonant)
crystal,
the
important
specifications of which are as follows:
Mode:
Frequency:
Frequency tolerance:
Temperature drift:
Load capacitance:
ESR:
Drive level:
Parallel (antiresonant)
11.0592 MHz
±50
ppm
at
initial
temperature.
±50 ppm additional over full
Range.
18pF or 20pF
75Ω max.
Less than 1mW.
73M2901/3.3V
Advanced Single
Chip Modem
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 3µs. At
power on, the voltage at VPD, VPA, and RESET
must come up at the same time for a proper reset.
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%).
PIN DESCRIPTIONS
POWER PIN DESCRIPTION
PIN NAME
VPA
VNA
VPD
VND
32-PIN 44-PIN
15
21
6, 25,
29
5, 22,
26
16
22
2,12,
27, 33
11, 24,
44, 28
TYPE
I
I
I
I
DESCRIPTION
Positive analog voltage (+ Analog Supply)
Negative analog voltage. (Analog Ground)
Positive digital voltage (+ Digital Supply)
Negative digital voltage. (Digital Ground)
ANALOG INTERFACE PIN DESCRIPTION
PIN NAME
RXA
TXAN
TXAP
HBDEN
32-PIN 44-PIN
20
16
17
14
21
17
18
15
TYPE
I
O
O
I
DESCRIPTION
Receive analog data
Transmit Analog -
Transmit Analog +
2w/4w hybrid driver enable pin
0 = Driver configured for 50kΩ or greater load (Tie to VND)
1 = Driver configured for driving line-coupling transformer (Tie to
VPD)
VBG
VREF
19
18
20
19
O
O
Analog Band Gap voltage reference pin (0.1µF to VNA)
Analog reference voltage pin (0.1µF to VNA)
EXTERNAL INTERRUPTS PIN DESCRIPTIONS
PIN NAME
RING
ASRCH
DTR
32-PIN 44-PIN
2
1
32
39
38
37
TYPE
I
I
I
DESCRIPTION
External interrupt – Line interface ring detection circuitry input
External interrupt – Autobaud detection, connected to TXD
External interrupt – DTE DTR signal input
3
73M2901/3.3V
Advanced Single
Chip Modem
PIN DESCRIPTIONS
(continued)
OSCILLATOR PIN DESCRIPTION
PIN NAME
OSCIN
OSCOUT
32-PIN 44-PIN
24
23
26
25
TYPE
I
O
DESCRIPTION
Crystal input for internal oscillator, also input for external
source.
Crystal oscillator output.
DIGITAL INTERFACE PIN DESCRIPTION
PIN NAME
RESET
RXCLK
RXD
TXCLK
TXD
USR10
32-PIN 44-PIN
13
31
30
28
27
12
9
36
35
31
30
8
TYPE
I
O
O
O
I
I/O
DESCRIPTION
Resets 73M2901/3.3V
Receive Data Synchronous Clock
Serial output to DTE.
Transmit Data Synchronous Clock
Serial data input from DTE.
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.
Programmable I/O port. This pin can ooptionnaly be used to
control an external switch for Caller ID decoding operations.
Request to Send
Clear to Send
Data Set Ready
Data Carrier Detect
Ring Indicator
Relay driver output
USR11
RTS
(USR12)
CTS
(USR13)
DSR
(USR14)
DCD
(USR15)
RI
(USR16)
RELAY
(USR17)
11
10
9
8
7
4
3
7
6
5
4
3
43
40
I/O
I
O
O
O
O
O
4
73M2901/3.3V
Advanced Single
Chip Modem
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Operation above maximum rating may permanently damage the device.
PARAMETER
Supply Voltage
Pin Input Voltage
Storage Temperature
RECOMMENDED OPERATING CONDITIONS
PARAMETER
Supply Voltage
Oscillator Frequency
Operating Temperature
TRANSMITTER
PARAMETER
ITU Guard Tone Power
Calling Tone
Answer Tone Power
DTMF Transmit Power
CONDITIONS
550Hz (relative to carrier)
1800Hz (relative to carrier)
1300Hz
2225/2100Hz
High band tones
Low band tones
MIN
-5
-8
-11
-11
-8.0
-10
NOM
-3.5
-6.5
MAX
-2
-5
-9.0
-9.0
-6.0
-8.0
UNIT
dB
dB
dBm0
dBm0
dBm0
1
1
1
RATING
-0.5V to +7.0V
-0.5V to VPD + 0.5V
-55ºC to 150°C
RATING
3.15V – 3.6V
11.0592MHz +/- 50ppm
-40C to +85°C
MAXIMUM TRANSMIT LEVELS
Vref =1.25V; VPA = 3.3V
QAM
DPSK
FSK
DTMF (high tone)
DTMF (low tone)
DTMF (total)
-9.6
-7.4
-5.3
-7.9
-9.8
-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 (475Ω resistor), transformer, and solid state off-hook relay.
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
rms
. dBm = 10log {Vrms
2
/[(1mW)(600Ω)]}
1
5
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