CR2010-2W-1071F 데이터 시트보기 (PDF) - Silicon Laboratories
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CR2010-2W-1071F Datasheet PDF : 36 Pages
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Si2493/57/34/15/04
Global ISOmodem-EVB
2.1.9. Direct Access Interface
While the motherboard supplies power through J8, J9,
or USB, power-on reset, and an RJ–11 jack for the
modem, the direct access interface (J103) is used to
connect the motherboard to an embedded system. J103
provides access to all Si2493/57/34/15/04 signals
available on the daughter card.
It is necessary to remove the jumper on JP23 to disable
both the RS-232 and USB interface and prevent signal
contention.
2.1.10. PCM Interface (24-Pin FT Only)
The Si2493/57/34/15/04 PCM interface can be
demonstrated using the voice motherboard, not with this
EVB.
2.1.11. AOUT Call Progress Audio Output
Call progress audio output is provided by the Si2493/57/
34/15/04 on the AOUT pin as a PWM signal. This signal
allows the user to monitor call progress signals, such as
dial tone, DTMF dialing, ring, busy signals, and modem
negotiation. Control of this signal is provided by AT
commands and register settings described in the
introduction. The AOUT signal is connected to an on
board amplifier, for a high-quality output. AOUT can
also be connected to a summing amplifier or multiplexer
in an embedded application as part of an integrated
audio system.
2.1.11.1. AOUT Audio Processing
The AOUT signal discussed in this section leaves the
Si2493/57/34/15/04 is processed (demodulated) by a
high pass filter: (R133,134,135, and C24, C25, 26,
C27). It is critically important to not put a dc load on the
AOUT pin since the pin also acts as a modem feature
control on reset and is internally weakly pulled up. Any
unintentional dc load on AOUT prevents proper
operation of the modem. See “AN93: Si3457/34/15/04
Modem Designer’s Guide” for more details on the
features controlled by pin strapping.
Since this PWM signal swings rail to rail and is simply
filtered by a low pass filter to acquire the audio. It is
important to keep the power supply to the modem free
of noise in the audio spectrum.
2.1.11.2. The Audio Output Amplifier (LM4819)
The Power amplifier on the EVB is powered by a current
limited 4.2 V supply. The current limit is implemented in
the EVB because it is intended for HW/SW
development and is not needed for a production design.
This amplifier can drive an 8 speaker with 200 mW of
Call progress audio (i.e., ISOmodem's call progress
dialing and negotiation tones).
The power amplifier itself is a low cost, rugged H bridge
type device. There are several pin compatible designs
from multiple vendors that can provide alternate price/
power tradeoffs for this amplifier. This power amp can
be shut down by removing jumper JP12. The signal at
JP12 can also be tied to a control signal to allow the
host to shut down the amplifier. The customer can
change the values of R172 and R173 when integrating
the EVB to his system, but should keep the RC formed
by C37 and R173 at a 50 Hz or higher corner to avoid a
power-on thump.
2.1.11.3. The Call Progress Speaker
The Call progress speaker, Regal RE-2308-NL is
connected to the amplifier via a jumper, JP14. If another
speaker is to be connected then it is necessary to
remove JP14 and connect the external speaker to JP11,
Pins 1 and 4. It is important to remember that the
speaker signal is differential. Both the output pins are
driven outputs and must not be grounded.
Table 3. DB9 Pin Connections
J1 Name
J1 Symbol
Carrier Detect
Received Data
Transmit Data
Data Terminal Ready
Signal Ground
Data Set Ready
Ready to Send
Clear to Send
Ring Indicator
*Note: JP6 jumper option.
CD
RXD
TXD
DTR
SG
DSR
RTS
CTS
RD
J1 Pin
1*
2
3
4*
5
6*
7*
8
9*
Si2493/57/34/15/ Si2493/57/34/15/
04 Pin
04 Name
See note
DCD/EESD
9
RXD
10
TXD
See note
ESC/RI
6
GND
See note
INT/AOUT
See note
RTS/RXCLK
11
CTS
17
RI
10
Rev. 0.7
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