ds22-l100-041 Conexant Systems, Inc., ds22-l100-041 Datasheet - Page 13

• Manufacturer Part Number: ds22-l100-041
• Description: Cx84100-41/-23 Scxv.22bis Modem V.22bis Modem With Cx20493 Smartdaa? Line Side Device
• Manufacturer: Conexant Systems, Inc.

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102339C
Hardware Description
CX84100 V.22bis Modem
Digital Isolation Barrier
CX20493 SmartDAA Line Side Device
SmartDAA technology (patent pending) eliminates the need for a costly analog
transformer, relays, and opto-isolators that are typically used in discrete DAA
implementations. The programmable SmartDAA architecture simplifies product
implementation in worldwide markets by eliminating the need for country-specific
components.
The CX84100 V.22bis Modem, packaged in a 28-pin TSSOP, includes a Microcontroller
(MCU), internal ROM code, internal RAM, and SmartDAA interface functions.
The modem connects to the host via a logical V.24 (EIA/TIA-232-E) serial DTE
interface.
The modem performs the command processing and host interface functions. The crystal
or clock input frequency is 28.224 MHz.
The modem performs telephone line signal modulation/demodulation in a hardware
digital signal processor (DSP) which reduces computational load on the host processor.
The SmartDAA Interface communicates with, and supplies power and clock to, the LSD
through the DIB.
The OEM-supplied Digital Isolation Barrier (DIB) electrically DC isolates the CX84100
V.22bis Modem from the CX20493 LSD and telephone line. The CX84100 V.22bis
Modem is connected to a fixed digital ground and operates with standard CMOS logic
levels. The LSD is connected to a floating ground and can tolerate high voltage input
(compatible with telephone line and typical surge requirements).
The DIB transformer couples power and clock from the CX84100 V.22bis Modem to the
CX20493 LSD.
The DIB data channel supports bidirectional half-duplex serial transfer of data, control,
and status information between the CX84100 V.22bis Modem and the CX20493 LSD
over two lines.
The CX20493 SmartDAA Line Side Device (LSD) includes a Line Side DIB Interface
(LSDI), a coder/decoder (codec), and a Telephone Line Interface (TLI).
The LSDI communicates with, and receives power and clock from, the SmartDAA
interface in the CX84100 V.22bis Modem through the DIB.
LSD power is received from the CX84100 PWRCLKP and PWRCLKN pins via the DIB
through a half-wave rectifying diode and capacitive power filter circuit connected to the
DIB transformer secondary winding.
The CLK input is also accepted from the DIB transformer secondary winding through a
capacitor and a resistor in series.
CX84100-41/-23 SCXV.22bis Modem Data Sheet
Conexant
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