CSP1034C-T11 Agere Systems, CSP1034C-T11 Datasheet - Page 3

• Manufacturer Part Number: CSP1034C-T11
• Description: Modem IC
• Manufacturer: Agere Systems

April 2005
Functional Description
Internal PLL for Low-Speed Crystal Support
OCM-22 supports low-speed, external crystals by
incorporating a PLL to support lower-cost crystals and
to ease the effort of minimizing EMI. If future code
needs higher clock rates, an internal multiplier can pro-
vide this without recertification or redesign of the exter-
nal hardware. OCM-22 requires an external 29.4912
MHz crystal or oscillator.
PWM Speaker Interface
The speaker driver employs a pulse-width modulated
algorithm, where 8-bit two's complement data is modu-
lated by a triangle wave. The following diagram shows
the recommended speaker configuration. This inex-
pensive configuration drives a low-impedance speaker
while obtaining a suitable volume. The SPKR signal is
fed to a transistor through a low-pass filter to remove
the carrier signal (cut-off frequency = 4 kHz).
Agere Systems Inc.
Figure 4. Lower-Impedance Speaker Configuration
(continued)
SPKR
Figure 3. Parallel Interface to DIA Port
ADDRESS
ADDR[1:0]
DECODE
DATA[7:0]
WRITEN
INTRPT
READN
3.3 kΩ
10 kΩ
One-Chip Modem for Embedded Applications
HD[7:0]
HA[1:0]
HRDN
HWRN
HINTR
HCSN
OCM-22 DEVICE
Power Requirements
Both the OCM-22 device and the CSP1034C are
manufactured in low-power CMOS technology and are
designed to operate using only a single 3.3 V supply.
During operation, OCM-22's on-chip PLL can be set to
provide only the minimum internal clock rate required.
The CSP1035A is also manufactured in low-power
CMOS technology. However, the CSP1035A is fully
line powered. A shunt regulator maintains a monitored
2.7 V supply, during off-hook conditions. If the voltage
falls below 2.2 V, the chip saves its registers and goes
into reset. This allows the CSP1035A to retain the reg-
ister settings during a call bridge where the tip/ring volt-
age can collapse to 0 V for up to 400 ms and start up
again at the completion of the call break.
6800 pF
+3.3 V
FDV301N
AT-08
5-8105 (F)
5-8104 (F) a
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