ch1817lm ETC-unknow, ch1817lm Datasheet - Page 4

• Manufacturer Part Number: ch1817lm
• Description: Family Of Low Profile Daa Modules
• Manufacturer: ETC-unknow

¤2002 Cermetek Microelectronics, Inc.
Cermetek Microelectronics, Inc.
CH1817-L: LOW POWER
The L Family is a Low Power version of the CH1817
DAA.
through V cc . When On-Hook, the L Family can be
configured so that the Ring Detection circuit can be
activated by a pull-up resistor on RI while V cc has
been disconnected from the power supply, thus
making the On-Hook power consumption virtually zero
(See Figure 4).
CH1817-D: 0 dB XMIT ATTENUATION
The D option has 0.0 dB insertion loss (typical) with
respect to a differential input between XMIT (-) and
XMIT (+). This allows the maximum signal strength of
–9dBm to be input while maintaining FCC compliance.
To use the CH1817-D as single end input device,
ground the XMIT (-) pin through a 0.1uF capacitor.
MOUNTING THE DAA
The DAA can be soldered directly to the host circuit
card or installed in sockets. To avoid the problems of
contamination, hand soldering is preferred to wave
soldering. When hand cleaning use only deionized
water; when wave soldering use washless flux.
DESIGN CONSIDERATIONS
The CH1817 DAA includes circuits that couple the
modem signals to the phone line and provides FCC
required
registration process by the host product can be
minimized provided that the following guidelines are
followed.
1. The mounting of the DAA in the final assembly
2. Connection to the phone line should be made
3. Circuit board traces from the DAA’s TIP and RING
4. TIP and RING traces should be as short as
must be made so that it is isolated from exposure to
any hazardous voltages within the assembly.
Adequate separation and restraint of cables and
cords must be provided.
through a standard FCC approved RJ-11C jack or
equivalent.
pins must exceed 0.1 inch spacing from all other
traces or other conducting material. The purpose
for this pacing is to maintain 1000 VAC isolation
between the phone line and the other traces.
Traces should have a nominal width of 0.020
inches or greater.
possible and should be oriented to prevent direct or
induced coupling with other signals on the host
circuit card.
When Off-Hook, this DAA draws only 4mA
isolation
and
protection.
The
FCC
Page 4
5. The DAA Module is a sensitive subsystem that
6. For data calls, Part 68 rules require silence on the
7. The CH1817 DAA as is meets or exceeds the
should
component.
supply to the DAA. The device handles signals in
the millivolt range. Even though it is designed to
handle noise in the power supply, steps should be
taken to assure the noise level does not exceed
50mV peak-peak.
phone line for at least 2 seconds after a data call
has been completed to allow central offices to
exchange billing information and specifies the
transmit level must not exceed -9dBm. The FCC
rules also require that for voice calls the final
system meet the requirements of Part 68 for Out-of
Band
Because
requirements for Part 68 registration for High
Voltage
certification of the product is normally a simple
process that often can be completed directly with
the FCC. If desired, independent testing labs are
available that can test the system and submit the
required paperwork to the FCC for approval.
Cermetek can assist with the registration.
hazardous
requirements of the FCC.
connect to Canadian phone lines, governed by the
DOC (Department of Communications) and to
further protect the CH1817 from field failure on
excessively poor quality lines and to maintain UL
recognition, a higher level of transient protection is
required, thereby making mandatory the circuit
consisting of two fuses and one varistor as shown
in Figure 3. Adding these three devices will not
affect FCC registration. Components L1, L2, C1,
C2 are optional and serve two purposes. First, they
restrict high frequency signals from reaching the
phone line and thereby add EMI protection.
Second, they protect against externally generated
RFI from degrading the modem’s ability to operate
on proper carrier signals. Adding these devices will
not affect FCC, DOC, or UL registration.
Energy,
be
isolation
the
treated
Pay special attention to the power
voltage,
CH1817 Family of Low Profile DAA Modules
Document No. 607-0007 Revision B (01/02)
CH1817
and
and
as
DTMF
surge
Surge
any
already
For applications that
Transmit
other
Protection,
and
meets
integrated
leakage
Levels.
FCC
the