CH1840D ET Cermetek Microelectronics, CH1840D ET Datasheet - Page 5

• Manufacturer Part Number: CH1840D ET
• Manufacturer: Cermetek Microelectronics

Specifications of CH1840D ET

• Operating Temperature Classification: Industrial
• Pin Count: 12
• Lead Free Status / RoHS Status: Supplier Unconfirmed

Cermetek Microelectronics, Inc.
SAMPLE APPLICATION
Figure 2 illustrates a typical application of the CH1840.
When transmitting data the controller must assert the
D/V pin low to provide the two second billing delay
required by the FCC. When transmitting voice signals,
the controller shoud drive the D/V pin high.
disavles the billing delay, and power squelch
One of the requirements of an FCC approved DAA is
that the signal transmitted to Tip and Ring does not
exceed –9.0 dBm.
automatic squelch
CH1840-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 CH1840-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 CH1840 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
©2009 Cermetek Microelectronics, Inc.
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
isolation
and
The CH1840 incorporates an
protection.
The
FCC
This
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5. The DAA Module is a sensitive subsystem that
6. For data calls, Part 68 rules require silence on the
MOUNTING THE CH1840
The CH1840 can be soldered directly to the host
circuit card or installed in sockets. Direct soldering
provides the most sound connection. To avoid the
problems of flux contamination, hand soldering is
preferred
manufacturers offer socket strips that accept the 0.025
inch square pins on 0.10 inch centers. When using
sockets mechanical restraint of the CH1840 should be
provided to keep it seated during shipment. Plastic
cable wraps are secure yet easily removed.
The DAA module contains static sensitive devices and
should be handled by personnel and in areas that are
properly protected against static discharge.
There
recommended for physically connecting the module to
your circuit card; 1) sockets, and 2) direct soldering.
Each approach has its own set of benefits and
challenges.
If the DAA module is wave soldered on a circuit card,
please use washless flux or hand solder. This part is
not hermetically sealed. Water or chemical intrusion
into the case can cause malfunction and void the
warranty.
induced coupling with other signals on the host
circuit card.
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.
are
Energy,
to
be
isolation
two
the
wave
treated
Pay special attention to the power
CH1840 Family of Low Profile DAA Modules
Document No. 607-0011 Revision C (09/09)
mounting
CH1840
and
and
soldering.
as
DTMF
Surge
any
already
techniques
Transmit
other
Protection,
Many
meets
integrated
that
Levels.
socket
FCC
are
the