CH1837F ETC1 [List of Unclassifed Manufacturers], CH1837F Datasheet - Page 5

• Manufacturer Part Number: CH1837F
• Description: CH1837A/7F/8A Data Access Arrangement Module V.34bis High Speed DAA Module
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

2002 Cermetek Microelectronics, Inc.
Cermetek Microelectronics, Inc.
Note:
1. When answering incoming calls in response to a ring indication on RI, internal degradation may occur if OFFHK
2. For CH1837A, the RI output is 2X the frequency of the incoming ring signal.
3. For CH1837F, the RI output is 1X the frequency of the incoming ring signal.
Note:
1. When answering incoming calls in response to a ring indicator on RI, internal degradation may occur if OFFHK
PIN
PIN
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
is set HIGH before RI returns to its HIGH state.
is set HIGH before RI returns to its HIGH state.
N/C
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
O
I
I
I
I
I
I
I
I
CH1837A/F
CH1838A
XMIT(+)
OFFHK
XMIT(-)
OFFHK
RING
GND
RCV
RING
GND
TIP
V
N/C
TIP
V
RI
T1
T2
RI
CC
CC
TIP. Direct PSTN line connection.
RING. Direct PSTN line connection.
OFF-HOOK. Used to toggle CH1837A/F product between On-Hook and Off-Hook.
When set LOW, CH1837A/F is On-Hook. When set HIGH, CH1837A/F is set Off-
Hook to answer or place a call. See Note 1.
RING INDICATION. Indicates the presence of a ring signal between TIP and RING
pins. RI output is a square wave coincident with the incoming AC ring signal. The
RI square wave output can be conditioned to produce an envelope of the incoming
AC ring signal by using the circuit in Figure 4. See Notes 2 and 3.
RECEIVE. Audio output signal with respect to GND. AC couple RCV through
0.1µF capacitor to eliminate any DC offset.
TRANSMIT(+).
CH1837A/F can be used in differential mode with XMIT(+) or in single ended mode
with respect to GND.
POWER SUPPLY. +5V±5%. Supply line noise should be less than 50mV peak to
peak.
TRANSMIT(-). Audio input signal for CH1837A/Fwhen used in differential mode
only. Connect to GND through 0.1µF capacity when CH1837A/F used in single
ended input via PIN 8.
GROUND. Supply line noise should be less than 50mV peak to peak.
TIP. Direct PSTN line connection.
RING. Direct PSTN line connection.
OFF-HOOK. Used to toggle CH18378 product between On-Hook and Off-Hook.
When set LOW, CH1838 is On-Hook. When set HIGH, CH1838 is set Off-Hook to
answer or place a call. See Note 1.
RING INDICATION. Indicates the presence of a ring signal between TIP and
RING pins. RI output is a square wave coincident with the incoming AC ring
signal. The RI square wave output can be conditioned to produce an envelope of
the incoming AC ring signal by using the circuit in Figure 4. The RI output is 2X
the frequency of the incoming ring signal.
RECEIVE. Audio input and output signal with respect to T2.
AUDIO INPUT/OUTPUT. Internally not connected. Either let float or connect to
GND.
POWER SUPPLY. +5V±5%. Supply line noise should be less than 50mV peak to
peak.
AUDIO INPUT/OUTPUT. Audio input and output signal with respect to T1.
GROUND. Supply line noise should be less than 50mV peak to peak.
Table 1. CH1837A/F Pin Description.
Table 2. CH1838A Pin Description.
Audio input signal.
Page 5
FUNCTION
FUNCTION
AC couple through 0.1µF capacitor.
CH1837A/7F/8A Data Access Arrangement Module
Document No. 607-0014 Revision C2 (12/02)
The