cx20493-35/app Conexant Systems, Inc., cx20493-35/app Datasheet - Page 58
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cx20493-35/app
Manufacturer Part Number
cx20493-35/app
Description
With Cx20493 Smartdaa?
Manufacturer
Conexant Systems, Inc.
Datasheet
1.CX20493-35APP.pdf
(92 pages)
Table 3-8. CX20493 LSD Pin Signal Definitions (Continued)
3-26
RAC1
TAC1
RAC2
TAC2
EIC
TRDC
EIO
DC_GND
EIF
RXI
RBias
VZ
TXO
TXF
GPIO1
NC
Notes:
1. I/O types*:
2. Refer to applicable reference design for exact component placement and values.
Label
CX81801-7x/8x SmartV.XX Modem in 128-Pin LQFP with CX20493 in 32-Pin LQFP Data Sheet
Ia
It
Oa
Ot12
AGND_LSD
GND_LSD
*See CX20493 LSD GPIO DC Electrical Characteristics (Table 3-9)
24
23
22
21
12
13
20
1, 9,
16, 18,
25
19
10
6
11
15
14
32
17
Pin
Analog input
Digital input, TTL-compatible
Analog output
Digital output, TTL-compatible, 12 mA, Z INTERNAL = 32 Ω
Isolated LSD Analog Ground
Isolated LSD Digital Ground
GND
I/O
I/O
O
O
O
I
I
I
I
I
I
I
I
I
I
AGND_LSD
I/O Type
It/Ot12
Oa
Oa
Oa
Ia
Ia
Ia
Ia
Ia
Ia
Ia
Ia
Ia
Ia
TIP and RING Interface
RING1 AC Coupled and TIP1 AC Coupled. AC-coupled voltage from
telephone line used to detect ring.
Connect RAC1 to the diode bridge AC node (RING) through R902
(connects to pin 24) and C902 in series.
Connect TAC1 to the diode bridge AC node (TIP) through R904
(connects to pin 23) and C904 in series.
RING2 AC Coupled and TIP2 AC Coupled. AC-coupled voltage from
telephone line used to optionally detect signal while on-hook.
Connect RAC2 to the diode bridge AC node (RING) through R948
(connects to pin 22) and C948. Leave open if not used.
Connect TAC2 to the diode bridge AC node (TIP) through R946
(connects to pin 21) and C946. Leave open if not used.
Electronic Inductor Capacitor Switch. Internally switched to TRDC
when pulse dialing. Connect to AGND_LSD through C958.
TIP and RING DC Measurement. Input on-hook voltage (from a resistive
divider). Used internally to extract TIP and RING DC voltage and Line
Polarity Reversal (LPR) information. R906 and C918 must be placed
very close to pin 13 (TRDC).
Electronic Inductor Output. Calculated voltage is applied to this output
to control off-hook and DC VI mask operation. Connect to base of Q902.
LSD Electronic Inductor Ground. Connect to AGND_LSD and to the
GND_LSD/AGND_LSD tie point (U908).
Electronic Inductor Feedback. Connect to emitter of Q904 through
R968.
Receive Analog Input. Receiver operational amplifier inverting input.
AC coupled to the Bridge CC node through R910 (connects to pin 10)
and C912 in series. R910 and C912 must be placed very close to pin 10.
The length of the PCB trace connecting R910 to the RXI pin must be
kept at an absolute minimum.
Receiver Bias. Connect to AGND_LSD through R954, which must be
placed close to pin 6.
Virtual Impedance. Input signal used to provide line complex
impedance matching for worldwide countries. AC coupled to Bridge CC
node through R908 (connects to pin 11) and C910 in series. R908 and
C910 must be placed very close to pin 11. The length of the PCB trace
connecting R908 to the VZ pin must be kept at an absolute minimum.
Transmit Output. Outputs transmit signal and impedance matching
signal; connect to base of transmitter transistor Q906.
Transmit Feedback. Connect to emitter of transmitter transistor Q906.
General Purpose I/O 1. Leave open if not used.
No Connect. No internal connection. Leave open.
Conexant
Not Used
Signal Name/Description
102247B