ELAN AG8888AP, AG8888N Datasheet
CALL WAITING DECODER
I. GENERAL DESCRIPTION
This is a Call W aiting decoder used on the telephone. Call Waiting service works by alerting a customer engaged
in a telephone call to a new incoming call. Thus, the customer can still receive important calls while engaged in
a current call. The Call Waiting decoder can detect dual-tone (2130Hz and 2750Hz) alert tone and generate a
valid timing on the data pins for micro controller.
II. FEATURES
• Compatible with Bellcore special report SR-TSV-002476
• 3.6V ~ 6.0V supply voltage
• Call-Waiting (2130Hz plus 2750Hz) alert tone detector
• Sensitivity compensated by adjusting OP Amp
• Internal buffer
• Detection block for alert tone detected and digital algorithm detection
• Package series --- 14-pin DIP or 16-pin SOP (150 mil)
AG8888AP for 14-pin DIP
AG8888N for 16-pin SOP (150 mil)
AG8888
III. APPLICATION
Feature phones, cordless phones and stand-alone product
IV. PIN CONFIGURATION
AG8888AP
TI/RI
BO
F1
AVSS
OE
NC
DVSS
1
2
3
4
5
6
78
OPO
14
AVDD
13
DO
12
NC
11
DVDD
10
OSCI
9
OSCO
TI/RI
BO
F1
AVSS
OE
NC
DVSS
NC
AG8888N
OPO
1
2
3
4
5
6
710
89
16
AVDD
15
DO
14
NC
13
DVDD
12
OSCI
11
OSCO
NC
* This specification are subject to be changed without notice.
8.8.2000
1
V. FUNCTIONAL BLOCK DIAGRAM
AG8888
CALL WAITING DECODER
TI/RI
OSCI
OSCO
OPO
Buffer
Vdd/2
Clock
Generator
BO FI
Tone
Filter
Voltage
Reference
Detection Block
DO
OE
VI. PIN DESCRIPTIONS
Pin I/O Description
TI/RI I Tip in or Ring in should be connected with twisted pair
OE I Output enable for alert tone detected. High is enable. Low is for factory test.
OSCI I 480KHz crystal in
OSCO O 480KHz crystal out
DO O Alert tone detected output. Normal low.
Under OE pin set to high, when call waiting alert tone is detected, this pin goes to high.
OPO O Output of OP Amp
BO O Internal buffer output
FI I Band pass filer input
AVDD Analog power.
DVDD Digital power.
AVSS Analog Ground.
DVSS Digital Ground.
NC Non connected
VII. FUNCTIONAL DESCRIPTIONS
Call Waiting service works by alerting a customer engaged in a telephone call to a new incoming call. Thus, the
customer can still receive important calls while engaged in a current call. The call waiting decoder can detect alert
tone (Call-Waiting Alerting Signal 2130Hz plus 2750Hz) and generate a valid timing on the data pins.
The call waiting decoder is designed to support the Caller Number Deliver feature, which is offered by regional
Bell Operating Companies. The call waiting decoder has four blocks, including OP Amp, band pass filter, and
detection block.
In a typical application, this IC receives Tip/Ring signals from twisted pairs. The signals as inputs of single-ended
pre-amplifier (OP Amp and Buffer Amp), and the amplifier sends input signal to a band pass filter. Once the
* This specification are subject to be changed without notice.
8.8.2000
2
AG8888
CALL WAITING DECODER
signal is filtered, the detection block decodes the information and sends a valid timing to DO pin. The output data
made available at DO pin. There is a OE pin to control DO pin's output enable.
There is an external clamp circuit between internal buffer amplifier and filter. In order to get great alert tone
detection and avoid false triggering while speech signal is coming, the external clamp circuit can restrict speech
signal to (0.6Vp-p from TIP/RING.
The input signal is call waiting alert tone signals. The DO pin is normal low. When OE pin set to high and this IC
detects 2130Hz and 2750Hz frequency , then DO pin goes to high. Because OE pin set to low be for factory test,
you should notice that the users don't set it to low.
For this decoder, we put some external elements for performance concern.
* This specification are subject to be changed without notice.
8.8.2000
3
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