1
* This specification are subject to be changed without notice.
AG8889
CALL WAITING DECODER
8.8.2000
I.
GENERAL DESCRIPTION
This is a new version of Call Waiting service decoder on the telephone. Call Waiting service works by alerting
a customer engaged in a telephone call to a new incoming call. This way 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
signal and generate a valid signal 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 Signal Detector
Good talkdown and talkoff performance
Sensitivity compensated by adjusting input OP gain
Package series --- 14-pin DIP or 16-pin SOP (150 mil)
AG8889AP for 14-pin DIP
AG8889N for 16-pin SOP (150 mil)
III.
APPLICATION
Feature phones
Cordless phones
Adjunct unit (stand alone)
IV. PIN CONFIGURATION
VSS
VDD
DO
OSCI
OSCO
14
13
12
11
9
1
2
3
4
5
6
7
8
OPO
RING
VREF
10
NC
PWD
NC
NC
NC
TIP
AG8889AP
VSS
VDD
DO
OSCI
OSCO
16
15
14
13
11
1
2
3
4
5
6
7
10
OPO
RING
VREF
12
NC
PWD
NC
NC
8
9
NC
NC
NC
TIP
AG8889N
* This specification are subject to be changed without notice.
AG8889
CALL WAITING DECODER
2
8.8.2000
V.
FUNCTIONAL BLOCK DIAGRAM
VI. PIN DESCRIPTIONS
Pin
I/O
Description
TIP
I
Tip in should be connected with twisted pair
RING
I
Ring in should be connected with twisted pair
OPO
O
Output of OP Amp
VREF
Reference voltage Vref = 1/2 Vdd
PWD
I
This pin is normal low enabling chip on normal operation and ready to detect CAS
tone signals.
This active high input sets the chip into power down mode and disable oscillator to
save power.
OSCI
I
3.58MHz oscillator in
OSCO
O
3.58MHz oscillator out
DO
O
DO : used as output, this pin determines whether DO signal is valid or not. High is
valid. Normal low.
VDD
Power
GND
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. This way the
customer can still receive important calls while engaged in a current call. The CALL WAITING DECODER can detect
CAS(Call-Waiting Alerting Signal 2130Hz plus 2750Hz) and generate a valid signal on the data pin.
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 three blocks, including differential amplifier, tone filter detection block
In a typical application, this IC receives Tip and Ring signals from twisted pairs. The signals as inputs of differential
amplifier, and the differential amplifier sends input signal to a band pass tone filter. Once the signal is filtered, the
digital detection block decodes the information. The output data made available at DO pin.
This IC is used for detecting CAS signals. Once the signal is detected, the detection indication is shown on the data
output DO pin. The DO pin is normal low. When this IC detects 2130Hz and 2750Hz frequency at the same time, then
DO pin goes to high.
TIP
Filter
Vdd/2
Voltage
Reference
Clock
Generator
DO
OPO
Tone
Detection Block
VREF
PWD
OSCI OSCO
RING
3
* This specification are subject to be changed without notice.
AG8889
CALL WAITING DECODER
8.8.2000
DC CHARACTERISTIC
VDD=5V, Vss=0V, Ta=25
C, fOSC=3.58MHz
Sym.
Description
Condition
Min.
Typ.
Max.
Unit
VDD
operating supply voltage
3.6
6
V
IDD
operating supply current
3.3
5
mA
VIL
low level input voltage
1.5
V
VIH
high level input voltage
3.5
V
VOL
low level output voltage
load=1mA
0.4
V
VOH
high level output voltage
load=1mA
4.6
V
Note: 1.both tones in the composite signal have equal amplitude.
2.tone pair is deviated by 0.5%.
3.addes a 0.1uf capacitor between Power and Ground.
AC ELECTRICAL CHARACTERISTIC
(VDD=+5V,Ta=+25
C)
CHARACTERISTIC
Min.
Typ.
Max.
Unit
Input sensitivity TIP and RING pins ,Vdd=+5V, Input G=1
-38
dBm
Input frequency tolerance for 2130Hz
1.2
%
Input frequency tolerance for 2750Hz
1.2
%
* This specification are subject to be changed without notice.
AG8889
CALL WAITING DECODER
4
8.8.2000
WAVE FORM TIMING
DO timing:
OSC timing:
line event
Tvd
CAS
Tinvd
normal on hook
Tfvd
Tfinvd
Tdvd
Tdinvd
Tvd=Tfvd+Tdvd
Tinvd=Tfinvd+Tdinvd
alert
tone
(~80ms)
off hook
engaged call
Sym.
Description
Min.
Typ.
Max.
Unit
Tfvd
filter output signal valid delay
6
ms
Tfinvd
filter output signal invalid delay
6
ms
Tdvd
digital delay of valid signal
36
ms
Tdinvd
digital delay of invalid signal
20
ms
Tvd
total delay of valid signal
42
ms
Tinvd
total delay of invalid signal
26
ms
alert
input alert tone length
80
ms
tone
(2130 ,2750 Hz @ -20dBm )
Tosc
Oscillator enable delay time
10
ms
OSCI
OSC on
OSC off
Tosc
(OSCO)
Power
power off
power on
on/off
PWD
Tosc
OSC off
Note: detected alert tone length shown above is assumed that no speech signals input.
test under alert tone signal = -22dBm (600
)
5
* This specification are subject to be changed without notice.
AG8889
CALL WAITING DECODER
8.8.2000
APPLICATION CIRCUIT 1
When PWD pin (pin 6) is controlled by MCU or external hook detect circuit, the users can use the following
application. (pin6 is connected to control pin of MCU or hook detect output)
TIP
VREF
GND
8-bit
MCU
TIP
RING
OSCI
OSCO
0.01u
0.01u
430k
250V
250V
0.1u
VDD 14
3
4
13
9
8
7
1
OPO
470k
5V
430k
51k
39k
62k
39k
5V
47p
2 RING
DO
PWD
6
3.58MHz
33p
Y1
C2
Y1
C1
C2
KBR-3.58MSB202
KYOCERA
33p
Note :
KBR-3.58MSB202 tolerrance :
-0.10% ~+0.15%
33p
C1
33p
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