nw6003 Integrated Device Technology, nw6003 Datasheet - Page 5

• Manufacturer Part Number: nw6003
• Description: Type Ii Caller Id Decoder
• Manufacturer: Integrated Device Technology

NW6003 TYPE II CALLER ID DECODER
CLIP/CID CALL ARRIVAL DETECTION
call arrival signals. The diode bridge works for both single ended and
balanced ring signals. R1 and R2 are used to set the maximum
loading and must be of some value to achieve balanced loading. The
ring signal is attenuated by R1, R3 and R4 resistor devider before
being applied to pin TRIGIN. The attenuation value is determined by
the detection of minimal ring voltage and maximum noise tolerance
between Ring/Tip and ground.
ground and pin TRIGOUT will stay inactive high. If TRIGIN increases
from ground to VT+ (Schmitt trigger high going threshold voltage), C3
gets discharged, TRIGRC becomes low and TRIGOUT is asserted.
The low going TRIGOUT can be used to interrupt or wake up the
microcontroller. When TRIGIN signal drops below VT- (Schmitt trigger
low going threshold voltage), C3 will start to charge up through R5C3
time constant. After TRIGRC pin reaches above the threshhold voltage
(VT+), TRIGOUT becomes inactive high and it stops to interrupt the
microcontroller. To ensure the minimum TRIGOUT low interval and to
filter the ring signal to get a smooth envelope output, the RC time
constant should be greater than the maximum cycle time of the Ring
Signal.
FSK data be transmitted between first and second ringings. The circuit
in Figure 6 will generate a ring envelope signal at pin TRIGOUT for
the ring voltage of 40 Vrms or greater. R5 and C3 are used to filter the
ring signal to provide the envelope output.
Figure 6 shows the typical application circuit to detect the CLIP/CID
When no signal is applied to telephone line, TRIGIN will be at
Ring Detection for Bellcore: Bellcore recommends that the CID
Ring/B
Tip/A
C2= 0.1 F
C1= 0.1 F
R1 = 500K
R2 = 500K
Figure 6. CLIP/CID Call Arrival Detection Circuit
To Microcontroller
R3 = 200K
C3 = 0.22 F
R4 = 300K
R5 = 330K
5
TRIGOUT
polarity reverse (+15 V to -15V between the two lines slewing in 30
ms) to indicate the arrival of an incoming CDS call. When line reverse
occurs, TRIGIN increases over VT+ and TRIGOUT signal becomes
active low. When reversal is over, TRIGIN falls below VT- and
TRIGOUT returns inactive high.
detect a single burst of ringing followed by the FSK data. The ring
pulse may varies from 30 to 75 Vrms with pulse duration 200 - 450
ms.
TRIGIN
TRIGRC
Line Reversal Detection for BT: British Telecom uses the line
Ring Burst Detection for CCA: The CCA requires the TE to
Ring Signal
TRIGOUT
TRIGRC
TRIGIN
Figure 5. TRIGIN, TRIGRC and TRIGOUT Operation
NW6003
N
INDUSTRIAL TEMPERATURE RANGE
Note:
Minimal triggerable ring voltage (peak to
peak) is:
Vpp(max ring)=
2(VT+(max)(R1+R3+R4)/R4+0.7)
Tolerance to noise between Tip/Ring and Vss
is:
Vmax noise=
VT+(min)(R1+R3+R4)/R4+0.7
Suggested RC component value:
10K
47 nF < C3 < 0.68 F
Time constant is:
T=R5×C3×In(VCC/(VCC-VT+))
VT+(min) = 0.7 VCC
VT+(max) = 0.5 VCC
< R5 < 500K
.
VT+
VT-
VT+