le79r70 Zarlink Semiconductor, le79r70 Datasheet - Page 18

• Manufacturer Part Number: le79r70
• Description: Ringing Subscriber Line Interface Circuit
• Manufacturer: Zarlink Semiconductor

APPLICATION CIRCUIT
RING
Assumptions:
1. 1.25 CF
2. 25 mA I
3. 100 mA Ringing Current Limit
Note:
The input should be 50% duty cycle CMOS-compatible input.
TIP
R
R
FA
FB
Bat1
= 50 Ω
= 50 Ω
1.5 µF
LOOP
C
RT
BAT1
BAT2
K1
G
K2
61089
TISP
12 kΩ
C
R
K1
K2
BX
RT2
A
A
D
D
1
= 2.2 nF
2
C
0.1 µF
0.1 µF
AX
515 kΩ
R
18 nF
= 2.2 nF
C
4. 5.2 kΩ High Battery Loop Threshold
5. 925 Ω Ringing Loop Threshold
6. 600 Ω Two-wire Impedance,
RT1
HP
600 Ω Z
I. Application Circuit
RTRIP1
RTRIP2
A(TIP)
HPA
HPB
B(RING)
VBAT1
VBAT2
RYOUT1
RYOUT2
RYE
BGND
L
Zarlink Semiconductor Inc.
RINGIN
AGND/
DGND
RSGH
VNEG
RSGL
RDCR
B2EN
18
VCC
RSN
DET
VTX
RDC
RD
C1
C2
C3
D1
D2
E1
15 kΩ
50 kΩ
R
R
R
66 kΩ
DC1
DCR1
R
T2
R
T1
D
C
T
+5 V
C
0.33 µF
SLEW
125 kΩ
125 kΩ
50 kΩ
R
C
150 kΩ
R
7. G
8. –67 V Vbat1, –24 V Vbat2
10 nF
open
R
DC2
C
DCR
SGH
820 nF
–5 V
SLEW
DC
42L
250 kΩ
R
= 1
R
RX
open
SGL
R
DCR2
15 kΩ
V
V
TX
See Note.
RX
BATTERY
GROUND
GROUND
GROUND
ANALOG
DIGITAL