Preliminary Information
MH88520-1
TIP
RING
Optional
Protection
Circuit
Earth Ground
K1
MH88520-1
1 TIP
3
RING
16
JUNC
15
MUTE
4
RF1
10
SHK
R1
RINGING
GENERATOR
90VRMS
∼
-24V
6 RF2
9
LED
19
RRC
17
RRD
DS1
14 VBAT
K1
VRLY 20
VEE AGND VDD RGND
8 13 12
18
Notes:
R1= 200Ω, 1/4W, 5%
K1= Relay E/M 5V, 1Form C
C1, C2 = 0.1uF, 50V, Ceramic
-5V
C1
+5V
C2
AUDIO
INPUT/OUTPUT
MUTE CONTROL
INPUT
SWITCH HOOK
OUTPUT
OFF-HOOK LED
RING CONTROL
INPUT
Figure 5 - Typical Application Circuit
R and RTHRESH (kΩ)
GND
RG
SLIC
11
THRESH
ADJ
RG = 6000 x I
VDD - (501 x I)
R
(kΩ)
60
50
40
30
20
10
RG(kΩ)
I = Threshold current (a)
in Amps
VDD = +5V
2 3 45 6 7 8
R and RTHRESH (kΩ)
VBAT
RV
SLIC
11
THRESH
ADJ
RV= (100 x VDD) - (6000 x I)
(501 x I) - VDD
R
(kΩ)
400
RV(kΩ)
(b)
200
10
15
20
25
Figure 6 - Off-Hook Threshold Adjust
2-69