U4076B TEMIC Semiconductors, U4076B Datasheet - Page 2

• Manufacturer Part Number: U4076B
• Description: Three-Tone Ringer for Telephone Sets
• Manufacturer: TEMIC Semiconductors

Pin Description
Pin Connections and Functional
Description Including External
Circuitry
Pin 1: Frequency monitoring
Frequency is monitored via Pin 1. The following possibi-
lities are available (three-state logic):
a) Pin 1 is open: ringing frequency is between 23 and
b) Pin 1 is grounded: ringing frequency is between 12
c) Pin 1 is connected to Pin 6 (7): ringing frequency has
Pins 2 and 3 (2, 3): Clock signal generator
A ceramic resonator for a frequency of 455 kHz must be
connected between Pin 2 (2) and Pin 3 (3). The clock
frequency of the generator is used for three-tone ringing
sequence and control signals for frequency identification.
Pin 4 (5): Ground
Reference point for all voltages.
Pins 5, 6 and 7 (6, 7, 8): Power supply
Pins 5 (6) and 7 (8) connect the circuit with a ringing ac
supplied by the exchange via lines a and b. A decoupling
capacitor of 1
needed for overvoltage protection and the insertion loss
requirement of the German Post Office specifications.
The supplied ac current is rectified by the on-chip bridge
circuit. The rectified current charges the capacitor on
Pin 6 (7), which supplies the dc voltage for the integrated
U4076B
2 (6)
(2, 3)
(6, 8)
(8, 9,
1 (1)
4 (5)
6 (7)
2, 3
5, 7
Pin
10)
54 Hz.
and 54 Hz.
no influence (dc operation)
Symbol
m
F in series with 2.2 k
Frequency monitoring
Open: 23 to 54 Hz
Ground: 12 to 54 Hz
With Pin 6 (7) connected:
Switched off
Clock signal generator
Ground
Power supply
Charging capacitor, C
bridge rectifier
Frequency oscillator
Function
Preliminary Information
W
L,
resistance is
for
circuit. Instead of a ringing ac current supplied by the ex-
change, the IC can be driven by a dc voltage applied
directly to terminals 6 (7) (+) and 4 (5) (–). An integrated
Z diode limits the maximum supply voltage range up to
27 V.
Pins 8, 9 and 10 (9, 10, 11):
Sequence frequency adjustment
The sequence of the three-tone ringing frequency (800,
1067 and 1333 Hz) is determined by the external network
calculated as follow:
f
if: k
if: k
if: k
The sequence frequency adjustment is determined by the
frequency prescaler ratio in the IC.
Pins 11 and 12 (12, 13): Output signal
The three-tone ringing sequence of 800 Hz, 1067 Hz and
1333 Hz is realized if the clock oscillator is synchronised
with a ceramic resonator of 455 kHz between Pins 2 (2)
and Pin 3 (3). This gives excellent tone frequency and
eliminates complicated frequency setting procedures.
The output signal without load is (2 V
output stage transducers in BTL configuration can pro-
cess an average current of up to 20 mA, whereas a short
time current of 40 mA is possible in both direction when
t = 0.1 ms. An external current limitation is necessary
when the IC is operating with voltage between Pin 6(7)
and Pin 4 (5). The tone sequence always starts at the
lower frequency.
(9, 10,
11, 12
2
8, 9,
(15)
(16)
(12,
Pin
11)
13)
14)
+
(4,
10
13
14



f
192
OSC
0.95 then R
1
1.2
Symbol
whereas f
then R
then R
v
v
v
OSC
Tone sequence
Frequency oscillator
Output signals
Output signal shape
Open = short pulse width
Ground = 1:1
Load resistance, R
Not connected
TELEFUNKEN Semiconductors
+
(43 k
=
=
>
W
Function
0 to 20 k
30 to 150 k
200 k
Rev. A1, 15-May-96
)
6(7)
IC
L
R
– 2.5) V
V
) 47 nF
pp.
The