U4076B

Preliminary Information

TELEFUNKEN Semiconductors
Rev. A1, 15-May-96

1 (6)

Three-Tone Ringer for Telephone Sets

Description

The three-tone ringing integrated circuit U4076B, in
conjunction with a piezo transducer or loudspeaker
replaces the normal electromechanical telephone bell. It
is operated with the ringing current from the exchange.

There is also a possibility of operating the IC with the dc
supply voltage, being developed for large operating
range. The integrated circuit is overload protected.

Features

D Three-tone ringing sequence with 800 Hz, 1067 Hz

and 1333 Hz

D Sequence frequency adjustable between 2.5 Hz and

25 Hz

D Adjustable volume
D Push-pull output stage
D Piezo transducer or loudspeaker connection
D Common input for frequency and call recognition
D Reduced pulse duration for electromagnetic

transducers

D Clock oscillator with ceramic resonator or LC series

cct possible

D Input protective diode

D On-chip rectifier bridge

D Protection circuit against ringing in a parallel circuit

Benefit

D Suitable for German Post Office Specification,

FTZ 121671 Pfl. 3, edition dated 24.03.82

Tone sequence

oscillator

Supply

(5)

(7)

10 (11)

(9)

Divider

32:1

Tone signal

generator

Reset

Level
monitoring

Divider

128:1

96 ms

127 ms

Divider

2:1

Reset

Frequency

monitoring

Frequency

Divider

32:1

Clock signal

generator

Divider

14:1

(10)

(15) 13

(8)

0.8 F

2.2 k

(6)

(16)

22 F

600 k

43 k

4.7 nF

Ground: output signal

Open: output signal

(13)

(12)

Three

state

(1)

100 k

log

2 (2)

3 (3)

455 kHz

93 7792 e

Figure 1. Block diagram and application circuit

Case: DIP14 or SO16-L (Pin connections for SO 16-L case in bracket)

U4076B

TELEFUNKEN Semiconductors

Rev. A1, 15-May-96

Preliminary Information

2 (6)

Pin Description

Symbol

Function

1 (1)

Frequency monitoring
Open: 23 to 54 Hz
Ground: 12 to 54 Hz
With Pin 6 (7) connected:
Switched off

2, 3

(2, 3)

Clock signal generator

4 (5)

Ground

5, 7

(6, 8)

Power supply

6 (7)

Charging capacitor, C

for

bridge rectifier

(8, 9,

10)

Frequency oscillator

Symbol

Function

8, 9,

Tone sequence

(9, 10,

11)

Frequency oscillator

11, 12

(12,

13)

Output signals

(15)

Output signal shape
Open = short pulse width
Ground = 1:1

(16)

Load resistance, R

(4,

14)

Not connected

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):

Pin 1 is open: ringing frequency is between 23 and
54 Hz.

b) Pin 1 is grounded: ringing frequency is between 12

and 54 Hz.

Pin 1 is connected to Pin 6 (7): ringing frequency has
no influence (dc operation)

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

mF in series with 2.2 kW resistance is

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

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:

OSC

192

whereas f

OSC

(43 k

W ) R

) 47 nF

if: k

0.95 then R

0 to 20 k

if: k

then R

30 to 150 k

if: k

1.2

then R

200 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

6(7)

� 2.5) V

pp.

The

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.

U4076B

Preliminary Information

TELEFUNKEN Semiconductors
Rev. A1, 15-May-96

3 (6)

Pin 13 (15): Output signal shape

Output signal has different duty cycles according to the
position of Pin 13 (15). When grounded it has a duty cycle
of 1:1. When using a dynamic loudspeaker (activa-
tion via transformer/capacitor),

reduced

signal

is recommended. This can be achieved by connecting a
capacitor greater than 1 nF between Pin 13 (15) and
ground.

Pin 14 (16): Switched on/off

Switched on/off is controlled by Pin 14 (16). The dc
voltage on the charge capacitor between Pin 4 (5) and 6
(7) is loaded a dummy load as long as the tone ringing is
not switched-on. In on-position (amplitude and frequency
recognition), Pin 14 (16) is connected internally with

(5) and the dummy load is switched-off. In

off-position, Pin 14 (16) is connected with Pin 6 (7)
internally and the dummy load is switched on.

Overload protection

The integrated circuit can withstand an ac voltage of
110 V / 50 Hz for 15 seconds between terminals a and b.

The circuit will not be damaged by a surge voltage test
with the following conditions:

Charging voltage of surge capacitance: V

= 2 kV

Pulse shape: 10/700

�

Pulse sequence: 30 s
No of surges: 10
Polarity change after five surges

Tone ringing

Figure 1

2 kV

93 7575 e

110

0.22

Figure 2. Surge voltage test circuit

Absolute Maximum Ratings

Reference point Pin 4 (5) unless otherwise specified

Parameters

Symbol

Value

Unit

Supply current

Pins 5 and 7 (6, 8)

Output current

Pins 11 and 12 (12, 13)

" I

Junction temperature

125

�

Ambient temperature range

amb

� 25 to + 60

�

Storage temperature range

stg

� 40 to + 125

�

Power dissipation
T

amb

= 60

�

DIP14
SO16-L

tot

860
720

mW
mW

Thermal Resistance

Parameters

Symbol

Value

Unit

Junction ambient
DIP14
SO16-L

thJA

75
90

K/W
K/W

U4076B

TELEFUNKEN Semiconductors

Rev. A1, 15-May-96

Preliminary Information

4 (6)

Electrical Characteristics

= 10 V, f

clock

= 455 kHz,T

amb

= 25 to 60

�

C. Reference point Pin 4 (5), Pin 13 (15) ground, unless otherwise specified.

Parameters

Test Conditions / Pins

Symbol

Min.

Typ.

Max.

Unit

Supply current (no load)
outputs open V

6(7)

= 10 V

amb

= +25

�

Pins 5 and 7 (6)

0.9

1.15

1.3

Frequency range of the
ringing input current
a) Pin 1 - open
b) Pin 1 - grounded
c) Pin 1 - connected to
Pin 6 (7)

Pins 5 and 7 (6, 8)

ring

23 to 54
12 to 54

operation

AC-operation
Switch-on threshold
Switch-off threshold

Pin 6 (7)

6.5
3.5

8.5
5.5

DC-operation
Switch-on threshold
Switch-off threshold
Output on resistances
at

20 mA

Output signal frequency

Pin 6 (7)
Pin 6 (7)
Pin 11 (12)
Pin 12 (13)

Pins 11 and 12 (12,13)

2.75

2.0

448/455
800/812

1067/1083
1333/1354

4.75

4.0

400
400

V
V

W
W

kHz

Hz
Hz
Hz

Build-up time of clock
oscillator

Internal voltage limitation
I

=1 mA

6�4 (7�5)

Pin 6 (7)

Repetition rate oscillator:
Low state
High state
Allowable resistor

Pin 8 (9)
Pin 8 (9)

Pins 8-10 (9-11)

8(9)

0.5

0.043

0.6
2.0

0.7

V
V

Ordering Information

Extended Type Number

Package

Remarks

U4076B-FL

SO16

U4076B

DIP14

Электронный компонент: U4076B