KA2418B/28

TONE RINGER WITH BRIDGE DIODE

INTRODUCTION

The KA2418B/28 is a

monolithic integrated circuit telephone tone

ringer with bridge diode, when coupled with an appropriate

transducer, it replaces the electromechanical bell. This device is

designed for use with either a piezo transducer or an inexpensive

transformer coupled speaker to produce a pleasing tone composed

resulting in a warble frequency. The supply voltage is obtained from

the AC ring signal and the circuit is designed so that noise on the

line or variation of the ringing signal can not affect correct operation

of the device.

FEATURES

• Built-in full wave bridge diode rectifier

• Low current consumption, in order to allow the

parallel operation of the 4 devices

• Few external components

• Tone and adjustable switching frequencies by

external components

• High noise immunity due to built-in voltage to

current hysteresis

• Adjustable activation voltage

• Internal zener diodes to protect against over

voltages

• Adjustable ringer impedance with external

components.

BLOCK DIAGRAM

Fig. 1

Device

Package

Operating Temperature

KA2418B

KA2428

8

1

7

-

+

2

POWER

SUPPLY

CONTROL

CIRCUIT

6

3

5

LOW

FREQ OSC

HIGH

FREQ OSC

OUTPUT

AMP

4

TIP

RING

GND

SWEEP RATE

CONTROL

CAPACITOR

OUTPUT FREQUENCY

CONTROL RESISTOR

OUTPUT

ACTIVATION

VOLTAGE ADJUSTABLE

RECTIFIER

CAPACITOR

8-DIP-300

- 20

°C ~ + 70°C

8-DIP-300

ORDERING INFORMATION

APPLICATIONS

• Electronic telephone ringers

• Extension ringers