UM3561 IC Sound Generator Circuit Diagram, and Its Working

The integrated circuit UM3561 is an outstanding ROM (Read Only Memory) IC. The main function of this chip is to produce different siren tones like Ambulance, Police, machine gun, and Fire brigade siren sound. This IC consists of an oscillator as well as tone selection pins, and it is a low-cost IC mainly designed for toy applications. The designing of this circuit can be done with a few basic electronic and electrical components. For example, a simple siren generator can be built with one external resistor as well as a speaker driver transistor. This article discusses an overview of the sound generator IC UM3561.

What is an IC UM3561?

The IC UM3561 comprises an oscillator as well as selector circuits. A compact sound module can be constructed with only a few additional components. The UM3561 contains a programmed mask ROM to simulate siren sound. There is a tone generator within UM3561, which is able to generate different tones using the oscillator clock and according to the data given by the ROM. Each data stored in the ROM corresponds to each tone and it can be selected by using the address of the data location. The typical operating voltage of UM3561 is 3V and the Operating Current Idd is 150μA. The output current of UM3561 is 3mA.

IC UM3561 Pin Configuration

The IC UM3561 Pin Configuration includes the following pins.

UM3561 IC Pin Configuration
UM3561 IC Pin Configuration
  • Pin-1 (SEL2): Selection of Sound effect
  • Pin-2 (Vss): Negative (-ve) power supply
  • Pin-3 (Output): Continuous tone output
  • Pin-4 (NC): Inner testing pin: For regular operation Leave open
  • Pin-5 (Vdd): Positive (+ve) power supply
  • Pin-6 (SEL1): Selection of sound effect pin-1
  • Pin-7 (OSC1): Exterior oscillator terminal-1
  • Pin-8 (OSC2): Exterior oscillator terminal-2

Block Diagram of IC UM3561

The block diagram of IC UM3561 is shown below. This IC includes an oscillator circuit and the oscillations frequency can be controlled with the resistor which is connected externally to the first oscillator or pin7 as well as scilaltor2 or pin8. Thus, the oscillations which are produced will be moved to a control circuit. This circuit can be worked depending on the selection of tone through the pin-6 and pin1.

UM3561 Block Diagram
UM3561 Block Diagram

The control circuit supplies the signal toward an address counter & to the ROM. Thus the generated tone pulses will be accessible from the o/p pin-3. Since the sound is feeble; an amplifier is needed to get loud sound. So the sound can be amplified by a single NPN-transistor.

UM3561 IC based Four Siren Sound Generator

The UM3561 IC can be used to build circuits like a Police siren, Fire engine siren, Ambulance siren, and Machine gun sound. The circuit of 4 siren sound generator with UM3561 IC is shown below. It is a low-power CMOS integrated circuit.


The 4 different siren sounds can be generated by pressing the three switches like S1, S2 &S3. This circuit can be employed for any kind of sound generation necessities. For instance, the generated sounds can be used as alarm circuit, tone generator, and siren circuit etc.

UM3561 Circuit Diagram
UM3561 Circuit Diagram

The designing of this circuit can be done with basic electronic components with a 3V battery and it is perfect for numerous low-voltage applications.

The UM3561 can drive a piezo without using any stage of amplification. In this circuit, a single transistor amplifier is used to drive an 8-ohm speaker. Furthermore, for more amplification of sound, the LM386 amplifier can be utilized in this circuit.

Features of IC UM3561

The main features of IC UM3561 include the following.

  • 4-sounds can be chosen
  • Power on RST (reset)
  • Operating voltage is 3V
  • Low-cost
  • Low-power CMOS LSI used in alarm and toy applications.

Specifications of IC UM3561

The specifications of IC UM3561 include the following.

  • DC Supply voltage is 3.0V to +5.0V
  • Input or Output voltage (Vss) is 3.0V to +3.0V VDD
  • Ambient operating temperature is -10°C to 60°C
  • The temperature for storage is-55°C to 125°C
  • Vdd (Operating voltage): Min-2.4V, Max-3.6V, and Typical-3V
  • Idd (Operating Current): 150µA

Thus, this is all about IC UM3561 sound generator, it is a siren generator used for generating a siren sound in the toy applications. Based on the selection, this IC can generate four different types of siren sounds like a gun sound, ambulance siren, police siren, and fire brigade siren. In the above article, we have discussed how we can design these four circuits for generating different sirens by selecting in the IC.