Single Chip FM Radio Circuit

Author	Views	Views Today	Rank	Comments
	3,642	55		0

This extremely simple FM radio receiver circuit is made possible by the special purpose TDA7000 IC. It integrates nearly all the functions necessary to build an FM receiver needing only a few external capacitors and a tuning circuit. Using a simple active RC filter made of only a single inductor, a few resistors and a varicap, this FM receiver will pick up broadcast radio between about 88 and 108 MHz. The mono output signal can then be used to drive a set of high impedance headphones, or feed a power amplifier.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
C1, C9, C12, C17	4	0.1uF Ceramic Disc Capacitor
C2, C4, C5, C6, C13	5	0.01uF Ceramic Disc Capacitor
C3	1	20pF Ceramic Disc Capacitor	See Notes
C7, C15, C16	3	0.001uF Ceramic Disc Capacitor
C8, C10, C11	3	220pF Ceramic Disc Capacitor
C14	1	100pF Ceramic Disc Capacitor
C18	1	200pF Ceramic Disc Capacitor
R1	1	22K 1/4W 5% Resistor
R2	1	100K 1/4W 5% Resistor
R3	1	100K Linear Taper Pot
D1	1	Motorola MV209 Varicap VHF Tuning Diode
U1	1	TDA7000 FM Radio IC	See Notes
L1	1	7 Turn Inductor (See Notes)
MISC	1	Board, Wire, Socket For U1, Case

Notes

Unfortunately, the TDA7000 went obsolete a few years ago. The original version is made by Signetics (now Philips) and is getting a bit hard to find these days. There are, however, other options. Philips makes the TDA7010T which is a surface mount version. The TDA7021T is also available which includes stereo capability. They are electrically similar but are only 16 pin chips so you'll need to compare the datasheets to build the circuit.

The value of C3 is noncritical and can be between 10pF and 20pF. Minor adjustments to L1 may be required based on the value of C3.

L1 is made by winding 7 turns of 24 AWG wire around pencil. Remove the pencil and then space the turns slightly.

Frequency selection is via R3.

Related Circuits

If you would like to leave a comment, you can do so using the form below. Comments can be things like suggestions, successes or failures, improvements, similar circuits, error reports, an answer to a previous commenter's question, or anything in between. However if you would like to ask a question it is suggested that you use the forum instead. The forum provides a more robust environment for discussion.

Important: If you post a technical question here, there is no guarantee it will be answered. All technical questions should be posted to the forum. The owner of this site generally does not answer questions in comments.

All comments are subject to approval before they are displayed here, so your comment will not appear immediately. This is done mainly to prevent spam and other abuse. If you wish to remain anonymous, simply enter "anonymous" for your name and/or email.

Name:
Email:
Subject:
Comments:
Anti Spam Code:	Please enter the exact text shown in the image above into the box below. Browser cookies must be enabled to comment on circuits.

Privacy Policy