Wiring Schematic Diagram

This is a FM transmitter circuit with semiconductor Maxim MAX2606 IC. In the circuit of rated frequency is 100 MHz for L1 inductor (390nH). Signals from the left and right channels of audio from its origin are added by R3 and R4, and attenuated by R2 POT. R2 can be used as a volume control. POT R1 can be used to select a transmission channel between 88MHz and 80 cm cable 108Mhz.Use long as the antenna.

Note:
* Use a battery for powering the circuit.It will reduce noise.
* An FM antenna from a old radio is a better option than the wire antenna.

IC MAX2606 Description

The MAX2605, MAX2609 are compact, high performance intermediate frequency (IF) voltage-controlled oscillator (VCO) designed specifically for demanding portable wireless communication systems. They combine monolithic construction with low noise, low operating power consumption of a small 6-pin SOT23 package.

Low-noise VCO, a feature on-chip varactor and feedback capacitors that eliminate the need for external adjustment elements, so the ideal MAX2605, MAX2609 for portable systems. Only an external coil is needed to establish the frequency of oscillation. In addition, a buffer integrated differential output is provided for driving a mixer or prescaler. The output buffer is capable of providing up-8dBm (differential) with a simple power game. It also provides isolation from load impedance variations.

The MAX2605, MAX2609 operate from a single 2.7 V to 5.5 V supply and provides low power consumption. IF these oscillators can cover the frequency range of 45MHz to 650MHz.

IC MAX2606 Absolute Maximum Rating

• VCC to GND..............................................................-0.3V to +6V
• IND to GND ................................................-0.6V to (VCC + 0.3V)
• TUNE to GND .............................................-0.3V to (VCC + 0.3V)
• OUT+, OUT- to GND ..................................-0.3V to (VCC + 0.6V)
• Continuous Power Dissipation (TA = +85°C)
• 6-Pin SOT23 (derate 8.7mW/°C above +70°C)...........696mW
• Operating Temperature Range ...........................-40°C to +85°C
• Junction Temperature......................................................+150°C
• Storage Temperature Range .............................-65°C to +150°C
• Lead Temperature (soldering, 10s) .................................+300°C