GSM generator on a RF3140 chip from a cell phone

chip rf3140

There are microcircuits in cell phones that amplify a weak high-frequency signal by power, and one of these microcircuits is the RF3140.This microcircuit was used in old cell phones, today it is out of production but it can still be bought.

Based on this chip, you can assemble a microwave power amplifier for the frequency ranges: 824-849 MHz (GSM850), 880-915 MHz (EGSM900), 1710-1785 MHz (DCS 1800), 1850-1910 MHz (PCS1900). Power supply from 3 to 5.5V. The output power when powered at 3.7V at a frequency of 1785 MHz is 2.2 W at a current consumption of 1.1 A. The output power can be adjusted.

A weak DCS / PCS signal is supplied to pin 1, and from pin 11 this amplified signal enters the antenna. A weak GSM / EGSM signal is supplied to pin 7 and from pin 9 to the antenna. Pin 2 is used to switch bands. At a high level, DCS / PCS will be connected, at low GSM / EGSM. According to the scheme, the DCS / PCS range is connected. Pin 3 is connected to plus through the resistor, pin 4 is the plus of the power supply. Pin 5 is the adjustment of the output power of the transmitter. A signal from the DAC is supplied to pin 6, but it is not used in the circuit.

The photo shows the pinout. All not indicated conclusions are a negative conclusion, including a large rectangle, and I connected the minus power supply to it.

Since I do not have a weak signal source for these frequencies, to generate a signal and test the microcircuit, I connected 4 cm long wire to pin 1. At frequencies in the range of 915 MHz, the microcircuit will start generating a signal that can be removed from pin 11. antenna 3.5-4 cm through an incandescent lamp 2.5 V * 150mA. The microcircuit will heat up with such a non-standard inclusion, part of the power does not go to the antenna, but is dissipated in the form of heat. The microcircuit must be installed on the radiator through heat-conducting paste.

When power is applied, the lamp will shine from the high-frequency current passing through the filament.

I will show how such a generator works in my video

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