BA datasheet, BA circuit, BA data sheet: ROHM – Fm Stereo Transmitter,alldatasheet, datasheet, Datasheet search site for Electronic. Page 4. Page 5. This datasheet has been downloaded from: Datasheets for electronic components. Part, BA Category, Communication => Freq/Signal Converters/Generators. Description, FM Stereo Transmitter. Company, ROHM Electronics. Datasheet.

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(PDF) BA1404 Datasheet download

Solar charger Coils values: This gives the best stopband attenuation because greater passband ripple results in more rapid stopband attenuation. Create the two islands for the FET gate and drain, as detailed in the above paragraph Solder copper tape between top and bottom faces of the PCB underneath where the source tabs will be Create the PCB islands, tin them, stick them on the PCB using the photograph as a guide Create and fit the screen between the amplifier and the LPF areas Fit all the remaining PCB components, with the exception of the FET Fit the PCB to the box and the heatsink Fit the and connect and the RF connectors and the feed-through capacitor Taking anti-static precautions again, apply the thinnest continuous film possible of heat transfer paste to the base of the FET.

Va1404 can substitute it with a coil of 1uH or more. Its a demonstration of what can be done with little to none resources. It has to be tuned every time you change frequency. Cool little FM transmitter. Connect a good 50R load to the input and connect a stabilised PSU power supply unit with a current limit set to mA.

Alignment of the circuit is very easy. To adjust the circuit tune your FM radio to a quite spot then adjust the trimmer capacitor C8 until you hear the signal that you are transmiting.

Now adjust R1 to add mA to that figure. It is originally made for 2m station, but is perfect for FM radio band as well. In this simulation, the drain feed was included in the simulation. The version used was 6. Having tuned for minimum passband return loss, the stopband attenuation takes care of itself, you shouldn’t tune for it as you will dagasheet up the passband insertion loss.


You will now need to fan cool the amplifier, unless you have fitted it with an enormous heatsink. The maximum dc voltage recommended is about volts. Why this design bq1404 necessary I believe the quality of the vast majority of schematics and designs for FM broadcast equipment available on the internet to be far from satisfactorily.

Suitable for study purposes, you can use the RF part of this transmitter easily for your projects. Bipolar VHF power transistors have a severe affinity for low frequency self-oscillation. Firstly the floor of the datahseet box is not particularly smooth, which results in a poor thermal path. na1404

A similar procedure was performed for the output network. As this design is wideband, this constrains the passband ripple to a level such that the passband return loss does not become to horrible.

Output power is 2. Regulate the 4 variable C1-C4, until you take the biggest force of expense. Daatsheet the final power flatness tuning, because I had access to a smart RF laboratory with everything you could possibly dwtasheet test equipment wise, anyway I used a Mini-Circuits ZHLW wideband amplifier to boost the output of the network analyser to enable me to tune the amplifiers’ gain response flat at full output power.

Do this with a spectrum analyser connected to the output via an appropriate amount of attenuation, at least 40dB to monitor for spurious oscillations. I used gate voltage of 0.

The antenna can be a standard telescopic antenna or a 2 foot length of wire. The test device is then removed, and a vector network analyser is used to measure the complex impedance looking back into the matching network, whilst these are terminated with 50 R. Heatsinks are 75 x x 50mm with a 10mm thick base. The transistors are a 2N and a MRF Using a PSU with a carefully set current limit will help prevent the amplifier doing anything stupid under these conditions.


The PCB board is a single sided copper board etched or grinded out to the shown layout. The IRF series of power transistors are available in various voltage and power ratings.

BA1404 Datasheet PDF

To do these kind of soldering jobs a 60W or greater soldering iron will be required – preferably a temperature controlled one. So for the absolute level of harmonic radiation in the second example to be the same as the first, we now need to suppress the third harmonic by 60dBc.

Very clean signal, but it is narrowband. In the first stage the resistor R1 1. The input is not DC isolated. Otherwise use the appropriately sized drill bit.

The base of the power device sits through a dataheet in the floor of the diecast box and is bolted directly onto datahseet small extruded aluminium heatsink. All info about the PLL is available at Plessey’s web page.

BA Datasheet pdf – Fm Stereo Transmitter – ROHM

A high bias at small output levels will reduce the DC to RF efficiency. The output power is about 1. Clean finally PCB from the residues of soldering.

This program also calculates the filter values for you, and outputs a netlist in a format suitable bq1404 inputting into the most popular linear circuit simulators.

The output is fairly clean and can drive an antenna or another stage.

BA Datasheet Rohm pdf data sheet FREE from

Using a 5 pole circuit allowed the optimisation goal to be achieved. Thanks to the use of two stages, the amplifier can be driven to full power with less than 1 watt driving power, so that a large gain margin results in this transmitter. Knowing the RF output power and gain accurately allowed me to calculate the input power to the power dqtasheet. For normal applications I recommend using a lower bias. This information comes from design experience.