Friday, May 15, 2015

CD2003 - yet another simple FM radio receiver

In last few days we are looking for some simple FM radio receiver to integrate into one of our ongoing project. For that we try several FM radio receiver ICs including TDA7000, CD2003/TA2003/TA8164, CXA1019 and KA22429. Out of all those chips we select CD2003 (or TA2003/TA8164) based receiver for our project because of its simplicity and outstanding performance. Except to CD2003, Sony CXA1019 also perform well but we drop it because of its higher component count.

We design our receiver based on Toshiba TA2003 datasheet and later we try TA8164 and CD2003 with same circuit. Either CD2003 or TA8164 can directly replace TA2003 IC, and as per our observations TA8164 gives excellent results out of those 3 chips.

Prototype version of CD2003 FM radio receiver

The PCB design and schematic which we used in our prototype project are available to download at google drive (including pin-outs of crystal filters and inductors).

Except CD2003 IC, this receiver consist with 12 components. Three inductors used in this receiver are home-produced and all the winding details are available with the schematic diagram. This component count can also reduce by introducing FM band pass filter module to FM RF input stage of TA2003 chip. We try BPW85 FM band pass filter with this circuit and it also give same results as original circuit.

In our testing we operate this receiver using 3.3V power supply and by average it draws 8mA - 12mA current from PSU.

To drive speaker(s), this receiver needs to connect with suitable AF power amplifier and in our testing we use TDA2050 base AF power amplifier with this receiver.

Sunday, May 3, 2015

3A Power supply for USB devices

This is 5V 3A power supply to drive two USB based devices simultaneously. This power supply is design around LM2576-5.0 switching regulator IC and the main reasons to choose this IC is its low parts count, small heat sink requirements and its inbuilt current limit protection feature.

Prototype version of 3A USB power supply

We specially design this power supply to work with development boards / single board computer (SBC) platforms such as Raspberry Pi, Banana Pi, BeagleBone, etc. This power supply can also be used to provide power to USB OTG peripherals over USB Y cables. We test this setup and got successful results with Huawei Ascend P6 mobile phone.