Sunday, June 01, 2008

Software and simple circuit to control inexpensive PLL chip from Sanyo LC 72131

I will try to present here a software made for control a simple comercial PLL chip, commonly used in receivers. The chip is a Sanyo LC 72131.
Some time ago I see the need of a PLL circuit to control some simple receivers made by me.
Many projects on the net, but some times dificul to find some chips, or frequency divisors required by project.
Looking in my "garbage" of eletronics I found some FM and AM comercial digital receivers, and inside its the pll controlers.
So, I get out the chip I think initialy best fit my needs. LC 72131; I think is only make by sanyo, since that the specs and this protocols are made by own Sanyo.
Some good things about this very inexpensive chip:
can get 160MHz!
Some time I will try receive 144Mhz in it yet.
Well, I make a simple software, in Windows, do control this chip, sending command by parallel interface, in a serial fashion, (almost like I2c), to manage all inside it.
Only needed, like other chips, few parts to use it; A good oscilator, a pulse to voltage conversor, and some others coupling parts.
I test the software and hardware with AM receivers, until 20Mhz, making some mistures with various comercial receivers. Until 11Mhz get very nice receiver and stability. Beyond this, i dont has good hardware to generate the high frequency.
Next post I will put the rest, schematics, software, source. Please, be patient.

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