We have designed a board with uses a LMH1983 from national and we use this as an input to the LMK03000
We AC coupled the inputs and have a differential swing of 800 mV and a frequentie of 148.35 or 148.5 Mhz .
and the LMK03000 give's it a DC offset of 1,5 Volts
(When we set PLL_MUX to 1 and 2 we kan toggle the LD pin manually)
We want to use the LD pin to test the input and the interal ref.
$port.WriteLine("[0x80 0x00 0x04 0x00]") //reset
$port.WriteLine("[0x00 0x00 0x04 0x00]") //output 0 off
$port.WriteLine("[0x00 0x03 0x05 0x01]") // only output 1 is turned on : CLK_MUX =DIVIDED
$port.WriteLine("[0x00 0x00 0x04 0x02]") //output 2 off
$port.WriteLine("[0x00 0x00 0x04 0x03]") //output 3 off
$port.WriteLine("[0x00 0x00 0x01 0x04]") //output 4 off
$port.WriteLine("[0x00 0x00 0x04 0x05]") //output 5 off
$port.WriteLine("[0x00 0x00 0x04 0x06]") //output 6 off
$port.WriteLine("[0x00 0x00 0x04 0x07]") //output 7 off
$port.WriteLine("[0x00 0x82 0x80 0x0B]") // DIV4 = on
$port.WriteLine("[0x02 0xA5 0x00 0x0D]") // OSC freq = 148 // VCO_R4 =0 //VCO R3 = 0 //VCO C3 C4 =0
$port.WriteLine("[0x18 0xB0 0x04 0x0E]") // Fout is ena // ENA Global CLK out // PLL_MUX = 0x09 // PLL_R = 0x04
$port.WriteLine("[0xC8 0x00 0x10 0x0F]") // CP_GAIN =3 // VCO_DIV = 2 // PLL N = 0x10 =16dec
I expected to see 148.35 / 4 = 37.0875 Mhz / 2 = 18.543Mhz on the LD pin.
When I measure this there is a Low signal.
kan any one help me out