24Oct2013 D. Seitz SPP FIELDS RFS Analog Peer Review 24OCT2013 1

24Oct2013 D. Seitz FIELDS RFS Analog Breadboard 2

24Oct2013 D. Seitz RFS Block Diagram 3

24Oct2013 D. Seitz RFS Analog Section Requirements 4 RFS Analog requirementsRTI = Signal input connector Input impedance50 Ohms +/-5% Noise RTI < 10nV above 100kHz; < 4nV above 1MHz 4Vpp output bandwidth> 18MHz Functional Requirements: Five inputs (V1, V2, V3, V4, SCM) Two independent ADC signal conditioning chains Each ADC chain: Single ended measurement of any selected input Difference measurement of any two selected inputs (V1-V4) Selectable high or low gain for V1-V4 inputs Balanced differential drive to ±2V range 12 bit ADC

24Oct2013 D. Seitz RFS Analog Section Components 5 All components are SQPL and at least 100krad except for output balun transformer – will have to be designed and built in-house at UCB SSL

24Oct2013 D. Seitz RFS Analog Breadboard Schematic 6

24Oct2013 D. Seitz RFS Analog Input Mux and Amp 7 Mux Ron x Cout = 29MHz with ±6 supply - increase supplies to ±8? AD8001 has plenty of BW But needs ±5, not ±6 Attempted differential measurement between coax center and shield with shield terminated through larger resistor does not work – explore values of RSAT (e.g. R85)

24Oct2013 D. Seitz RFS Analog Diff and Gain Amps 8 LM6172 requires lower R values for best performance – reduce to 499Ω Need to reduce impedance between LM6172 and output mux - DC couple!

24Oct2013 D. Seitz RFS Analog Output Mux and Amp 9 Output mux Ron x Cout also limits BW - increase supply to ±8 - CD4052 dual 4:1 has ½ Cout but hard to procure… Output LM6172 will be reconfigured as 2 pole lowpass and R42 reduced to 50Ω for ÷2; 4Vpp => 2Vpp for ADC Balun transformer (not shown) yet to be tested - using Mini-Systems commercial part for BB but will have to design in-house for EM and flight

24Oct2013 D. Seitz RFS SCM input buffer 10 Nothing here yet! Plan to standardize on input buffers used on TDS and DFB