SNA PDet
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This page describes the Power Detector for the rev0SNA 50-2500 MHz Scalar Network Analyzer.
Summary
The Power Detector is based around the ADL5513 1MHz-4GHz 80dB logarithmic detector. The PCB includes a low-noise 3.3V power supply and has SMA connectors for RF input and Log output.
Testing
- 11.3.2013: The PCB was assembled and tested for basic functionality by measuring voltage with and without an antenna attached. Voltage was higher as expected when connected to an antenna.
- 11.5.2013: The voltage vs. power and frequency was measured for 50-4000 MHz, as well as the input port match. Results are shown graphically and tabulated below. Input match suffers above 2 GHz, with <10 dB return loss (2:1 VSWR). It is suspected that this is due to a mismatched connector layout. The device shows good linearity from 0 to -60 dBm, with a loss of linearity below -60 dBm (though monotonic and usable to -75 dBm), and non-monotonic behavior above 5 dBm. The device will be used in the range of 3.8 to -75 dBm in typical use.
Revisions
- 1.0: Initial revision.
Bill of Materials (v1.0)
| Part | Quantity | Unit Cost | Total Cost | Source |
| ADL5513 | 1 | $11.36 | $11.36 | Digi-Key |
| ADP124 | 1 | $1.95 | $1.95 | Digi-Key |
| AP1115 | 1 | $0.54 | $0.54 | Digi-Key |
| 0402 100nF Capacitor | 2 | $0.011 | $0.11 | Digi-Key |
| 0402 10pF Capacitor | 2 | $0.0116 | $0.12 | Digi-Key |
| 0402 33nF Capacitor | 2 | $0.024 | $0.05 | Digi-Key |
| 0603 4.7uF Capacitor | 3 | $0.1484 | $0.45 | Digi-Key |
| 0805 10uF Capacitor | 1 | $0.30 | $0.30 | Digi-Key |
| 0603 Capacitor | 1 | $0.0096 | $0.01 | eBay - mib_instruments |
| 0603 Resistor | 2 | $0.00294 | $0.01 | eBay - mib_instruments |
| 0402 Resistor | 1 | $0.025 | $0.03 | eBay - mib_instruments |
| 0603 Ferrite Bead (470 Ohm) | 1 | $0.0472 | $0.05 | Digi-Key |
| Male Header | 3 | $0.01 | $0.03 | eBay |
| SMA Female Connector | 1 | $3.37 | $3.37 | Digi-Key |
| SMA Female Connector | 1/5 | $2.51 | $0.50 | Dealextreme |
| PCB | 0.675"x0.75"/3 | $10.00 | $1.69 | Laen's PCB |
| Total Unit Cost | $20.57 |
PCB/Construction Photos
- Rev0VTx VCO PCB Bottom.jpg
Bottom of unpopulated PCB
- Rev0VTx VCO PCB Top.jpg
Top of unpopulated PCB
- Rev0VTx VCO Top.jpg
Populated PCB