Difference between revisions of "PE4302 RF Attenuator"

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Revision as of 11:01, 12 September 2021

RF Atten-Front-01.jpg

RF Atten-Rear-01.jpg

Features

  • PE4302 RF attenuator module
  • Parallel immediate mode
  • Program control gain attenuation range is from 0 to 31.5dB
  • Bandwidth 1MHz to 4GHz

Specifications

  • Power Supply Voltage
    • 2.7-3.3 VDC - 3V typical
    • Typical current 5mA
  • Program control gain attenuation range
    • 0~31.5DB
    • 10K pull down resistors to ground
    • Step size: 0.5DB
  • Input/Output Impedance
    • 50 ohm
  • Bandwidth
    • 1MHz~4GHz
    • Attenuation value will differ under different frequency
  • Max Input power (50Ω)
    • +30 dBm
    • 1W = 7.1V RMS
  • Connectors
    • SMA-female

My Design

  • A lot of designs use Arduino/OLED, etc to control the card - unnecessary
    • Could add noise from OLED
    • Doesn't need to switch too often
  • Mount in small 80mm x 50mm x 20mm project box
  • SMA connectors
    • Board connector for one SMA
    • Short cable male SMA to SMA female bulkhead SMA for other end
  • PE6402 remove straight header, replace with right angle connector over card
  • Mini360 Adapter Board for wide input voltage range
    • 4.75-23V input
    • 3V output
    • Concern over EMI?
    • Right angle connector 2x3 min
  • Use SWLEDX8 to control attenuation selection
    • Right angle 2x10 under card for low profile installation
    • Use SW1-SW6 switches (centered horizontally on card)
    • Digital Input High 0.7xVDD in V = 2.1V
    • Using 1.2K-1.5K pullup to counter the 10K pulldowns on the card = 2.6V
    • When switch is on/low - 3V / 1.5K = 2 mA
    • Adds to current 2 mA x 6 = 12 mA when all switches are low
    • Use D7 for power indication
      • Vf = 1.8V, 3V-1.8V = 1.2V, 3 mA for lower light level - use 470 ohm resistor
  • Cabling
    • 1x7 pin PE4302 connector (Use 1x8, ignore 8th pin)
    • 2x10 Dupont connector for SWLEDX8
      • Ground, power to D7 LED, 6 switches
    • 2x3 Dupont connector with pins from Mini360 Adapter Board

SWLEDX8-720px.jpg

Measurements

  • NanoVNA
  • 1-300 MHz
  • All switches set to GND
  • Min -1.2 dB insertion loss

SW All 0s.PNG

  • S21 Gain zoomed in

SW All 0s-ZoomedIn.PNG

  • All switches set to GND
  • Min -1.2 dB insertion loss

SW All 1s.PNG

References