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ADL5902 Pin test condition of Output Noise, Rise and Fall Times vs. CLPF Capacitance ?

Category: Datasheet/Specs
Product Number: ADL5902

Hi all,

Regarding the ADL5902 data sheet test conditions.

Which input level is correct, 0dBm or -10dBm ?

Figure 46. Output Noise, Rise and Fall Times vs. CLPF Capacitance, SingleCarrier W-CDMA (TM1-64) at 2.14 GHz with PIN = 0 dBm

Figure 46 also shows how CLPF affects the response time of VOUT.
To measure this, a RF burst at 2.14 GHz at −10 dBm was applied to the ADL5902. The 10% to 90% rise time and 90% to 10% fall time is then measured.

Figure 48. Residual Ripple, Rise and Fall Times Using an RC Low-Pass Filter at VOUT, PIN = 0 dBm at 2.14 GHz

Figure 48 shows the resulting rise and fall times (signal is pulsed between off and −10 dBm) with CLPF equal to 10 nF.

A 2 kΩ resistor is placed in series with the VOUT pin, and the capacitance from this resistor to ground (CFILTER in Figure 47) is varied up to 1 μF.

Best Regards,

sss

Parents
  • Greetings sss,

    As with AD8362, LTC5582, and many other Analog Devices RMS detectors, the ADL5902 incorporates an RF internal RF attenuator, square cell, and feedback loop. In normal operation, the RF level into the square cell is 'leveled' at a value determined by an external target voltage, set by the voltage on VTGT pin in the case of ADL5902. 

    This means RF level into and out of the square cell is relatively constant, thus tending to stabilize ripple level at the detector output. In other words, ripple due to amplitude modulation components should hold constant, provided that the RF drive level is within the low error measurement window of the device. 

    Output rise and fall times will vary somewhat with drive level, as shown on datasheet figures 22, 23, 25, and 26. For the more demanding applications where best rise and fall times are required, but also lowest possible ripple is required, the text accompanying figures 47 and 48 describe how higher order external filter or RC filter at the output can further assist. 

Reply
  • Greetings sss,

    As with AD8362, LTC5582, and many other Analog Devices RMS detectors, the ADL5902 incorporates an RF internal RF attenuator, square cell, and feedback loop. In normal operation, the RF level into the square cell is 'leveled' at a value determined by an external target voltage, set by the voltage on VTGT pin in the case of ADL5902. 

    This means RF level into and out of the square cell is relatively constant, thus tending to stabilize ripple level at the detector output. In other words, ripple due to amplitude modulation components should hold constant, provided that the RF drive level is within the low error measurement window of the device. 

    Output rise and fall times will vary somewhat with drive level, as shown on datasheet figures 22, 23, 25, and 26. For the more demanding applications where best rise and fall times are required, but also lowest possible ripple is required, the text accompanying figures 47 and 48 describe how higher order external filter or RC filter at the output can further assist. 

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