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APPLICATION NOTE 1745

The MAX3510/MAX3514/MAX3516 Cable Upstream Amplifiers ACPR (Adjacent Channel Power Ratio) Performance

Abstract: Provides performance data for MAX3510/MAX3514/MAX3516 cable upstream driver amplifiers. ACPR and gain data are provided in graphical and tabular form. Units meet DOCSIS 2.0 standards with margin. Data is taken from 5MHz to 65MHz.

Additional Information The MAX3510/MAX3514/MAX3516 were tested for adjacent channel power ratio (ACPR). The test conditions were 5.0V supply and an input of +34dBmV. A set of plots was made to show the test results. The following data meets DOCSIS 2.0 with margin.

ACPR is an important parameter in cable amplifiers because a transmitted carrier may occur in an adjacent channel that could be occupied by a carrier of the same or different modulation rate. ACPR is defined as channel power ratio between the primary channel and adjacent channel. According to DOCSIS a 160kHz measurement bandwidth is used with 200kHz channel spacing.

The MAX3510/MAX3514/MAX3516 are a family of programmable-gain upstream amplifiers designed for use in CATV upstream applications. They operate over a frequency range of 5MHz to 65MHz and drives up to +64dBmV QPSK (MAX3516). Since both input and output ports are differential, an external balun at the output port is required. The variable gain feature provides greater than 56dB of dynamic range (MAX3514/MAX3516) and is controlled by a SPI 3-wire interface. Gain control is available in 0.5dB steps (MAX3514/MAX3516) or 1dB step (MAX3510).

Test Conditions

  • All tests at room temperature.
  • VCC = 5.0V - PIN = -13dBm (+34dBmV in 50Ω system)
  • Input signal: QPSK modulation with 20bit PRBS, root cosine filter, α = 0.25
  • High power mode
  • Input ACPR -66dBc
  • 200kHz channel spacing
  • 160kHz measurement bandwidth

Corrections and Unit Conversion

  • In 50Ω system, PIN/OUT (dBmV) = PIN/OUT (dBm) + 47dB
  • In 75Ω system, PIN/OUT (dBmV) = PIN/OUT (dBm) + 49dB
  • The MAX3510EVKit board has 3.5dB loss at the output, so POUT (dBmV) = POUT (dBm) + 47dB + 3.5dB + cable loss
  • The MAX3514/MAX3516EVKit boards have 7.5dB minimum loss pad at the output, so POUT (dBmV) = POUT (dBm) + 47dB + 7.5dB + cable loss

Test Equipment List

  • Signal generator capable of generating QPSK signals (RODHE & SCHWARZ SMIQ 06B)
  • Spectrum analyzer (RODHE & SCHWARZ FSEB)
  • Power meter (HP437B)
  • Power sensor (HP8482A)
  • Power supply (Agilent E3632A)
  • DMM (HPE3631A)
Figure 1. Test equipment set up.
For Larger Image
Figure 1. Test equipment set up.

Figure 2.
Figure 2.

Table 1. The MAX3510 ACPR vs. Output Power and Frequency
  Input (dBm) GCW Output (dBm) Output (dBmV) ACPR (dBc)
5MHz -13 49 4.41 51.41 -66
-13 52 7.16 54.16 -66
-13 55 9.92 56.92 -64.5
-13 59 13.59 60.59 -61.2
-13 61 15.5 62.5 -51.8
-13 63 17.03 64.03 -42
20MHz -13 49 4.03 51.03 -66
-13 52 6.82 53.82 -65.3
-13 55 9.59 56.59 -64
-13 59 13.29 60.29 -60.3
-13 61 15.19 62.19 -51.7
-13 63 16.72 63.72 -42.2
42MHz -13 50 4.30 51.30 -66
-13 53 7.29 54.29 -63.6
-13 56 10.06 57.06 -61.5
-13 59 12.81 59.81 -58.6
-13 61 14.76 61.76 -50.1
-13 63 16.29 63.29 -41.8
65MHz -13 50 3.95 50.95 -65.5
-13 53 6.73 53.73 -62.6
-13 56 9.5 56.5 -59.6
-13 59 12.26 59.26 -56.9
-13 61 14.24 61.24 -50.1
-13 63 15.76 62.76 -40.5

Figure 3.
Figure 3.

Table 2. The MAX3514 ACPR vs. Output Power and Frequency
  Input (dBm) GCW Output (dBm) Output (dBmV) ACPR (dBc)
5MHz -13 114 9.17 56.17 -66
-13 120 12.15 59.15 -66
-13 122 13.14 60.14 -66
-13 125 14.61 61.61 -66
20MHz -13 114 9.1 56.1 -66
-13 120 12.1 59.1 -65
-13 122 13.09 60.09 -64.5
-13 125 14.56 61.59 -63.4
42MHz -13 110 6.85 53.85 -66
-13 114 8.9 55.9 -64.2
-13 120 11.87 58.87 -62.9
-13 122 12.86 59.86 -62.9
-13 125 14.32 61.32 -61.2
65MHz -13 112 7.13 54.13 -66
-13 116 9.11 56.11 -61.5
-13 122 12.04 59.04 -59.8
-13 124 13.01 60.01 -58.5
-13 125 13.5 60.5 -58.2

Figure 4.
Figure 4.

Table 3. The MAX3516 ACPR vs. Output Power and Frequency
  Input (dBm) GCW Output (dBm) Output (dBmV) ACPR (dBc)
5MHz -13 116 13.39 60.39 -66
-13 120 15.34 62.34 -64.2
-13 122 16.31 63.31 -63.8
-13 125 17.68 64.68 -51.6
20MHz -13 116 13.41 60.41 -66
-13 120 15.38 62.38 -64.4
-13 122 16.38 63.36 -61.9
-13 125 17.74 64.74 -51.2
42MHz -13 12 11.01 58.01 -66
-13 116 12.94 59.94 -63.2
-13 120 14.9 61.9 -61
-13 122 15.87 62.87 -58.7
-13 125 17.23 64.23 -48.7
65MHz -13 112 10.10 57.10 -65
-13 116 12.18 59.18 -59.4
-13 120 14.11 61.11 -57.7
-13 122 15.07 62.07 -55.3
-13 125 16.42 63.42 -47.4

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More Information  APP 1745: Sep 27, 2002
MAX3510 Upstream CATV Amplifier Full Data Sheet
(PDF, 156kB)
MAX3514 Upstream CATV Amplifiers Full Data Sheet
(PDF, 532kB)
Free Samples
MAX3516 Upstream CATV Amplifiers Full Data Sheet
(PDF, 532kB)
Free Samples
 

Download, PDF FormatDownload, PDF Format (212kB)
 AN1745, AN 1745, APP1745, Appnote1745, Appnote 1745


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