AD8352ACPZ-R7 datasheet(13/20 Pages) AD

13 / 20 page

AD8352

Rev. A | Page 13 of 20

–60

–110

FREQUENCY (MHz)

140

190

240

–70

–80

–90

–100

3RDS, 2V p-p OUT

3RDS, 1V p-p OUT

Figure 29. Single-Ended, Third-Order Harmonic Distortion, 200 Ω Load

–60

–110

FREQUENCY (MHz)

140

190

240

–70

–80

–90

–100

2NDS, 1V p-p OUT

2NDS, 2V p-p OUT

Figure 30. Single-Ended, Second-Order Harmonic Distortion, 1 kΩ Load

–60

–110

FREQUENCY (MHz)

140

190

240

–70

–80

–90

–100

3RDS, 1V p-p OUT

3RDS, 2V p-p OUT

Figure 31. Single-Ended, Third-Order Harmonic Distortion, 1 kΩ Load

Table 7. Distortion Cancellation Selection Components

(RD and CD) for Required Gain, 200 Ω Load

AV (dB)

RG (Ω)

CD (pF)

RD (kΩ)

4.3 k

Open

4.3

540

Open

4.3

220

0.1

4.3

120

0.3

4.3

0.6

4.3

0.9

4.3

Table 8. Distortion Cancellation Selection Components

(RD and CD) for Required Gain, 1 kΩ Load

AV (dB)

RG (Ω)

CD (pF)

RD (kΩ)

3 k

Open

4.3

470

Open

4.3

210

0.2

4.3

120

0.3

4.3

0.5

4.3

NARROW-BAND, THIRD-ORDER

INTERMODULATION CANCELLATION

Broadband, single tone, third-order harmonic optimization

does not necessarily result in optimum (minimum) two tone,

third-order intermodulation levels. The specified values for CD

and RD in Table 5 and Table 6 were determined for minimizing

broadband, single tone, third-order levels.

Due to phase-related distortion coefficients, optimizing single

tone, third-order distortion does not result in optimum in band

(2f1 − f2 and 2f2 − f1), third-order distortion levels. By proper

selection of CD (using a fixed 4.3 kΩ RD), IP3s of better than

45 dBm are achieved. This results in degraded out-of-band,

third-order frequencies (f2 + 2f1, f1 + 2f2, 3f1 and 3f2). Thus,

careful frequency planning is required to determine the

tradeoffs.

Figure 32 shows narrow band (2 MHz spacing) OIP3 levels

optimized at 32 MHz, 70 MHz, 100 MHz, and 180 MHz using

the CD values specified in Figure 33. These four data points (the

CD value and associated IP3 levels) are extrapolated to provide

close estimates of IP3 levels for any specific frequency between

30 MHz and 180 MHz. For frequencies below approximately

140 MHz, narrow-band tuning of IP3 results in relatively higher

IP3s (vs. the broadband results shown in Table 2 specifications).

Though not shown, frequencies below 30 MHz also result in

improved IP3s when using proper values for CD.

FREQUENCY (MHz)

100

150

RL = 200Ω

RD = 4.3kΩ

CD = 0.3pF

6dB

10dB

15dB

18dB

AV =

Figure 32. Third-Order Intermodulation Distortion vs. Frequency for

Various Gain Settings

AD8352ACPZ-R7 Datenblatt(PDF) 13 Page - Analog Devices

AD8352ACPZ-R7 Datenblatt(HTML) 13 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datenblatt Download

Link URL