AD8352-EVALZ(RevA) Ver la hoja de datos (PDF) - Analog Devices
Número de pieza
componentes Descripción
Lista de partido
AD8352-EVALZ Datasheet PDF : 20 Pages
| |||
APPLICATIONS
GAIN AND DISTORTION ADJUSTMENT
(DIFFERENTIAL INPUT)
Table 5 and Table 6 show the required value of RG for the gains
specified at 200 Ω and 1 kΩ loads. Figure 22 and Figure 24 plot
gain vs. RG up to 18 dB for both load conditions. For other
output loads (RL), use Equation 1 to compute gain vs. RG.
AVDifferential
=
⎜⎛
⎜⎝
(RG
+
RG + 500
5) (RL + 53)
+
430
⎟⎞
⎟⎠
R
L
(1)
where:
RL = single-ended load.
RG = gain setting resistor.
The third-order harmonic distortion can be reduced by using
external components RD and CD. Table 5 and Table 6 show the
required values for RD and CD for the specified gains to achieve
(single tone) third-order distortion reduction at 180 MHz.
Figure 23 and Figure 25 show any gain (up to 18 dB) vs. CD for
200 Ω and 1 kΩ loads, respectively. When these values are
selected, they result in minimum single tone, third-order
distortion at 180 MHz. This frequency point provides the best
overall broadband distortion for the specified frequencies below
and above this value. For applications above approximately
300 MHz, CD and RD are not required. See the Specifications
section and third-order harmonic plots in the Typical
Performance Characteristics section for more details.
CD can be further optimized for narrow-band tuning require-
ments below 180 MHz that result in relatively lower third-order
(in-band) intermodulation distortion terms. See the Narrow-
Band, Third-Order Intermodulation Cancellation section for
more information. Though not shown, single tone, third-order
optimization can also be improved for narrow-band frequency
applications below 180 MHz with the proper selection of CD,
and 3 dB to 6 dB of relative third-order improvement can be
realized at frequencies below approximately 140 MHz.
Using the information listed in Table 5 and Table 6, an extrapolated
value for RD can be determined for loads between 200 Ω and 1 kΩ.
For loads above 1 kΩ, use the 1 kΩ RD values listed in Table 6.
Table 5. Broadband Selection of RG, CD, and RD: 200 Ω Load
AV (dB)
RG (Ω)
CD (pF)
RD (kΩ)
3
390
Open
6.8
6
220
Open
4.3
9
140
0.1
4.3
10
115
0.2
4.3
12
86
0.3
4.3
15
56
0.6
4.3
18
35
1
4.3
AD8352
Table 6. Broadband Selection of RG, CD, and RD: 1 kΩ Load
AV (dB)
RG (Ω)
CD (pF)
RD (kΩ)
3
750
Open
6.8
6
360
Open
6.8
9
210
Open
6.8
10
180
0.05
6.8
12
130
0.1
6.8
15
82
0.3
6.8
18
54
0.5
6.8
20
18
16
14
12
10
8
6
4
2
0
0
50 100 150 200 250 300 350 400
RG (Ω)
Figure 22. Gain vs. RG, RL = 200 Ω
20
18
16
14
12
10
8
6
4
2
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
CD (pF)
Figure 23. Gain vs. CD, RL = 200 Ω
Rev. A | Page 11 of 20
Share Link: 