ISL55210-ABEVAL1Z Intersil, ISL55210-ABEVAL1Z Datasheet - Page 6

• Manufacturer Part Number: ISL55210-ABEVAL1Z
• Description: Amplifier IC Development Tools ISL55210 Eval Diff. Amp, Active Balun
• Manufacturer: Intersil
• Type: Differential Amplifiersr
• Series: ISL55210r

Specifications of ISL55210-ABEVAL1Z

• Rohs: yes
• Product: Evaluation Board
• Tool Is For Evaluation Of: ISL55210
• Operating Supply Voltage: 3.3 V
• Description/function: Evaluation board to test the performance of the active balun
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Operating Supply Current: 34 mA
• For Use With: ISL55210

The ISL55210 does show true intercept performance on the 3rd
order terms and Figure 10 is showing the expected rolloff in the
intercept for this low power device as the loop gain rolls off.
Going to higher gains will move this curve down while going to
lighter loads will move it up. Offering >39dBm OIP3 through
200MHz is exceptional for a 115mW device. Below 100MHz the
3rd order intermodulation tones become very difficult to
measure where the intercept is exceeding 50dBm.
Options and Summary
This simple building block can be tested for any target input
impedance and gain setting to get its performance prior to
combining with other system elements before and after this
stage. It does depend on the source impedance being close to
the expected value in the desired frequency band. If that source
impedance deviates widely out of band, a passive bandpass filter
at the output is recommended in the design to limit out of band
noise peaking issues [4]. The ISL55210 is, however, internally
compensated to remain stable for any source impedance. It does
need to avoid direct capacitive loads at the outputs but adding at
least 10Ω series output elements is adequate to isolate that
effect. While the ISL55210 includes input protection diodes
across the input, high overdrives have been found to latch the
device into a low loop gain condition. This can be reset using the
disable function of the device but if possible avoid high overdrive
conditions.
This board can be set literally for any input impedance and gain
by changing the R1 'R4 values in Figure 4 using Equations 1
and 2. For example, a set of values for a 75Ω input are shown in
Table 1 with estimated F-3dB bandwidths to the FDA output pins.
FIGURE 10. MEASURED AND LINE FIT OIP3 FOR THE CIRCUIT OF
50
45
40
35
30
25
20
100
FIGURE 1 DRIVING A DOUBLY TERMINATED 50Ω LOAD
LINEAR (OIP3 AT 50Ω LOAD)
CENTER FREQUENCY (MHz) (±100kHz)
OIP3 AT 50Ω LOAD
6
Application Note 1831
The parametric response curves from iSim PE are shown in
Figure 11 for these settings and a 75Ω source into this active
balun configuration of the ISL55210. These response curves are
from the input of R
amplifier.
12.59
15.85
19.95
25.12
50.12
10.00
31.62
39.81
GAIN
5.01
6.31
7.94
V/V
FIGURE 11. PARAMETRIC RESPONSE CURVES FOR 75Ω INPUT
TABLE 2. RESISTOR VALUES AND SIMULATED F-3DB FOR SWEPT
36
33
30
27
24
21
18
15
12
1M
GAIN
GAIN = 14dB
GAIN = 16dB
GAIN = 18dB
GAIN = 20dB
(dB)
14
16
18
20
22
24
26
28
30
32
34
GAIN 75Ω INPUT IMPEDANCE
DESIGNS
161.0353
195.705
238.525
291.6667
357.877
440.6207
544.2603
674.2841
837.5952
1042.876
1301.049
Rf
g1
to the differential output pins of the
10M
14.26153
12.03431
10.05704
8.333333
6.85436
5.602576
4.555264
3.68747
2.974174
2.391731
1.918696
FREQUENCY (Hz)
Rg1
GAIN = 22dB
GAIN = 24dB
GAIN = 26dB
GAIN = 28dB
64.26153
62.03431
60.05704
58.33333
56.85436
55.60258
54.55526
53.68747
52.97417
52.39173
51.9187
Rg2
100M
SIMULATED BW
GAIN = 30dB
GAIN = 32dB
GAIN = 34dB
(MHz)
3900
3155
2037
1200
811
588
445
330
260
205
158
April 5, 2013
AN1831.0
1G