8
FN6526.1
June 24, 2008
Applications Information
Product Description
The ISL55016 Silicon Bipolar amplifier can match a 75Ω
single-ended source to a 100Ω differential load. This feature
makes the ISL55016 ideal for a wide range of general
purpose applications, such as Satellite TV.
Typical Application Circuit
ISL55016 is a true differential amplifier. Figure 29 shows the
Typical Application Circuit of ISL55016. Pins 2 and 3 are
equivalent.
The ISL55016 can configured so that it is driven with a
single-ended input. If either pin 2 or pin 3 is used as a
single-ended input, the other needs to be connected to an
AC ground. The input is internally matched to 75Ω
single-ended and the output is matched to 50Ω single-ended
or 100Ω differential.
The ISL55016 can be used as differential-in and differential-
out as well since pin 2 and pin 3 are equivalent, balanced
inputs.
Balun Function
In many applications of ISL55012, the amplifier will be
followed with a Balun structure to transfer the single-ended
signal to a differential tuner. The ISL55016 will eliminate the
need for an external balun structure and provide significant
savings in BOM cost and PCB real-estate (see Figure 30).
FIGURE 25. DIFFERENTIAL P1dB vs FREQUENCY FIGURE 26. DIFFERENTIAL OIP2 vs FREQUENCY
FIGURE 27. NOISE FIGURE vs FREQUENCY
FIGURE 28. DIFFERENTIAL OIP3 vs FREQUENCY
Typical Performance (V) 50Ω Environment, Z
RSC
= 50Ω, Z
LOAD
Port 2 = 50Ω, Z
LOAD
Port 3 = 50Ω, Measured on Evaluation Board. (Continued)
0
2
4
6
8
10
12
14
16
18
0 500M 1G 1.5G 2.0G
FREQUENCY (Hz)
dBm
27Ω
0Ω
0
10
20
30
40
50
60
70
0 500M 1G 1.5G 2.0G
FREQUENCY (Hz)
dBm
27Ω
0Ω
0
2
4
6
8
10
12
0 500M 1G 1.5G 2.0G 2.5G 3.0G
FREQUENCY (Hz)
dB
20
25
30
35
500M 1G 1.5G 2.0G
FREQUENCY (Hz)
dBm
15
10
5
0
0
27Ω
0Ω
1
2
3
6
5
4
RF IN 1
RF IN 2
ISL55016
C1
C2
C5
C4
RF Out 2
RF Out 1
C3
L1
L2
R2
R1
+5V
C6
FIGURE 29. APPLICATION CIRCUIT
ISL55016
