NE5204 Philips, NE5204 Datasheet - Page 8

• Manufacturer Part Number: NE5204
• Description: Wide-band high-frequency amplifier
• Manufacturer: Philips

Philips Semiconductors
PC BOARD MOUNTING
In order to realize satisfactory mounting of the NE5204A to a PC
board, certain techniques need to be utilized. The board must be
double-sided with copper and all pins must be soldered to their
respective areas (i.e., all GND and V
power supply should be decoupled with a capacitor as close to the
V
the supply and the device. Caution should be exercised in the
connection of input and output pins. Standard microstrip should be
observed wherever possible. There should be no solder bumps or
burrs or any obstructions in the signal path to cause launching
problems. The path should be as straight as possible and lead
lengths as short as possible from the part to the cable connection.
Another important consideration is that the input and output should
be AC-coupled. This is because at V
approximately at 1V while the output is at 3.1V. The output must be
decoupled into a low-impedance system, or the DC bias on the
output of the amplifier will be loaded down, causing loss of output
power. The easiest way to decouple the entire amplifier is by
soldering a high-frequency chip capacitor directly to the input and
output pins of the device. This circuit is shown in Figure 18. Follow
these recommendations to get the best frequency response and
noise immunity. The board design is as important as the integrated
circuit design itself.
SCATTERING PARAMETERS
The primary specifications for the NE5204A are listed as
S-parameters. S-parameters are measurements of incident and
reflected currents and voltages between the source, amplifier, and
load as well as transmission losses. The parameters for a two-port
network are defined in Figure 19.
1992 Feb 25
CC
Wide-band high-frequency amplifier
pins as possible, and an RF choke should be inserted between
V
IN
Coupling and Power Supply Decoupling
CAPACITOR
COUPLING
Figure 18. Circuit Schematic for
AC
NE5204A
V
CC
RF CHOKE
CC
CC
CAPACITOR
COUPLING
=6V, the input is
pins on the package). The
AC
DECOUPLING
CAPACITOR
V
OUT
SR00210
8
the voltage standing wave ratios. These relationships are as follows:
Actual S-parameter measurements using an HP network analyzer
(model 8505A) and an HP S-parameter tester (models 8503A/B) are
shown in Figure 20.
Values for the figures below are measured and specified in the data
sheet to ease adaptation and comparison of the NE/SA/SE5204A to
other high-frequency amplifiers.
The most important parameter is S
of the power gain, and, in decibels, is equal to voltage gain as
shown below:
Z
P
P
V
Measured value for the
and V
In decibels:
P
V
Also measured on the same system are the respective voltage
standing wave ratios. These are shown in Figure 21. The VSWR
can be seen to be below 1.5 across the entire operational frequency
range.
Relationships exist between the input and output return losses and
NE/SA/SE5204A = |S
D
IN
I
I
I(dB)
I(dB)
=Insertion Power Gain
=Insertion Voltage Gain
P
P
=Z
P
P
P
I
I
I(dB)
OUT
=V
IN
IN
I
=10 Log | S
= 20 Log S
=Z
I
V
2
Z
= V
P
IN
OUT
D
P
OUT
V
2
IN
V
I(dB)
OUT
V
IN
V
for the NE/SA/SE5204A
OUT
Z
Z
IN
D
D
= S
NE5204A
21
2
21
2
| S
= 20dB
21(dB)
|
Z
2
D
21
21
P
= 20dB
V
I
|
V
|
= 20dB
2
OUT
2
IN
= 100
2
2
S
P
21
OUT
100
21
P
. It is defined as the square root
I
10
V
NE/SA5204A
OUT
Z
D
2
Product specification