INA-12063 Ver la hoja de datos (PDF) - HP => Agilent Technologies
Número de pieza
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Fabricante
INA-12063 Datasheet PDF : 24 Pages
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While there are any number of
means of supplying the Ibias
control current, the simplest way
is to merely place a resistor
between the Vd and Ibias termi-
nals, shown as “Rbias” in
Figure␣ 10. R bias will be suffi-
ciently high to act as a current
source. The value for Rbias is
calculated as follows:
( ) Rbias = 10
Vd – 0.8
Ic
(1)
where Vd is the device voltage, Ic
is the desired collector current,
and Rbias is the value of the bias
determining resistor. For ex-
ample, for a desired collector
current of 1.5 mA and a power
supply of 2.7 volts, the value of
Rbias would be 12.7 KΩ.
Power Down
A power-down function for the
INA-12063 can be conveniently
implemented by switching the
Ibias current. This method has the
advantage of switching only a
very small current since Ibias is
typically only a fraction of a mA.
GND 2
RF
INPUT
Vd
ACTIVE
BIAS
CIRCUIT
Rbias
SUPPLY
VOLTAGE
Ibias
BIAS
ISOLATION
Vc
RF
TRANSISTOR
Ic
RF OUTPUT
RF
FEEDBACK
CIRCUIT
GND 1
Figure 10. Single-Resistor Bias
Circuit.
Amplifier Application
Guidelines
This section describes the general
approach for designing amplifiers
using the INA-12063. This is a
generic design approach and is
applicable for most low noise RF
or IF amplifiers or for general
purpose gain and buffer stages.
The following “10-step” program
is suggested as the design se-
quence:
1. Determine performance goals.
2. Select the bias condition.
3. Choose PCB material.
4. Check stability.
5. Determine required DC
connections.
6. Design the input impedance
matching network.
7. Design the output impedance
matching network.
8. Layout the printed circuit
board.
9. Computer optimization and
performance verification.
10. Fabricate, assemble, and test.
Each of these steps in the design
sequence will now be discussed
in the following sections.
Step 1. Establish Performance
Goals
The first step in the design of an
INA-12063 amplifier stage is to
establish performance goals. It
may be necessary to consider
performance tradeoffs between
some amplifier parameters, such
as Noise Figure, Input VSWR,
Gain, Output Power, Output
VSWR, Stability, and DC power
consumption.
Some of these parameters are
counterposed, for example,
increased output power requires
greater DC power consumption.
The tradeoff decisions may
require consideration of the
choice of DC bias which is
discussed in the next section. The
final design will often be a
balance between system-critical
performance and those param-
eters of lesser significance.
Step 2. Choose Bias
Conditions
The second step of the design
process is to choose the bias
conditions, i.e., the RF transistor
operating voltage (Vc) and
current (Ic). The bias conditions
are chosen at this step in the
design sequence since many of
the RF design characteristics
(e.g., S-parameters and noise
parameters) are dependent on
current and/or voltage.
The choice of bias voltage is often
preemptive as it is normally fixed
by available system resources,
such as a battery voltage or
system power supply. The
INA-12063 will operate from
supply voltages from 1.5 to
5␣ volts, with +3 volts considered
to be the typical operating
voltage.
Although noise figure and gain
are somewhat insensitive to
device voltage as an independent
variable, some increase in output
power can be realized with higher
device voltages.
The bias current has the greatest
effect on RF performance and the
following tradeoffs should be
considered:
Noise Figure increases with
device current. The data in the
Typical Noise Parameter tables
shows an increase in Fmin of from
1.4 dB at 1.5 mA of bias current to
2.0 dB at 8 mA.
Gain – Transducer gain, |S21|2,
increases significantly in propor-
tion to device current.
Output Power – One of the
benefits of increased device
current is greater output power. A
typical increase in current from
1.5 to 8 mA results in a corre-
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