2002 Jul 03 4
Philips Semiconductors Product specification
MMIC wideband amplifier BGA2748
APPLICATION INFORMATION
Figure 2 shows a typical application circuit for the
BGA2748 MMIC. The device is internally matched to 50 Ω,
and therefore does not need any external matching. The
value of the input and output DC blocking capacitors C2,
C3 should be not more than 100 pF for applications above
100 MHz. However, when the device is operated below
100 MHz, the capacitor value should be increased.
The 22 nF supply decoupling capacitor, C1 should be
located as closely as possible to the MMIC.
Separate paths must be used for the ground planes of the
ground pins GND1, GND2, and these paths must be as
short as possible. When using vias, use multiple vias per
pin in order to limit ground path inductance.
Figure 3 shows two cascaded MMICs. This configuration
doubles overall gain while preserving broadband
characteristics. Supply decoupling and grounding
conditions for each MMIC are the same as those for the
circuit of Fig.2.
The excellent wideband characteristics of the MMIC make
it and ideal building block in IF amplifier applications such
as LBNs (see Fig.4).
As a buffer amplifier between an LNA and a mixer in a
receiver circuit, the MMIC offers an easy matching, low
noise solution (see Fig.5).
In Fig.6 the MMIC is used as a driver to the power amplifier
in part of a transmitter circuit. Good linear performance
and matched input and output offer quick design solutions
in such applications.
handbook, halfpage
MGU435
RF outRF in
C1
C2 C3
GND2GND1
Vs
Vs
RF input RF output
Fig.2 Typical application circuit.
handbook, halfpage
DC-block
100 pF DC-block
100 pF
DC-block
100 pF
input output
MGU437
Fig.3 Easy cascading application circuit.
handbook, halfpage
from RF
circuit to IF circuit
or demodulator
MGU438
mixer
oscillator
wideband
amplifier
Fig.4 Application as IF amplifier.
handbook, halfpage
antenna to IF circuit
or demodulator
MGU439
mixer
oscillator
LNA wideband
amplifier
Fig.5 Application as RF amplifier.
handbook, halfpage
from modulation
or IF circuit to power
amplifier
MGU440
mixer
oscillator
wideband
amplifier
Fig.6 Application as driver amplifier.