2002 Aug 06 4
NXP Semiconductors Product specification
MMIC wideband amplifier BGA2709
APPLICATION INFORMATION
Figure 2 shows a typical application circuit for the
BGA2709 MMIC. The device is internally matched to 50 ,
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 nominal value of the RF choke, L1 is 100 nH. At
frequencies below 100 MHz this value should be
increased to 220 nH. At frequencies above 1 GHz a much
lower value must be used (e.g. 10 nH) to improve return
losses. For optimal results, a good quality chip inductor
such as the TDK MLG 1608 (0603), or a wire-wound SMD
type should be chosen.
Both the RF choke, L1 and 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
MGU436
RF outRF in
C1
L1
C2 C3
GND2GND1
V
s
V
s
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 Simple cascade circuit.
handbook, halfpage
from RF
circuit
to IF circuit
or demodulator
MGU438
mixer
oscillator
wideband
amplifier
Fig.4 IF amplifier application.
handbook, halfpage
antenna
to IF circuit
or demodulator
MGU439
mixer
oscillator
LNA
wideband
amplifier
Fig.5 RF amplifier application.
handbook, halfpage
from modulation
or IF circuit
to power
amplifier
MGU440
mixer
oscillator
wideband
amplifier
Fig.6 Power amplifier driver application.
