VMMK-3803 Avago Technologies, VMMK-3803 Datasheet - Page 7

• Manufacturer Part Number: VMMK-3803
• Description: 3 - 11 Ghz Uwb Low Noise Ampli?er In Smt Package
• Manufacturer: Avago Technologies

VMMK-3803 Applications Information
Figure 13. Demo Board (available to qualified customers upon request)
Biasing and Operation
The VMMK-3803 is biased with a positive supply connected
to the output pin Vd through an external user supplied bias
decoupling network. Typical bias is 3 V at 20 mA. The “on”
state also requires that the input port of the VMMK-3803
also be biased at 3 V for normal gain operation. 0V on the
input puts the VMMK-3803 in the “off” state.
Figure 14. Example demonstration circuit of VMMK-3803 for broadband
operation (3GHz to 11GHz).
Figure 15. Biasing the VMMK-3803
7
Input
0.1 F
100 pF
10 K
50 Ohm line
Vpd
Input
Pad
Amp
Ground
Pad
Output
Pad
50 Ohm line
0.1 F
100 pF
Vdd
100 pF
6.8 nH
Output
Table 3. VMMK-3803 Demo Board BOM
An example of simple user supplied bias tees is shown in
Figure 13. The output bias decoupling network feeding
Vdd consists of a shunt 6.8 nH inductor. At the input, a 10
Kohm resistor is needed to feed the power-down control
voltage. The input and output dc blocking capacitors are
each 100 pF. The “on” and “off” S Parameters shown in the
preceding tables reflect the operation of the circuit shown
in Figure 13.
A layout of a typical demo board is shown in Figure 15.
The input and output bias decoupling network can be
easily constructed using small surface mount compo-
nents. The value of the shunt inductors can have a major
effect on both low and high frequency operation. The
demo board uses small value inductors that have self
resonant frequencies higher than the maximum desired
frequency of operation. If the self-resonant frequency of
the inductor is too close to the operating band, the value
of the inductor will need to be adjusted so that the self-
resonant frequency is significantly higher than the highest
frequency of operation.
Typically a passive component company like Murata does
not specify S parameters at frequencies higher than 5 or
6 GHz for larger values of inductance making it difficult
to properly simulate amplifier performance at higher fre-
quencies. It has been observed that the Murata LQW15AN
series of 0402 inductors actually works quite well above
their normally specified frequency.
The parallel combination of the 100 pF and 0.1 μF bypass
capacitors provide a low impedance in the band of
operation and at lower frequencies and should be placed
as close as possible to the inductor. The low frequency
bypass provides good rejection of power supply noise
and also provides a low impedance termination for
third order low frequency mixing products that will be
generated when multiple in-band signals are injected into
any amplifier.
Component
DUT
C1
C2
R1
C5
C6
L1
Value
VMMK-3803
100 pF
100 pF
10 KOhms
0.1 μF
100 pF
6.8 nH