8

Figure 14. Biasing the VMMK-3603

Figure 12. Evaluation/Test Board (available to qualified customers upon

request)

VMMK-3603 Applications and Usage Information

Table 3. VMMK-3603 Demo Board BOM

Component

Value

DUT

VMMK-3603

C1

100 pF

C2

8.2 pF

C5

0.1

μF

C6

100 pF

R1

820 Ohms

R2

10 Ohms

L1

10 nH

Biasing and Operation

TheVMMK-3603 is biased with a positive supply connected

to the output pin Vd through an external user supplied

bias decoupling network. Nominal current draw is 22 mA.

A typical biasing scheme is shown in Figure 12.

Figure 13. Example demonstration circuit of VMMK-3603 for broadband

operation (1 GHz to 6 GHz).

A layout of a typical demo board is shown in Figure 14. The

output bias decoupling network can be easily constructed

using small surface mount components. The value of the

output inductor can have a major effect on both low and

high frequency operation. The demo board uses a 10 nH

inductor that has a self resonant frequency 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 sig-

nificantly higher than the highest frequency of operation.

A 10 ohm resistor is placed in series with the inductor

to help provide greater bandwidth and to help with low

frequency stability. To help with low frequency stability an

820 ohm resistor is used to shunt the input line to ground.

8.2 pF capacitors are used as dc blocks on the RF input and

RF output lines.

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 capaci-

tors 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.

Amp

Input

Vdd

Output

Output

Pad

Ground

Pad

Input

Pad

50 Ohm line

50 Ohm line

100 pF

0.1

µF

10 nH

8.2 pF

820

8.2 pF

10