6

Biasing and Operation

The AMMP-6522 is normally biased with a positive

drain supply connected to the Vd pin and a negative

gate voltage connected to the Vg pin through bypass

capacitors as shown in Figure 17. The recommended

drain supply voltage is 4 V and gate bias voltage is -1V.

The corresponding currents are 75 mA and 0.1 mA re-

spectively. The typical required LO level is +15 dBm and

it should come from a low noise driver to ensure that

overall Front End NF is low.

The image rejection performance is dependent on the

selection of the IF quadrature hybrid. The performance

of the IF hybrid as well as the phase balance and VSWR

of the interface to the AMMP-6522 will affect the overall

front end performance.

There is minimal performance degradation if Vdd is

lowered to 3 V or raised to 5 V. If lower current is re-

quired, then Vd = 3 V will provide considerably similar RF

performance.

Figure 17. Application of receiver with IF Balun

The recommended Vg is -1 V. However, depending on

the operating frequency, Vg can be changed to achieve

better performance for that particular frequency.

Please refer to Figures 9 and 10 for how to best select the

appropriate Vg for the intended frequency of operation.

Theoretically IF frequencies can be as low as DC. However,

when direct conversion is used (IF = DC), a so-called

phenomenon DC-offset could occur at the two IF

outputs. In most practical applications, IF should be

more than a few hundreds kHz to avoid DC-offset cor-

rection.

Refer the Absolute Maximum Ratings table for allowed

DC and thermal condition.

RF

IF1

LSB

NC

IF2

Vd

Vd

USB

LO

IF

RF

1000 pF

NC

Vg

LO

LO

+15 dBm

IF

1-3.5 GHz

USB

TOP VIEW

PACKAGE BASE: GND

IF

Vg

1000 pF

LSB