ZABG6002 Datasheet, PDF (7/12 Pages) Diodes Incorporated – LOW POWER 6 STAGE FET LNA AND MIXER BIAS CONTROLLER

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Diodes Incorporated
ZABG6002
Application Information
The ZABG6002 is a flexible device and can be set up in a number of ways.
1. 6 LNA stages to provide standard bias to the GaAs or HEMT FET’s
2. 4 LNA stages to provide standard bias to the GaAs or HEMT FET’s plus 2 active mixer stages
3. Power down FET groups for LNA switching or power saving.
The truth table below shows the function of these features.
R_cal Pin Resistor Termination
Rcal1
Gnd
Gnd
Gnd
Gnd
3V
3V
3V
3V
Rcal2
Gnd
Gnd
3V
3V
Gnd
Gnd
3V
3V
RcalM
Open
Gnd
Open
Gnd
Open
Gnd
Open
Gnd
1st LNA
Stages
Bias 1 Bias 4
On
On
On
On
On
On
On
On
Off
Off
Off
Off
Off
Off
Off
Off
FET Stage
2nd LNA
Stages
Bias 2 Bias 5
On
On
On
On
Off
Off
Off
Off
On
On
On
On
Off
Off
Off
Off
3rd LNA/Mixer
Stages
Bias 3 Bias 6
On
On
Mixer
Mixer
Off
Off
Mixer
Mixer
On
On
Mixer
Mixer
Off
Off
Mixer
Mixer
ZABG6002 in 6 LNA mode
Below is a partial applications circuit for the ZABG6002 showing all external components needed for biasing one of
the six FET stages available as a normal LNA bias. Each bias stage is provided with a gate and drain pin. The drain
pin provides a regulated 2.0V supply that includes a drain current monitor. The drain current taken by the external
FET is compared with a user selected level, generating a signal that adjusts the gate voltage of the FET to obtain
the required drain current. If for any reason, an attempt is made to draw more than the user set drain current from
the drain pin, the drain voltage will be reduced to ensure excess current is not taken. The gate pin drivers are also
current limited.
Vcc
L*
C*
JF2
L*
C1
10nF
D2
G2
D3
G3
RcalM
ZABG6002
D5
G5
D6
G6
Rcal1
C*
C2
10nF
* Stripline Elements
CNB
47nF
CSUB
47nF
RCAL2
36k
RCAL1
36k
The bias stages are split up into two groups, with the drain current of each group set by an external R_CAL resistor.
R_CAL1 sets the drain currents of stages 1 and 4, whilst R_CAL2 sets the drain currents of stages 2,3,5 and 6.
ZABG6002
Document number: DS32078 Rev. 1 - 2
7 of 12
www.diodes.com
May 2010
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