RMDA29000 Ver la hoja de datos (PDF) - Fairchild Semiconductor
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RMDA29000 Datasheet PDF : 8 Pages
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Recommended Procedure for Biasing and Operation
CAUTION: LOSS OF GATE VOLTAGE (Vg) WHILE
DRAIN VOLTAGE (Vd) IS PRESENT MAY DAMAGE THE
AMPLIFIER CHIP.
The following sequence of steps must be followed to
properly test the amplifier:
Step 1: Turn off RF input power.
Step 2: Connect the DC supply grounds to the ground of
the chip carrier. Slowly apply negative gate bias supply
voltage of -1.5V to Vg.
Step 3: Slowly apply positive drain bias supply voltage of
+5V to Vd.
Step 4: Adjust gate bias voltage to set the quiescent
current of Idq = 250mA.
Step 5: After the bias condition is established, the RF input
signal may now be applied at the appropriate frequency
band.
Step 6: Follow turn-off sequence of:
(i) Turn off RF input power,
(ii) Turn down and off drain voltage (Vd),
(iii) Turn down and off gate bias voltage (Vg).
An example auto bias sequencing circuit to apply negative
gate voltage and positive drain voltage for the above
procedure is shown below.
D3
D1N6098
+6V
D2
D1N6098
R1
3.0k
C1
0.1µF
R3
1.0k
–2.62V
R4
1.2k
*
+ V+ U2
AD820/AD
V-
–
R2
0
6.8k
0
1
U1A 3
2 7400
C2
0 0.47µF
LM2941T
2 CNT
4 IN
3
5
OUT
GND
ADJ
1
MMIC_+VDD
C3
22µF
R6
R5
0
0 1k
3k
0
*Adj. For –Vg
–5V
*–5V Off: +3.33V
–5V Off: +1.80V
C4
R7
0.1µF
8.2k
R8
1.0k
C5
0.1µF
MMIC_–VG
0
0
0
©2004 Fairchild Semiconductor Corporation
RMDA29000 Rev. C
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