RMPA39000 Просмотр технического описания (PDF) - Fairchild Semiconductor
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RMPA39000 Datasheet PDF : 10 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 = 700mA.
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).
Note: 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
Figure 5. Application Information Auto-Bias Circuit
©2004 Fairchild Semiconductor Corporation
RMPA39000 Rev. D
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