Datasheet
SLVS324A − JULY 2001 REVISED NOVEMBER 2004
18
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APPLICATION INFORMATION
shutting down the TPS6040x
If shutdown is necessary, use the circuit in Figure 32. The output resistance of the TPS6040x will typically be
15 Ω plus two times the output resistance of the buffer.
Connecting multiple buffers in parallel can reduce the output resistance of the buffer driving the IN pin.
TPS60400
OUT C1+
IN
C1− GND
1
2
3
5
4
C
(fly)
1 µF
C
O
1 µF
C
I
1 µF
V
O
(−V
I
)
GND
V
I
GND
SDN
Figure 32. Shutdown Control
GaAs supply
A solution for a –2.7-V/3-mA GaAs bias supply is proposed in Figure 33. The input voltage of 3.3 V is first inverted
with a TPS60403 and stabilized using a TLV431 low-voltage shunt regulator. Resistor R
P
with capacitor C
P
is
used for filtering the output voltage.
TPS60400
OUT C1+
IN
C1− GND
1
2
3
5
4
C
(fly)
0.1 µF
C
O
1 µF
C
I
0.1 µF
V
O
(−2.7 V/3 mA)
GND
V
I
(3.3 V)
GND
R
P
TLV431
R2
R1
C
P
Figure 33. GaAs Supply
V
O
+*
ǒ
1 )
R1
R2
Ǔ
V
ref
* R1 I
I(ref)
A 0.1-µF capacitor was selected for C
(fly)
. By this, the output resistance of the inverter is about 52 Ω.