R_10032

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Rev. 1.0 — 24 July 2012

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NXP Semiconductors

R_10032

CA-330-11; LDMOS bias module

U2 is a high-current operational amplifier chosen because it is stable with any capacitive

load. As shown in Figure 3, the output impedance of the bias source is low (less than

2.5

) because of the feedback around U2. However, practical LDMOS applications may

require an additional series gate resistor of 5

 to 20  to ensure low-frequency device

stability.

Fig 2.

Gate voltage as a function of temperature

temp

0

100

80

40

60

20

aaa-004139

2

1.5

2.5

3

1

(V)

(11)

(10)

(9)

(8)

(7)

(6)

(5)

(4)

(3)

(2)

(1)