ADL5604 Analog Devices, ADL5604 Datasheet - Page 21

• Manufacturer Part Number: ADL5604
• Description: 700 MHz To 2700 MHz 1 W RF Driver Amplifier
• Manufacturer: Analog Devices

Table 7. Evaluation Board Configuration Options, 2140 MHz
Component
C1, C2
C3, C4
C5
L1, L2, R9, R10
C6, C7, C8, C9,
C10, C11, C12,
C14, C15
R6, R8
R2, R4, R5
U2, R1, R3
Exposed Paddle
Figure 44. Evaluation Board Layout, Topside
Function/Notes
Input/output dc blocking capacitors at 2140 MHz. C3 provides dc blocking; therefore, a jumper is
installed in place of C1.
Input matching capacitors. The input match is set for 2140 MHz but is easily changed for other
frequencies. C3 is set at a specific distance from C4 so that the microstrip line can act as inductance for
part of the match. If space is at a premium, an inductor can take the place of the microstrip line. The
ADL5604 is sensitive to the input match; therefore, the tolerance of these components and their
placement must be tight.
Output matching capacitor. The output match is set for 2140 MHz but is easily changed for other
frequencies. The tolerance for this capacitor should be tight. C5 is set at a specific distance from the
input; therefore, the microstrip line can act as inductance for part of the match. If space is at a
premium, an inductor can take the place of the microstrip line. There is a short length of low
impedance line on the output that is embedded in the match. The ADL5604 is less sensitive to the
output match than the input match, but the tolerance still must be tight.
The main bias for the ADL5604 comes through L1 to its output. L1 should be high impedance for
the frequency of operation, while providing low resistance for the dc current. The evaluation
board uses a Coilcraft 0603HP-16NX_H inductor. It is a 16 nH inductor, which provides some of
the match at 2140 MHz. As the operating frequency gets lower, the inductance must increase,
but as the inductance increases, the current is more limited for a 0603 package. R9 and R10 can
be removed and L2 added to allow for low frequency operation. L2 has the footprint for a
Coilcraft SLC7530D-101MLB (0.4 μH).
Power supply decoupling. The need for power supply decoupling capacitance is based on the
noise and potential for noise on the power supply. The smallest capacitor should be the closest
to the ADL5604. The main bias that goes through RFOUT is the most sensitive to noise because
the bias is connected directly to the output.
R6 and R8 can be removed to eliminate any parasitic elements of VBIAS and VCC2 if a fast
response time is required.
The ADL5604 can be shut down using VBIAS alone or VBIAS and VCC2. The ADL5604 has a
shutdown current of 13 mA when only VBIAS is used. The shutdown current is < 1 μA if VBIAS and
VCC2 are used. However, VCC2 draws 5 mA when biased, setting the current drive capability of
the shutdown controller. R2, R4, and R5 allow custom configuration of the shutdown.
If VCC2 is used to shut down the ADL5604, 5 mA must be sourced when the part is enabled. U2,
R1, and R3 are configured as a buffer to source the 5 mA.
The paddle should be connected to both thermal and electrical ground.
Rev. 0 | Page 21 of 24
Figure 45. Evaluation Board Layout, Bottom Side
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L1 = 16 nH,
L2 = open,
R9 = 0 Ω,
R10 = 0 Ω
C6, C9, C11 = 10nF,
C7, C10, C12, C14,
C15 = 0.1uF,
C8 = 10 uF
R6 = 0 Ω,
R8 = 0 Ω
R2, R5 = 0 Ω,
R4 = open
U2 = AD8009,
R1 = 3.01 Ω,
R3 = open
Default Value
C1 = 0 Ω,
C2 = 22 pF
C3 = 1.3 pF HQ,
C4 = 2.7 pF HQ
C5 = 2.4 pF
ADL5604