Analog Devices EVAL-ADPA1106 User manual

User Guide | EVAL-ADPA1106
UG-2037
Evaluating the ADPA1106 46 dBm (40 W), 2.7 GHz to 3.5 GHz, GaN Power Amplifier
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS. Rev. 0 | 1 of 13
FEATURES
►2-layer Rogers 4350B evaluation board with heat spreader
►End launch SMA jack RF connectors
►Through calibration path
►Drain or gate pulsing capability
EVALUATION KIT CONTENTS
►ADPA1106-EVALZ evaluation board
►50 V drain pulser board
EQUIPMENT NEEDED
►Pulse generator
►Oscilloscope
►50 V, 2 A power supply
►−4 V power supply
►Tektronix TCPA312A current probe
►Tektronix TCPA300 current probe amplifier
►RF signal generator
►Directional coupler
►RF power sensor
►RF power meter
►RF attenuator
DOCUMENTS NEEDED
►ADPA1106 data sheet
GENERAL DESCRIPTION
The ADPA1106-EVALZ consists of a 2-layer printed circuit board
(PCB) fabricated from a 10 mil thick, Rogers 4350B copper clad
mounted to an aluminum heat spreader. The heat spreader assists
in providing thermal relief to the device as well as mechanical
support to the PCB. Mounting holes on the heat spreader allow the
spreader to be attached to a heat sink. Alternatively, the spreader
can be clamped to a hot and cold plate. The RFIN and RFOUT
ports on the ADPA1106-EVALZ are populated by Subminiature
Version A (SMA) female coaxial connectors, and the respective
RF traces have a 50 Ω characteristic impedance. The ADPA1106-
EVALZ is populated with components suitable for use over the
entire operating temperature range of the device. To calibrate board
trace losses, a through calibration path is provided between the J6
and J5 connectors. J6 and J5 must be populated with SMA RF
connectors to use the through calibration path.
Ground, power, gate control, and the detector output voltage are
provided through the two 24-pin headers (P4 and P5) on the
ADPA1106-EVALZ. The pinouts for these two headers are shown in
Table 1.
RF traces on the ADPA1106-EVALZ are 50 Ω, grounded, coplanar
waveguide. The package ground leads and the exposed paddle
connect directly to the ground plane. Multiple vias connect the top
and bottom ground planes with particular focus on the area directly
beneath the ground pad to provide adequate electrical conduction
and thermal conduction to the heat spreader.
The ADPA1106-EVALZ ships with a drain pulser board that can
be plugged into the ADPA1106-EVALZ headers and configured to
control the biasing of the ADPA1106 by providing a negative gate
voltage and a control signal that connects and disconnects the
drain voltage to the ADPA1106-EVALZ. The ADPA1106-EVALZ can
also operate alone in gate pulsed mode where a negative pulse is
applied to the VGG1 and VGG2 pins of the ADPA1106.
For full details on the ADPA1106, see the ADPA1106 data sheet,
which must be consulted in conjunction with this user guide when
using the ADPA1106-EVALZ.

User Guide EVAL-ADPA1106
TABLE OF CONTENTS
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Features................................................................ 1
Evaluation Kit Contents......................................... 1
Equipment Needed................................................1
Documents Needed...............................................1
General Description...............................................1
Evaluation Board Photographs..............................3
Header Pinout........................................................4
Insertion Loss of the Through Calibration Path..... 5
Operating the ADPA1106-EVALZ with a
Pulsed Gate Voltage............................................6
Setup..................................................................6
Operation ...........................................................6
Operating the ADPA1106-EVALZ with the
Drain Bias Pulser Board...................................... 7
Setup..................................................................8
Operation............................................................9
Making Average to Pulsed Approximations.........10
Evaluation Board Schematic and Artwork........... 11
Ordering Information............................................13
Bill of Materials.................................................13
REVISION HISTORY
4/2022—Revision 0: Initial Version

User Guide EVAL-ADPA1106
EVALUATION BOARD PHOTOGRAPHS
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Figure 1. ADPA1106-EVALZ Evaluation Board, Primary Side Figure 2. ADPA1106-EVALZ Evaluation Board, Secondary Side

User Guide EVAL-ADPA1106
HEADER PINOUT
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The schematic for the ADPA1106-EVALZ is shown in Figure 6.
The ADPA1106-EVALZ contains two headers, P4 and P5. Table 1
describes the pinout of these headers.
Table 1. P4 and P5 Header Connections on the ADPA1106-EVALZ
Header Header Pin Number Header Pin Name
P4 1 to 5, 7, 9, 11 to 17, 19, 21 GND
6, 8 VGG1
10 VGG2
18, 20, 22 Not connected
23 VDET
24 VDET_BIAS
P5 1 VREF
2 VREF_BIAS
3, 5, 7, 9 to 15, 17, 19, 21 to 24 GND
4, 6 VDD2
8 VDD1
16, 18, 20 Not connected

User Guide EVAL-ADPA1106
INSERTION LOSS OF THE THROUGH CALIBRATION PATH
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To calibrate board trace losses, a through calibration path is provid-
ed between the J6 and J5 connectors. J6 and J5 must be populated
with SMA RF connectors to use the through calibration path.
Figure 3 shows the insertion loss, input return loss, and output
return loss of the through calibration path. Table 2 lists the insertion
loss of the through path vs. frequency.
Figure 3. Insertion Loss, Input Return Loss, and Output Return Loss of
Through Calibration Path
Table 2. Insertion Loss of Through Calibration Path
Frequency (GHz) Insertion Loss (dB)
1 −0.24
2 −0.36
3 −0.48
4 −0.45
5 −0.5
6 −0.55
7 −0.61
8 −0.64
9 −0.65
10 −0.65

User Guide EVAL-ADPA1106
OPERATING THE ADPA1106-EVALZ WITH A PULSED GATE VOLTAGE
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To implement gate pulsed operation, apply a negative voltage pulse
to the VGG1 and VGG2 inputs of the ADPA1106 while the voltage
on the VDD1 and VDD2 pins of the ADPA1106 is held constant.
SETUP
All power supply, ground, and control signals are applied to the P4
and P5 headers of the ADPA1106-EVALZ. For this mode of opera-
tion, pulse the gate voltage between −4 V (off) and approximately
−2.3 V (on) to set the quiescent current (IDQ) to approximately
300 mA. The pulse width and duty cycle must be approximately
100 µs and 10%, respectively.
OPERATION
Take the following steps to power up the ADPA1106-EVALZ:
1. Set VDDx (Pin 4, Pin 6, and Pin 8 of P5) to 0 V.
2. Set VGGx (Pin 6, Pin 8, and Pin 10 of P4) to off (VGG1 =
VGG2 = −4 V).
3. Set the supply voltage (VDD) to 50 V.
4. Turn on the gate voltage pulse (VGG1 and VGG2 pulsing
between −4 V and approximately −2.3 V).
5. Fine tune the pulse high voltage to achieve the desired IDQ
(nominally 300 mA) while maintaining the pulse off voltage level
at −4 V.
6. Apply the RF input signal.
Take the following steps to power down the ADPA1106-EVALZ:
1. Turn off the RF signal.
2. Turn off the pulse to VGG1 and VGG2 (VGG1 = VGG2 = −4 V).
3. Set VDD to 0 V.
4. Increase the pulse to VGG1 and VGG2 to 0 V.

User Guide EVAL-ADPA1106
OPERATING THE ADPA1106-EVALZ WITH THE DRAIN BIAS PULSER BOARD
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The ADPA1106-EVALZ ships with a drain bias pulser board. A block
diagram of the pulser board is shown in Figure 4. The pulser board
has two primary components. The BSC340N08NS3 is an 80 V/
23 A, metal-oxide semiconductor field effect transistor (MOSFET)
that switches the drain voltage to the ADPA1106 on and off, and the
LTC7000 is a high-side, negative channel metal-oxide semiconduc-
tor (NMOS), static switch driver that controls the MOSFET.
The pulser board plugs into the P4 and P5 headers of ADPA1106-
EVALZ and can be configured to provide a pulsed drain voltage
and a negative gate control voltage to control the biasing of the
ADPA1106.
Figure 4. Analog Devices, Inc., Pulser Board Schematic

User Guide EVAL-ADPA1106
OPERATING THE ADPA1106-EVALZ WITH THE DRAIN BIAS PULSER BOARD
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SETUP
The connections required to use the ADPA1106-EVALZ with the
drain bias pulser board are shown in Figure 5. Before applying any
bias or signals, plug the pulser board into the ADPA1106-EVALZ
so that the P2 header connector of the pulser board connects to
the P5 header of the ADPA1106-EVALZ, and the P3 header of the
pulser board connects to the P4 header of the ADPA1106-EVALZ.
All external supply voltages and control signals are applied to the
J1 thru J4 BNC connectors of the pulser board, which are listed in
Table 3.
Table 3. Pulser Board J1 to J4, TP1 to TP4, and P2 and P3 Header
Connections to the ADPA1106
Header Header Pin Number Header Pin Name
J1 Not applicable VDD
J2 Not applicable SENSE
J3 Not applicable PULSE
J4 Not applicable VGG
J5 Not applicable PULSED VDD
TP1 Not applicable VDET_BIAS
TP2 Not applicable VDET
TP3 Not applicable VREF
TP4 Not applicable VREF_BIAS
P2 1 VREF
2 VREF_BIAS
3, 5, 7, 9 to 15, 17, 19, 21 to 24 GND
Table 3. Pulser Board J1 to J4, TP1 to TP4, and P2 and P3 Header
Connections to the ADPA1106
Header Header Pin Number Header Pin Name
4, 6, 8 PULSED_VDD
16, 18, 20 VGG
P3 1 to 5, 7, 9, 11 to 17, 19, 21 GND
6, 8, 10 VGG
18, 20, 22 PULSED_VDD
23 VDET
24 VDET_BIAS
The gate control voltage applied to the J4 connector passes directly
through the pulser board and drives the VGG1 and VGG2 pins of
the ADPA1106. Because the VDD and GND lines carry currents up
to 2 A, the use of heavy gauge twister pair wires is recommended
to minimize voltage drops. To observe the pulsed drain voltage
(PULSED_VDD) that drives the VDD1 and VDD2 pins of the AD-
PA1106, connect an oscilloscope to the J5 coaxial connector on the
pulser board.
Connect a digital pulse generator that can generate 0 V to 5 V
pulses with a pulse width of 100 µs and a duty cycle of 10% to the
pulse input, J3.
To observe and measure the drain current and the ADPA1106
RF output power, use a current probe and a pulsed RF power
meter. If these methods are not available, make approximations as
described in the Making Average to Pulsed Approximations section.
Figure 5. Setup Block Diagram

User Guide EVAL-ADPA1106
OPERATING THE ADPA1106-EVALZ WITH THE DRAIN BIAS PULSER BOARD
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OPERATION
Take the following steps to power up (unless otherwise stated, all
signals are applied to the pulser board) the ADPA1106-EVALZ:
1. Set the voltage on J3 (PULSE) to 0 V.
2. Set the voltage on J4 (VGG) to −4 V.
3. Set the voltage on J1 (VDD) to 50 V.
4. Turn on PULSE (0 V/5 V, 100 µs, 10% duty cycle).
5. Increase the voltage on J4 (VGG) until the target IDQ is reached
(nominally 300 mA).
6. Apply the RF input signal to the RFIN connector of the
ADPA1106-EVALZ.
Take the following steps to power down the ADPA1106-EVALZ:
1. Turn off the RF input signal.
2. Set the voltage on J4 (VGG) to −4 V.
3. Turn off PULSE (set to 0 V).
4. Set the voltage on J1 (VDD) to 0 V.
5. Set the voltage on J4 (VGG) to 0 V.

User Guide EVAL-ADPA1106
MAKING AVERAGE TO PULSED APPROXIMATIONS
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Instruments that can be triggered are required to measure the RF
power, drain current, and power added efficiency (PAE) accurately
under pulsed operation. When such instrumentation is not availa-
ble, use averaging and approximations. The most common approxi-
mations involve measuring the average values and then adjusting
those values to account for the duty cycle. These approximations
can result in errors because of limited measurement bandwidths
of instruments and/or the inclusion of on and off transients and/or
partial periods in the measurement.
To ensure that partial periods do not contribute significant errors
to the measurements, perform averaging over a large number of
pulse periods. The results of such approximations can vary with the
instruments and settings used. Therefore, experimentation can be
necessary to achieve credible and repeatable results. When it is
not possible to make pulse triggered measurements, the only pulse
connection required is the connection from the pulse generator to
the J3 connector of the pulser (see Figure 5).