ADXUD1A Up/Down Converter

The ADXUD1AEBZ is a quad-channel X/C band frequency converter that bridges the gap between X-Band RF signals (8–12 GHz) used by the ADAR1000 beamforming board and the C-Band IF signals (4.2–6.3 GHz) that the AD9081 MxFE can process.

Figure 1 ADXUD1AEBZ Up/Down Converter Board

Overview

The ADXUD1AEBZ provides four independent up/down converter channels. Each channel contains a mixer (HMC773A), IF amplifiers (ADL8111, HMC8411), TX/RX amplifiers (HMC903), and an RF switch (ADRF5020) for TX/RX path selection. A common LO distribution network feeds all four channels from either an external source or the on-board ADF4371 PLL.

Tip

Schematics & Resources

• ADXUD1AEBZ Schematic (Rev D)

• ADXUD1AEBZ BOM

Interposer Board

• Interposer Schematic (Rev B)

• Interposer BOM (Rev B)

Component Product Pages

• ADF4371 - Microwave Wideband Synthesizer with Integrated VCO

• HMC773A - GaAs MMIC Fundamental Mixer

• ADL8111 - IF Variable Gain Amplifier

• HMC8411 - GaAs pHEMT MMIC Low Noise Amplifier

• HMC903 - GaAs pHEMT MMIC Driver Amplifier

• ADRF5020 - Silicon SPDT Switch

Block Diagram

Figure 2 ADXUD1AEBZ Rev D Block Diagram

Key Specifications

Parameter	Value
RF Frequency Range	8 – 12 GHz
IF Frequency Range	4.2 – 6.3 GHz
Number of Channels	4 (independent TX/RX)
RF Connectors	4× SMA-F
IF Connectors	8× SMPM (4 TX + 4 RX)
LO Input	SMA-F (external) or on-board ADF4371
Supply Voltage	12V DC
Power Consumption	~15W

RF Performance

Receive — High Gain Mode

Frequency	Gain (dB)	Noise Figure (dB)	IIP3 (dBm)
8 GHz	14.63	14.72	7.59
12 GHz	13.38	16.17	10.40

Figure 3 RX High Gain — Conversion Gain (S21)

Figure 4 RX High Gain — Noise Figure

Figure 5 RX High Gain — IIP3

Receive — Low Gain Mode

Approximately 14 dB lower gain than high-gain mode with improved linearity.

Figure 6 RX Low Gain — Conversion Gain (S21)

Figure 7 RX Low Gain — Noise Figure

Figure 8 RX Low Gain — IIP3

Transmit Mode

Parameter	Value
Conversion Gain	−12 to −14 dB
OIP3	Comparable to RX IIP3

Figure 9 TX — Conversion Gain (S21)

Figure 10 TX — OIP3

Return Loss

Figure 11 RX High Gain — S11 (RF Input)

Figure 12 RX High Gain — S22 (IF Output)

Figure 13 RX Low Gain — S11 (RF Input)

Figure 14 RX Low Gain — S22 (IF Output)

Figure 15 TX — S11 (IF Input)

Figure 16 TX — S22 (RF Output)

Board Architecture

Key Components

Component	Function
ADRF5020	RF TX/RX switch (4× per board)
HMC773A	Mixer — frequency conversion
HMC903	TX/RX RF amplifier
ADL8111	IF variable-gain amplifier
HMC8411	IF amplifier
ADF4371	On-board wideband PLL/VCO (optional LO)

Connector Layout

Figure 17 ADXUD1AEBZ Top View — Connector Locations

Figure 18 ADXUD1AEBZ Bottom View

Control Interface

Figure 19 XUD1A Control Block Diagram

Digital control operates at 1.8V logic with on-board level translation to 3.3V. Two interface options are available:

PMOD Interface

Figure 20 XUD1A PMOD Connector Pinout

The PMOD connector enables GPIO and SPI communication for:

• Per-channel TX/RX switching

• Switchable receive gain (high/low)

• SPI programming of the ADF4371 PLL

SDP-S Interface

Figure 21 XUD1A SDP-S Connector

Alternative control path via the SDP-S connector for standalone evaluation without an FPGA.

Connection to ZCU102

• ZCU102 HPC1 Connector → FMC extension cable → Interposer Board → PMOD cable → XUD1A

• Optional: 14-pin 6-inch PMOD cable for easier RF access when shields are installed

LO Configuration

The ADXUD1AEBZ supports both external and internal LO sources:

• External LO (default): Signal fed via SMA-F connector, distributed to all four channels through an on-board splitter network

• On-board ADF4371 PLL: Generates LO internally using a 100 MHz on-board VCXO reference or an external reference clock

Refer to the Clocking Configuration page for details on switching between these options.

Switching Speed

Measured TX/RX switching performance:

• Rising edge: ~159 ns average

• Falling edge: ~14 ns average

Note

The on-board IF bandpass filters (FL3, FL6, FL7, FL8) provide basic filtering. Additional external filters (VLF-8400+, VLF-5500+) are recommended for optimized system performance to suppress mixing products, LO feedthrough, and DAC images.