Analog Devices Inc. AD9681-125EBZ

Overview

AD9681-125EBZ from Analog Devices is an evaluation board for the AD9681 14-bit, 125 MSPS octal analog-to-digital converter. It provides full signal chain support including transformer-coupled analog inputs (up to 200 MHz), on-board crystal oscillator (125 MHz), SPI-configurable LDO/switching power regulation, and LVDS serial output routing to FPGA-based data capture hardware.

For engineers reviewing the AD9681-125EBZ datasheet, AD9681-125EBZ pinout, AD9681-125EBZ application, or AD9681-125EBZ equivalent, this board enables rapid characterization of AC performance (SNR, SFDR), clock jitter sensitivity, multi-channel synchronization, and SPI register-level configuration of the underlying AD9681 ADC in real-world signal acquisition systems.

Technical Context

The AD9681-125EBZ implements a complete reference design for the AD9681 ADC, featuring dual 100Ω differential LVDS output lanes routed to edge connectors J1 and J2, a transformer-coupled 50Ω single-ended clock input with internal divider support (1×–8×), and eight double-balun analog input channels with 50Ω termination. It supports both standalone (pin-mode) and SPI-controlled operation via P1 header jumpers.

Power delivery includes on-board LDOs or optional switching regulators, configurable VREF sourcing (internal 1V, buffered AD822, or external), and jumper-selectable bias current (RBIAS = 10 kΩ default). The board interfaces exclusively with the HSC-ADC-EVALDZ FPGA capture platform via high-speed serial links and USB control.

Key Specifications

Availability

AD9681-125EBZ is available at Aetrix Electronics and suitable for high-speed data acquisition, radar receiver front-ends, and communications test equipment requiring stable component supply and validated reference designs for 14-bit, 125 MSPS ADC evaluation.

Supply support for AD9681-125EBZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with deep expertise in precision and high-speed data conversion.

The AD9681-125EBZ belongs to Analog Devices' high-speed ADC evaluation platform family, designed specifically to accelerate development of wideband signal acquisition systems using their octal, 14-bit, 125–250 MSPS ADC portfolio.

FAQ

What is the primary function of the AD9681-125EBZ?

The AD9681-125EBZ is an evaluation board-not a standalone IC-that enables full characterization and system integration testing of the AD9681 14-bit, 125 MSPS octal ADC. It provides all necessary support circuitry, including clock generation, analog input conditioning, power regulation, and LVDS data capture interface, allowing engineers to validate AC performance, timing margins, and SPI register control before custom PCB design.

Does the AD9681-125EBZ include the AD9681 ADC chip?

Yes, the AD9681-125EBZ board is populated with the AD9681-125EBZ's target device: the AD9681BCPZ-125, a 14-bit, 125 MSPS octal analog-to-digital converter in a 72-lead LFCSP package. The board is designed exclusively for evaluating this specific variant and cannot be reconfigured for other sample rates or resolutions without hardware modification.

What software tools are required to operate the AD9681-125EBZ?

Operation of the AD9681-125EBZ requires two core software tools: VisualAnalog® for FFT analysis, data visualization, and template-based testing; and SPIController for low-level register configuration of the AD9681 ADC. Both are provided free by Analog Devices and must be installed alongside compatible FPGA firmware (.mcs file containing "AD9681" in the filename) loaded onto the companion HSC-ADC-EVALDZ capture board.

Can the AD9681-125EBZ operate without the HSC-ADC-EVALDZ?

No-the AD9681-125EBZ does not include onboard data storage or USB interface. Its LVDS serial outputs (J1/J2) are designed exclusively for connection to the HSC-ADC-EVALDZ FPGA-based data capture platform. Without that board-and its associated VisualAnalog and SPIController software stack-the AD9681-125EBZ cannot acquire, process, or display digitized samples.

How is clocking configured on the AD9681-125EBZ?

The AD9681-125EBZ defaults to using its on-board 125 MHz crystal oscillator (Y801) as the master clock source. To use an external clock, jumper J804 must be removed and capacitor C810 optionally desoldered; the external signal is then applied to SMA connector J802. The AD9681's internal clock divider (1×–8×) remains accessible via SPI regardless of source, enabling flexible sampling rate derivation from higher-frequency clocks.