Analog Devices Inc. AD9218BST-RL105

Overview

AD9218BST-RL105 from Analog Devices is a dual 10-bit, 105 MSPS analog-to-digital converter with on-chip track-and-hold and internal reference, designed for high-speed I/Q sampling in communications receivers and ultrasound front-ends. It delivers 57 dB SNR at 41 MHz input with 300 MHz analog bandwidth per channel, operates from a single 3.0 V supply (2.7–3.6 V), and supports 1 V_p-p or 2 V_p-p differential analog input ranges.

For engineers reviewing the AD9218BST-RL105 datasheet, AD9218BST-RL105 pinout, AD9218BST-RL105 application, or AD9218BST-RL105 equivalent, key selection considerations include its dual-channel pipeline architecture, –75 dBc inter-channel crosstalk, user-selectable twos complement/offset binary output format, and compatibility with low-jitter 105 MSPS encode clocks for direct IF sampling systems.

Technical Context

The AD9218BST-RL105 implements a bit-per-stage pipeline ADC architecture with switch-capacitor techniques, delivering 7 MSBs per stage plus a 3-bit flash sub-converter. Each channel features independent differential analog inputs with self-biased common-mode voltage (V_D/3) and supports dc- or ac-coupled operation via external drivers like the AD8138.

Its digital interface uses TTL/CMOS-compatible outputs powered from a separate V_DD rail (2.5–3.6 V), enabling direct interfacing with 2.5 V or 3.3 V logic. User-selectable S1/S2 pins configure power-down modes (both channels or Channel B only) and data alignment-enabling synchronized dual-channel output on one clock edge when two 180°-phase-shifted clocks are applied.

Key Specifications

Pinout & Package

The AD9218BST-RL105 is housed in a 48-lead LQFP package (7 mm × 7 mm, 0.5 mm pitch), rated for industrial temperature range (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel ADC applications.

Compared with AD9218BST-80 and AD9288BSTZ-80, the AD9218BST-RL105 delivers 2-bit higher resolution and 31% faster sampling-enabling wider instantaneous bandwidth and improved SFDR in software-defined radio and medical imaging systems where quantization noise directly impacts signal fidelity.

Availability

AD9218BST-RL105 is available at Aetrix Electronics and suitable for communications receiver design, ultrasound equipment development, and portable test instrumentation requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for AD9218BST-RL105 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA, with R&D centers worldwide.

The AD9218 product line was engineered specifically for high-speed, low-power dual-channel digitization in communications, medical imaging, and test equipment-emphasizing integration (on-chip reference, THA), channel isolation, and flexible digital interfacing.

FAQ

What is the maximum analog input frequency supported by the AD9218BST-RL105?

The AD9218BST-RL105 has a 300 MHz analog bandwidth per channel, allowing accurate digitization of signals up to ~51 MHz (Nyquist limit at 105 MSPS). Measured SNR remains 57 dB at 41 MHz input with 80 MSPS encoding, confirming usable performance well into the IF band. Performance beyond 51 MHz is limited by aliasing, not bandwidth roll-off.

Does the AD9218BST-RL105 require an external reference voltage?

No-the AD9218BST-RL105 includes an internal 1.24 V reference (REFOUT) that can directly drive REFINA and REFINB pins. External references are optional for precision calibration; using the internal reference eliminates two external components and simplifies layout while maintaining 57 dB SNR and ±0.75 LSB INL over temperature.

How does the power-down mode affect the AD9218BST-RL105 digital outputs?

In power-down mode (configured via S1/S2 pins), the AD9218BST-RL105 drives all digital outputs (D0A–D9A, D0B–D9B) to high-impedance state within 10 clock cycles. This prevents bus contention during sleep states and reduces system-level power consumption. The internal reference and track-and-hold remain functional, enabling fast wake-up without recalibration.

Can the AD9218BST-RL105 interface directly with 2.5 V FPGA I/O banks?

Yes-the AD9218BST-RL105's VDD pin accepts 2.5 V to 3.6 V, and its digital outputs are TTL/CMOS-compatible with logic-high voltage ≥2.45 V and logic-low ≤0.05 V at 2.5 V supply. When VDD = 2.5 V, output swing meets 2.5 V LVTTL specifications, enabling direct connection to Xilinx Artix-7 or Intel Cyclone V FPGA banks without level shifters.

What is the significance of the –75 dBc crosstalk specification for the AD9218BST-RL105?

The –75 dBc crosstalk rating means that a full-scale signal on one channel induces less than –75 dBc (≈0.00018× full scale) interference into the other channel. This enables true simultaneous sampling for I/Q demodulation without analog-domain correction, preserving EVM <1.5% in 64-QAM wireless receivers and eliminating need for post-processing crosstalk cancellation algorithms in ultrasound beamformers.