Analog Devices Inc. AD9218BST-40

Overview

AD9218BST-40 from Analog Devices is a dual 10-bit, 40 MSPS analog-to-digital converter with on-chip track-and-hold and internal reference, operating from a single 3.0 V supply (2.7–3.6 V), delivering 59 dB SNR at 10.3 MHz input and –75 dBc crosstalk between channels, used in handheld scopemeters and low-cost digital oscilloscopes.

For engineers reviewing the AD9218BST-40 datasheet, AD9218BST-40 pinout, AD9218BST-40 application, or AD9218BST-40 equivalent, this page provides verified specifications, package mapping, functional pin roles, real-world use scenarios, and two confirmed alternative parts for I/Q demodulation, ultrasound, and battery-powered instrumentation design.

Technical Context

The AD9218BST-40 implements a bit-per-stage pipeline ADC architecture with differential analog inputs, independent channel operation, and five-cycle pipeline latency. Each channel features user-selectable twos complement or offset binary output format, data alignment mode, and power-down control via S1/S2 pins.

It supports 1 V_p-p or 2 V_p-p differential analog input range, 300 MHz full-power analog bandwidth per channel, and TTL/CMOS-compatible encode and digital outputs. The internal 1.24 V reference (REFOUT) is stable to ±40 ppm/°C and can be overdriven externally for gain adjustment.

Key Specifications

Pinout & Package

AD9218BST-40 is housed in a 48-lead LQFP (7 mm × 7 mm, 0.5 mm pitch), specified for industrial temperature range (–40°C to +85°C). Pin functions are validated per Analog Devices Rev. D datasheet Figure 5 and Table 8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9218BST-40, AD9288BST-40 trades 2-bit resolution for lower cost and power, while ADS5272IPFP offers higher SNR at the expense of external support components and non-compatible packaging-making AD9218BST-40 optimal for compact, self-contained, battery-operated instrumentation requiring integrated reference and proven LQFP manufacturability.

Availability

AD9218BST-40 is available at Aetrix Electronics and suitable for handheld scopemeters, low-cost digital oscilloscopes, and battery-powered instrumentation requiring stable component supply, long-term lifecycle support, and industrial-temperature-grade reliability.

Supply support for AD9218BST-40 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 Wilmington, MA, serving industrial, automotive, communications, and healthcare markets.

The AD9218 product line delivers dual-channel, medium-speed ADCs optimized for portable test equipment and communications receivers, emphasizing integrated functionality, low power, and ease of system integration without external support ICs.

FAQ

What is the maximum analog input frequency supported by AD9218BST-40?

The AD9218BST-40 has a full-power analog bandwidth of 300 MHz, meaning it maintains rated SNR and SFDR performance for differential input signals up to 300 MHz. However, its 40 MSPS sampling rate limits usable Nyquist bandwidth to 20 MHz; higher input frequencies are aliased unless filtered externally. This makes AD9218BST-40 suitable for direct IF sampling of signals centered at 10–20 MHz with appropriate anti-alias filtering.

Does AD9218BST-40 require an external reference voltage?

No, AD9218BST-40 does not require an external reference voltage. It integrates a precision 1.24 V internal reference (REFOUT) that can directly drive REFINA and REFINB pins. External reference is optional and only needed if tighter initial accuracy (<±0.5%) or lower drift (<±40 ppm/°C) is required. Using the internal reference simplifies design and reduces component count for most portable instrument applications.

Can AD9218BST-40 operate with a 2.5 V digital supply?

Yes, AD9218BST-40 supports digital supply voltages from 2.5 V to 3.6 V on the VDD pin. Its digital outputs are TTL/CMOS-compatible and will correctly interface with 2.5 V logic families when VDD = 2.5 V. This flexibility allows seamless integration with low-voltage FPGAs or ASICs without level-shifting circuitry, provided the 3.0 V analog supply (VD) remains within 2.7–3.6 V.

How is channel synchronization achieved in AD9218BST-40?

AD9218BST-40 achieves precise channel synchronization through independent but phase-matched encode inputs (ENCA and ENCB) and identical pipeline latency (5 cycles). When driven by the same clock source, both channels sample simultaneously with sub-nanosecond skew. The S1/S2 pins further enable data alignment mode, delaying Channel B output by half a clock cycle to align with rising edges of Clock A-critical for time-interleaved or I/Q data merging in FPGA logic.

What power-saving modes does AD9218BST-40 support?

AD9218BST-40 supports two power-saving modes controlled by S1/S2 pins: full power-down (both channels disabled, IVDD ≈ ±10 µA) and Channel B-only power-down (Channel A active, IVDD reduced by ~50%). In either mode, digital outputs enter high-impedance state. Recovery takes exactly 10 clock cycles, enabling rapid wake-up for burst-mode acquisition in battery-powered instruments without firmware overhead.