AD9218BST-105

Overview

The AD9218BST-105 is a dual-channel, 10-bit pipelined analog-to-digital converter (ADC) from Analog Devices Inc., operating at a maximum sampling rate of 105 MSPS. It features a 300 MHz full-power analog bandwidth and supports differential input ranges of 1 Vp-p or 2 Vp-p. The device operates on a single 3.0 V supply (2.7 V to 3.6 V range), consuming approximately 275 mW per channel at the maximum speed. Key performance metrics include a typical Signal-to-Noise Ratio (SNR) of 54 dB at Nyquist frequencies and an aperture jitter of 3 ps rms. It integrates an internal voltage reference and offers configurable digital output formats, including two's complement and offset binary.

Feature Summary

• Dual-channel architecture with independent operation capabilities and low inter-channel crosstalk.
• Integrated track-and-hold circuits and on-chip voltage reference for simplified system design.
• Configurable data alignment and power-down modes for optimized power management.
• TTL/CMOS compatible digital outputs supporting multiple encoding formats.

Applications

• I and Q communications demodulation
• Low-cost digital oscilloscopes
• Hand-held scopemeters
• Battery-powered instruments
• Ultrasound equipment

Procurement Notes

Verify that the specific ordering suffix matches the required speed grade, as the AD9218 family includes variants with different maximum sampling rates. Confirm package availability in the 48-lead LQFP format and ensure the industrial temperature range specifications align with the target application environment. Cross-reference the datasheet revision to confirm current testing levels and parameter guarantees.

Selection Notes

Select this component when a dual-channel solution with high dynamic performance and low power consumption is required. Ensure the system clock meets the minimum pulse width requirements for the 105 MSPS grade. Consider the pin compatibility with the 8-bit AD9288 if migrating from legacy designs. Verify that the analog input impedance and drive requirements are met by the preceding circuit stage to maintain optimal SNR and SFDR.

Part Context

The AD9218 series serves as a versatile mid-range ADC solution, bridging the gap between lower-speed converters and higher-performance, higher-power devices. It is designed for applications requiring direct IF sampling, reducing the need for complex analog front-end filtering. The device shares architectural similarities with other ADI pipeline ADCs but distinguishes itself through its specific combination of 10-bit resolution, 3V operation, and dual-channel integration.

Replacement Considerations

The AD9218 is pin-compatible with the 8-bit AD9288, allowing for potential upgrades in resolution without PCB redesign. No direct functional equivalents with identical pinouts and specifications are listed in the provided documentation. Evaluate alternative dual-channel ADCs only if they meet the specific 105 MSPS, 10-bit, and 3V supply constraints.

FAQ

What is the guaranteed missing codes specification for the AD9218BST-105?

For the 105 MSPS grade, no missing codes are guaranteed at room temperature. Missing codes across the full industrial temperature range are not tested for this specific speed grade.

How does the DFS/GAIN pin affect the analog input range?

The DFS/GAIN pin configures both the output coding format and the analog input range. Setting it low enables offset binary output with a 1 Vp-p range, while setting it high enables two's complement output with a 1 Vp-p range. Floating or connecting to VREF enables two's complement output with a 2 Vp-p range.

What is the pipeline delay for the AD9218?

The AD9218 has a fixed pipeline delay of 5 clock cycles. Data outputs become valid one propagation delay after the rising edge of the encode command.