AD9238BSTZ-20

Overview

The AD9238BSTZ-20 is a dual-channel, 12-bit analog-to-digital converter (ADC) from Analog Devices Inc., operating at a maximum sampling rate of 20 MSPS. It utilizes a multistage differential pipelined architecture with output error correction logic to ensure no missing codes across the full industrial temperature range (-40°C to +85°C). The device features dual high-performance sample-and-hold amplifiers (SHAs) and an integrated voltage reference. It operates on a single 3 V supply (2.7 V to 3.6 V) and offers flexible analog input ranges from 1 V p-p to 2 V p-p. The component is housed in a 64-lead LQFP package.

Feature Summary

• Dual-channel pipeline ADC architecture with integrated sample-and-hold amplifiers
• Integrated voltage reference with selectable 1 V or 0.5 V modes
• Clock duty cycle stabilizer for maintaining performance under varying clock conditions
• Flexible analog input support for differential or single-ended applications

Applications

• Ultrasound equipment
• Direct conversion or IF sampling receivers
• WB-CDMA, CDMA2000, WiMAX systems
• Battery-powered instruments
• Hand-held scopemeters

Procurement Notes

Verify the specific speed grade suffix '-20' corresponds to the required 20 MSPS sampling rate during procurement. Confirm that the LQFP-64 package dimensions match the PCB footprint requirements. Ensure the ordering suffix matches the exact pinout and thermal characteristics specified in the official datasheet to avoid compatibility issues with evaluation boards or existing designs.

Selection Notes

Select this component when dual-channel synchronization is required within a low-power, 3 V system. The AD9238BSTZ-20 is suitable for applications needing 12-bit resolution at moderate speeds up to 20 MSPS. Consider the AD9238-40 or AD9238-65 variants if higher sampling rates are necessary, noting the associated increase in power consumption. Verify that the input signal range fits within the 1 V p-p to 2 V p-p window supported by the internal reference.

Part Context

The AD9238 series includes variants optimized for different speed grades: 20 MSPS, 40 MSPS, and 65 MSPS. The AD9238BSTZ-20 specifically denotes the 20 MSPS version in a Pb-free LQFP package. It is pin-compatible with the 14-bit AD9248, allowing for design flexibility between resolution and channel count. The 'BSTZ' suffix indicates the lead-free LQFP packaging option available from Analog Devices.

Replacement Considerations

The AD9238BSTZ-40 and AD9238BSTZ-65 are direct pin-compatible replacements offering higher sampling rates of 40 MSPS and 65 MSPS respectively. These alternatives maintain the same package and interface but consume more power. For single-channel applications requiring similar performance, the AD9235 series may be considered, though it lacks the dual-channel integration.