AD7609BSTZ

ADCs/DACs - Special Purpose Overview

The AD7609BSTZ is an 18-bit, 8-channel true differential simultaneous sampling analog-to-digital data acquisition system (DAS) manufactured by Analog Devices Inc. It operates from a single 5 V analog supply and accommodates ±20 V or ±10 V bipolar input ranges. The device integrates a second-order antialiasing filter with a 32 kHz cutoff frequency, track-and-hold amplifiers, and an 18-bit charge redistribution SAR ADC. It supports throughput rates up to 200 kSPS across all channels. Key performance metrics include a typical Signal-to-Noise Ratio (SNR) of 98 dB and Total Harmonic Distortion (THD) of -107 dB. The component features flexible parallel and serial interfaces, analog input clamp protection tolerating ±16.5 V, and a 1 MΩ input impedance.

ADCs/DACs - Special Purpose Feature Summary

• 18-bit resolution with 8 simultaneously sampled true differential inputs
• Integrated second-order antialiasing filter with 32 kHz (-3 dB) cutoff
• Supports ±20 V and ±10 V bipolar input ranges via RANGE pin selection
• Flexible digital interface compatible with SPI, QSPI, MICROWIRE, and DSP protocols

ADCs/DACs - Special Purpose Applications

• Power line monitoring and protection systems
• Multiphase motor control applications
• Instrumentation and control systems
• Multiaxis positioning systems
• Data acquisition systems (DAS)

ADCs/DACs - Special Purpose Procurement Notes

Verify the specific suffix 'BSTZ' corresponds to the commercial temperature range (-40°C to +85°C) and LQFP-64 package configuration. Confirm that the ordering information matches the Rev D datasheet specifications, particularly regarding the updated ±20 V input range capabilities. Ensure compatibility with companion products such as external references (ADR421, ADR431) if higher precision is required beyond the internal 2.5 V reference.

ADCs/DACs - Special Purpose Selection Notes

Select the AD7609BSTZ when true differential signaling and high channel count are required without external driver amplifiers. The 1 MΩ input impedance eliminates the need for buffer op-amps in many applications. Choose this part over single-ended variants like the AD7606 if common-mode noise rejection is critical. Consider the oversampling capability via OS pins if improved SNR is needed at lower effective bandwidths.

ADCs/DACs - Special Purpose Part Context

The AD7609 belongs to Analog Devices' family of high-resolution, bipolar input, simultaneous sampling DAS solutions. It serves as the differential counterpart to the single-ended AD7608. Within the 18-bit resolution category, it provides 8 channels, distinguishing it from lower channel counts found in other series members. It is designed to replace discrete ADC and front-end amplifier assemblies in compact PCB layouts.

ADCs/DACs - Special Purpose Replacement Considerations

The AD7608 is the single-ended equivalent within the same resolution and channel count class. For applications requiring lower resolution but similar form factors, the 16-bit AD7606 series may be considered, though it lacks true differential inputs. Verify pinout compatibility if substituting with older revisions or different package options within the AD760x family.

ADCs/DACs - Special Purpose FAQ

Can the AD7609 handle true differential inputs directly?

Yes, the AD7609 is designed specifically for true differential inputs. Each channel has positive (Vx+) and negative (Vx-) terminals that accept signals 180° out of phase.

What is the function of the RANGE pin?

The RANGE pin selects the analog input voltage range. A logic high configures the inputs for ±20 V, while a logic low configures them for ±10 V.

How does the internal reference operate?

The device includes a 2.5 V internal reference. It can be enabled by setting the REF SELECT pin to logic high, or disabled to allow an external 2.5 V reference to be applied to the REFIN/REFOUT pin.