AD1555BPZ

Overview

The AD1555BPZ is a fourth-order sigma-delta modulator with an integrated programmable gain amplifier (PGA), packaged in a 28-lead PLCC. It operates from dual ±5 V analog supplies and a +5 V digital supply, consuming 77 mW typical power. The device supports a sampling rate of 256 kSPS with a differential input range of ±2.25 V at PGA Gain 1. Key performance metrics include a minimum dynamic range of 116.5 dB at 1 kHz output word rate and a maximum total harmonic distortion of –111 dB. It features five PGA gain settings (1, 2.5, 8.5, 34, 128) and operates within a temperature range of –55°C to +85°C.

Feature Summary

• Fourth-order continuous-time sigma-delta modulator architecture eliminating the need for external antialias filters.
• Integrated programmable gain amplifier with five selectable gains: 1, 2.5, 8.5, 34, and 128.
• High dynamic range performance with 116.5 dB minimum SNR at 1 kHz output rate and –111 dB max THD.
• Robust analog inputs supporting ±2.25 V full-scale range with high common-mode rejection.

Applications

• Seismic data acquisition systems
• Chromatography instrumentation
• Automatic test equipment

Procurement Notes

Verify component authenticity through authorized distribution channels due to potential availability constraints. Confirm that the specific BP suffix denotes the –55°C to +85°C industrial temperature grade. Ensure compatibility with the companion AD1556 digital filter/decimator for complete ADC functionality. Check for end-of-life status or discontinuation notices prior to finalizing procurement plans.

Selection Notes

Select the AD1555BPZ when low-frequency, high-dynamic-range measurement is required without external antialias filtering. Choose this model over the AP grade if operation below 0°C is necessary. Ensure the system design accommodates dual ±5 V analog supplies and a separate +5 V digital supply. Verify that the required output word rates align with the available decimation options when paired with the AD1556.

Part Context

The AD1555BPZ belongs to the AD1555/AD1556 chipset family designed for 24-bit analog-to-digital conversion. It functions as the analog front-end modulator, while the AD1556 serves as the digital FIR filter and decimator. Together, they form a complete high-performance ADC solution optimized for precision measurement applications requiring high resolution and low noise.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should evaluate the AD1555AP for identical electrical specifications but with a restricted 0°C to +85°C operating temperature range.