AD1555BP

Overview

The AD1555BP is a fourth-order sigma-delta modulator with an integrated programmable gain amplifier (PGA), designed for high dynamic range, low-frequency measurement applications. It operates from dual ±5 V analog supplies and a +5 V digital supply, dissipating 77 mW typically at a sampling rate of 256 kSPS. The device features five PGA gain settings (1, 2.5, 8.5, 34, 128) and supports a full-scale differential input range of ±2.25 V. It achieves a minimum dynamic range of 116.5 dB at a 1 kHz output word rate and includes robust input protection. Packaged in a 28-lead PLCC, it is specified for operation between -55°C and +85°C.

Feature Summary

• Fourth-order continuous-time sigma-delta modulator architecture eliminating the need for external antialias filters
• Integrated programmable gain amplifier with gains of 1, 2.5, 8.5, 34, and 128
• High dynamic range performance: 116.5 dB minimum at 1 kHz output word rate
• Low power consumption: 77 mW typical dissipation with standby and power-down modes

Applications

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

Procurement Notes

Verify component authenticity through authorized Analog Devices distributors or direct manufacturer channels. Confirm the specific BP grade designation (-55°C to +85°C temperature range) matches system requirements. Check for RoHS compliance status and moisture sensitivity level (MSL 3) handling precautions during storage and assembly.

Selection Notes

Select the AD1555BP when extended industrial temperature coverage (-55°C to +85°C) is required; the AP grade is limited to 0°C to +85°C. Ensure the system design accommodates the dual ±5 V analog supply rails and +5 V digital logic levels. Pair with the AD1556 digital filter/decimator to realize a complete 24-bit ADC solution.

Part Context

The AD1555BP belongs to the AD1555/AD1556 chipset family, where the AD1555 serves as the analog front-end modulator and the AD1556 acts as the digital FIR filter/decimator. This combination forms a complete 24-bit sigma-delta ADC optimized for low-frequency, high-resolution signal processing tasks requiring high dynamic range.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should evaluate the AD1555AP for identical functionality if the operating environment remains within 0°C to +85°C.