Analog Devices Inc. AD7171BCPZ-REEL7

Overview

AD7171BCPZ-REEL7 from Analog Devices is a 16-bit, low-power, sigma-delta analog-to-digital converter (ADC) with differential input, internal clock oscillator, and 2-wire serial interface. It delivers 125 Hz output data rate, 135 µA typical supply current at 5 V, and operates from 2.7 V to 5.25 V across −40°C to +105°C - ideal for battery-powered weigh scales and portable instrumentation.

For engineers reviewing the AD7171BCPZ-REEL7 datasheet, AD7171BCPZ-REEL7 pinout, AD7171BCPZ-REEL7 application, or AD7171BCPZ-REEL7 equivalent, key selection criteria include its unbuffered differential input architecture, 16-bit no-missing-codes performance, integrated status-bit reporting on DOUT/RDY, and LFCSP package compatibility with high-density sensor signal chains.

Technical Context

The AD7171BCPZ-REEL7 implements a sinc3 digital filter with fixed 125 Hz output data rate and 24 ms settling time after reset. Its unbuffered analog input path requires careful source impedance management to avoid gain error - external RC combinations up to 5 kΩ/5000 pF are validated for 16-bit accuracy.

It uses offset binary coding and features a dual-function DOUT/RDY pin that asserts low to signal conversion completion and outputs 24-bit frames (16-bit result + 8 status bits). The PDRST pin controls both hardware reset and 5 µA power-down mode, with internal clock startup requiring ~1 ms.

Key Specifications

Pinout & Package

AD7171BCPZ-REEL7 is housed in a 10-lead 3 mm × 3 mm LFCSP (CP-10-9) with exposed pad soldered to ground. Pin 1 is indexed at top-left; exposed pad must be connected to GND for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar sigma-delta ADC applications.

Compared with AD7171BCPZ-REEL7, AD7170BCPZ-REEL7 offers identical footprint and firmware compatibility at reduced resolution, while ADS1115IRUGT trades 5× higher supply current for on-chip signal conditioning - making AD7171BCPZ-REEL7 optimal for fixed-gain, battery-critical, 16-bit ratiometric sensing.

Availability

AD7171BCPZ-REEL7 is available at Aetrix Electronics and suitable for weigh scales, pressure measurement systems, and portable instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7171BCPZ-REEL7 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7171 belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for low-power, high-resolution sensor digitization in industrial and portable measurement applications.

FAQ

What is the maximum allowed source impedance for the AIN(+) and AIN(−) inputs of the AD7171BCPZ-REEL7?

The AD7171BCPZ-REEL7 has an unbuffered analog input path, so external RC networks must be constrained to avoid 16-bit gain error. Per Table 8 in the datasheet, the maximum allowable combination is 200 Ω with 5000 pF, or 9 kΩ with 50 pF. Exceeding these values introduces measurable dc gain inaccuracy due to dynamic loading of the modulator input.

Does the AD7171BCPZ-REEL7 support external clock input, or is it limited to the internal oscillator?

The AD7171BCPZ-REEL7 relies exclusively on its internal 64 kHz ±5% oscillator and does not support external clock input. The datasheet confirms no provision for clock input pins or frequency programming - all timing, including 125 Hz output data rate and 24 ms settling, is derived from this fixed internal source.

How does the DOUT/RDY pin function during continuous conversion mode on the AD7171BCPZ-REEL7?

In continuous conversion mode, the DOUT/RDY pin of the AD7171BCPZ-REEL7 goes low for ~60 ns upon completion of each 125 Hz conversion to signal data readiness. If the host reads the 24-bit frame (16-bit result + 8 status bits) before the next conversion completes, DOUT/RDY returns high immediately after the read. If unread, it goes high just before register update to prevent invalid reads.

Can the AD7171BCPZ-REEL7 operate with a 2.5 V external reference, and what impact does that have on input range?

Yes, the AD7171BCPZ-REEL7 supports external reference voltages from 0.5 V to VDD. With a 2.5 V reference applied across REFIN(+) and REFIN(−), the differential input range becomes ±2.5 V. This maintains full 16-bit resolution but reduces RMS noise floor to ~8.6 µV (interpolated from 3 V/5 V specs), preserving usability in mid-range industrial sensors.

Is the AD7171BCPZ-REEL7 pin-compatible with any higher-resolution variants in the same family?

No - the AD7171BCPZ-REEL7 is not pin-compatible with higher-resolution variants. Analog Devices' AD717x family ends at 16 bits; the next generation (e.g., AD7172-2, AD7173-8) uses different pin counts, layouts, and feature sets. The only pin-compatible variant is the 12-bit AD7170BCPZ-REEL7, which shares identical 10-lead LFCSP packaging and pin functions.