Analog Devices Inc. AD7715AN-5

Overview

AD7715AN-5 from Analog Devices is a 16-bit sigma-delta analog-to-digital converter (ADC) optimized for low-frequency, high-precision sensor signal conditioning. It features a programmable gain amplifier (PGA) with gains of 1, 2, 32, and 128; differential analog and reference inputs; and a three-wire SPI-compatible serial interface. Designed for direct transducer interfacing, it supports unipolar (0 V to 2.5 V) and bipolar (±2.5 V) input ranges at 5 V operation with ±0.0015% integral nonlinearity and 450 µA max supply current.

For engineers reviewing the AD7715AN-5 datasheet, AD7715AN-5 pinout, AD7715AN-5 application, or AD7715AN-5 equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation value, and two confirmed alternative parts with functional and selection guidance - all grounded in Rev. E datasheet specifications for the AD7715-5 variant in PDIP package.

Technical Context

The AD7715AN-5 employs a charge-balancing sigma-delta modulator with on-chip digital filtering, where the first notch frequency is software-programmable to set output update rate and 50/60 Hz rejection. Its PGA front end conditions microvolt-level transducer signals before digitization, while the buffered or unbuffered analog input path (configurable via BUF bit) directly supports strain gage and RTD interfaces without external amplification.

It operates from a single 5 V AVDD supply (4.75–5.25 V) and 3–5 V DVDD, with independent AGND/DGND separation. The three-wire serial interface (SCLK, DIN, DOUT, CS, DRDY) supports SPI, QSPI, and MICROWIRE protocols, enabling seamless integration into microcontroller-based systems with minimal I/O overhead and built-in self- and system-calibration routines.

Key Specifications

Pinout & Package

AD7715AN-5 is housed in a 16-lead, 0.3-inch-wide plastic dual-in-line package (PDIP), pin-compatible with SOIC_W and TSSOP variants. Thermal impedance θ_JA = 105°C/W; max power dissipation = 450 mW.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7714BN, AD7715AN-5 offers lower system cost and smaller PCB area for single-sensor nodes; versus ADS1220IPWR, it provides superior analog isolation via dedicated AVDD/AGND and differential reference - critical for industrial noise immunity.

Availability

AD7715AN-5 is available at Aetrix Electronics and suitable for pressure measurement, temperature monitoring, and smart transmitter applications requiring stable component supply, long-term obsolescence management, and traceable sourcing for industrial OEMs.

Supply support for AD7715AN-5 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 AD7715 belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for low-frequency industrial and instrumentation applications demanding high resolution, low power, and integrated signal conditioning.

FAQ

What is the maximum master clock frequency supported by AD7715AN-5?

The AD7715AN-5 is specified to operate with a master clock frequency up to 2.4576 MHz, though characterization confirms functionality from 400 kHz to 2.5 MHz. At 2.4576 MHz, the device achieves optimal timing margins for serial interface operation and supports faster output update rates when configured with lower PGA gains (1 or 2). Exceeding 2.5 MHz may compromise conversion accuracy or cause timing violations.

Does AD7715AN-5 support both unipolar and bipolar input configurations?

Yes, AD7715AN-5 supports both unipolar (0 mV to 20 mV, 0 mV to 80 mV, 0 V to 1.25 V, 0 V to 2.5 V) and bipolar (±20 mV, ±80 mV, ±1.25 V, ±2.5 V) input ranges. Configuration is controlled by the B/U bit in the setup register. For bipolar operation, the negative input (AIN(−)) serves as the zero-reference point, enabling true differential measurement relative to system ground or sensor common.

How does the AD7715AN-5 handle power supply rejection at 50 Hz and 60 Hz?

The AD7715AN-5 achieves 98 dB normal-mode and 150 dB common-mode rejection at both 50 Hz and 60 Hz through its programmable digital filter notch. When the filter notch is set to 25 Hz or 50 Hz, PSRR exceeds 120 dB at 50 Hz; at 20 Hz or 60 Hz notches, PSRR exceeds 120 dB at 60 Hz. This performance is inherent to the sigma-delta architecture and requires no external components.

Can AD7715AN-5 operate with an external 2.5 V reference, and what tolerance is acceptable?

Yes, AD7715AN-5 is designed for a 2.5 V nominal reference voltage (REF IN(+) − REF IN(−)), with ±1% tolerance (2.475 V to 2.525 V) required for guaranteed performance per datasheet Table 1. Operation remains functional outside this range, but INL, noise, and gain error specifications are not assured. The reference must be low-noise and well-decoupled to maintain 16-bit effective resolution.

What is the purpose of the BUF bit in the AD7715AN-5 setup register?

The BUF bit controls whether the analog input buffer is enabled (BUF = 1) or disabled (BUF = 0). When enabled, the buffer allows common-mode input voltage up to AVDD − 1.5 V and improves rejection of source impedance variations, but increases supply current by ~0.3 mA. When disabled, input bias current drops to 1 nA and power consumption is minimized - ideal for high-impedance sensors with low output drive capability.