Analog Devices Inc. AD7795BRUZ

Overview

AD7795BRUZ from Analog Devices is a 16-bit, low-noise, low-power Σ-Δ analog-to-digital converter with integrated instrumentation amplifier, on-chip band gap reference, six differential analog inputs, and programmable excitation current sources. It delivers 40 nV RMS noise at 4.17 Hz and operates from 2.7 V to 5.25 V supply, targeting high-precision industrial sensor signal conditioning in weigh scales and pressure transducers.

For engineers reviewing the AD7795BRUZ datasheet, AD7795BRUZ pinout, AD7795BRUZ application, or AD7795BRUZ equivalent, key selection considerations include its 16-bit resolution with no missing codes up to 470 Hz update rate, simultaneous 50/60 Hz rejection capability, internal clock oscillator, and 24-lead TSSOP package with dual-function pins (e.g., AIN5(+)/IOUT2) enabling compact bridge sensor interface design.

Technical Context

The AD7795BRUZ implements a chopper-stabilized Σ-Δ modulator with digital filtering supporting output rates from 4.17 Hz to 470 Hz. Its on-chip instrumentation amplifier provides programmable gain (1–128), low input bias current (±250 pA max at gain ≥4), and buffered/unbuffered input modes with defined common-mode voltage constraints.

It integrates two programmable current sources (10/210/1000 μA), a bias voltage generator (AVDD/2), reference detect circuitry, and a low-side power switch (RON ≤9 Ω) for bridge sensor power gating. The device supports SPI/QSPI/MICROWIRE/DSP-compatible 3-wire serial interface with Schmitt-triggered SCLK and independent DVDD/AVDD supplies.

Key Specifications

Pinout & Package

AD7795BRUZ is housed in a 24-lead TSSOP package (4.4 mm × 7.8 mm, 0.65 mm pitch) with exposed pad for thermal enhancement. Pin functions support mixed-signal integration: analog inputs share terminals with excitation current outputs and GPIOs, requiring careful PCB routing to avoid coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7794BRUZ, AD7795BRUZ trades resolution for lower cost and reduced digital processing overhead, while ADS1248IPWR offers higher integration at the expense of pin compatibility and added complexity in calibration flow.

Availability

AD7795BRUZ is available at Aetrix Electronics and suitable for weigh scales, pressure transducers, and temperature measurement systems requiring stable component supply across industrial temperature ranges (−40°C to +105°C).

Supply support for AD7795BRUZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD779x series was designed specifically for high-precision, low-power industrial sensor signal conditioning-emphasizing integrated analog front-end functionality, robust noise rejection, and simplified system-level calibration.

FAQ

What is the maximum update rate of the AD7795BRUZ while maintaining 16-bit no-missing-codes performance?

The AD7795BRUZ guarantees no missing codes at 16-bit resolution up to 470 Hz output update rate in both chop-enabled and chop-disabled modes. At this rate, RMS noise increases to 85 nV, but the device maintains monotonicity and specified integral nonlinearity (±15 ppm of FSR). For applications requiring lower noise, reducing the update rate to 4.17 Hz achieves 40 nV RMS noise while preserving full 16-bit resolution.

Does the AD7795BRUZ support external reference inputs, and what are the voltage limits?

Yes, the AD7795BRUZ accepts two independent differential external references via REFIN1(±) and REFIN2(±). Each reference input supports voltages from 0.1 V to AVDD, with absolute pin limits of GND − 0.3 V to AVDD + 0.3 V. The nominal reference voltage is 2.5 V, and the device includes reference detect circuitry that asserts the NOXREF bit if the reference falls below 0.3 V, enabling fail-safe system response in the AD7795BRUZ.

How does the low-side power switch (PSW) function in the AD7795BRUZ, and what is its maximum current rating?

The PSW pin in the AD7795BRUZ controls an internal low-side switch used to disconnect bridge sensors from ground between conversions. It has a maximum on-resistance of 9 Ω at AVDD = 3 V and supports continuous current up to 30 mA. This feature minimizes self-heating in precision strain gage or load cell circuits, directly improving long-term measurement stability. System firmware must coordinate PSW activation with conversion timing to ensure proper sensor biasing in the AD7795BRUZ.

Can the AD7795BRUZ perform simultaneous 50 Hz and 60 Hz rejection, and what configuration is required?

Yes, the AD7795BRUZ achieves simultaneous 50 Hz and 60 Hz rejection using its internal digital filter with FS[3:0] = 1010 setting, delivering ≥80 dB rejection at both frequencies with internal clock operation. This capability is inherent to the modulator architecture and requires no external components. When using an external 64 kHz clock, the same rejection is achieved, making the AD7795BRUZ suitable for global deployments where mains frequency varies between regions.

What are the key differences between the AD7795BRUZ and AD7794BRUZ beyond resolution?

Both AD7795BRUZ and AD7794BRUZ share identical pinout, package, power supply range, temperature grade (B-grade: −40°C to +105°C), and feature set-including six differential inputs, on-chip reference, excitation currents, and PSW. The sole functional difference is resolution: AD7795BRUZ is specified for 16-bit no-missing-codes operation, while AD7794BRUZ guarantees 24-bit performance. All other electrical specifications (noise, drift, rejection, current consumption) are identical for the AD7795BRUZ and AD7794BRUZ within their respective resolution limits.