Analog Devices Inc. AD7790BRMZ

Overview

AD7790BRMZ from Analog Devices is a low-power, 16-bit buffered sigma-delta ADC with integrated PGA (gains 1/2/4/8), rail-to-rail input buffer, internal clock oscillator, and simultaneous 50 Hz/60 Hz rejection - designed for precision sensor front ends in battery-powered instrumentation and smart transmitters operating from 2.5 V to 5.25 V.

For engineers reviewing the AD7790BRMZ datasheet, AD7790BRMZ pinout, AD7790BRMZ application, or AD7790BRMZ equivalent, key selection considerations include its 1.1 µV rms noise at 9.5 Hz, 3.5 ppm typical INL, VDD monitor channel, 10-lead MSOP package, and SPI/QSPI/MICROWIRE-compatible 3-wire serial interface with Schmitt-triggered SCLK.

Technical Context

The AD7790BRMZ implements a single-channel, fully differential sigma-delta modulator with on-chip digital filtering and programmable output update rates (9.5–120 Hz). Its internal clock eliminates external timing components, and clock division (×2/×4/×8) enables reduced current modes down to 1 µA in power-down.

It integrates a rail-to-rail input buffer and digital PGA supporting four gain settings (1–8), enabling direct connection to high-impedance sensors while maintaining 16-bit p-p resolution and ±15 ppm max integral nonlinearity across –40°C to +105°C.

Key Specifications

Pinout & Package

AD7790BRMZ is housed in a 10-lead MSOP (3 mm × 3 mm, 0.5 mm pitch) package with exposed pad for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7790BRMZ, AD7791BRMZ adds channel flexibility at identical power/noise, while ADS1115IDGSR trades off mains rejection and ultra-low power for higher speed and integrated comparator - making AD7790BRMZ optimal for battery-powered, noise-sensitive industrial sensing where 120 Hz max update suffices.

Availability

AD7790BRMZ is available at Aetrix Electronics and suitable for smart transmitters, battery-powered instrumentation, and portable sensor measurement systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7790BRMZ 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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7790BRMZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for low-power, high-accuracy sensor signal conditioning in industrial, instrumentation, and IoT edge devices.

FAQ

What is the maximum update rate supported by the AD7790BRMZ?

The AD7790BRMZ supports a maximum output update rate of 120 Hz in full-power mode with FS2–FS0 = 000. At this rate, rms noise increases to 40 µV, and 50/60 Hz rejection drops to 25 dB. The default setting (FS2–FS0 = 100) provides 16.6 Hz update rate with 65 dB simultaneous rejection and 1.5 µV rms noise - balancing speed, noise, and interference immunity for most sensor applications. AD7790BRMZ achieves this via internal clock division and configurable digital filter coefficients.

Does the AD7790BRMZ require an external clock source?

No, the AD7790BRMZ does not require an external clock source. It integrates a precision internal clock oscillator, eliminating the need for crystals, oscillators, or clock generators. This simplifies design, reduces bill-of-materials cost, and improves reliability in space-constrained or high-vibration environments. The internal clock frequency is fixed but can be divided by factors of 2, 4, or 8 via the CDIV1/CDIV0 bits in the filter register to reduce current consumption - a feature unique to AD7790BRMZ among its class of low-power sigma-delta converters.

How does the VDD monitor function work in the AD7790BRMZ?

The AD7790BRMZ includes a dedicated VDD monitor channel activated by setting CH1–CH0 = 11 in the communications register. It internally divides the VDD supply by 5 and converts the result using the on-chip 1.17 V ±5% reference. This yields a digital reading proportional to supply voltage with ~200 mV resolution at 3 V - enabling real-time battery health monitoring or brown-out detection without external resistive dividers. The VDD monitor operates independently of the main AIN channel and shares the same 16-bit data register structure as other conversions. AD7790BRMZ retains this capability across its full –40°C to +105°C operating range.

What are the absolute voltage limits for the analog inputs of the AD7790BRMZ?

In buffered mode, the AD7790BRMZ analog input pins (AIN(+) and AIN(–)) must remain within GND + 100 mV to VDD − 100 mV. In unbuffered mode, the allowable range expands to GND − 30 mV to VDD + 30 mV, but input current rises significantly (±400 nA/V typ). Exceeding these limits risks damage or increased offset error. These specifications are defined in the Absolute Maximum Ratings table and confirmed in the Analog Inputs section of the AD7790BRMZ datasheet Rev. A. The device includes internal ESD protection, but sustained violation of these limits degrades long-term reliability.

Can the AD7790BRMZ perform simultaneous 50 Hz and 60 Hz rejection without external filtering?

Yes, the AD7790BRMZ achieves simultaneous 50 Hz and 60 Hz rejection through its configurable digital sinc³ filter. With FS2–FS0 = 100 (default), it delivers ≥65 dB rejection at both frequencies - verified in characterization data and specified in Table 1 of the AD7790BRMZ datasheet. This is accomplished by setting the output word rate to 16.6 Hz, which places nulls in the filter response at exactly 50 Hz and 60 Hz. No external analog filters, notch circuits, or software-based DSP are required, making AD7790BRMZ ideal for globally deployed equipment subject to variable mains frequencies.