Analog Devices Inc. AD7787BRMZ

Overview

AD7787BRMZ from Analog Devices is a low-power, 24-bit sigma-delta analog-to-digital converter with two analog input channels (one differential AIN1, one single-ended AIN2), rail-to-rail buffered input capability, internal clock oscillator, and simultaneous 50 Hz/60 Hz rejection - designed for precision sensor measurement in battery-powered instrumentation and smart transmitters.

For engineers reviewing the AD7787BRMZ datasheet, AD7787BRMZ pinout, AD7787BRMZ application, or AD7787BRMZ equivalent, key selection criteria include its 1.1 µV rms noise at 9.5 Hz, 19.5-bit p-p resolution, 75 µA max normal-mode current, 10-lead MSOP package, and SPI-compatible 3-wire serial interface with Schmitt-triggered SCLK.

Technical Context

The AD7787BRMZ implements a 24-bit sigma-delta modulator with programmable output update rate (9.5–120 Hz), internal clock division (×1/2/4/8), and dual-channel multiplexing between differential AIN1(±) and single-ended AIN2. Its on-chip VDD monitor channel uses an internal 1.17 V reference and 5:1 resistor divider to support supply voltage supervision without external components.

It supports both unipolar (0 to REFIN) and bipolar (±REFIN) input ranges, configurable buffer enable/disable (BUF bit), burnout current sourcing (100 nA), and simultaneous 50/60 Hz rejection via programmable digital filter settings (FS[2:0]). The device operates from 2.5 V to 5.25 V and achieves 3.5 ppm typical integral nonlinearity with 1 µA max power-down current.

Key Specifications

Pinout & Package

AD7787BRMZ is housed in a 10-lead MSOP (3 mm × 3 mm, 0.5 mm pitch) package with exposed pad for thermal performance. Pin functions are validated per Analog Devices AD7787 Rev. A datasheet Figure 5 and Table 4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7787BRMZ, AD7788BRMZ trades extended temperature range for lower cost, while ADS124S08IPW adds PGA and GPIOs at the expense of higher power (350 µA vs. 75 µA) and larger footprint - making AD7787BRMZ optimal for compact, ultra-low-power, high-temp sensor nodes.

Availability

AD7787BRMZ 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 AD7787BRMZ 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 AD7787BRMZ belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for low-power, high-resolution measurement in constrained environments such as handheld instruments and loop-powered field devices.

FAQ

What is the maximum sampling rate of the AD7787BRMZ?

The AD7787BRMZ supports a software-programmable output update rate ranging from 9.5 Hz to 120 Hz. At the highest setting (120 Hz), rms noise increases to ~3.5 µV, while the 9.5 Hz rate delivers 1.1 µV rms noise and 19.5-bit p-p resolution. The update rate scales directly with internal clock division settings (CDIV1/CDIV0).

Does the AD7787BRMZ require an external clock source?

No, the AD7787BRMZ includes an internal clock oscillator and does not require an external clock. The user configures the output update rate and power consumption via the filter register (CDIV1/CDIV0 bits), which divides the internal clock by factors of 1, 2, 4, or 8 - enabling trade-offs between speed, noise, and current draw without external components.

Can the AD7787BRMZ measure both differential and single-ended signals simultaneously?

The AD7787BRMZ supports either differential (AIN1±) or single-ended (AIN2) input per conversion cycle, but not simultaneously in one sample. Channel selection is controlled by CH1/CH0 bits in the communications register. Switching between channels resets the digital filter and initiates a new conversion, so interleaved acquisition requires software coordination.

What is the purpose of the VDD monitor channel in the AD7787BRMZ?

The VDD monitor channel in the AD7787BRMZ uses an internal 5:1 resistor divider and 1.17 V reference to measure the supply voltage without external components. When CH1/CH0 = 11, the ADC converts the scaled VDD value, enabling real-time supply supervision in smart transmitters and battery-operated systems - critical for detecting brown-out conditions or verifying loop integrity.

How does the AD7787BRMZ achieve simultaneous 50 Hz and 60 Hz rejection?

The AD7787BRMZ achieves simultaneous 50 Hz and 60 Hz rejection through its programmable sinc³ digital filter, configured via FS[2:0] bits in the filter register. With FS[2:0] = 100, the filter provides 73 dB typical rejection at both frequencies in a single conversion cycle - eliminating need for dual-notch analog filters or firmware-based post-processing in globally deployed equipment.