Analog Devices Inc. AD7793BRUZ

Overview

AD7793BRUZ from Analog Devices is a 24-bit, low-noise, low-power Σ-Δ analog-to-digital converter with integrated instrumentation amplifier, on-chip band gap reference, and three differential input channels. It delivers 23 bits effective resolution at 4.17 Hz, 40 nV rms noise, and operates from 2.7 V to 5.25 V supply across –40°C to +105°C - enabling high-precision thermocouple and RTD measurements in portable industrial sensors.

For engineers reviewing the AD7793BRUZ datasheet, AD7793BRUZ pinout, AD7793BRUZ application, or AD7793BRUZ equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative options, and supply-ready availability details - all grounded in Analog Devices Rev. B datasheet (2007) and official package documentation.

Technical Context

The AD7793BRUZ integrates a programmable-gain instrumentation amplifier (gain 1–128), internal 1.17 V ±0.01% band gap reference (4 ppm/°C drift), and dual 10/210/1000 μA excitation current sources - all optimized for direct connection to resistive and thermoelectric sensors. Its Σ-Δ modulator supports simultaneous 50 Hz/60 Hz rejection via software-selectable update rates (4.17–470 Hz).

It features independent AVDD (analog) and DVDD (digital I/O) supplies, Schmitt-triggered SCLK for noise immunity, and a 3-wire SPI-compatible serial interface with DOUT/RDY dual-function pin. The on-chip bias voltage generator sets AIN common-mode to AVDD/2, and burnout currents support open-circuit detection in RTD/thermistor circuits.

Key Specifications

Pinout & Package

AD7793BRUZ is housed in a 16-lead TSSOP package (4.4 mm × 5.0 mm, 0.65 mm pitch) with exposed pad for thermal enhancement. Pin functions are validated per Analog Devices Rev. B datasheet Figure 5 and Table 4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7793BRUZ, AD7124-4BRUZ offers higher speed but omits critical sensor excitation and fault-detection features, while ADS124S08IPWR provides similar excitation capability but with higher reference drift and no burnout - making AD7793BRUZ uniquely suited for certified industrial temperature transmitters requiring hardware-level diagnostics.

Availability

AD7793BRUZ is available at Aetrix Electronics and suitable for thermocouple measurement, RTD-based temperature sensing, portable blood analysis, and smart industrial transmitter applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7793BRUZ 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 AD7793BRUZ belongs to the AD779x precision Σ-Δ ADC family, designed specifically for low-power, high-resolution sensor measurement in industrial, medical, and instrumentation systems - emphasizing integrated signal conditioning and robust noise rejection.

FAQ

What is the maximum effective resolution of the AD7793BRUZ and under what conditions is it achieved?

The AD7793BRUZ achieves up to 23 bits effective resolution at 4.17 Hz update rate with gain = 64 and an external 2.5 V reference, per Analog Devices Rev. B datasheet Table 6. This corresponds to 40 nV rms noise and is validated for bipolar input ranges. At higher update rates or with the internal 1.17 V reference, effective resolution decreases - e.g., 20.5 bits at 16.7 Hz (gain = 64, internal ref). The AD7793BRUZ does not guarantee 24-bit monotonicity across all conditions; its 24-bit output word supports oversampling and post-processing headroom.

Does the AD7793BRUZ support both internal and external reference configurations, and how do they affect performance?

Yes, the AD7793BRUZ supports both internal (1.17 V ±0.01%, 4 ppm/°C drift) and external (0.1 V to AVDD, typically 2.5 V) references. Using the internal reference simplifies BOM and layout but increases rms noise by ~20% at 4.17 Hz (e.g., 40 nV → 48 nV) and reduces effective resolution by ~0.5 bits versus external 2.5 V reference. External reference use requires routing REFIN(+) and REFIN(−) to dedicated pins (9 and 10), which also serve as AIN3(+) and AIN3(−) - enabling flexible 3-channel or 2-channel + reference topologies. The AD7793BRUZ maintains full specification compliance in both modes.

How does the AD7793BRUZ handle 50 Hz and 60 Hz interference rejection, and is external filtering required?

The AD7793BRUZ achieves simultaneous 50 Hz and 60 Hz normal-mode rejection (≥80 dB min) using its Σ-Δ modulator's inherent notch response when configured with internal clock and appropriate filter settings (FS[3:0] = 1010). No external analog filters are required - the rejection is implemented digitally via programmable output word rate and sinc³ filter characteristics. With external 64 kHz clock, rejection improves to ≥94 dB at 50 Hz and ≥90 dB at 60 Hz. This capability is validated per datasheet Table 1 and eliminates line-frequency-induced offset drift in thermocouple and RTD systems.

Can the AD7793BRUZ drive RTD sensors directly, and what are the excitation current specifications?

Yes, the AD7793BRUZ integrates two matched programmable excitation current sources (IOUT1 and IOUT2) configurable for 10 μA, 210 μA, or 1000 μA output. Current matching is ±0.5% typ between sources, drift is 200 ppm/°C, and compliance voltage is AVDD − 0.65 V (for 10/210 μA) or AVDD − 1.1 V (for 1 mA). These sources directly drive 2-, 3-, or 4-wire RTDs - e.g., 1000 μA through a Pt100 yields 100 mV signal, compatible with the AD7793BRUZ's ±VREF/Gain input range. Burnout currents (enabled via register) further support open-circuit detection.

What package type and thermal characteristics apply to the AD7793BRUZ, and how does this impact PCB design?

The AD7793BRUZ uses a 16-lead TSSOP package (RU-16) with 4.4 mm × 5.0 mm footprint, 0.65 mm lead pitch, and exposed thermal pad. Its θJA is 128°C/W and θJC is 14°C/W (Rev. B datasheet Table 3), indicating strong junction-to-case thermal conduction. For reliable operation at +105°C ambient, the PCB must include adequate copper pour under the exposed pad (soldered to GND plane) and ≥4 thermal vias. The package is RoHS-compliant and rated for reflow per JEDEC J-STD-020. No thermal derating is required below 100 mW total power dissipation - well within the AD7793BRUZ's 2.1 mW max (5.25 V × 400 μA).