AD7797BRUZ - 24-Bit Sigma-Delta ADC for Bridge Sensors | Analog Devices
MPN: AD7797BRUZ ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.49 | $5.49 |
| 10 | $4.95 | $49.50 |
| 100 | $4.36 | $436.00 |
| 500 | $3.88 | $1,940.00 |
| 1,000 | $3.49 | $3,490.00 |
AD7797BRUZ Overview
A sigma-delta ADC is a type of analog-to-digital converter that uses oversampling and noise shaping to achieve high resolution. It is part of the broader category of ADCs, which are essential components in data acquisition systems, converting analog signals into digital data for processing. The AD7797BRUZ is a complete analog front end, combining the ADC with an instrumentation amplifier and reference, simplifying the design of precision measurement systems.
Key features include a 24-bit resolution, a fixed gain of 128, and a low power consumption of typically 500 µA. The device also includes a 2-wire serial interface (SPI) for communication, an internal reference, and a temperature sensor. The AD7797BRUZ is designed for bridge sensor applications, providing high accuracy and stability over temperature.
The AD7797BRUZ uses a sigma-delta architecture with a digital filter, achieving high resolution and low noise. The on-chip instrumentation amplifier has a fixed gain of 128, allowing direct connection to bridge sensors without external amplification. The device also includes a burnout current source for sensor fault detection, enhancing system reliability.
Typical applications include weigh scales, strain gauge measurements, pressure sensors, and other bridge-based transducers. The AD7797BRUZ is ideal for battery-powered portable instruments due to its low power consumption and small package size.
When designing with the AD7797BRUZ, ensure proper decoupling of the power supply and reference pins. The SPI interface should be isolated from noisy digital lines to maintain accuracy. The device is available in a 16-lead TSSOP package, which is suitable for compact PCB layouts.
Drop-in alternatives for AD7797BRUZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AD7797BRUZ (same form factor and footprint) — differing in Package, Resolution, Supply Voltage, Operating Temperature, Number of Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7798BRUZ
✅ Drop-In✓ In Stock
$3.85 / Unit
View Datasheet →AD7799BRUZ
✅ Drop-In✓ In Stock
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View Datasheet →AD7781BRUZ
✅ Drop-In✓ In Stock
$5.06 / Unit
View Datasheet →AD7730BRUZ
✅ Drop-In✓ In Stock
$13.1 / Unit
View Datasheet →AD7797BRUZ Maximum Ratings & Electrical Characteristics
| Resolution | 24 Bit |
| Number of Inputs | 1 |
| Input Type | Differential |
| Architecture | Sigma-Delta |
| Gain | 128 (fixed) |
| Supply Voltage Range | 2.7 V to 5.25 V |
| Power Consumption | 500 µA (typical) |
| Interface | SPI |
| Internal Reference | Yes |
| Temperature Sensor | Yes |
| Burnout Current Source | Yes |
| Package | 16-TSSOP |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40°C to +105°C |
| RoHS Status | Compliant |
AD7797BRUZ Pin Configuration
| Pin 1 | SCLK — Serial Clock Input |
| Pin 2 | CS — Chip Select (active low) |
| Pin 3 | DIN — Serial Data Input |
| Pin 4 | DOUT — Serial Data Output |
| Pin 5 | DVDD — Digital Supply Voltage |
| Pin 6 | AVDD — Analog Supply Voltage |
| Pin 7 | AINP — Positive Analog Input |
| Pin 8 | AINN — Negative Analog Input |
| Pin 9 | REFIN(+) — Positive Reference Input |
| Pin 10 | REFIN(-) — Negative Reference Input |
| Pin 11 | GND — Ground |
| Pin 12 | GND — Ground |
| Pin 13 | PDR — Power-Down Reset |
| Pin 14 | SYNC — Synchronization Input |
| Pin 15 | RESET — Reset Input |
| Pin 16 | AVDD — Analog Supply Voltage |
Typical Applications
AD7797BRUZ is suitable for 6 applications: Weigh Scales, Strain Gauge Measurements, Pressure Sensors, Portable Instruments, Industrial Process Control, Medical Monitoring.
Weigh Scales
The AD7797BRUZ is ideal for weigh scale applications due to its 24-bit resolution and fixed gain of 128, which allows direct connection to load cells. The low power consumption of 500 µA enables battery-powered portable scales. The internal reference and temperature sensor simplify design and improve accuracy over temperature. The SPI interface allows easy integration with microcontrollers for digital readout and calibration.
Recommended
Strain Gauge Measurements
The AD7797BRUZ is well-suited for strain gauge measurements, where small resistance changes need to be accurately digitized. The fixed gain of 128 amplifies the tiny signals from the Wheatstone bridge, while the 24-bit sigma-delta ADC provides high resolution. The burnout current source helps detect sensor faults, enhancing reliability. The low power consumption makes it suitable for portable data loggers.
Recommended
Pressure Sensors
The AD7797BRUZ is designed for pressure sensor applications, where bridge-based transducers produce small differential signals. The integrated instrumentation amplifier with gain of 128 allows direct interface to the sensor, eliminating external amplification. The internal reference and temperature sensor provide stable operation over temperature. The SPI interface enables easy digital communication with microcontrollers for pressure monitoring systems.
Recommended
Portable Instruments
The AD7797BRUZ is ideal for portable instruments due to its low power consumption of 500 µA and small 16-TSSOP package. It can be powered directly from a 3.3V battery, and the internal reference reduces external component count. The SPI interface allows low-power sleep modes and efficient data transfer. Applications include handheld multimeters, portable data loggers, and battery-powered weigh scales.
Recommended
Industrial Process Control
The AD7797BRUZ is suitable for industrial process control, where precise measurement of bridge sensors is critical. The 24-bit resolution and fixed gain of 128 provide high accuracy for pressure and force transducers. The device operates over a wide temperature range and includes burnout detection for sensor fault monitoring. The SPI interface allows integration with PLCs and industrial controllers.
Recommended
Medical Monitoring
The AD7797BRUZ can be used in medical monitoring devices that require high precision measurement of physiological signals from bridge sensors, such as blood pressure and force sensors. The low power consumption and small package make it suitable for wearable and portable medical devices. The internal reference and temperature sensor ensure stable performance over body temperature variations.
Recommended
Recommended Products Summary
Engineering reference data for AD7797BRUZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7798BRUZ | AD7799BRUZ | AD7781BRUZ | AD7730BRUZ |
|---|---|---|---|---|---|
| Package | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 24-bit | 16-bit | 24-bit | 24-bit | 24-bit |
| Gain | 128 (fixed) | 128 (fixed) | 1 to 128 (programmable) | 128 (fixed) | 1 to 128 (programmable) |
| Supply Voltage | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V | 2.7V to 5.25V |
| Power Consumption | 500 µA | 500 µA | 500 µA | 330 µA | 6.5 mA |
| Temperature Sensor | Yes | Yes | Yes | No | No |
| Lifecycle Status | Last Time Buy | Active | Active | Active | Active |
Key Differentiators
- Fixed gain of 128 simplifies bridge sensor interface (vs AD7730BRUZ)
- Lower power consumption than AD7730BRUZ (vs AD7730BRUZ)
- Includes temperature sensor (vs AD7781BRUZ)
Design Notes
The AD7797BRUZ operates from 2.7V to 5.25V. Use separate analog and digital supply pins (AVDD and DVDD) with proper decoupling. Place 0.1µF and 10µF capacitors close to each supply pin to filter high-frequency noise and provide stable operation. The low power consumption of 500 µA makes it suitable for battery-powered designs, but ensure the supply voltage remains within the specified range during battery discharge.
For optimal performance, keep the analog input traces short and shielded from digital signals. Use a solid ground plane and separate analog and digital ground areas, connecting them at a single point. Place the reference decoupling capacitors close to the REFIN pins. The SPI lines (SCLK, DIN, DOUT, CS) should be routed away from analog inputs to minimize crosstalk.
Avoid exceeding the absolute maximum ratings on any pin. Ensure the reference voltage is stable and within the specified range. The burnout current source can be enabled to detect open or shorted sensors, but it adds a small offset; account for this in calibration. The device is in 'Last Time Buy' status, so plan for end-of-life and consider drop-in replacements like AD7799BRUZ for new designs.
Compliance Information
RoHS compliant per Analog Devices product page. Not AEC-Q100 qualified. Lead-free per datasheet.
