AD7890AN-2 - 8-Channel 12-Bit Serial ADC | Analog Devices
MPN: AD7890AN-2 ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.2 | $112.00 |
| 100 | $9.8 | $980.00 |
| 500 | $8.5 | $4,250.00 |
| 1,000 | $7.2 | $7,200.00 |
AD7890AN-2 Overview
A data acquisition system (DAS) is a complete signal chain that samples multiple analog signals, converts them to digital words, and transfers the data to a host processor. The AD7890AN-2 combines the multiplexer, track/hold, ADC, reference, and serial interface in a single IC, simplifying board design and reducing component count. It is part of the broader family of analog-to-digital converters (ADCs) used in industrial control, data logging, and medical monitoring systems.
Key features include a fast 12-bit ADC with a 5.9 µs conversion time, eight single-ended analog input channels, and a serial interface that supports SPI-compatible communication. The on-chip 2.5 V reference eliminates the need for an external reference, while the track/hold amplifier ensures accurate sampling of dynamic signals. The device also allows separate access to the multiplexer and ADC, providing flexibility in system design.
Technically, the AD7890AN-2 uses a successive approximation register (SAR) architecture, which offers a good balance of speed and power consumption. The 117 kSPS sampling rate is suitable for multi-channel monitoring applications where each channel is sampled sequentially. The serial interface reduces pin count and simplifies isolation in industrial environments. The device operates over the industrial temperature range of -40°C to +85°C.
Typical applications include industrial process control, data acquisition systems, battery monitoring, and medical instrumentation. The 0 V to 2.5 V input range is ideal for sensors with unipolar outputs, such as temperature and pressure transducers. The serial interface allows easy connection to microcontrollers and DSPs.
When designing with the AD7890AN-2, ensure that the analog input signals are within the specified range and that the reference is properly decoupled. The serial clock should be limited to the maximum specified frequency to ensure accurate data transfer. Consider using a low-pass filter on each analog input to reduce aliasing.
Drop-in alternatives for AD7890AN-2 — 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 AD7890AN-2 (same form factor and footprint) — differing in Input Voltage Range, Number of Channels, Package, Reference Type, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7890ANZ-10
✅ Drop-In✓ In Stock
$11.75 / Unit
View Datasheet →AD7890SQ-2
✅ Drop-In📋 Reference alternative (not in catalog)
AD7890BQ-2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD7892AN-2
✅ Drop-In📋 Reference alternative (not in catalog)
AD7851ANZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7890AN-2 Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 8 |
| Sampling Rate | 117 kSPS |
| Input Type | Single-Ended |
| Input Voltage Range | 0 V to 2.5 V |
| Interface | SPI |
| Architecture | SAR |
| Reference Type | Internal, 2.5 V |
| Supply Voltage | 5 V |
| Conversion Time | 5.9 µs |
| Operating Temperature Range | -40°C to +85°C |
| Package | 24-PDIP (N) |
| Mounting Type | Through Hole |
| Product Status | Obsolete |
| RoHS Status | unknown |
AD7890AN-2 Pin Configuration
| Pin 1 | VIN1 — Analog input channel 1 |
| Pin 2 | VIN2 — Analog input channel 2 |
| Pin 3 | VIN3 — Analog input channel 3 |
| Pin 4 | VIN4 — Analog input channel 4 |
| Pin 5 | VIN5 — Analog input channel 5 |
| Pin 6 | VIN6 — Analog input channel 6 |
| Pin 7 | VIN7 — Analog input channel 7 |
| Pin 8 | VIN8 — Analog input channel 8 |
| Pin 9 | GND — Ground |
| Pin 10 | VDD — Power supply (5 V) |
| Pin 11 | SCLK — Serial clock input |
| Pin 12 | SDATA — Serial data output |
| Pin 13 | CS — Chip select (active low) |
| Pin 14 | REF — Reference output (2.5 V) |
Typical Applications
AD7890AN-2 is suitable for 6 applications: Industrial Process Control, Data Acquisition Systems, Battery Monitoring, Medical Instrumentation, Test and Measurement, Automotive Test Systems.
Industrial Process Control
The AD7890AN-2 is ideal for industrial process control systems that monitor multiple analog sensors. Its 8-channel input multiplexer allows sampling of up to eight different signals, such as temperature, pressure, and flow, with a single ADC. The 12-bit resolution provides adequate precision for most industrial transducers, and the serial interface simplifies wiring and isolation. The 0-2.5 V input range is compatible with many sensor outputs, and the 117 kSPS sampling rate is sufficient for slow-changing process variables. The device operates over the industrial temperature range, ensuring reliability in harsh environments.
Recommended
Data Acquisition Systems
In general-purpose data acquisition systems, the AD7890AN-2 provides a complete analog front-end, integrating multiplexing, sampling, and conversion. Its 8 channels can be used to digitize multiple analog signals for logging or analysis. The on-chip track/hold amplifier ensures accurate sampling of dynamic signals, while the internal 2.5 V reference reduces external component count. The serial interface allows easy connection to microcontrollers or DSPs, and the 117 kSPS throughput is adequate for many applications. The 24-pin PDIP package is convenient for prototyping and breadboarding.
Recommended
Battery Monitoring
The AD7890AN-2 can be used in battery monitoring systems to measure cell voltages and temperatures. Its 8 channels allow monitoring of multiple cells in a battery pack, and the 0-2.5 V input range is suitable for individual cell voltages. The low power consumption of the SAR ADC is beneficial for battery-powered systems. The serial interface enables daisy-chaining or isolated communication. However, the 117 kSPS sampling rate is more than sufficient for battery monitoring, which typically requires slower updates. The device's industrial temperature range ensures operation in various environments.
Recommended
Medical Instrumentation
In medical instrumentation, the AD7890AN-2 can be used for monitoring physiological signals such as temperature, pressure, and bio-potentials. Its 8 channels allow simultaneous sampling of multiple sensors, and the 12-bit resolution is adequate for many diagnostic applications. The serial interface simplifies isolation for patient safety. The 0-2.5 V input range is compatible with many medical sensor outputs. The device's small footprint and low power consumption are advantageous for portable devices. However, for higher resolution requirements, consider alternatives like the AD7851ANZ with 14-bit resolution.
Recommended
Test and Measurement
The AD7890AN-2 is suitable for test and measurement equipment that requires multi-channel data acquisition. Its 8 channels can be used to digitize multiple test points, and the 12-bit resolution provides good accuracy for general-purpose measurements. The serial interface allows easy integration into automated test systems. The 117 kSPS sampling rate is sufficient for many applications, such as logging voltage and current waveforms. The device's through-hole package is convenient for prototyping and repair. However, for higher speed or resolution, consider the AD7892AN-2 or AD7851ANZ.
Recommended
Automotive Test Systems
In automotive test systems, the AD7890AN-2 can be used to monitor sensor outputs from engine control units, battery management, and environmental controls. Its 8 channels allow simultaneous sampling of multiple signals, and the 12-bit resolution is adequate for many automotive sensors. The serial interface simplifies wiring in test setups. The device operates over the industrial temperature range, making it suitable for under-hood or test bench environments. However, for automotive-grade qualification, consider the AD7890SQ-2 (military grade) or other AEC-Q100 qualified ADCs. The 0-2.5 V input range may require signal conditioning for higher voltage sensors.
Recommended
Recommended Products Summary
Engineering reference data for AD7890AN-2 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7890ANZ-10 | AD7890SQ-2 | AD7892AN-2 | AD7851ANZ |
|---|---|---|---|---|---|
| Package | 24-PDIP (N) | 24-PDIP (N) | 24-PDIP (N) | 24-PDIP (N) | 24-PDIP (N) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 14 bits |
| Interface | SPI | SPI | SPI | SPI | SPI |
| Operating Temperature | -40°C to +85°C | -40°C to +85°C | -55°C to +125°C | -40°C to +85°C | -40°C to +85°C |
| Lifecycle Status | Obsolete | Active | Obsolete | Obsolete | Active |
Key Differentiators
- 8-channel multiplexer integrated (vs AD7851ANZ)
- Lower sampling rate but sufficient for many applications (vs AD7892AN-2)
- 0-2.5 V input range optimized for unipolar sensors (vs AD7890ANZ-10)
Design Notes
The AD7890AN-2 operates from a single 5 V supply. Ensure that the supply is clean and well-regulated, as noise on VDD can affect conversion accuracy. Use a 0.1 µF ceramic capacitor and a 10 µF tantalum capacitor close to the VDD pin for decoupling. The internal reference is 2.5 V; if an external reference is used, ensure it is stable and low-noise.
For optimal performance, place the AD7890AN-2 on a PCB with a solid ground plane. Keep analog input traces short and shielded from digital signals to minimize noise coupling. Use separate analog and digital ground planes if possible, and connect them at a single point. Decouple the reference pin with a 0.1 µF capacitor to ground.
A common pitfall is exceeding the absolute maximum input voltage on the analog inputs. The AD7890AN-2 accepts 0-2.5 V; applying higher voltages can damage the device. Also, ensure that the serial clock frequency does not exceed the maximum specified in the datasheet to avoid data corruption. When the part is obsolete, verify availability before designing it into a new product.
Compliance Information
Compliance information not provided in the verified data. The part is obsolete, so compliance may not be guaranteed.
