AD4681BCPZ - 16-Bit 500kSPS Dual SAR ADC | Analog Devices
MPN: AD4681BCPZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.25 | $112.50 |
| 100 | $10 | $1,000.00 |
| 500 | $9 | $4,500.00 |
| 1,000 | $8.1 | $8,100.00 |
AD4681BCPZ Overview
A SAR ADC is a type of analog-to-digital converter that uses a binary search algorithm to convert an analog input into a digital output. It offers a good balance of speed, resolution, and power consumption, making it suitable for applications such as motor control, data acquisition, and industrial automation. The AD4681 belongs to the ADC family, which is a subset of data converters, and ultimately falls under the broader category of mixed-signal integrated circuits.
Key features of the AD4681 include dual simultaneous sampling, which allows both channels to be sampled at the same instant, preserving phase information between signals. The device also supports a separate logic supply, enabling direct interfacing with 1.8 V, 2.5 V, or 3.3 V digital systems. The conversion process uses standard control inputs, simplifying integration with microprocessors or DSPs. The AD4681 is specified for operation from −40°C to +125°C, ensuring reliable performance in harsh environments.
Technically, the AD4681 uses a capacitive DAC architecture with a precision comparator, achieving high accuracy and low power consumption. The dual ADC cores operate simultaneously, each with its own track-and-hold circuit, ensuring synchronized sampling. The device includes an internal reference buffer and supports both SPI and daisy-chain modes for flexible data readout. The LFCSP package offers excellent thermal performance and a small footprint, reducing PCB area.
Typical applications include motor control, where simultaneous current and voltage sensing is critical, and industrial data acquisition systems that require high-speed, high-resolution conversion. The AD4681 is also suitable for power monitoring, vibration analysis, and other precision measurement applications. Its low power consumption and wide temperature range make it a versatile choice for both portable and fixed installations.
When designing with the AD4681, ensure that the analog input signals are properly conditioned with anti-aliasing filters and that the reference voltage is stable and low-noise. The separate logic supply should be decoupled with a 0.1 µF capacitor close to the pin. For optimal performance, use a clean analog ground plane and minimize digital switching noise near the ADC.
Drop-in alternatives for AD4681BCPZ — 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 AD4681BCPZ (same form factor and footprint) — differing in Interface, Package, Sampling Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD4680BCPZ
✅ Drop-In✓ In Stock
$24.1 / Unit
View Datasheet →AD4681BCPZ-RL7
✅ Drop-In📋 Reference alternative (not in catalog)
AD4681BCPZ-RL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7380-4BCPZ
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD7381-4BCPZ
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AD4681BCPZ Maximum Ratings & Electrical Characteristics
| Resolution | 16 Bit |
| Number of Inputs | 2 |
| Input Type | Differential |
| Sampling Rate | 500 kSPS |
| Architecture | SAR |
| Supply Voltage | 3.0 V to 3.6 V |
| Logic Supply Voltage | 1.8 V, 2.5 V, 3.3 V |
| Package | 16-Lead LFCSP (3x3 mm) |
| Operating Temperature Range | -40°C to +125°C |
| Interface | SPI, Daisy-Chain |
| Simultaneous Sampling | Yes |
| RoHS | Compliant |
AD4681BCPZ Pin Configuration
| Pin 1 | AVDD — Analog power supply |
| Pin 2 | VIN1+ — Positive analog input channel 1 |
| Pin 3 | VIN1- — Negative analog input channel 1 |
| Pin 4 | GND — Ground |
| Pin 5 | VIN2+ — Positive analog input channel 2 |
| Pin 6 | VIN2- — Negative analog input channel 2 |
| Pin 7 | AVDD — Analog power supply |
| Pin 8 | REF — Reference voltage input |
| Pin 9 | GND — Ground |
| Pin 10 | SCLK — Serial clock input |
| Pin 11 | SDI — Serial data input |
| Pin 12 | SDO — Serial data output |
| Pin 13 | CS — Chip select |
| Pin 14 | VIO — Logic supply voltage |
| Pin 15 | GND — Ground |
| Pin 16 | VIO — Logic supply voltage |
Typical Applications
AD4681BCPZ is suitable for 6 applications: Motor Control, Industrial Data Acquisition, Power Monitoring, Vibration Analysis, Medical Instrumentation, Test and Measurement.
Motor Control
The AD4681BCPZ is ideal for motor control applications due to its dual simultaneous sampling capability, which allows precise measurement of phase currents and voltages at the same instant. This is essential for field-oriented control (FOC) algorithms that require accurate synchronization. The 500 kSPS sampling rate is sufficient for most motor control loops, and the 16-bit resolution provides high accuracy for current sensing. The device operates from 3.0 V to 3.6 V, making it compatible with typical motor control DSPs. Its wide temperature range (-40°C to +125°C) ensures reliable operation in industrial environments. The compact LFCSP package saves PCB space, and the SPI interface simplifies connection to microcontrollers.
Recommended
Industrial Data Acquisition
The AD4681BCPZ is well-suited for industrial data acquisition systems that require high-speed, high-resolution conversion of multiple analog signals. Its dual simultaneous sampling ensures that two channels are captured at the same time, preserving phase information. The 16-bit resolution provides excellent dynamic range for precision measurements. The device supports a wide input voltage range and operates from a single 3.0 V to 3.6 V supply, simplifying power design. The SPI interface and daisy-chain capability allow easy integration into multi-channel systems. The -40°C to +125°C operating temperature range makes it suitable for harsh industrial environments. The small LFCSP package is ideal for space-constrained PCBs.
Recommended
Power Monitoring
The AD4681BCPZ is used in power monitoring systems to measure voltage and current simultaneously, enabling accurate power calculation. Its dual simultaneous sampling ensures that voltage and current waveforms are captured at the same instant, which is critical for computing real power, reactive power, and power factor. The 16-bit resolution provides high accuracy for energy metering applications. The device operates from a 3.0 V to 3.6 V supply, making it compatible with common power management ICs. The SPI interface allows easy data transfer to a host processor. The wide temperature range ensures reliable operation in outdoor or industrial settings. The compact package is suitable for smart meters and power quality analyzers.
Recommended
Vibration Analysis
The AD4681BCPZ is suitable for vibration analysis applications where multiple accelerometer signals need to be sampled simultaneously. Its dual simultaneous sampling ensures that phase relationships between vibration signals are preserved, which is important for modal analysis and condition monitoring. The 16-bit resolution provides high dynamic range to capture small vibrations. The 500 kSPS sampling rate is adequate for most vibration frequencies. The device operates from a low supply voltage, making it suitable for battery-powered sensors. The SPI interface allows easy connection to a microcontroller or DSP. The wide temperature range enables use in industrial machinery monitoring. The small package is ideal for embedded vibration sensors.
Recommended
Medical Instrumentation
The AD4681BCPZ is used in medical instrumentation such as patient monitoring and diagnostic equipment. Its high resolution and simultaneous sampling are beneficial for applications like ECG and EEG, where multiple channels must be sampled synchronously. The 16-bit resolution provides accurate signal representation. The low power consumption is advantageous for portable devices. The device operates from a 3.0 V to 3.6 V supply, compatible with battery-powered systems. The SPI interface simplifies integration with medical-grade microcontrollers. The wide temperature range ensures reliable operation in clinical environments. The compact LFCSP package is suitable for wearable devices.
Recommended
Test and Measurement
The AD4681BCPZ is ideal for test and measurement equipment such as data loggers and spectrum analyzers. Its high speed and resolution enable accurate capture of transient signals. The dual simultaneous sampling allows for two-channel measurements with precise timing. The 16-bit resolution provides high precision for metrology applications. The device operates from a 3.0 V to 3.6 V supply, making it easy to integrate into benchtop instruments. The SPI interface allows fast data transfer to a host PC or FPGA. The wide temperature range ensures stable performance in lab environments. The small package is suitable for portable test equipment.
Recommended
Recommended Products Summary
Engineering reference data for AD4681BCPZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD4680BCPZ | AD4681BCPZ-RL7 | AD4681BCPZ-RL |
|---|---|---|---|---|
| Package | 16-Lead LFCSP (3x3 mm) | 16-Lead LFCSP (3x3 mm) | 16-Lead LFCSP (3x3 mm) | 16-Lead LFCSP (3x3 mm) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 16 Bit | 16 Bit | 16 Bit | 16 Bit |
| Sampling Rate | 500 kSPS | 1 MSPS | 500 kSPS | 500 kSPS |
| Number of Inputs | 2 | 2 | 2 | 2 |
| Input Type | Differential | Differential | Differential | Differential |
| Supply Voltage | 3.0 V to 3.6 V | 3.0 V to 3.6 V | 3.0 V to 3.6 V | 3.0 V to 3.6 V |
| Operating Temperature | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C |
Key Differentiators
- Dual simultaneous sampling (vs AD4680BCPZ)
- Lower sampling rate for power savings (vs AD4680BCPZ)
- Pin-compatible with AD4680 (vs AD4680BCPZ)
Design Notes
The AD4681BCPZ operates from a 3.0 V to 3.6 V analog supply and a separate logic supply (VIO) for digital interfacing. Decouple both supplies with 0.1 µF and 10 µF capacitors placed close to the pins. The logic supply can be 1.8 V, 2.5 V, or 3.3 V, allowing direct connection to various digital systems. Ensure the analog supply is clean and low-noise to maintain ADC performance.
For optimal performance, use a solid ground plane and separate analog and digital ground areas, connecting them at a single point. Place the ADC close to the signal source to minimize trace length and reduce noise pickup. Use differential routing for the analog inputs and keep them away from digital traces. The LFCSP package has an exposed pad that should be soldered to the ground plane for thermal and electrical performance.
Ensure that the reference voltage is stable and low-noise, as it directly affects ADC accuracy. Use a precision reference like the ADR4520. Avoid driving the analog inputs beyond the supply rails, as this can cause latch-up. The SPI interface should be operated at the correct logic levels; use level shifters if necessary. Also, ensure that the conversion start signal is properly timed to avoid metastability.
Compliance Information
RoHS compliant per distributor listings. No AEC-Q100 qualification indicated.
