AD7684BCPZ - 16-Bit 100kSPS PulSAR ADC | Analog Devices
MPN: AD7684BCPZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.29 | $8.29 |
| 10 | $7.46 | $74.60 |
| 100 | $6.63 | $663.00 |
| 500 | $5.8 | $2,900.00 |
| 1,000 | $5.39 | $5,390.00 |
AD7684BCPZ Overview
What is a successive approximation register (SAR) ADC? 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 typically consists of a comparator, a digital-to-analog converter (DAC), and a successive approximation register. SAR ADCs are known for their high speed, low power consumption, and excellent accuracy, making them ideal for applications such as industrial process control, medical instrumentation, and portable battery-powered devices. They are a subset of the broader ADC family, which also includes delta-sigma and pipeline converters, and are widely used in data acquisition systems.
Key features of the AD7684BCPZ include a 16-bit resolution with no missing codes, a throughput of 100 kSPS, and a differential input. The device also features a low noise performance, with a typical SNR of 92 dB and a typical THD of -110 dB. It includes an internal conversion clock and a serial interface that is SPI-compatible, simplifying integration with microcontrollers and DSPs. The power consumption is typically 4.5 mW at 5 V and 2.5 mW at 2.7 V, making it suitable for power-sensitive applications.
The AD7684BCPZ uses a charge redistribution architecture, which provides inherent sample-and-hold functionality and excellent linearity. The device includes a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies up to 45 kHz. The reference input is buffered, allowing the use of low-cost external references. The device also features a power-down mode that reduces current consumption to 1 uA, ideal for battery-powered systems.
Typical applications for the AD7684BCPZ include battery-powered instrumentation, portable medical devices, data acquisition systems, and industrial process control. Its high accuracy and low power make it an excellent choice for applications where precision and energy efficiency are critical.
When designing with the AD7684BCPZ, ensure that the reference voltage is stable and well-decoupled, as it directly affects the conversion accuracy. The analog input should be driven by a low-impedance source, and proper layout techniques should be used to minimize noise and parasitic capacitance.
Drop-in alternatives for AD7684BCPZ — 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 AD7684BCPZ (same form factor and footprint) — differing in Sampling Rate, Input Type, Supply Voltage, Resolution, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7682BCPZ
✅ Drop-In✓ In Stock
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View Datasheet →AD7685BCPZ
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
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View Datasheet →AD7686BCPZ
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
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View Datasheet →AD7690BCPZRL7
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View Datasheet →AD7980BCPZ-RL7
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$18 / Unit
View Datasheet →AD7684BCPZ Maximum Ratings & Electrical Characteristics
| Resolution | 16 bits |
| Sampling Rate | 100 kSPS |
| Input Type | Differential |
| Number of Inputs | 1 |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Interface | SPI |
| Architecture | SAR |
| SNR (typ) | 92 dB |
| THD (typ) | -110 dB |
| Power Dissipation (typ) | 4.5 mW at 5 V |
| Power-Down Current | 1 uA |
| Operating Temperature Range | -40C to +85C |
| Package | 20-Lead LFCSP (4x4 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
AD7684BCPZ Pin Configuration
| Pin 1 | IN+ — Positive analog input |
| Pin 2 | IN- — Negative analog input |
| Pin 3 | GND — Ground |
| Pin 4 | VDD — Power supply |
| Pin 5 | REF — Reference input |
| Pin 6 | REFGND — Reference ground |
| Pin 7 | SDI — Serial data input |
| Pin 8 | SDO — Serial data output |
| Pin 9 | SCK — Serial clock |
| Pin 10 | CNV — Convert input |
Typical Applications
AD7684BCPZ is suitable for 6 applications: Battery-Powered Instrumentation, Portable Medical Devices, Data Acquisition Systems, Industrial Process Control, Precision Measurement Equipment, Audio Test and Measurement.
Battery-Powered Instrumentation
The AD7684BCPZ's low power consumption (4.5 mW at 5 V) and wide supply range (2.7 V to 5.5 V) make it ideal for portable instruments. Its 16-bit resolution and 100 kSPS sampling rate provide accurate measurements while preserving battery life. The power-down mode (1 uA) further extends battery life in duty-cycled applications. The SPI interface simplifies connection to low-power microcontrollers, enabling compact, energy-efficient designs.
Recommended
Portable Medical Devices
In portable medical devices like glucose monitors and pulse oximeters, the AD7684BCPZ provides high accuracy (16-bit, 92 dB SNR) and low power, essential for battery operation. Its small LFCSP package saves board space, and the SPI interface allows easy integration with medical-grade microcontrollers. The differential input rejects common-mode noise from patient contact, ensuring reliable readings. The device's industrial temperature range (-40C to +85C) supports a wide range of clinical environments.
Recommended
Data Acquisition Systems
The AD7684BCPZ is a key component in multi-channel data acquisition systems, offering 16-bit resolution and 100 kSPS throughput. Its SPI interface supports daisy-chaining, allowing multiple ADCs to share a single bus. The differential input provides excellent common-mode rejection, crucial for accurate measurements in noisy industrial environments. The device's low power dissipation minimizes thermal drift, ensuring stable performance over time. It is compatible with a wide range of sensors and signal conditioning circuits.
Recommended
Industrial Process Control
In industrial process control, the AD7684BCPZ provides precise, reliable analog-to-digital conversion for monitoring and control loops. Its 16-bit resolution and 92 dB SNR ensure accurate representation of process variables. The device operates over -40C to +85C, suitable for harsh factory environments. The SPI interface enables fast communication with PLCs and industrial microcontrollers. The differential input helps reject electrical noise from motors and power lines, maintaining signal integrity.
Recommended
Precision Measurement Equipment
The AD7684BCPZ is used in precision measurement equipment such as digital multimeters and bench instruments. Its high accuracy (16-bit, no missing codes) and low noise (92 dB SNR) ensure reliable measurements. The device's internal conversion clock simplifies design, and the SPI interface allows easy integration with measurement processors. The small LFCSP package enables compact instrument designs. The wide supply range (2.7 V to 5.5 V) provides flexibility in power supply design.
Recommended
Audio Test and Measurement
The AD7684BCPZ's high SNR (92 dB) and low THD (-110 dB) make it suitable for audio test equipment. It can digitize audio signals with high fidelity, enabling accurate analysis of frequency response and distortion. The differential input reduces common-mode noise, preserving signal quality. The device's 100 kSPS sampling rate is sufficient for audio bandwidths up to 45 kHz. The SPI interface allows connection to audio processors for real-time analysis.
Recommended
Recommended Products Summary
Engineering reference data for AD7684BCPZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7682BCPZ | AD7685BCPZ | AD7686BCPZ |
|---|---|---|---|---|
| Package | 20-Lead LFCSP (4x4 mm) | 20-Lead LFCSP (4x4 mm) | 20-Lead LFCSP (4x4 mm) | 20-Lead LFCSP (4x4 mm) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 16 bits | 16 bits | 16 bits | 16 bits |
| Sampling Rate | 100 kSPS | 250 kSPS | 250 kSPS | 500 kSPS |
| Input Type | Differential | Pseudo-differential | Single-ended | Differential |
| Number of Inputs | 1 | 4 | 1 | 1 |
| SNR (typ) | 92 dB | 92 dB | 92 dB | 92 dB |
| Power Dissipation (typ) | 4.5 mW at 5 V | 12.5 mW at 5 V | 12.5 mW at 5 V | 20 mW at 5 V |
Key Differentiators
- Lower power consumption compared to higher-speed alternatives (vs AD7682BCPZ)
- Differential input provides better noise rejection (vs AD7685BCPZ)
- Lower sampling rate but sufficient for many applications (vs AD7686BCPZ)
Design Notes
The AD7684BCPZ operates from a single 2.7 V to 5.5 V supply. Use a low-noise LDO regulator to supply VDD, and place a 10 uF and 0.1 uF decoupling capacitor close to the VDD pin. The reference input should be decoupled with a 10 uF capacitor to ensure stable operation. In power-down mode, the supply current drops to 1 uA, but ensure the power supply can handle the transition.
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 ADC close to the signal source to minimize noise pickup. The LFCSP package has an exposed pad that should be soldered to the ground plane for thermal and electrical performance.
Ensure the reference voltage is stable and within the specified range (0.5 V to VDD). The analog input voltage must not exceed the reference voltage to avoid clipping. The SPI interface timing must meet the datasheet specifications; use a clock frequency within the specified range. Avoid floating the CNV pin; tie it to a logic high or low as needed.
Compliance Information
RoHS compliant per Analog Devices product page. Other compliance data not specified in provided sources.
