AD7688BCPZ - 16-Bit 500kSPS PulSAR ADC | Analog Devices
MPN: AD7688BCPZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $23.69 | $23.69 |
| 10 | $21.32 | $213.20 |
| 100 | $18.95 | $1,895.00 |
| 500 | $16.58 | $8,290.00 |
| 1,000 | $14.21 | $14,210.00 |
AD7688BCPZ Overview
A SAR ADC is a type of analog-to-digital converter that uses a binary search algorithm to determine the digital output. It compares the input signal against a reference voltage using a successive approximation register, converging to the final value in N steps for an N-bit converter. SAR ADCs are widely used in data acquisition systems, industrial process control, medical instrumentation, and portable devices due to their high resolution, low latency, and low power consumption. The AD7688 belongs to the PulSAR family, known for its high precision and ease of use.
Key features of the AD7688BCPZ include 16-bit resolution with no missing codes, a throughput of 500 kSPS, and a true differential analog input range that can be configured for unipolar or bipolar operation. The device offers a serial interface (SPI) that operates at clock speeds up to 50 MHz, allowing for high-speed data transfer. It also includes a busy indicator and a conversion result readback feature, simplifying system integration. The LFCSP package is lead-free and RoHS compliant, making it suitable for environmentally conscious designs.
Technically, the AD7688 uses a charge redistribution architecture with an internal reference buffer, eliminating the need for an external reference driver in many applications. The device provides excellent linearity with a maximum INL of ±1.5 LSB (±23 ppm of FSR) and a THD of -118 dB at 20 kHz, ensuring high-fidelity signal acquisition. The input range is fully differential, allowing the ADC to reject common-mode noise and improve dynamic performance. The device operates over the industrial temperature range of -40°C to +85°C, making it suitable for harsh environments.
Typical applications include high-speed data acquisition systems, medical imaging equipment, industrial process control, and portable instrumentation. The AD7688's combination of high speed, high resolution, and low power makes it ideal for battery-powered devices where performance and efficiency are critical. Its small package footprint also enables compact PCB designs.
When designing with the AD7688BCPZ, ensure that the reference voltage is stable and well-decoupled, as it directly affects conversion accuracy. Use a low-noise reference such as the ADR4550 and place decoupling capacitors close to the VDD and VIO pins. The differential input should be driven with a low-impedance source to maintain linearity.
Drop-in alternatives for AD7688BCPZ — 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 AD7688BCPZ (same form factor and footprint) — differing in Sampling Rate, Input Type, Resolution, Data Interface, INL (Max).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7688BCPZ-R2
✅ Drop-In📋 Reference alternative (not in catalog)
AD7980BCPZ-RL7
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$18 / Unit
View Datasheet →AD7690BCPZRL7
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$17.6 / Unit
View Datasheet →AD7688BCPZ Maximum Ratings & Electrical Characteristics
| Resolution | 16 bits |
| Sampling Rate | 500 kSPS |
| Input Type | Differential |
| INL (Typ) | ±0.4 LSB |
| INL (Max) | ±1.5 LSB (±23 ppm of FSR) |
| SNR | 95.5 dB @ 20 kHz |
| THD | -118 dB @ 20 kHz |
| Dynamic Range | 96.5 dB |
| Supply Voltage (VDD) | 4.5 V to 5.5 V |
| Logic Supply Voltage (VIO) | 2.3 V to 5.5 V |
| Operating Temperature Range | -40°C to +85°C |
| Package | 10-Lead LFCSP-WD (3x3 mm) |
| Interface | SPI |
| RoHS Status | Compliant |
| Lead-Free | Yes |
AD7688BCPZ Pin Configuration
| Pin 1 | IN+ — Positive differential analog input |
| Pin 2 | IN- — Negative differential analog input |
| Pin 3 | GND — Ground |
| Pin 4 | VDD — Analog power supply (4.5V to 5.5V) |
| Pin 5 | VIO — Logic power supply (2.3V to 5.5V) |
| Pin 6 | SCK — Serial clock input |
| Pin 7 | SDI — Serial data input (for configuration) |
| Pin 8 | SDO — Serial data output |
| Pin 9 | CNV — Convert input (start conversion) |
| Pin 10 | REF — Reference voltage input |
Typical Applications
AD7688BCPZ is suitable for 6 applications: High-Speed Data Acquisition, Medical Imaging, Industrial Process Control, Portable Instrumentation, Test and Measurement, Audio Test Equipment.
High-Speed Data Acquisition
The AD7688BCPZ's 500 kSPS sampling rate and 16-bit resolution make it ideal for high-speed data acquisition systems. Its true differential input rejects common-mode noise, ensuring accurate capture of fast-changing signals. The SPI interface allows easy integration with microcontrollers and DSPs, enabling real-time processing in applications like vibration analysis and transient recording.
Recommended
Medical Imaging
In medical imaging systems such as ultrasound and MRI, the AD7688BCPZ provides high-resolution digitization of analog sensor signals. Its 95.5 dB SNR and -118 dB THD ensure minimal distortion, preserving image quality. The small LFCSP package fits compact probes, and the low power consumption extends battery life in portable devices. The differential input helps reject interference from other medical equipment.
Recommended
Industrial Process Control
The AD7688BCPZ is well-suited for industrial process control, where precise measurement of temperature, pressure, and flow is critical. Its 16-bit resolution and ±1.5 LSB max INL ensure accurate readings, while the wide operating temperature range (-40°C to +85°C) allows deployment in harsh factory environments. The SPI interface simplifies connection to PLCs and industrial microcontrollers, and the differential input rejects common-mode noise from long sensor leads.
Recommended
Portable Instrumentation
For battery-powered portable instruments like handheld multimeters and data loggers, the AD7688BCPZ offers a balance of performance and power efficiency. Its low power consumption extends battery life, while the 3x3 mm LFCSP package minimizes PCB area. The device operates from a single 5V supply, simplifying power design. The SPI interface supports low-voltage logic (2.3V), enabling direct connection to low-power microcontrollers.
Recommended
Test and Measurement
In test and measurement equipment such as spectrum analyzers and oscilloscopes, the AD7688BCPZ provides high-speed, high-resolution digitization of input signals. Its 500 kSPS throughput and 16-bit resolution enable accurate capture of waveforms and spectral content. The true differential input allows direct connection to balanced sources, reducing noise. The small package and SPI interface facilitate compact, multi-channel designs.
Recommended
Audio Test Equipment
The AD7688BCPZ is used in audio test equipment for measuring THD and SNR of audio systems. Its -118 dB THD and 95.5 dB SNR ensure accurate characterization of audio components. The differential input interfaces directly with balanced audio outputs, and the high sampling rate supports analysis up to 250 kHz. The device's low power consumption is beneficial for portable audio analyzers.
Recommended
Recommended Products Summary
Engineering reference data for AD7688BCPZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7688BCPZ-R2 | AD7980BCPZ | AD7690BCPZ |
|---|---|---|---|---|
| Package | 10-Lead LFCSP-WD (3x3 mm) | 10-Lead LFCSP-WD (3x3 mm) | 10-Lead LFCSP-WD (3x3 mm) | 10-Lead LFCSP-WD (3x3 mm) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 16 bits | 16 bits | 16 bits | 16 bits |
| Sampling Rate | 500 kSPS | 500 kSPS | 1 MSPS | 400 kSPS |
| Input Type | Differential | Differential | Differential | Differential |
| INL (Max) | ±1.5 LSB | ±1.5 LSB | ±1.5 LSB | ±1.5 LSB |
| SNR | 95.5 dB | 95.5 dB | 95.5 dB | 95.5 dB |
| Supply Voltage (VDD) | 4.5V to 5.5V | 4.5V to 5.5V | 2.3V to 5.5V | 2.3V to 5.5V |
Key Differentiators
- Higher sampling rate than AD7690BCPZ (vs AD7690BCPZ)
- Lower power consumption than AD7980BCPZ (vs AD7980BCPZ)
- True differential input (vs AD7682BCPZ)
Design Notes
Decouple the VDD and VIO pins with 0.1 µF and 10 µF capacitors placed as close to the pins as possible. Use a low-noise LDO for the analog supply to minimize noise coupling into the ADC. The reference input (REF) should be driven by a low-impedance source, such as the ADR4550, with a 10 µF decoupling capacitor to ensure stable operation.
For optimal performance, use a solid ground plane under the ADC and route analog and digital signals separately. Keep the analog input traces short and shielded to reduce noise pickup. The LFCSP package has an exposed pad; solder it to the ground plane for improved thermal and electrical performance.
Avoid driving the analog inputs beyond the supply rails, as this can cause latch-up or damage. Ensure the reference voltage is within the specified range (typically 2.5V to VDD) and is stable during conversion. The SPI interface should be operated within the specified clock frequency (up to 50 MHz) to avoid timing errors.
Compliance Information
RoHS compliant and lead-free per Analog Devices product page. AEC-Q100 not applicable for this non-automotive part.
