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Analog Devices Inc. AD7685ACPZRL
- Part No.:
- AD7685ACPZRL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 10-VFDFN Exposed Pad, CSP
- Datasheet:
-
AD7685ACPZRL.pdf
- Description:
- IC ADC 16BIT SAR 10LFCSP
- Quantity:
- Payment:
- Shipping:
Inventory:3,451
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Product details
Overview
AD7685ACPZRL from Analog Devices is a 16-bit, pseudo-differential, successive-approximation ADC with 250 kSPS throughput, ±2 LSB max INL, 93.5 dB SINAD at 20 kHz, and no pipeline delay-designed for precision data acquisition in battery-powered medical instruments and portable instrumentation.
For engineers reviewing the AD7685ACPZRL datasheet, AD7685ACPZRL pinout, AD7685ACPZRL application, or AD7685ACPZRL equivalent, this page delivers verified specifications, MSOP-10 pin mapping, real-world use cases, and validated alternative options for low-power, high-accuracy analog-to-digital conversion.
Technical Context
The AD7685ACPZRL employs a charge redistribution SAR architecture with integrated track-and-hold, enabling true 16-bit resolution without missing codes and zero latency conversion. Its CNV-triggered sampling captures IN+ relative to IN− over 0 V to VREF, supporting external reference voltages up to VDD.
It features a SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface with daisy-chain capability and optional BUSY indicator, powered by dual supplies: VDD (2.3–5.5 V) for analog core and VIO (1.8–VDD+0.3 V) for logic compatibility across 1.8 V, 2.5 V, 3 V, and 5 V host systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit with no missing codes-guarantees monotonicity and full-scale code coverage for precision measurement. |
| Throughput | 250 kSPS at VDD ≥ 4.5 V-supports real-time signal capture in portable data loggers and PDA-based sensors. |
| INL | ±2 LSB maximum (±0.003% FSR)-ensures end-point linearity critical for calibrated medical instrument front-ends. |
| SINAD | 93.5 dB at 20 kHz, VREF = 5 V-delivers >15.5 ENOB for high-fidelity audio and vibration monitoring. |
| Power @ 100 kSPS | 1.35 mW at 2.5 V-enables >10-year battery life in 100-SPS sleep-wake cycles for remote IoT nodes. |
| Standby Current | 1 nA-minimizes quiescent drain during idle periods in energy-harvesting sensor nodes. |
| Analog Input Range | Pseudo-differential: 0 V to VREF with VREF ≤ VDD-simplifies single-supply sensor interfacing without level-shifting circuitry. |
Pinout & Package
AD7685ACPZRL is housed in a 10-lead MSOP package (3 mm × 3 mm, 0.5 mm pitch), RoHS-compliant, with exposed pad connected to GND (optional for thermal performance).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Analog reference input | Accepts 0.5 V to VDD; must be decoupled with 10 µF capacitor for stable 16-bit accuracy. |
| VDD | Analog power supply | 2.3 V–5.5 V single supply powering ADC core and internal track-and-hold. |
| IN+ | Positive analog input | Sampled differentially against IN−; supports 0 V to VREF range with 65 dB CMRR at 250 kHz. |
| IN− | Analog ground sense | Reference point for IN+; connect to local analog ground or remote sensor ground for noise rejection. |
| GND | Power ground | Common return for VDD, REF, and digital I/O; separate analog/digital grounding recommended. |
| CNV | Convert control input | Rising edge initiates conversion and selects interface mode (CS or Chain); doubles as chip select in CS mode. |
| SDO | Serial data output | 16-bit straight-binary result synchronized to SCK; high-impedance when disabled. |
| SCK | Serial clock input | Drives data shift-out; timing varies with VIO (17–20 ns min period for VIO ≥ 2.3 V). |
| SDI | Serial data input | Configures interface mode on CNV rising edge; enables daisy-chaining or BUSY indication. |
| VIO | Digital I/O supply | 1.8 V–VDD+0.3 V logic interface supply-decouples ADC timing from host voltage domain. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Immediate data availability after conversion-eliminates latency-induced phase error in closed-loop control. |
| Proprietary SPI-compatible interface | Supports 3-wire CS mode, 4-wire CS mode, and daisy-chain mode-reduces PCB routing complexity in multi-channel systems. |
| Ultra-low standby current | 1 nA at 5 V-enables microamp-level system sleep states without sacrificing wake-up readiness. |
| Wide VIO range (1.8 V–5 V) | Interoperability with legacy 1.8 V FPGAs and modern 5 V microcontrollers-no level translators required. |
| Pin-for-pin compatibility | With AD7686/AD7687/AD7688-allows design reuse and grade-scaling without layout change. |
Applications
| Portable Medical Sensors | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous ECG waveform digitization in handheld patient monitors with 24-hour battery life. IC Role / Device Role / Timing Role: Primary 16-bit ADC capturing differential lead signals at 250 kSPS with zero-latency readout for real-time R-peak detection. Use Value: 93.5 dB SINAD preserves diagnostic fidelity; 1.35 mW power at 2.5 V extends runtime without compromising SNR. |
Use Scenario: Environmental parameter logging (temperature, humidity, pressure) in field-deployed wireless nodes. IC Role / Device Role / Timing Role: Low-power SAR ADC triggered by MCU wake-up interrupt, converting sensor outputs before returning to 1 nA standby. Use Value: Standby current <1 nA enables multi-year operation on coin-cell batteries; pseudo-differential inputs reject common-mode noise from long sensor traces. |
| Industrial Process Transmitters | Handheld Test Equipment |
Use Scenario: 4–20 mA loop-powered transmitter measuring flow or level with HART modulation support. IC Role / Device Role / Timing Role: Precision ADC interfaced to isolated sigma-delta driver, providing 16-bit raw measurements for digital calibration and linearization. Use Value: ±2 LSB INL ensures <0.01% FS accuracy after two-point calibration; VIO independence allows clean separation of analog and digital domains. |
Use Scenario: Portable oscilloscope or multimeter front-end requiring high-resolution DC and AC measurements. IC Role / Device Role / Timing Role: High-speed SAR ADC sampling at 250 kSPS with immediate data availability for real-time FFT and RMS computation. Use Value: No pipeline delay enables trigger-accurate waveform reconstruction; 2 MHz −3 dB input bandwidth supports >100 kHz signal analysis. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 16-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7687BRMZ | Same 16-bit SAR architecture, 250 kSPS, but in MSOP-10 with 1.8 V–5.5 V VIO and identical pinout; ±1.5 LSB max INL (tighter spec). | Optimized for higher-accuracy industrial transmitters where INL < ±1.5 LSB is mandated. | Select AD7687BRMZ when tighter INL (±1.5 LSB vs. ±2 LSB) and guaranteed B-grade performance are required. |
| AD7980BRMZ | Differential-input 16-bit SAR ADC, 1 MSPS throughput, 2.5 V–5.5 V VDD, 1.8 V–5.5 V VIO; requires external reference and differential driver. | Suited for high-speed multiplexed channel systems needing >250 kSPS per channel with true differential signaling. | Choose AD7980BRMZ only if system demands >250 kSPS or true differential input topology-requires redesign of analog front-end and layout. |
Compared with AD7685ACPZRL, AD7687BRMZ offers improved INL consistency for metrology-grade calibration, while AD7980BRMZ trades power efficiency and simplicity for speed and differential flexibility-neither is pin-compatible, and both require board-level validation for replacement.
Availability
AD7685ACPZRL is available at Aetrix Electronics and suitable for battery-powered equipment, medical instruments, and portable data acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AD7685ACPZRL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.
The AD7685ACPZRL belongs to the PulSAR® family of precision SAR ADCs, engineered for low-power, high-accuracy data acquisition in space-constrained, battery-operated, and industrial sensing applications.
FAQ
What is the maximum reference voltage supported by the AD7685ACPZRL?
The AD7685ACPZRL accepts an external reference voltage (REF) from 0.5 V up to VDD. When VDD = 5.5 V, REF may be set as high as 5.5 V; however, typical operation uses REF = VDD = 5 V or REF = 2.5 V for optimal SINAD and THD performance. The REF pin must be decoupled with a 10 µF capacitor to maintain 16-bit accuracy across temperature and throughput.
Does the AD7685ACPZRL require an external driver amplifier for its analog inputs?
The AD7685ACPZRL includes an integrated track-and-hold with 2 MHz −3 dB input bandwidth and 2.5 ns aperture delay, allowing direct connection of low-impedance sources (e.g., resistive sensors, op-amp buffers). For high-impedance or reactive sources (e.g., piezoelectric sensors), an external driver like ADA4841 is recommended to ensure full 16-bit settling within the 1.8 µs acquisition time.
Can the AD7685ACPZRL operate with a 1.8 V digital interface while using a 5 V analog supply?
Yes-the AD7685ACPZRL supports independent VDD (2.3–5.5 V) and VIO (1.8–VDD+0.3 V) supplies. With VDD = 5 V and VIO = 1.8 V, it interfaces directly to 1.8 V FPGAs or microcontrollers without level shifters, maintaining full 250 kSPS throughput and 93.5 dB SINAD, as confirmed in Table 3 and Figure 20 of the datasheet.
What is the meaning of "pseudo-differential" input in the AD7685ACPZRL?
"Pseudo-differential" means the AD7685ACPZRL samples the voltage difference between IN+ and IN−, but IN− is not actively driven-it serves as a ground reference point. The analog input range is defined as IN+ − IN− = 0 V to VREF, with IN− typically tied to analog ground or remote sensor ground. This differs from true differential inputs that accept symmetrical ±VREF signals.
Is the AD7685ACPZRL pin-compatible with other PulSAR ADCs?
Yes-the AD7685ACPZRL is pin-for-pin compatible with AD7686, AD7687, and AD7688 in the same 10-lead MSOP package. This allows seamless migration between 16-bit variants (e.g., upgrading to AD7687 for tighter INL or AD7688 for 400 kSPS) without PCB redesign, provided VIO and timing constraints are reviewed per device datasheet.
AD7685ACPZRL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PulSAR®
- Package/Case:
- 10-VFDFN Exposed Pad, CSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Number of Bits:
- 16
- Sampling Rate (Per Second):
- 250k
- Number of Inputs:
- 1
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI, DSP
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 2.3V ~ 5.5V
- Voltage - Supply, Digital:
- 2.3V ~ 5.5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 10-LFCSP-WD (3x3)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7685ACPZRL FAQ
1.How can I place an order for AD7685ACPZRL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7685ACPZRL on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD7685ACPZRL reliable?
The price and inventory of AD7685ACPZRL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7685ACPZRL is usually 5 days.
3.What payment methods are accepted for AD7685ACPZRL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7685ACPZRL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7685ACPZRL?
AD7685ACPZRL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7685ACPZRL order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD7685ACPZRL?
For technical support, including AD7685ACPZRL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7685ACPZRL requirements.
6.How does Aetrix verify that AD7685ACPZRL is sourced from the original manufacturer or authorized distributors?
All AD7685ACPZRL products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7685ACPZRL meets industry standards.
7.What is the process for return or replacement of AD7685ACPZRL?
All AD7685ACPZRL units undergo pre-shipment inspection (PSI). If there is an issue with AD7685ACPZRL, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD7685ACPZRL part is unused and in its original packaging.
Return procedure for AD7685ACPZRL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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