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Analog Devices Inc. AD7685BRMZ
- Part No.:
- AD7685BRMZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
AD7685BRMZ.pdf
- Description:
- IC ADC 16BIT SAR 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:143
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Product details
Overview
AD7685BRMZ from Analog Devices is a 16-bit, pseudo-differential successive approximation register (SAR) ADC with 250 kSPS throughput, ±2 LSB max INL, 93.5 dB SINAD at 20 kHz, and no pipeline delay-designed for high-precision, low-power data acquisition in battery-powered medical instruments and portable instrumentation.
For engineers reviewing the AD7685BRMZ datasheet, AD7685BRMZ pinout, AD7685BRMZ application, or AD7685BRMZ equivalent, this page delivers verified electrical specifications, MSOP-10 pin mapping, real-world interface timing constraints, and validated alternative options for precision analog-to-digital conversion in space-constrained, single-supply systems.
Technical Context
The AD7685BRMZ employs a charge redistribution SAR architecture with integrated track-and-hold, enabling true 16-bit resolution without missing codes and zero latency conversion. Its pseudo-differential input accepts 0 V to VREF signals referenced to IN−, supporting external reference voltages up to VDD (5.5 V).
Digital interfacing uses a SPI-/QSPI-/MICROWIRE-/DSP-compatible serial protocol with configurable CS or daisy-chain modes, BUSY indicator support, and independent VIO supply (1.8 V to 5 V) decoupled from VDD (2.3 V to 5.5 V), ensuring compatibility across mixed-voltage host systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 16-bit with no missing codes-guarantees monotonic transfer function for closed-loop control and metrology. |
| Throughput | 250 kSPS at VDD ≥ 4.5 V-supports real-time sampling of audio-band and sensor signals up to ~100 kHz Nyquist. |
| INL | ±2 LSB maximum (±0.003% FSR)-enables <12-bit effective linearity over full temperature range without calibration. |
| SINAD | 93.5 dB at 20 kHz, 5 V REF-corresponds to 15.3 ENOB, suitable for high-fidelity signal capture in medical ECG/EEG front-ends. |
| Power @ 100 kSPS | 1.35 mW at 2.5 V, 4 mW at 5 V-scales linearly with throughput, enabling ultra-low idle power via on-demand conversion. |
| Aperture Delay | 2.5 ns at VDD = 5 V-minimizes sampling jitter for coherent multi-channel synchronization. |
| Reference Range | 0.5 V to VDD-allows flexible scaling from low-voltage battery monitoring (e.g., 1.8 V REF) to full 5 V range. |
Pinout & Package
AD7685BRMZ is housed in a 10-lead MSOP package (3 mm × 3 mm, 0.5 mm pitch) with exposed pad connected to GND. Pinout matches industry-standard PulSAR® 10-lead footprint and supports drop-in replacement for AD7686/AD7687/AD7688.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| REF | Analog reference input | Accepts 0.5 V–VDD external reference; requires local 10 µF decoupling for noise immunity. |
| VDD | Analog power supply | 2.3 V–5.5 V single supply; powers core ADC and internal track-and-hold. |
| IN+ | Pseudo-differential analog input | Input voltage range = 0 V to VREF relative to IN−; supports unipolar sensor outputs. |
| IN− | Analog ground sense | Reference point for IN+; connect to clean analog ground or remote sensor ground. |
| GND | Power ground | Common return for VDD and analog circuitry; tie to exposed pad for thermal performance. |
| CNV | Convert trigger / interface mode select | Rising edge initiates conversion; logic level at CNV rising edge selects CS or daisy-chain mode. |
| SDO | Serial data output | 16-bit straight-binary output synchronized to SCK; high-impedance when not selected. |
| SCK | Serial clock input | Drives data shift-out; minimum period 15 ns (VDD ≥ 4.5 V), supports up to 66.7 MHz clock rate. |
| SDI | Serial data input / mode control | Configures interface mode (CS vs. chain); enables daisy-chaining or BUSY indicator in CS mode. |
| VIO | Digital I/O supply | 1.8 V–5 V logic interface supply-decouples digital timing from analog VDD for noise isolation. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Immediate data availability after conversion-eliminates buffer management overhead in real-time control loops. |
| 1 nA standby current | Enables >10-year battery life in intermittent-sampling applications like portable gas analyzers. |
| Proprietary SPI-compatible interface | Supports 3-wire CS mode, 4-wire CS mode, and daisy-chain mode-reduces PCB routing complexity in multi-ADC systems. |
| Single-supply operation | VDD = 2.3 V–5.5 V with independent VIO = 1.8 V–5 V-simplifies power architecture in mixed-voltage embedded designs. |
| Pin-for-pin compatibility | Direct replacement for AD7686/AD7687/AD7688-enables family-based design reuse and BOM flexibility. |
Applications
| Portable Medical Instrumentation | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous ECG waveform digitization in handheld patient monitors with 3.3 V Li-ion supply and isolated analog front-end. IC Role / Device Role / Timing Role: Primary 16-bit ADC capturing differential lead-II signals at 250 kSPS with <1 µs transient response for R-wave detection. Use Value: 93.5 dB SINAD ensures diagnostic-grade SNR; 1.35 mW power at 2.5 V extends runtime per charge cycle by >35% versus competing SAR ADCs. |
Use Scenario: Environmental sensor hub logging temperature, humidity, and pressure every 10 seconds using a 3.0 V coin cell. IC Role / Device Role / Timing Role: Low-duty-cycle ADC activated only during measurement bursts, leveraging 1 nA standby current for ultra-low quiescent drain. Use Value: Sub-µW average power consumption enables >5-year operational life; pseudo-differential inputs reject common-mode noise from shared PCB ground. |
| Industrial Process Monitoring | Mobile Communications Test Equipment |
Use Scenario: 4–20 mA loop-powered transmitter digitizing RTD or thermocouple outputs in hazardous-area field devices. IC Role / Device Role / Timing Role: High-accuracy ADC with ±2 LSB INL operating from 3.3 V isolated supply, referenced to precision 2.5 V bandgap. Use Value: 0.003% FSR linearity eliminates need for factory calibration; MSOP-10 footprint fits tight DIN-rail enclosure layouts. |
Use Scenario: Portable RF power meter measuring CW and modulated signals with real-time FFT analysis on ARM Cortex-M7 MCU. IC Role / Device Role / Timing Role: High-speed data capture engine feeding 16-bit samples into hardware-accelerated DSP pipeline at 250 kSPS. Use Value: No pipeline delay enables deterministic sample-to-result latency; SPI interface synchronizes cleanly with DMA-driven acquisition buffers. |
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 |
|---|---|---|---|
| AD7686BRMZ | Same 10-lead MSOP package, 500 kSPS throughput, ±1.5 LSB max INL, higher power (6.5 mW @ 5 V/100 kSPS) | Better speed/linearity trade-off for higher-bandwidth test equipment where 250 kSPS is limiting | Select AD7686BRMZ when system requires >300 kSPS while retaining identical layout and firmware interface. |
| ADS8860IDRCT | 16-bit, 1 MSPS, SPI interface, 1.8 V–3.6 V supply only, ±1.25 LSB max INL, 92.5 dB SINAD | Optimized for ultra-low-voltage battery systems (<3.3 V) but lacks VIO/VDD separation and daisy-chain capability | Choose ADS8860IDRCT for compact wearable sensors powered solely by 2.0 V coin cells where 1 MSPS is needed and reference flexibility is secondary. |
Compared with AD7685BRMZ, AD7686BRMZ offers higher throughput at increased power and cost, while ADS8860IDRCT provides faster sampling in narrow-voltage systems but sacrifices interface versatility and reference scalability-making AD7685BRMZ optimal for general-purpose, single-supply, mid-speed precision acquisition.
Availability
AD7685BRMZ is available at Aetrix Electronics and suitable for battery-powered medical instruments, portable data loggers, and industrial process monitoring requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for AD7685BRMZ 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 Wilmington, MA, with design centers worldwide.
The AD7685BRMZ belongs to the PulSAR® family of precision SAR ADCs, engineered specifically for low-power, high-accuracy data acquisition in portable, battery-operated, and space-constrained industrial systems.
FAQ
What is the maximum recommended reference voltage for AD7685BRMZ?
The AD7685BRMZ supports an external reference voltage from 0.5 V up to VDD, with VDD rated from 2.3 V to 5.5 V. Therefore, the absolute maximum reference voltage is 5.5 V. However, for optimal performance and to maintain specified INL and SINAD, Analog Devices recommends using VREF ≤ VDD and ensuring proper decoupling with a 10 µF capacitor directly at the REF pin. The AD7685BRMZ achieves best AC performance (e.g., 93.5 dB SINAD) at VREF = 5 V.
Does AD7685BRMZ require an external driver amplifier for its analog inputs?
The AD7685BRMZ integrates a low-noise, wide-bandwidth track-and-hold circuit and can directly accept signals from low-impedance sources (e.g., precision voltage references or op-amp buffers). For high-impedance or reactive sources (e.g., passive RC filters or piezoelectric sensors), an external driver such as the ADA4841 or AD8675 is recommended to ensure full 16-bit settling within the 1.8 µs acquisition time. The datasheet specifies 2 MHz −3 dB input bandwidth and 2.5 ns aperture delay, confirming suitability for direct connection to well-designed front-ends.
Can AD7685BRMZ operate with a 1.8 V digital interface while using a 5 V analog supply?
Yes. AD7685BRMZ features separate VIO and VDD supplies: VIO (1.8 V to 5 V) powers the digital I/O pins (SDI, SDO, SCK, CNV), while VDD (2.3 V to 5.5 V) powers the analog core. This allows full 1.8 V logic compatibility-verified down to 1.8 V VIO-even when VDD = 5 V. Timing parameters (e.g., tSCK = 20 ns min) remain valid at 1.8 V VIO, enabling seamless integration with modern ultra-low-voltage MCUs without level-shifting circuitry.
Is AD7685BRMZ pin-compatible with other PulSAR® ADCs in MSOP-10 packages?
Yes. AD7685BRMZ is explicitly specified as pin-for-pin compatible with AD7686BRMZ, AD7687BRMZ, and AD7688BRMZ in the 10-lead MSOP package. All share identical pin configuration (REF, VDD, IN+, IN−, GND, CNV, SDO, SCK, SDI, VIO), identical footprint, and compatible timing-allowing hardware reuse and firmware adaptation across the 16-bit PulSAR® family based on required throughput (250 kSPS → 500 kSPS → 1 MSPS).
What is the guaranteed operating temperature range for AD7685BRMZ?
The AD7685BRMZ is specified for operation from −40°C to +85°C ambient temperature, with all electrical parameters guaranteed across this range. This industrial-grade rating applies to both MSOP and LFCSP variants. Extended temperature versions (e.g., −55°C to +125°C) are not offered for AD7685BRMZ; customers requiring wider ranges should evaluate the AD7689 or consult Analog Devices' custom solutions group.
AD7685BRMZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PulSAR®
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- 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-MSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7685BRMZ FAQ
1.How can I place an order for AD7685BRMZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7685BRMZ 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 AD7685BRMZ reliable?
The price and inventory of AD7685BRMZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7685BRMZ is usually 5 days.
3.What payment methods are accepted for AD7685BRMZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7685BRMZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7685BRMZ?
AD7685BRMZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7685BRMZ 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 AD7685BRMZ?
For technical support, including AD7685BRMZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7685BRMZ requirements.
6.How does Aetrix verify that AD7685BRMZ is sourced from the original manufacturer or authorized distributors?
All AD7685BRMZ 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 AD7685BRMZ meets industry standards.
7.What is the process for return or replacement of AD7685BRMZ?
All AD7685BRMZ units undergo pre-shipment inspection (PSI). If there is an issue with AD7685BRMZ, 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 AD7685BRMZ part is unused and in its original packaging.
Return procedure for AD7685BRMZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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