AD7680ARM - 16-Bit 100kSPS SAR ADC | Analog Devices
MPN: AD7680ARM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.1 | $8.10 |
| 10 | $7.28 | $72.80 |
| 100 | $6.45 | $645.00 |
| 500 | $5.82 | $2,910.00 |
| 1,000 | $5.18 | $5,180.00 |
AD7680ARM Overview
A SAR ADC is a type of analog-to-digital converter that performs a binary search through an internal capacitive DAC to determine each digital output code, one bit per conversion clock cycle. SAR ADCs are valued for low latency, deterministic behavior, and excellent DC accuracy. They sit under the broader hierarchy of ADC -> data converter -> signal chain IC -> semiconductor. The AD7680 specifically targets low-power, mid-speed instrumentation where successive-approximation precision outweighs the throughput needs of pipeline or flash converters.
Key specifications include 16-bit resolution with no missing codes, 100 kSPS maximum throughput, ±5 V input range with single-supply operation from 2.5 V to 5.5 V, and typical power dissipation of 3 mW at 100 kSPS with a 2.5 V supply (rising to about 16.7 mW at 5 V). The serial interface is SPI/QSPI/MICROWIRE-compatible, allowing direct connection to most microcontrollers and DSPs without glue logic. The part offers ±0.4 LSB typical DNL, ±0.7 LSB typical INL, and an SNR of approximately 86 dB for high-quality signal acquisition.
Architecturally, the AD7680 uses a charge-redistribution SAR core with an input bandwidth exceeding 1.5 MHz on the track-and-hold front end. The internal oscillator eliminates the need for an external clock source in most applications, and the power-down mode reduces consumption to microwatts between conversions, an essential feature for handheld instrumentation. The wide input bandwidth preserves signal integrity well beyond the Nyquist limit of the 100 kSPS sample rate, simplifying anti-aliasing filter design.
Typical applications include portable data acquisition modules, weigh scales and load-cell digitizers, industrial process control loops, and battery-powered medical instrumentation such as patient monitors. The wide input range lets it digitize signals directly from 0 V to VDD without external signal conditioning in many single-ended configurations.
For design success, place a 0.1 µF decoupling capacitor as close as possible to the AVDD pin and keep analog and digital grounds on separate planes joined at a single point beneath the device. Because the device offers no internal buffer on REF, a low-noise external reference such as the ADR291 is recommended when DC accuracy below 1 LSB matters.
This page synthesizes distributor stock data, drop-in alternatives, and practical SOT-23 layout tips not collected in the datasheet alone.
Drop-in alternatives for AD7680ARM — 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 AD7680ARM (same form factor and footprint) — differing in Architecture, Input Voltage Range, Operating Temperature, Package, Power Dissipation (5 V).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7680ARMZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7680BRMZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7680ACPZ
✅ Drop-In📋 Reference alternative (not in catalog)
ADS8320E/250
✅ Drop-In📋 Reference alternative (not in catalog)
ADS8325E/250
✅ Drop-In📋 Reference alternative (not in catalog)
AD7680ARM Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Sample Rate | 100 kSPS |
| Architecture | SAR (Successive Approximation) |
| Number of Inputs | 1 |
| Input Voltage Range | 0 V to VDD (unipolar, single-ended) |
| Supply Voltage | 2.5 V to 5.5 V |
| Power Dissipation (typ) | 3 mW at 2.5 V / 100 kSPS |
| Power Dissipation (5 V) | 16.7 mW at 5 V / 100 kSPS |
| DNL (typ) | ±0.4 LSB |
| INL (typ) | ±0.7 LSB |
| SNR (typ) | 86 dB |
| Interface | SPI / QSPI / MICROWIRE-compatible serial |
| Input Bandwidth | 1.5 MHz (track-and-hold) |
| Operating Temperature | -40 C to +85 C |
| Package | 6-pin SOT-23 (MO-178AB) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
AD7680ARM Pin Configuration
| Pin 1 | AVDD — Analog supply input; 2.5 V to 5.5 V; bypass with 0.1 µF capacitor |
| Pin 2 | AIN — Analog input; single-ended, 0 V to VDD input range |
| Pin 3 | GND — Analog and digital ground return |
| Pin 4 | SDOUT — Serial data output; SPI/QSPI/MICROWIRE-compatible |
| Pin 5 | SCK — Serial clock input for data readback |
| Pin 6 | CNVST — Convert start; active-low input that initiates ADC conversion |
Typical Applications
AD7680ARM is suitable for 6 applications: Portable Data Acquisition Modules, Weigh Scales and Load-Cell Digitizers, Industrial Process Control Loops, Battery-Powered Medical Instrumentation, Sensor Digitization and Transducer Conditioning, Audio and Vibration Analysis Front Ends.
Portable Data Acquisition Modules
The AD7680ARM's 16-bit resolution at 100 kSPS with only 3 mW dissipation at 2.5 V supply makes it a near-ideal ADC for handheld multi-channel data loggers and USB-powered acquisition pods. Placed behind a front-end instrumentation amplifier and an external low-noise reference such as the ADR291, it streams accurate samples to a host microcontroller over SPI while pulling minimal current from a Li-ion battery. Compared with higher-throughput pipeline ADCs that burn 100+ mW, the AD7680ARM extends runtime by an order of magnitude in portable instrumentation.
Recommended
Weigh Scales and Load-Cell Digitizers
Weigh scales and load-cell digitizers demand 16-bit-plus DC accuracy, low noise, and stable gain over temperature - all of which the AD7680ARM delivers in a compact SOT-23 footprint. The internal track-and-hold bandwidth of 1.5 MHz preserves the integrity of low-frequency bridge signals while its pseudo-differential input pairs cleanly with bridge excitation powered from the same 5 V rail. Designers typically run the part at a reduced sample rate (around 60 kSPS) to optimize noise and reduce average power to below 2 mW in battery-powered scales.
Recommended
Industrial Process Control Loops
In 4-20 mA loop-powered sensors and process transmitters, the AD7680ARM digitizes transducer signals directly while drawing as little as 3 mW from a 2.5 V supply, well within the available loop budget. Operating temperature spans -40 C to +85 C covering Class A industrial environments, and the SOT-23 package fits inside tight sensor housings. The serial interface supports SPI at up to the maximum SCK frequency, enabling 100 kSPS throughput for fast update rates required in valve positioning and flow metering loops.
Recommended
Battery-Powered Medical Instrumentation
Portable medical devices such as pulse-oximeters, single-lead ECG patches, and blood-glucose meters rely on the AD7680ARM's combination of 16-bit precision and sub-3 mW power consumption. The device's power-down mode draws microamp-level quiescent current between conversions, extending battery life across multi-day patient-monitoring applications. The 86 dB SNR supports high-fidelity waveform digitisation for diagnostic algorithms while the 6-lead SOT-23 keeps the BOM footprint small enough for wearable form factors.
Recommended
Sensor Digitization and Transducer Conditioning
The AD7680ARM is well-suited for digitizing outputs from strain gauges, RTDs, thermocouples, and pressure sensors in compact transducer modules. Its 16-bit no-missing-codes performance and ±0.7 LSB INL delivers accuracy that scales linearly from raw sensor output to digital domain. The wide 2.5 V to 5.5 V supply range lets the same ADC pair with both legacy 5 V analog signal chains and modern 3.3 V microcontrollers, simplifying multi-platform sensor designs.
Recommended
Audio and Vibration Analysis Front Ends
Although ADI markets dedicated audio ADCs for high-fidelity work, the AD7680ARM's 1.5 MHz input bandwidth and 100 kSPS throughput make it viable for low-cost vibration analysis, condition-monitoring sensors, and cost-sensitive audio metering. Sampling at 96 kSPS, the device captures vibration spectra to roughly 48 kHz, sufficient for bearing-fault harmonics in industrial predictive-maintenance modules. Pairing the AD7680ARM with an op-amp anti-aliasing filter and an FFT-capable MCU yields a complete compact signal-chain front end under 15 mW total.
Recommended
Recommended Products Summary
Engineering reference data for AD7680ARM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7680ARMZ | AD7680BRMZ | AD7680ACPZ | ADS8320E/250 | ADS8325E/250 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | Texas Instruments |
| Package | SOT-23-6 (MO-178AB) | SOT-23-6 - same | SOT-23-6 - same | SOT-23-6 - same | SOT-23-6 - same | SOT-23-6 - same |
| Resolution | 16 bit | 16 bit | 16 bit | 16 bit | 16 bit | 16 bit |
| Sample Rate (max) | 100 kSPS | 100 kSPS | 100 kSPS | 100 kSPS | 100 kSPS | 100 kSPS |
| Supply Voltage Range | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Power (typ, 100 kSPS @ low supply) | 3 mW at 2.5 V | 3 mW at 2.5 V | 3 mW at 2.5 V | 3 mW at 2.5 V | 4 mW at 3 V | 4 mW at 3 V |
| Interface | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE | SPI / QSPI / MICROWIRE |
| INL (max, A-grade) | ±0.7 LSB (typ) | ±0.7 LSB (typ) | ±0.5 LSB (B-grade) | ±0.7 LSB (A-grade) | ±1.5 LSB | ±1.5 LSB |
Key Differentiators
- Smallest true 16-bit ADC footprint in the ADI portfolio (vs AD7685CRMZ (10-lead LFCSP))
- Industry's lowest power at 16-bit/100 kSPS (vs ADS8320E/250)
- Wide 2.5 V to 5.5 V single-supply operation (vs ADS8325E/250)
Design Notes
Place a 0.1 µF X7R ceramic bypass capacitor as physically close as possible to the AD7680ARM AVDD pin (pin 1), ideally within 2 mm of the pad. Route analog and digital grounds on separate planes and stitch them together at a single point directly under the ADC ground pin. Keep the analog input trace short and shielded with a ground guard ring to minimise coupling of digital SCK edges into the analog signal path.
Do not assume the AD7680ARM can operate below 2.5 V - the datasheet absolute minimum is 2.5 V and operation below the minimum can damage the device. With a 5 V supply, dissipation rises to ~16.7 mW at 100 kSPS, so thermal management still matters in sealed enclosures. Power-down mode only saves substantial current when conversions are spaced apart by more than the 1 µs wake-up time, so do not toggle it at high frequency.
Add a 100 ohm series-termination resistor close to the SCK output of the host microcontroller when the trace length exceeds 25 mm, to dampen ringing and keep SCK edges below 200 MHz spectral content. Apply the same termination discipline to the CNVST line because its rising edge begins the conversion window; ringing on CNVST directly shows up as input-sampled noise. For multi-channel systems, share the SCK and SDOUT lines but route CNVST to each ADC's dedicated pin to prevent contention.
Compliance Information
Per Analog Devices product page the AD7680ARM is RoHS compliant and lead-free. Halogen-free status was not stated in the verified web data and is listed as unknown. AEC-Q100 automotive qualification is not applicable for this industrial-grade -40 C to +85 C ADC.
