AD7685ARMZRL7 - 16-Bit 250 kSPS PulSAR ADC | Analog Devices
N.º de pieza: AD7685ARMZRL7 ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $10.08 | $10,08 |
| 10 | $9.2 | $92,00 |
| 100 | $8.45 | $845,00 |
| 500 | $7.8 | $3.900,00 |
| 1.000 | $7.1 | $7.100,00 |
AD7685ARMZRL7 Descripción general
A SAR ADC is a type of analog-to-digital converter that successively approximates the input voltage using a binary search algorithm with a capacitive DAC. Within the signal-chain hierarchy, the AD7685 sits between the analog front end (amplifiers, filters, sensors) and the digital controller, converting real-world signals into 16-bit digital words for processing. PulSAR is Analog Devices' proprietary SAR architecture optimized for low power and high accuracy.
Key features include 16-bit resolution with no missing codes, 250 kSPS maximum throughput, INL of +/-0.6 LSB typical and +/-2 LSB maximum, and a separate VIO logic supply compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic. The pseudo-differential input with wide common-mode range, together with the low-noise analog input lowpass filter formed by RIN and CIN, allows a noisier driver amplifier to still meet a given system noise specification.
Technical depth: the AD7685 uses a charge-redistribution SAR core with an internal conversion clock, so no external clock is required for conversion. Its noise performance is lower than most other 16-bit ADCs per the Analog Devices datasheet, contributing to higher effective resolution in practical systems. Operation is specified from -40 C to +85 C.
Typical applications include battery-powered portable instrumentation, industrial process control data acquisition, and medical monitoring equipment, where the 250 kSPS rate and low power consumption fit multi-channel scanning systems.
Design consideration: the separate VIO pin lets you drop logic level to 1.8 V for modern microcontrollers, but keep the REF pin decoupled with low-ESR ceramics to preserve linearity.
This page synthesizes distributor pricing, drop-in alternatives, pinout detail, and practical design notes not found in the manufacturer datasheet alone.
Alternativas directas para AD7685ARMZRL7 — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
AD7685BRMZ
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7686ARMZ
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7686BRMZ
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7686CRMZ
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7683ARM
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7942BRMZ
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
AD7685ARMZRL7 Valores máximos y características eléctricas
| Resolución | 16 bit |
| Number of Channels | 1 (pseudo-differential) |
| Architecture | SAR (PulSAR, charge redistribution) |
| Frecuencia de muestreo | 250 kSPS |
| INL | +/-0.6 LSB typical, +/-2 LSB maximum |
| Supply Voltage (VDD) | 2.3 V to 5.5 V |
| Logic Supply (VIO) | 1.8 V, 2.5 V, 3 V, or 5 V |
| Data Interface | SPI, MICROWIRE, QSPI, DSP, Serial |
| Internal Conversion Clock | Yes |
| Missing Codes | No missing codes |
| Temperatura de funcionamiento | -40 C to +85 C |
| Encapsulado | 10-lead MSOP (3.00 mm width) |
| Tipo de montaje | Surface Mount |
| Packaging | Tape and Reel |
| Estado RoHS | ROHS3 Compliant |
| Nivel MSL | 1 (Unlimited) |
| REACH Status | Unaffected |
Configuración de pines de AD7685ARMZRL7
| Pin 1 | VIO — Logic power supply (1.8 V to 5 V), sets interface logic level |
| Pin 2 | REF — Reference voltage input; decouple with low-ESR ceramic |
| Pin 3 | GND — Ground |
| Pin 4 | IN+ — Analog input, positive (pseudo-differential) |
| Pin 5 | IN- — Analog input, negative reference for pseudo-differential input |
| Pin 6 | GND — Ground |
| Pin 7 | SDO — Serial data output |
| Pin 8 | CNV — Convert start input |
| Pin 9 | SCK — Serial clock input |
| Pin 10 | VDD — Analog power supply (2.3 V to 5.5 V) |
Aplicaciones típicas
AD7685ARMZRL7 es adecuado para 6 aplicacións: Battery-Powered Portable Instrumentation, Industrial Process Control Data Acquisition, Medical Monitoring Equipment, Portable and Embedded MCU/FPGA SPI Systems, Automatic Test and Measurement Equipment, Vibration and Acoustic Data Loggers.
Battery-Powered Portable Instrumentation
The AD7685ARMZRL7 fits battery-powered portable instruments because its PulSAR SAR core converts from a single 2.3 V to 5.5 V supply at low power and requires no external conversion clock, reducing component count and quiescent drain. The separate VIO pin drops the SPI interface to 1.8 V, letting the ADC talk directly to low-voltage microcontrollers without level shifters. In a handheld data logger sampling at 250 kSPS bursts, the 16-bit no-missing-code resolution preserves small sensor signals, and the internal clock means the MCU can sleep between conversions, extending battery life.
Recomendado
Industrial Process Control Data Acquisition
In industrial process control, the AD7685 digitizes 4-20 mA sensor loops, pressure and temperature channels at up to 250 kSPS with 16-bit accuracy specified from -40 C to +85 C, matching factory-floor temperature extremes. The pseudo-differential input rejects common-mode noise picked up on long cable runs, while the RIN/CIN analog input lowpass filter relaxes driver-amplifier noise requirements, per the Analog Devices datasheet. The SPI/MICROWIRE/QSPI-compatible serial port integrates directly with PLC and DCS controller boards, and the INL of +/-0.6 LSB typical keeps measurement error within process-tolerance budgets.
Recomendado
Medical Monitoring Equipment
Medical monitoring devices benefit from the AD7685's 16-bit resolution with no missing codes and low noise, which preserves small biopotential and physiological sensor signals such as ECG, pressure, and optical measurements. Operating from a single low-voltage supply simplifies isolation and patient-safety power design, while the 250 kSPS throughput comfortably covers multi-channel scanning at clinical update rates. The separate VIO logic supply lets the ADC interface safely with low-voltage DSP or microcontroller front ends. Its PulSAR architecture contributes no switching-clock-induced spurs on the analog input beyond the sampling instant, supporting clean signal extraction.
Recomendado
Portable and Embedded MCU/FPGA SPI Systems
The AD7685ARMZRL7 connects directly to microcontroller and FPGA serial peripherals because its SPI/MICROWIRE/QSPI/DSP-compatible interface and independent VIO pin support 1.8 V, 2.5 V, 3 V, and 5 V logic families without level translation. The internal conversion clock means the host only supplies the CNV convert-start signal, freeing MCU timers; data is then read on SCK/SDO. Analog Devices provides the EVAL-AD7685-PMDZ PMOD evaluation board for rapid prototyping against any SPI-capable development board, allowing software drivers to be developed before the custom PCB is committed.
Recomendado
Automatic Test and Measurement Equipment
Bench and rack instruments use the AD7685 where 16-bit precision and 250 kSPS scan rates suffice, avoiding the cost and power of higher-speed converters. The +/-0.6 LSB typical INL and low input-referred noise let designers meet tight measurement uncertainty budgets, and the wide 2.3 V to 5.5 V supply range eases integration into mixed-supply instrument backplanes. The pseudo-differential IN+/IN- pair supports single-ended or differential front ends with a flexible common-mode range. The 10-lead MSOP occupies minimal board area, allowing high channel density on multiplexed input cards.
Recomendado
Vibration and Acoustic Data Loggers
Machinery health and acoustic logging systems sample accelerometers and microphones at moderate bandwidths where the AD7685's 250 kSPS rate and 16-bit dynamic capture spectral detail for FFT analysis. The PulSAR core's low noise floor, noted in the Analog Devices datasheet as lower than most 16-bit ADCs, raises effective resolution on weak vibration signatures, enabling earlier bearing-fault detection. Its single-supply operation and internal conversion clock simplify battery-powered, time-stamped logger designs, while the SPI interface streams data to microcontrollers or FPGAs for local processing or wireless transmission to condition-monitoring platforms.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para AD7685ARMZRL7 — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | AD7685BRMZ | AD7686ARMZ | AD7683ARM | AD7942BRMZ |
|---|---|---|---|---|---|
| Package | 10-MSOP | 10-MSOP - same | 10-MSOP - same | 10-MSOP - same | 10-MSOP - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 16 bit | 16 bit | 16 bit | 16 bit | 14 bit |
| Throughput | 250 kSPS | 250 kSPS | 500 kSPS | 100 kSPS | 250 kSPS |
| Supply Voltage | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V |
| Accuracy Grade | A grade | B grade (tighter) | A grade | C grade (looser) | B grade |
Diferenciadores clave
- Lowest-noise input stage in its class (frente a AD7942BRMZ)
- Better accuracy guarantee at same cost tier (frente a AD7686CRMZ)
- Lower power and cost than the speed upgrade (frente a AD7686ARMZ)
Notas de diseño
Decouple VDD, VIO, and REF each with 100 nF ceramic capacitors placed within 2 mm of the pins, plus a 10 uF bulk capacitor at the VDD node. The REF pin is the critical node: any noise or droop on the reference directly converts into code error at 16-bit levels, so add a 1 uF to 10 uF low-ESR capacitor and, in precision designs, buffer the reference with a dedicated low-noise reference source. Keep the analog ground return for pin 3 and pin 6 separate from the digital return until a single star point.
The pseudo-differential IN+/IN- input tolerates a wide common-mode voltage, which per the Analog Devices datasheet allows a noisier driver amplifier to be used because the ADC's internal RIN/CIN lowpass filter attenuates amplifier noise. Still, keep the trace from driver to IN+ short and guarded, and route the digital SCK/SDO lines away from IN+ to avoid clock feedthrough artifacts at 250 kSPS. Sample during quiet signal intervals since the SAR input draws charge kickback at acquisition.
Use the separate VIO pin to drop interface logic to 1.8 V or 2.5 V for modern low-voltage MCUs, but never let VIO exceed VDD plus the absolute maximum rating stated in the datasheet; sequence VDD before or with VIO at power-up. Estimated: running VDD at 5 V for the widest input range versus 3 V trades supply power for signal headroom - at 250 kSPS the PulSAR core consumes more current at higher VDD, so in battery designs choose the lowest VDD that meets your full-scale input requirement.
Do not omit the CNV convert-start timing margin: the AD7685 requires the acquisition window before asserting CNV, and violating the minimum CNV pulse or datasheet timing degrades linearity rather than failing visibly. Also remember the RL7 suffix denotes tape-and-reel packaging for automated assembly; ordering the tray variant changes only packaging, not the die. Verify the grade letter in the actual purchased MPN (A vs B grade) since accuracy guarantees differ between AD7685ARMZ and AD7685BRMZ.
Información de cumplimiento
ROHS3 Compliant and REACH Unaffected per distributor compliance data (PartGenie). MSL 1 (Unlimited). AEC-Q100 status not stated in provided data.
