AD7691BCPZRL - 18-Bit, 250kSPS PulSAR ADC | Analog Devices
Teilenummer: AD7691BCPZRL ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $19.5 | $19,50 |
| 10 | $17.8 | $178,00 |
| 100 | $15.2 | $1.520,00 |
| 500 | $13.1 | $6.550,00 |
| 1.000 | $11.5 | $11.500,00 |
| 2.500 | $10.4 | $26.000,00 |
AD7691BCPZRL Übersicht
An SAR ADC is a precision data converter that uses a binary-search algorithm through an internal capacitive DAC to digitize an input voltage in a single conversion cycle, producing a sample on demand with deterministic latency. SAR converters like the AD7691 sit in the hierarchy of analog-to-digital converters -> data converters -> signal chain ICs -> mixed-signal semiconductors. Compared with delta-sigma ADCs, SAR parts excel at multi-channel multiplexed systems and DC-to-multiplexed Nyquist applications because they do not require decimation filters and offer excellent DC accuracy.
Key features of the AD7691BCPZRL include 18-bit no-missing-codes performance, an SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface, an optional SDI input for daisy-chaining multiple ADCs on a single 3-wire bus, an external REF pin, and a low 6 mW typical power dissipation at 250 kSPS with 5V supply. The PulSAR charge-redistribution core achieves true 18-bit resolution without latency, and the analog input span scales with the reference voltage so the same part serves 5V industrial, 3.3V logic, and low-voltage sensor rails.
Typical applications include industrial process control loops, weigh scales and load-cell digitizers, precision data acquisition front-ends, instrumentation, sensor interfaces, and medical monitoring equipment. The wide 2.3V to 5V supply range and external reference allow a single BOM to span legacy 5V systems and modern 3.3V MCU platforms.
When designing with this part, ensure the REF pin is decoupled with at least 10uF (low-ESR ceramic recommended) and that the analog input common-mode stays within the linear range supported by VDD/REF. Average power scales linearly with throughput, so duty-cycling the CONVST pin enables significant power savings in battery-powered sensor nodes. Designers should also add a small RC anti-alias filter on the input to remove out-of-band noise above the Nyquist frequency.
Drop-in-Alternativen für AD7691BCPZRL – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit AD7691BCPZRL (gleiche Bauform und Footprint) – abweichend in Architecture, Package, Input Type, Sampling Rate, Supply Voltage (VDD).
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
AD7683BCPZRL
✅ Drop-In✓ Auf Lager
$7.09 / Stück
Datenblatt ansehen →AD7683ACPZRL
✅ Drop-In✓ Auf Lager
$5.45 / Stück
Datenblatt ansehen →AD7691BCPZRL7
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7691BCPZRL Grenzwerte & elektrische Eigenschaften
| Number of Bits | 18 |
| Abtastrate | 250 kSPS |
| Number of Inputs | 1 |
| Architecture | SAR (PulSAR, charge-redistribution) |
| Input Type | Differential (pseudo-bipolar capable with REF) |
| Data Interface | SPI, QSPI, MICROWIRE, DSP-compatible serial |
| INL (max) | ±1.5 LSB (±6 ppm of FSR) |
| INL (typical) | ±0.75 LSB |
| Dynamic Range | 102 dB (typical @ 250 kSPS) |
| Reference | External (REF pin, up to VDD) |
| Supply Voltage (VDD) | 2.3 V to 5 V |
| Power Dissipation (typ. @ 5V, 250 kSPS) | 6 mW |
| Betriebstemperatur | -40C to +85C |
| Gehäuse | 10-LFCSP-WD (3x3 mm) with exposed pad |
| Daisy-Chain Support | Yes (SDI input for multi-ADC 3-wire bus) |
| Montageart | Surface Mount |
| MSL-Level | 3 (168 hours) |
| RoHS-Status | Compliant |
AD7691BCPZRL Pin-Konfiguration
| Pin 1 | VDD — Power supply input (2.3V to 5V) |
| Pin 2 | GND — Ground |
| Pin 3 | REF — External reference input (decouple with >= 10uF) |
| Pin 4 | IN+ — Positive analog input (differential pair) |
| Pin 5 | IN- — Negative analog input (differential pair) |
| Pin 6 | CNV — Convert start / chip select (rising edge initiates conversion) |
| Pin 7 | SDI — Serial data input (daisy-chain mode) |
| Pin 8 | SCK — Serial clock input |
| Pin 9 | SDO — Serial data output |
| Pin 10 | BUSY — Optional busy indicator / end-of-conversion |
Typische Anwendungen
AD7691BCPZRL ist geeignet für 7 Anwendungs: Industrial Weigh Scales / Load Cell Digitizer, Precision Data Acquisition (DAQ) Front-Ends, Industrial Process Control / PLC Analog Input Modules, Medical Monitoring Equipment, Sensor Signal Conditioning / IoT Edge Nodes, Audio Bandwidth / Vibration Analysis, Test and Measurement Instrumentation.
Industrial Weigh Scales / Load Cell Digitizer
The AD7691BCPZRL fits weigh-scale front-ends because its 18-bit no-missing-codes resolution and ±1.5 LSB max INL give 1 part in 131072 step accuracy, well inside the 10-50kg industrial scale precision class. The PulSAR architecture delivers a fresh sample every 4us at 250 kSPS, allowing oversampling plus digital averaging at the MCU to push effective resolution toward 20 bits without filter-induced group delay. Differential inputs reject industrial ground noise from motor drives and HVAC inverters, and the external reference pin lets designers temperature-compensate the load-cell excitation so thermal drift cancels at the converter reference. Power consumption at 6 mW typical enables mains-powered scales or battery-powered portable units alike.
Empfohlen
Precision Data Acquisition (DAQ) Front-Ends
The AD7691BCPZRL brings 18-bit Nyquist sampling at 250 kSPS to generic DAQ cards, instrumentation recorders, and bench-top meters. With 102 dB dynamic range, the converter captures both DC transducer outputs and audio-bandwidth AC signals with one device, simplifying BOM. The SPI-compatible digital interface supports streaming into modern MCUs and DSPs, while the SDI pin allows up to four ADCs to share a single 3-wire bus for synchronized channel expansion. Because the analog input span follows REF, a single 5V or 3.3V rail feeds the whole analog front-end, dropping the part into ruggedized PCI/PCIe DAQ boards or USB-based portable data loggers.
Empfohlen
Industrial Process Control / PLC Analog Input Modules
Inside a PLC analog input module the AD7691BCPZRL provides 18-bit accuracy across the 4-20mA or 0-10V signal chain, while drawing only 6 mW at full speed. The SAR architecture's deterministic 4us latency makes it well suited to control loops where digital filtering delays would be unacceptable. The wide 2.3V to 5V supply supports both legacy 5V PLC backplanes and modern 3.3V MCU-based edge controllers. Channel-by-channel analog input multiplexers can drive the differential input, and the SDI pin's daisy-chain mode lets one SPI master service multiple AD7691s per module, increasing channel density without extra isolated buses.
Empfohlen
Medical Monitoring Equipment
Patient monitors, ECG front-ends, and blood-pressure modules benefit from the AD7691BCPZRL's combination of 18-bit DC accuracy and 250 kSPS burst-capable sampling. Medical EEG front-ends appreciate the differential input topology that rejects 50/60 Hz mains pickup when paired with a 60 Hz notch, while the small 3x3 mm LFCSP footprint permits compact wearable designs. Because the reference scales with VDD, low-voltage (3.3V) battery-powered designs can still achieve over 100 dB dynamic range. Power scales linearly with throughput, so duty-cycling the CONVST pin dramatically reduces sleep current for battery-backed telemetry devices.
Empfohlen
Sensor Signal Conditioning / IoT Edge Nodes
Battery-powered sensor hubs and IoT edge nodes rely on the AD7691BCPZRL to digitize strain gauges, RTD thermistors, and piezoelectric outputs with 18-bit resolution. By duty-cycling the CONVST pin the ADC draws power only during active conversion, allowing average supply current in the microamp range - critical for energy-harvesting or coin-cell designs. The differential input stage rejects common-mode pickup on long sensor harnesses, and the SPI interface integrates with low-power MCUs like STM32L4 or SAMD. The 3x3 mm LFCSP footprint adds less than 9 mm2 to the PCB, keeping node size minimal.
Empfohlen
Audio Bandwidth / Vibration Analysis
Audio analyzers, condition-monitoring vibration systems, and active noise control platforms use the AD7691BCPZRL as a wideband 18-bit converter for 50 kHz+ analog signals. Its 102 dB dynamic range covers pro-audio 96 kHz noise floor while the SAR topology remains glitch-free across the conversion window - critical for continuous vibration monitoring without missing transient events. The differential input pair plus external reference supports the bipolar input shifts needed at microphone arrays, and the SPI interface streams raw PCM into DSPs or ARM Cortex-M4 cores for FFT-based diagnostics.
Empfohlen
Test and Measurement Instrumentation
Bench-top multimeters, source-measurement units, and waveform recorders use the AD7691BCPZRL to deliver 18 bits of single-conversion accuracy at 250 kSPS, which simplifies the front-end versus discrete multi-converter averaging. The 10-LFCSP-WD (3x3) package and 2.3V to 5V supply design easily into handheld and rack-mounted instruments alike. SDI daisy-chain lets multiple AD7691s share a single SPI bus for synchronized voltage/current/channels, reducing FPGA pins and BOM count. The 6 mW typical power keeps heat out of sealed enclosures that must operate in calibration labs from -40C to +85C ambient.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für AD7691BCPZRL – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | AD7683BCPZRL | AD7683ACPZRL | AD7691BCPZRL7 |
|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 10-LFCSP-WD (3x3) | 10-LFCSP-WD (3x3) - same footprint | 10-LFCSP-WD (3x3) - same footprint | 10-LFCSP-WD (3x3) - same footprint |
| Resolution | 18 bits | 16 bits | 16 bits | 18 bits |
| Sampling Rate | 250 kSPS | 100 kSPS | 100 kSPS | 250 kSPS |
| INL (max) | ±1.5 LSB | ±0.5 LSB | ±0.5 LSB | ±1.5 LSB |
| Supply Voltage | 2.3 V to 5 V | 2.3 V to 5 V | 2.3 V to 5 V | 2.3 V to 5 V |
| Dynamic Range | 102 dB | 94 dB | 94 dB | 102 dB |
| Power Dissipation (typ.) | 6 mW @ 5V, 250 kSPS | 3 mW @ 5V, 100 kSPS | 3 mW @ 5V, 100 kSPS | 6 mW @ 5V, 250 kSPS |
| External Reference | Yes (REF pin) | Yes (REF pin) | Yes (REF pin) | Yes (REF pin) |
| Reel Format | 13-inch reel (R) | 13-inch reel (R) | 13-inch reel (R) | 7-inch reel (R7) |
Wichtigste Unterscheidungsmerkmale
- Same package as the lower-resolution AD7683 family, allowing field-upgrade in-production (vs. AD7683BCPZRL)
- External reference scales input span with VDD for a single-BOM-rail design (vs. ADS8860IDR (cross-brand 18-bit SAR))
- Daisy-chain SDI input enables multi-ADC 3-wire SPI sharing (vs. AD7691BCPZRL7 (same die))
Designhinweise
The AD7691BCPZRL power dissipation scales linearly with throughput. At 250 kSPS and 5V supply it consumes approximately 6 mW typical. Estimated: duty cycling CNV at 10 percent (10 kSPS average) drops supply current by ~90 percent, reaching ~600 uA - ideal for battery-powered sensor nodes. Decouple VDD with a 1uF X7R ceramic in parallel with a 0.1uF X7R placed within 2 mm of the pin; place the REF decoupling cap (>10uF low-ESR) directly at the REF pin and ground plane adjacent.
Place analog and digital sections on separate ground planes joined only at the AD7691 GND pin to prevent digital switching noise from coupling into the analog path. Keep the analog input traces short and routed directly over a contiguous ground plane to maintain low impedance. The exposed pad under the 10-LFCSP-WD package must be soldered to a copper pad of at least 1 square inch on the top layer to dissipate the modest (6 mW) heat and to provide the low-impedance ground return. Avoid routing the SCK signal across the analog IN+ and IN- traces to prevent capacitive crosstalk into the sampled input.
Three common pitfalls: (1) Using REF values above VDD or below 0.5 V causes device damage or saturation - keep REF <= VDD and > 0.5 V for normal operation. (2) Driving a single-ended source into IN- while tying IN+ to VDD/2 without buffering degrades INL - buffer both inputs to maximize 18-bit linearity. (3) Forgetting to read the BUSY/SDO line before the next CNV rising edge leads to digital contention; ensure every CNV cycle follows a complete SCK stream-out (or use BUSY to gate conversion start). According to the AD7691 datasheet Rev E, a missing-code test must be run at full 250 kSPS to confirm 18-bit performance.
Add a simple RC anti-alias filter at the analog input (typical values: 100 ohm + 1 nF for -3 dB at 1.6 MHz) to suppress out-of-band noise beyond the ADC's Nyquist band. Match the filter bandwidth to be slightly greater than the input source's settling time constant at 18 bits. The differential inputs (IN+, IN-) should each see the same source impedance for best common-mode rejection. For multi-channel multiplexed systems use an ADG1408 or ADG787 analog mux ahead of the AD7691BCPZRL input pair with switch resistance below 100 ohm.
Compliance-Informationen
RoHS and lead-free confirmed per ADI product page. AEC-Q100 not applicable for this commercial/industrial-grade part; AD7691-EP variant supports defense/aerospace AQEC standard.
