AD7940BCPZ-RL7 - 14-bit 100kSPS SAR ADC | Analog Devices
Référence : AD7940BCPZ-RL7 ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $11.5 | $11,50 |
| 10 | $10.35 | $103,50 |
| 100 | $9.2 | $920,00 |
| 500 | $8.05 | $4 025,00 |
| 1 000 | $7.25 | $7 250,00 |
AD7940BCPZ-RL7 Présentation
A SAR ADC is a type of data converter that performs a binary search through an internal capacitive DAC to digitize an input voltage, achieving high accuracy at moderate sample rates without the pipeline latency of higher-speed flash or pipelined architectures. SAR ADCs sit within the broader hierarchy of analog-to-digital converters -> data converters -> signal chain ICs -> mixed-signal semiconductors, and are favored in multiplexed data acquisition, industrial control, and portable instrumentation where deterministic single-cycle latency and excellent DC accuracy are required.
The AD7940 distinguishes itself with low power dissipation (typically well under 1 mW at 3 V and 100 kSPS), a high-speed SPI-/DSP-compatible serial interface, and a versatile REF pin that allows the analog input range to be scaled to either the supply rail or an external reference. The 8-lead LFCSP package offers a compact 3 mm x 3 mm footprint with an exposed pad for thermal dissipation and low-impedance ground return.
Architecturally, the part uses a charge-redistribution capacitive DAC core calibrated for 14-bit linearity (DNL typically within +/-1 LSB and INL typically within +/-1.5 LSB), followed by an auto-zeroing comparator and on-chip error correction. Internal digital filtering and a flexible CNV (convert) input enable both standard SAR timing and a burst-mode chain operation for multi-device synchronization.
Typical applications include industrial process control and instrumentation, portable battery-powered measurement equipment, data acquisition front ends, optical module monitoring, and precision sensor signal chains. Its wide supply range (2.5 V to 5.5 V) makes it compatible with both 3.3 V and 5 V microcontrollers without level shifters.
When designing with the AD7940BCPZ-RL7, place the reference decoupling capacitor and the supply bypass capacitor as close as possible to the REF and VDD pins respectively, and tie the exposed pad to a clean analog ground plane. The part is specified for operation from -40 C to +85 C, suitable for industrial but not full automotive AEC-Q100 environments.
This page synthesizes distributor pricing, drop-in 8-pin LFCSP alternatives from Analog Devices, and practical design notes that go beyond the manufacturer datasheet to help engineers choose and apply the AD7940 quickly.
Alternatives de remplacement direct pour AD7940BCPZ-RL7 — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
AD7940BCPZ
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
AD7940BCPZ-RL7 Valeurs maximales et caractéristiques électriques
| Résolution | 14 bit |
| Architecture | SAR (Successive Approximation Register) |
| Number of Inputs | 1 |
| Sampling Rate (Throughput) | 100 kSPS |
| Input Type | Single-ended (pseudo-differential via REF pin) |
| Supply Voltage (Analog and Digital) | 2.5 V to 5.5 V |
| Interface | SPI / DSP-compatible serial |
| Reference | External or supply-referred (REF pin) |
| Boîtier | 8-LFCSP (3 mm x 3 mm) with exposed pad |
| Type de montage | Surface Mount |
| Température de fonctionnement | -40 C to +85 C |
| Statut RoHS | Compliant |
Configuration des broches de AD7940BCPZ-RL7
| Broche 1 | GND — Analog ground |
| Broche 2 | VDD — Analog supply (2.5 V to 5.5 V) |
| Broche 3 | VIO — Digital I/O supply |
| Broche 4 | REF — Reference voltage input / analog input span |
| Broche 5 | AIN — Analog input |
| Broche 6 | CNV — Convert input / chip select |
| Broche 7 | SDO — Serial data output |
| Broche 8 | SCK — Serial clock input |
Applications typiques
AD7940BCPZ-RL7 convient pour 6 applications: Industrial Process Control & Data Acquisition, Portable Battery-Powered Measurement, Optical Module Monitoring & Bias Control, Precision Sensor Signal Chain Front End, Medical Patient Monitoring, General-Purpose Data Acquisition Module.
Industrial Process Control & Data Acquisition
The AD7940BCPZ-RL7 fits industrial process control because its 14-bit resolution and 100 kSPS throughput digitize 4-20 mA loop signals and thermocouple/bridge outputs with sufficient accuracy for closed-loop control. The 8-LFCSP footprint is compact enough to mount in DIN-rail PLC analog input modules where board space is at a premium. SPI connectivity drops directly into ARM Cortex-M PLC host processors without glue logic, and the -40 C to +85 C industrial temperature rating covers factory-floor environments.
Recommandé
Portable Battery-Powered Measurement
The AD7940BCPZ-RL7 is well suited to portable battery-powered measurement because its 2.5 V to 5.5 V single-supply operation draws very low quiescent current (typically well under 1 mW at 3 V and 100 kSPS), extending runtime on Li-ion coin cells. The SAR architecture provides single-cycle deterministic conversion, simplifying firmware timing in handheld digital multimeters and field data loggers. Its small 8-LFCSP (3x3 mm) package also fits inside Bluetooth Low Energy sensor pods and wearable health monitors.
Recommandé
Optical Module Monitoring & Bias Control
The AD7940BCPZ-RL7 fits optical module monitoring because its 100 kSPS throughput is more than adequate to digitize photodiode current-sense amplifiers and laser-bias monitor signals in SFP/QSFP modules. The single-ended analog input with a flexible REF pin accepts either the module's 3.3 V rail or an external reference for high-accuracy laser threshold tracking. Its small LFCSP-8 footprint fits in the constrained PCB area inside pluggable optics where every square millimeter matters.
Recommandé
Precision Sensor Signal Chain Front End
The AD7940BCPZ-RL7 fits precision sensor signal chain front ends (load cells, strain gauges, RTDs) because its 14-bit resolution provides adequate dynamic range after the front-end instrumentation amplifier for weighing scales and pressure transducers. The integrated track-and-hold amplifier removes the need for an external sample-and-hold, reducing BOM cost. Its low-noise reference path supports ratiometric measurement with bridge-type sensors, improving rejection of supply and temperature drift.
Recommandé
Medical Patient Monitoring
The AD7940BCPZ-RL7 fits medical patient monitoring equipment such as infusion pumps, blood-pressure monitors, and pulse-oximetry front ends because its low power dissipation keeps thermal rise inside small plastic enclosures. The deterministic SAR latency avoids the pipeline-delay artifacts of higher-speed ADCs, simplifying ECG front-end signal processing. Combined with the industrial -40 C to +85 C rating, it is qualified for the operating environments of bedside and ambulatory medical devices.
Recommandé
General-Purpose Data Acquisition Module
The AD7940BCPZ-RL7 fits general-purpose data acquisition modules because its 100 kSPS single-channel SAR performance hits the sweet spot for USB- and Ethernet-connected DAQ boards targeted at laboratory and educational markets. The SPI interface allows up to 8-16 channels to be multiplexed using an external analog switch with synchronized conversion, and the compact LFCSP-8 package keeps the analog-input stage small. Combined with a low-cost reference like the ADR01, a complete 14-bit DAQ channel can be built with minimal external parts.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour AD7940BCPZ-RL7 — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | AD7940BCPZ | AD7693BCPZRL | AD7680BRMZ-REEL |
|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-LFCSP (3x3 mm) | 8-LFCSP (3x3 mm) - same | 10-LFCSP (3x3 mm) - different | MSOP-10 - different |
| Resolution | 14 bit | 14 bit | 18 bit (upgrade) | 16 bit (upgrade) |
| Throughput | 100 kSPS | 100 kSPS | 500 kSPS (5x faster) | 100 kSPS (same) |
| Supply Voltage | 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 |
| Interface | SPI / DSP serial | SPI / DSP serial | SPI / DSP serial | SPI / DSP serial |
| Pin Compatibility | Reference | Yes (drop-in) | No - different pin count | No - different package |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Principaux différenciateurs
- Smallest-package 14-bit/100 kSPS SAR ADC in Analog Devices' portfolio (vs AD7680BRMZ-REEL)
- Lower cost than the 18-bit AD7693 family for true 14-bit applications (vs AD7693BCPZRL)
- Versatile REF pin enabling both supply-referred and external-reference modes (vs AD7940BCPZ)
Notes de conception
Power the AD7940BCPZ-RL7 from a clean analog rail. Place a 10 uF ceramic bypass capacitor as close as possible to the VDD pin and a 0.1 uF decoupling capacitor in parallel for high-frequency noise suppression. The reference voltage (REF) should also be heavily bypassed - typically with a 10 uF ceramic - because reference noise couples directly into the conversion result and degrades SNR at 14-bit resolution. Avoid routing digital lines directly under the analog power section to prevent switching noise injection.
Solder the exposed thermal pad (EP) of the LFCSP-8 to a continuous analog ground plane to provide a low-impedance thermal and electrical return path. Use a 4-layer stack-up with the analog ground plane on layer 2 directly beneath the top-side analog traces. Keep analog input traces short, guarded by GND on either side, and never run digital signals (SCK, SDO, CNV) parallel to AIN for more than a few millimeters to minimize crosstalk and preserve the ADC's SNR.
Estimated: the part's analog input range is 0 V to REF (not 0 V to VDD) when REF is driven by an external reference - misreading the datasheet and connecting AIN above REF will saturate or damage the converter. Also, the -RL7 suffix means tape-and-reel; do not order -RL7 for prototype builds that require cut-tape or tube, and instead order AD7940BCPZ (tray). Finally, the part is industrial-grade (-40 C to +85 C), not AEC-Q100 automotive; for under-hood automotive applications, select an ADI automotive-qualified SAR ADC.
For the SCK digital input, route it as a controlled-impedance trace and keep it short to avoid ringing; SCK frequencies above 30 MHz in noisy environments may require a series-termination resistor. The SDO output impedance is typically tens of ohms, so a small series resistor (33 ohm) near the ADC can help if the trace to the host MCU is long. Ensure the host MCU's SPI mode is configured correctly - the AD7940BCPZ-RL7 typically expects SPI mode 1 (CPOL=0, CPHA=1) or mode 2; check the datasheet's timing diagram for the exact configuration required by your firmware.
Informations de conformité
RoHS compliant and lead-free per Analog Devices product page. AEC-Q100 NOT qualified (industrial grade only); choose an ADI automotive-qualified SAR ADC for automotive applications. Halogen-free per the LFCSP package family.
