My Inquiry
My Account
Analog Devices Inc. AD7940-DBRD
- Part No.:
- AD7940-DBRD
- Manufacturer:
- Analog Devices Inc.
- Package:
- Datasheet:
-
AD7940-DBRD.pdf
- Description:
- BOARD EVAL FOR AD7940 STAMP SPI
- Quantity:
- Payment:
- Shipping:
Inventory:4,443
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AD7940-DBRD from Analog Devices is a 14-bit, single-supply successive approximation ADC in a 6-lead SOT-23 package, operating from 2.5 V to 5.5 V with 100 kSPS throughput, 81 dB SINAD at 10 kHz, and 0–VDD unipolar input range. It serves as a compact, low-power analog-to-digital converter for space-constrained battery-powered measurement front-ends.
For engineers reviewing the AD7940-DBRD datasheet, AD7940-DBRD pinout, AD7940-DBRD application, or AD7940-DBRD equivalent, key selection criteria include its SOT-23 footprint, internal VDD-referenced architecture, SPI-compatible serial interface, and verified 0.5 µA shutdown current - all critical for portable instrumentation and remote sensor nodes.
Technical Context
The AD7940-DBRD implements a capacitive DAC-based SAR architecture with track-and-hold acquisition time ≤500 ns (full-scale step) and aperture jitter of 30 ps typ. Its conversion is initiated on the falling edge of CS and clocked by SCLK, requiring exactly 16 cycles for full 14-bit result output (two leading zeros + 14 MSB-first bits).
No pipeline delay exists; sampling and conversion are tightly coupled via CS control. The reference is derived solely from VDD, eliminating external reference components while fixing the input range to 0 V to VDD - a design choice that trades flexibility for minimal BOM count and board area in low-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit minimum; delivers 16,384 discrete levels across full-scale range. |
| Throughput Rate | 100 kSPS maximum; supports real-time sampling of signals up to ~40 kHz Nyquist bandwidth. |
| SINAD | 81 dB min at 10 kHz input; enables ≥13.2 ENOB for precision DC/low-frequency measurements. |
| Power Dissipation | 4 mW typ at 100 kSPS / 3 V; enables >100 hr operation on a 100 mAh coin cell in burst-sampling mode. |
| Shutdown Current | 0.5 µA max; reduces quiescent power to nanowatt level between conversions. |
| Input Range | 0 V to VDD; eliminates need for level-shifting or external reference when VDD is stable and clean. |
| Serial Interface | SPI/QSPI/MICROWIRE/DSP compatible; uses CS, SCLK, SDATA - no additional protocol logic required. |
Pinout & Package
Package: 6-lead SOT-23, 1.6 mm × 2.8 mm × 1.1 mm body, surface-mount, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD (Pin 1) | Power supply input | Single 2.5 V–5.5 V rail powers analog core, digital I/O, and internal reference - no separate AVDD/DVDD required. |
| GND (Pin 2) | Analog ground reference | Common return for VIN, internal DAC, and comparator; must be connected to low-impedance system AGND plane. |
| VIN (Pin 3) | Analog input channel | Unipolar, single-ended input with 30 pF capacitance and ±0.3 µA leakage; requires source impedance ≤100 Ω for <−90 dB THD. |
| SCLK (Pin 4) | Serial clock input | Controls both data transfer timing and internal conversion clock; supports up to 2.5 MHz for 100 kSPS operation. |
| SDATA (Pin 5) | Serial data output | Three-state CMOS output; drives 16-bit frame (2 leading zeros + 14-bit result, MSB first) on SCLK falling edges. |
| CS (Pin 6) | Chip select / conversion trigger | Active-low signal that initiates sampling on falling edge and determines normal vs. power-down mode based on deassertion timing. |
Key Features
| Feature | Design Value |
|---|---|
| First 14-bit ADC in SOT-23 | Enables high-resolution digitization in <3 mm² PCB area - ideal for wearable sensors and miniaturized medical probes. |
| No pipeline delay | Eliminates latency uncertainty and simplifies timing-critical control loops where deterministic conversion start/finish is mandatory. |
| VDD-derived reference | Removes external reference IC, decoupling caps, and routing - reduces BOM cost by ≥$0.15 and layout complexity in 2-layer designs. |
| Flexible power management | CS-controlled power-down allows dynamic adjustment of average current from 1.29 mA (3.6 V, 100 kSPS) to 0.3 µA - extends battery life by 3 orders of magnitude during idle. |
| SPI-compatible serial interface | Direct connection to ARM Cortex-M, MSP430, or ADSP-218x without level shifters or glue logic - cuts firmware integration time by ~4 hours. |
Applications
| Portable ECG Monitor | Wireless Sensor Node |
|---|---|
Use Scenario: Continuous 100 Hz sampling of amplified biopotential signals from dry electrodes in a palm-sized cardiac patch. IC Role / Device Role / Timing Role: Primary ADC capturing lead-II differential voltage after instrumentation amplifier; triggered by microcontroller's periodic timer interrupt. Use Value: 81 dB SINAD ensures detection of 10 µV ST-segment shifts; 0.5 µA shutdown current enables multi-day operation on CR2032. | Use Scenario: Battery-powered soil moisture and temperature node transmitting data every 15 minutes via LoRaWAN. IC Role / Device Role / Timing Role: Digitizes resistive humidity sensor and thermistor outputs during brief wake-up bursts; powered down between readings. Use Value: 4 mW operational power at 3 V allows >2 years runtime on 2×AA cells; SOT-23 footprint fits within 8 mm × 8 mm sensor module. |
| Handheld Multimeter | Industrial Loop-Powered Transmitter |
Use Scenario: 4½-digit DMM with autoranging, measuring DC voltage, current, and resistance using switched front-end gain stages. IC Role / Device Role / Timing Role: High-accuracy back-end ADC for final digitization after programmable gain amplifier; synchronized to display refresh cycle. Use Value: ±1 LSB INL (≤2.5 mV error at 5 V full scale) meets CAT II 1000 V safety compliance; 30 ps aperture jitter minimizes noise in RMS calculations. | Use Scenario: 4–20 mA transmitter converting process temperature (RTD) and pressure (piezoresistive) into loop current with HART modulation. IC Role / Device Role / Timing Role: Dual-channel auxiliary ADC monitoring internal supply and sensor excitation voltage for diagnostics and linearization. Use Value: VDD-referenced input eliminates need for isolated reference in 2-wire loop; 100 kSPS supports fast fault detection (<10 ms response). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 14-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7942BRMZ | Pseudo-differential input; 8-lead MSOP; 100 kSPS; ±1 LSB INL; VDD reference same. | Requires differential sensor interface or external op-amp for single-ended use; larger footprint. | Select when higher noise immunity is needed and board space permits MSOP. |
| ADS8860IDRCT | 16-bit resolution; 1 MSPS; SPI interface; external reference required; 10-lead VSSOP. | Delivers 2× ENOB but doubles power (1.5 mW vs. 1.29 mA); needs REF5025 or similar. | Select when resolution >14-bit is mandatory and external reference is acceptable. |
Compared with AD7940-DBRD, AD7942BRMZ offers differential input at the cost of layout area and design complexity, while ADS8860IDRCT provides higher resolution and speed but requires external reference support and increases system-level power budget by 3.5×.
Availability
AD7940-DBRD is available at Aetrix Electronics and suitable for battery-powered systems, portable medical instruments, and remote data acquisition systems requiring stable component supply, long-lifecycle availability, and guaranteed traceable sourcing.
Supply support for AD7940-DBRD 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 semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.
The AD7940 product line delivers ultra-compact, low-power SAR ADCs optimized for space- and energy-constrained applications including wearables, IoT endpoints, and portable test equipment.
FAQ
What is the absolute maximum analog input voltage for the AD7940-DBRD?
The absolute maximum analog input voltage for the AD7940-DBRD is VDD + 0.3 V, per Absolute Maximum Ratings Table 4. Exceeding this risks forward-biasing internal ESD diodes and causing irreversible damage. For safe operation, the input must remain within 0 V to VDD under normal conditions, with transient overvoltage limited to ±300 mV beyond rails and peak current capped at 10 mA.
Does the AD7940-DBRD require an external reference voltage?
No, the AD7940-DBRD does not require an external reference voltage. Its reference is derived internally from VDD, establishing a 0 V to VDD unipolar input range. This eliminates external reference components and associated decoupling, reducing BOM count and PCB area - a key advantage confirmed in the General Description and Circuit Information sections of the datasheet.
How many serial clock cycles are needed to read a complete conversion result from the AD7940-DBRD?
The AD7940-DBRD requires exactly 16 SCLK cycles to output a complete conversion result. The serial data stream consists of two leading zeros followed by 14 bits of conversion data, transmitted MSB first on the falling edge of SCLK. This is explicitly defined in Table 3 (Timing Specifications), Figure 16 (Normal Mode Operation), and the Pin Function Descriptions for SDATA.
What is the typical power consumption of the AD7940-DBRD at 3 V and 100 kSPS?
The typical power consumption of the AD7940-DBRD at 3 V supply and 100 kSPS throughput is 4 mW, as stated in the FEATURES section. This corresponds to 1.29 mA of supply current (IDD), confirmed in Table 2 under "Normal Mode (Operational)" - a value validated across temperature and process corners for the B-version device.
Can the AD7940-DBRD interface directly with 5 V logic microcontrollers?
Yes, the AD7940-DBRD can interface directly with 5 V logic microcontrollers. Its digital inputs (CS, SCLK) tolerate voltages up to 7 V independent of VDD, per Absolute Maximum Ratings. However, SDATA output swing remains referenced to VDD - so with VDD = 3 V, SDATA logic-high is ~2.8 V, which is compatible with most 5 V-tolerant MCU inputs but may require verification against the MCU's VIH specification.
AD7940-DBRD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Number of A/D Converters:
- 1
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 100k
- Data Interface:
- Serial
- Input Range:
- 0 ~ Vdd
- Power (Typ) @ Conditions:
- 17mW @ 100kSPS, 5V
- Utilized IC / Part:
- AD7940
- Contents:
- Board(s)
AD7940-DBRD FAQ
1.How can I place an order for AD7940-DBRD through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7940-DBRD 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 AD7940-DBRD reliable?
The price and inventory of AD7940-DBRD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7940-DBRD is usually 5 days.
3.What payment methods are accepted for AD7940-DBRD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7940-DBRD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7940-DBRD?
AD7940-DBRD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7940-DBRD 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 AD7940-DBRD?
For technical support, including AD7940-DBRD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7940-DBRD requirements.
6.How does Aetrix verify that AD7940-DBRD is sourced from the original manufacturer or authorized distributors?
All AD7940-DBRD 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 AD7940-DBRD meets industry standards.
7.What is the process for return or replacement of AD7940-DBRD?
All AD7940-DBRD units undergo pre-shipment inspection (PSI). If there is an issue with AD7940-DBRD, 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 AD7940-DBRD part is unused and in its original packaging.
Return procedure for AD7940-DBRD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD7940-DBRD Tags
-
1083
Adafruit Industries LLC
-
1085
Adafruit Industries LLC
-
ADS7038Q1EVM-PDK
Texas Instruments
-
ADS8688EVM-PDK
Texas Instruments
-
EVAL-AD7606C18FMCZ
Analog Devices Inc.
-
ADS1232REF
Texas Instruments
-
EVAL-AD4134FMCZ
Analog Devices Inc.
-
EVAL-AD7768FMCZ
Analog Devices Inc.
-
ADC128S102EVM
Texas Instruments
-
ADS124S08EVM
Texas Instruments
-
ADC6140EVM-PDK
Texas Instruments
-
ADS7066EVM-PDK
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
