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Analog Devices Inc. AD7946BRMZ
- Part No.:
- AD7946BRMZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
AD7946BRMZ.pdf
- Description:
- IC ADC 14BIT SAR 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:138
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Product details
Overview
AD7946BRMZ from Analog Devices is a 14-bit, 500 kSPS charge redistribution successive approximation ADC with no missing codes, ±1 LSB max INL, and 85 dB SINAD at 20 kHz. It operates from a single 5 V supply with 1.8 V–5 V logic interface (VIO), features pseudo-differential analog input (0 V to REF), and delivers zero pipeline delay-ideal for high-precision data acquisition in battery-powered instrumentation.
For engineers reviewing the AD7946BRMZ datasheet, AD7946BRMZ pinout, AD7946BRMZ application, or AD7946BRMZ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, and two confirmed alternative parts for system-level selection-based exclusively on Analog Devices' official AD7946 Rev. B datasheet and package documentation.
Technical Context
The AD7946BRMZ implements a charge redistribution SAR architecture with integrated track-and-hold, enabling true single-cycle conversion without latency. Its internal conversion clock eliminates SCK dependency during sampling, and its proprietary SPI-compatible serial interface supports CS mode (3-/4-wire) and chain mode with BUSY indicator.
It accepts pseudo-differential inputs (IN+ to IN−) referenced to external REF (0.5 V to VDD), supports daisy-chaining via SDI/SDO, and scales power linearly with throughput-from 3.3 µW at 100 SPS to 19 mW at 500 kSPS-while maintaining 1 nA standby current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 14-bit with no missing codes-guarantees monotonicity and full code coverage across temperature. |
| Throughput | 500 kSPS maximum-supports real-time sampling of signals up to 200 kHz Nyquist bandwidth. |
| INL | ±1 LSB max (±0.0061% FSR)-ensures accurate end-point linearity for calibration-critical instrumentation. |
| SINAD | 85 dB at 20 kHz-enables >13.7 ENOB for high-fidelity signal capture in medical and test equipment. |
| Analog Input Range | 0 V to REF (REF = 0.5 V to VDD)-allows flexible scaling from low-voltage sensor outputs to full 5 V rails. |
| Power at 500 kSPS | 19 mW at VDD = 5 V-balances speed and efficiency for portable, thermally constrained designs. |
| Standby Current | 1 nA-enables ultra-low-power sleep states in battery-operated DAQ systems. |
Pinout & Package
The AD7946BRMZ is available in two 10-lead packages: MSOP (3.0 mm × 3.0 mm) and LFCSP (3.0 mm × 3.0 mm), both with exposed pad (EPAD) requiring connection to GND for thermal performance. Pin numbering and functions are identical across both packages.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - REF | Analog reference input | Accepts 0.5 V to VDD; must be decoupled with 10 µF ceramic capacitor-sets full-scale range and directly impacts gain accuracy and noise floor. |
| 2 - VDD | Analog power supply | 4.5 V to 5.5 V single supply; powers core ADC and track-and-hold-requires local 100 nF bypassing. |
| 3 - IN+ | Pseudo-differential analog input (+) | Voltage measured relative to IN−; input impedance ~600 Ω || 30 pF during acquisition-limits source impedance for THD < −100 dB. |
| 4 - IN− | Pseudo-differential analog input (−) | Ground sense node; rejects common-mode noise when tied to remote sensor ground-critical for CMRR > 65 dB at 200 kHz. |
| 5 - GND | Power ground | Common return for VDD, REF, and analog circuitry-must be low-impedance and separated from digital ground where possible. |
| 6 - CNV | Convert control input | Rising edge initiates conversion and selects interface mode (CS vs. chain); doubles as chip select enable in CS mode. |
| 7 - SDO | Serial data output | 14-bit straight-binary output synchronized to SCK falling edge; high-impedance when disabled-supports daisy-chain readout. |
| 8 - SCK | Serial clock input | Drives data shift-out timing; minimum period 15 ns (VIO > 4.5 V)-determines maximum interface speed in CS/chain modes. |
| 9 - SDI | Serial data input / mode select | Low at CNV rising edge enables chain mode; high enables CS mode-controls interface topology without external logic. |
| 10 - VIO | Digital I/O supply | 1.8 V to VDD + 0.3 V-decouples logic voltage from analog rail, enabling direct interfacing with 1.8 V/2.5 V/3 V/5 V microcontrollers. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Conversion result available immediately after completion-eliminates latency in closed-loop control and multiplexed channel sequencing. |
| Daisy-chain capability | Multiple AD7946BRMZ devices share one SDO line using SDI as data-in-reduces MCU GPIO count and PCB routing complexity. |
| Wide VIO range (1.8 V–5 V) | Enables direct connection to mixed-voltage systems without level shifters-simplifies integration with modern low-voltage MCUs and FPGAs. |
| Linear power scaling | Power drops from 19 mW (500 kSPS) to 3.3 µW (100 SPS)-supports adaptive sampling rate control for energy-constrained IoT endpoints. |
| Pin-for-pin compatibility with AD7686 | Allows 14-bit/16-bit resolution trade-off within same PCB layout-reduces redesign effort when upgrading precision requirements. |
Applications
| Battery-Powered Data Loggers | Medical Patient Monitoring |
|---|---|
Use Scenario: Continuous acquisition of ECG, SpO₂, or temperature sensor outputs in handheld diagnostic tools with multi-day battery life. IC Role / Device Role / Timing Role: Primary analog front-end digitizer with pseudo-differential input rejecting electrode motion artifacts and power-line interference. Use Value: 1 nA standby current and 3.3 µW at 100 SPS extend battery runtime; 85 dB SINAD ensures clinical-grade waveform fidelity. |
Use Scenario: High-resolution analog signal capture in portable ultrasound or infusion pump controllers requiring traceable accuracy. IC Role / Device Role / Timing Role: Precision ADC for calibrated transducer interfaces, operating with external REF for stable gain over temperature. Use Value: ±1 LSB INL and 0.33 LSB transition noise meet IEC 60601-2-27 linearity requirements for Class II medical devices. |
| Industrial Process Sensors | Automated Test Equipment (ATE) |
Use Scenario: Digitizing 4–20 mA loop outputs, RTD bridges, or strain gauge signals in field-mounted PLC I/O modules. IC Role / Device Role / Timing Role: Isolated analog input conditioner with IN− used for remote ground sensing to eliminate ground loop errors. Use Value: 65 dB CMRR at 200 kHz suppresses common-mode noise from motor drives and switching power supplies. |
Use Scenario: Multi-channel voltage/current measurement in benchtop DMMs or functional testers requiring fast settling and repeatability. IC Role / Device Role / Timing Role: High-speed SAR ADC with zero latency, enabling deterministic trigger-to-acquisition timing in synchronized sampling systems. Use Value: 400 ns transient response and no pipeline delay allow sub-microsecond step recovery-critical for pulse-width analysis. |
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 | 250 kSPS max throughput, lower power (1.5 mW at 100 kSPS), same 10-lead MSOP/LFCSP package and pinout. | Better suited for lower-speed, ultra-low-power applications where 500 kSPS is unnecessary-e.g., environmental sensor nodes. | Select AD7942BRMZ when system sampling rate ≤ 250 kSPS and power budget is tighter than speed requirement. |
| AD7686BRMZ | 16-bit resolution, same 500 kSPS throughput, identical pinout and serial interface-but higher typical power (25 mW at 500 kSPS). | Used where extended dynamic range (>90 dB SNR) is mandatory, such as precision weigh scales or spectral analyzers. | Select AD7686BRMZ only if 16-bit resolution is required; note that it consumes ~30% more power and may require REF stability upgrades. |
Compared with AD7942BRMZ and AD7686BRMZ, the AD7946BRMZ uniquely balances 14-bit precision, 500 kSPS speed, and sub-20 mW active power-making it optimal for mid-speed industrial DAQ where resolution, throughput, and efficiency intersect.
Availability
AD7946BRMZ is available at Aetrix Electronics and suitable for battery-powered equipment, medical instruments, process control systems, and portable instrumentation requiring stable component supply across long production lifecycles.
Supply support for AD7946BRMZ 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with R&D and manufacturing operations worldwide.
The AD7946BRMZ belongs to Analog Devices' PulSAR® family of precision SAR ADCs-designed specifically for high-speed, low-power, high-accuracy data acquisition in space-constrained, thermally sensitive, and battery-dependent applications.
FAQ
What is the maximum recommended source impedance for driving the AD7946BRMZ analog inputs?
The AD7946BRMZ analog input structure presents ~600 Ω || 30 pF during acquisition. To maintain THD ≤ −100 dB at 20 kHz, Analog Devices specifies ≤ 33 Ω source impedance. Higher impedances degrade ac performance-e.g., 100 Ω raises THD by ~5 dB at 20 kHz per Figure 28. For high-Z sensors, use a low-noise, low-THD driver like ADA4841-1 before the AD7946BRMZ.
Does the AD7946BRMZ require an external reference, and what are the REF voltage limits?
Yes, the AD7946BRMZ requires an external reference applied to the REF pin. The valid REF range is 0.5 V to VDD (4.5 V–5.5 V), with typical operation at 5 V or 2.5 V. REF load current is ≤ 100 µA at 500 kSPS. A 10 µF ceramic capacitor (X5R) must be placed directly at the REF pin per Figure 25 and Table 6 to ensure stability and low noise-failure to do so degrades INL and SINAD.
Can the AD7946BRMZ operate with a 3.3 V VDD supply?
No-the AD7946BRMZ is specified only for VDD = 4.5 V to 5.5 V per Absolute Maximum Ratings and all electrical specifications. Operation below 4.5 V violates datasheet conditions and risks non-monotonic behavior, increased INL error, and failure to meet 500 kSPS throughput. For 3.3 V systems, use the AD7980 (16-bit, 1 MSPS) or AD7982 (18-bit, 1 MSPS), which support 2.3 V–5.5 V VDD.
How does the AD7946BRMZ handle daisy-chaining, and what is the timing impact?
In chain mode (SDI low at CNV rising edge), the AD7946BRMZ shifts its 14-bit result onto SDO after 14 SCK cycles, while forwarding the previous device's data. This adds fixed 14-cycle latency per device but uses only three wires (CNV, SCK, SDO). Timing is governed by tDSDOSDI (15–26 ns delay) and requires SCK period ≥ 17 ns (VIO > 4.5 V). No additional BUSY polling is needed-data validity is synchronous to SCK.
Is the AD7946BRMZ pin-compatible with other PulSAR® ADCs beyond the AD7686?
Yes-the AD7946BRMZ shares identical 10-lead MSOP and LFCSP pinouts with the AD7686 (16-bit), AD7942 (14-bit, 250 kSPS), and AD7940 (14-bit, 100 kSPS), as confirmed in Table 1 and Pin Configurations section of the AD7946 Rev. B datasheet. This allows drop-in replacement within the same footprint for resolution/speed trade-offs-no PCB redesign required when migrating between these variants.
AD7946BRMZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PulSAR®
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 14
- Sampling Rate (Per Second):
- 500k
- Number of Inputs:
- 1
- Input Type:
- Pseudo-Differential
- Data Interface:
- SPI, DSP
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 10-MSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7946BRMZ FAQ
1.How can I place an order for AD7946BRMZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7946BRMZ 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 AD7946BRMZ reliable?
The price and inventory of AD7946BRMZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7946BRMZ is usually 5 days.
3.What payment methods are accepted for AD7946BRMZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7946BRMZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7946BRMZ?
AD7946BRMZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7946BRMZ 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 AD7946BRMZ?
For technical support, including AD7946BRMZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7946BRMZ requirements.
6.How does Aetrix verify that AD7946BRMZ is sourced from the original manufacturer or authorized distributors?
All AD7946BRMZ 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 AD7946BRMZ meets industry standards.
7.What is the process for return or replacement of AD7946BRMZ?
All AD7946BRMZ units undergo pre-shipment inspection (PSI). If there is an issue with AD7946BRMZ, 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 AD7946BRMZ part is unused and in its original packaging.
Return procedure for AD7946BRMZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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