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Analog Devices Inc. AD7939BSU
- Part No.:
- AD7939BSU
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 32-TQFP
- Datasheet:
-
AD7939BSU.pdf
- Description:
- 10-BIT SAR ADC, 8 CH, PARALLEL
- Quantity:
- Payment:
- Shipping:
Inventory:871
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Product details
Overview
AD7939BSU from Analog Devices is a 10-bit, 8-channel, 1.5 MSPS successive approximation register (SAR) analog-to-digital converter with integrated channel sequencer, on-chip 2.5 V reference (±0.2% @ 25°C), and flexible parallel interface supporting word/byte modes. It operates from a single 2.7 V to 5.25 V supply, consumes 6 mW at 3 V, and supports single-ended, pseudo-differential, or fully differential input configurations for industrial data acquisition systems.
For engineers reviewing the AD7939BSU datasheet, AD7939BSU pinout, AD7939BSU application, or AD7939BSU equivalent, key selection considerations include its 10-bit resolution with ±0.5 LSB INL, 61 dB SINAD at 50 kHz, 125 ns track-and-hold acquisition time, and support for software-configurable analog input ranges (0–VREF or 0–2×VREF) in embedded sensor interface and multichannel monitoring designs.
Technical Context
The AD7939BSU implements a SAR architecture with no pipeline delay, enabling deterministic conversion timing controlled by a 25.5 MHz master clock (CLKIN) and initiated on the falling edge of CONVST. Its internal sequencer allows preprogrammed channel scanning across VIN0–VIN7 without host intervention.
It features dual ground domains (AGND/DGND), VDRIVE-independent logic interface, and configurable output coding (straight binary or twos complement). The on-chip 2.5 V reference provides 25 ppm/°C tempco and can be overdriven by an external source, while the analog input structure supports 8 single-ended, 4 fully differential, or 7 pseudo-differential channel configurations via control register MODE bits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 10-bit - delivers 1024 discrete digital codes for medium-precision sensor digitization. |
| Throughput Rate | 1.5 MSPS - enables real-time sampling of fast transients up to 50 MHz full-power bandwidth. |
| SINAD | 61 dB min at 50 kHz - ensures usable dynamic range for vibration, audio, or motor current sensing. |
| INL | ±0.5 LSB max - guarantees monotonicity and linearity critical for closed-loop control feedback. |
| Power Dissipation | 6 mW max at 3 V - supports low-power portable or battery-backed data loggers. |
| Reference Accuracy | ±0.2% @ 25°C, 25 ppm/°C - eliminates need for external precision reference in cost-sensitive designs. |
| Input Configuration | Software-selectable single-ended / pseudo-differential / fully differential - simplifies hardware reuse across varied signal sources. |
Pinout & Package
AD7939BSU is available in a 32-lead LFCSP (Lead Frame Chip Scale Package) with exposed paddle, optimized for thermal performance (θJA = 108.2°C/W) and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DB0–DB7 | Data Bus (Low Byte) | Three-state I/O pins carrying LSBs of conversion result; DB0–DB1 always 0 when reading AD7939BSU, LSB on DB2. |
| DB8/HBEN | Data Bit 8 / High-Byte Enable | In word mode: DB8; in byte mode: HBEN controls whether DB0–DB7 carry low byte or top 4 bits + channel ID. |
| DB9–DB11 | Data Bus (High Nibble) | Carry MSBs of 10-bit result in word mode; unused in byte mode and tied to DGND. |
| CONVST | Conversion Start | Falling-edge-triggered; initiates track-to-hold transition and starts 13-clock-cycle SAR conversion. |
| BUSY | Conversion Status Output | Active-high open-drain signal indicating conversion in progress; goes low when result is latched. |
| VIN0–VIN7 | Analog Input Channels | Eight multiplexed inputs configurable as single-ended, pseudo-differential (7-channel), or fully differential (4-channel). |
| VREFIN/VREFOUT | Reference I/O | 2.5 V internal reference output; accepts external reference 0.1 V to VDD; requires 470 nF AGND decoupling. |
| VDRIVE | Logic Interface Supply | Sets parallel bus voltage level (2.7–5.25 V); independent of VDD but must not exceed VDD + 0.3 V. |
| W/B | Word/Byte Mode Select | High = 10-bit word transfer on DB0–DB11; low = byte mode with DB8/HBEN as enable and channel ID on DB4–DB6. |
Key Features
| Feature | Design Value |
|---|---|
| 8-channel sequencer with programmable scan order | Reduces host CPU overhead by automating multi-channel acquisition without software polling. |
| VDRIVE-independent parallel interface | Allows direct connection to 3 V or 5 V microcontrollers regardless of core VDD, simplifying mixed-voltage system design. |
| No pipeline delay | Enables precise timing-critical sampling (e.g., phase-aligned motor control) with deterministic 13-clock-cycle latency. |
| Flexible analog input configuration | Single register write reconfigures all 8 channels between single-ended, pseudo-differential, or fully differential modes. |
| Full shutdown mode (2 μA) | Extends battery life in intermittent-sampling applications such as environmental sensor nodes. |
Applications
| Industrial Process Monitoring | Motor Drive Current Sensing |
|---|---|
|
Use Scenario: Continuous monitoring of temperature, pressure, and flow sensors across 8 PLC I/O modules. IC Role / Device Role / Timing Role: ADC front-end digitizing conditioned analog signals with sequenced channel scanning and synchronized CONVST triggering. Use Value: 1.5 MSPS throughput captures transient faults; ±0.5 LSB INL ensures accurate calibration traceability per channel. |
Use Scenario: Real-time sampling of three-phase motor currents using shunt resistors and isolated amplifiers. IC Role / Device Role / Timing Role: Simultaneous pseudo-differential acquisition of 6 current channels (VIN0–VIN5) plus DC bus voltage (VIN6). Use Value: 61 dB SINAD preserves harmonic content for FOC algorithms; VDRIVE compatibility enables direct interfacing with 3.3 V DSPs. |
| Portable Data Logger | Medical Sensor Hub |
|
Use Scenario: Battery-powered environmental logger recording humidity, ambient light, and CO₂ over 24-hour cycles. IC Role / Device Role / Timing Role: Low-power ADC managing sleep/wake cycles via autostandby mode and sequenced wake-up conversions. Use Value: 6 mW at 3 V extends runtime; on-chip 2.5 V reference eliminates external component count and drift errors. |
Use Scenario: Multi-parameter patient monitor acquiring ECG leads, respiration, and SpO₂ analog waveforms. IC Role / Device Role / Timing Role: High-fidelity digitizer supporting 10-bit resolution and 50 MHz bandwidth for artifact-free waveform capture. Use Value: 125 ns acquisition time resolves rapid ECG slew rates; channel isolation >75 dB prevents cross-talk between biopotential inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit multichannel SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7938BSU | 12-bit resolution, ±1 LSB INL, 70 dB SINAD - higher precision but 3× higher code density and larger memory footprint. | Preferred where calibration-grade accuracy is required (e.g., test equipment), not needed for basic monitoring. | Select AD7938BSU only if system firmware and storage support 12-bit data paths and SNR >68 dB is mandatory. |
| ADS8325IPW | 16-bit, 100 kSPS, SPI interface - lower speed, higher resolution, serial-only communication requiring additional GPIO handling. | Suitable for low-channel-count, high-accuracy applications (e.g., precision weight scales) with relaxed timing constraints. | Choose ADS8325IPW when board space is constrained and SPI is already used elsewhere, accepting 15× lower throughput. |
Compared with AD7939BSU, AD7938BSU offers higher resolution at identical speed and package, while ADS8325IPW trades speed and parallel simplicity for resolution and interface flexibility-making AD7939BSU optimal for cost-sensitive, medium-speed, 8-channel industrial digitization.
Availability
AD7939BSU is available at Aetrix Electronics and suitable for industrial process monitoring, motor drive current sensing, portable data logging, medical sensor hubs, and multichannel test instrumentation requiring stable component supply and long-term manufacturability.
Supply support for AD7939BSU 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.
The AD793x family was designed specifically for high-speed, low-power, multichannel data acquisition in space-constrained industrial and instrumentation systems where parallel interface simplicity and sequencer autonomy are critical.
FAQ
What is the maximum sampling rate supported by the AD7939BSU?
The AD7939BSU supports a maximum throughput rate of 1.5 MSPS, achieved with a 25.5 MHz master clock (CLKIN) and 13 clock cycles per conversion. This rate is maintained across its full operating temperature range (−40°C to +85°C) and supply range (2.7 V to 5.25 V), making AD7939BSU suitable for real-time transient capture in demanding industrial environments.
Does the AD7939BSU require an external reference voltage?
No, the AD7939BSU includes an accurate on-chip 2.5 V reference with ±0.2% initial accuracy at 25°C and 25 ppm/°C temperature coefficient, sufficient for most industrial applications. However, the VREFIN/VREFOUT pin can be overdriven with an external reference from 0.1 V to VDD if higher precision or custom voltage scaling is required - the AD7939BSU remains fully functional in either configuration.
How does the AD7939BSU handle analog input configuration for different signal types?
The AD7939BSU uses its internal control register to configure all eight analog inputs (VIN0–VIN7) as single-ended, pseudo-differential (7-channel), or fully differential (4-channel) via MODE bits. This configuration is software-selectable and applies uniformly across the sequenced channels, allowing one register write to reconfigure the entire front end - a capability confirmed in the AD7939BSU datasheet's Analog Input Selection section.
What power management modes are available on the AD7939BSU?
The AD7939BSU offers three power states: Normal Mode (2.7 mA max at 5 V), Autostandby Mode (160 μA typ at 100 kSPS), and Full/Autoshutdown Mode (2 μA max). These are controlled via the control register and allow dynamic adaptation to sampling duty cycle - for example, entering autoshutdown between bursts in a battery-powered AD7939BSU data logger to minimize average current draw.
Can the AD7939BSU interface directly with a 3.3 V microcontroller?
Yes, the AD7939BSU's VDRIVE pin allows its parallel interface to operate at 3.3 V independently of VDD, which may be set to 5 V for analog performance. With VDRIVE = 3.3 V, DB0–DB11, RD, WR, CS, and BUSY meet 3.3 V logic thresholds (VIH = 2.4 V min, VIL = 0.8 V max), enabling direct, level-shift-free connection to common 3.3 V microcontrollers - a feature explicitly validated in the AD7939BSU timing and logic specifications.
AD7939BSU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- AD7939
- Package/Case:
- 32-TQFP
- Packaging:
- Bulk
- Product Status:
- Active
- Number of Bits:
- 10
- Sampling Rate (Per Second):
- 1.5M
- Number of Inputs:
- 8
- Input Type:
- Differential, Pseudo-Differential, Single Ended
- Data Interface:
- Parallel
- Configuration:
- MUX-S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- External, Internal
- Voltage - Supply, Analog:
- 2.7V ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 32-TQFP (7x7)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7939BSU FAQ
1.How can I place an order for AD7939BSU through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7939BSU 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 AD7939BSU reliable?
The price and inventory of AD7939BSU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7939BSU is usually 5 days.
3.What payment methods are accepted for AD7939BSU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7939BSU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7939BSU?
AD7939BSU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7939BSU 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 AD7939BSU?
For technical support, including AD7939BSU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7939BSU requirements.
6.How does Aetrix verify that AD7939BSU is sourced from the original manufacturer or authorized distributors?
All AD7939BSU 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 AD7939BSU meets industry standards.
7.What is the process for return or replacement of AD7939BSU?
All AD7939BSU units undergo pre-shipment inspection (PSI). If there is an issue with AD7939BSU, 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 AD7939BSU part is unused and in its original packaging.
Return procedure for AD7939BSU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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