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Analog Devices Inc. AD7938BCPZ-6REEL7
- Part No.:
- AD7938BCPZ-6REEL7
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 32-VFQFN Exposed Pad, CSP
- Datasheet:
-
AD7938BCPZ-6REEL7.pdf
- Description:
- IC ADC 12BIT SAR 32LFCSP
- Quantity:
- Payment:
- Shipping:
Inventory:2,803
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Product details
Overview
AD7938BCPZ-6REEL7 from Analog Devices is a 12-bit, 8-channel, 625 kSPS successive approximation register (SAR) ADC with integrated channel sequencer, on-chip 2.5 V reference (±0.2% max at 25°C), parallel interface supporting word/byte modes, and single-supply operation from 2.7 V to 5.25 V. It supports software-configurable analog input types-single-ended, pseudo-differential, or fully differential-and targets high-accuracy data acquisition in industrial PLCs, motor control feedback loops, and multichannel sensor monitoring systems.
For engineers reviewing the AD7938BCPZ-6REEL7 datasheet, AD7938BCPZ-6REEL7 pinout, AD7938BCPZ-6REEL7 application, or AD7938BCPZ-6REEL7 equivalent, key selection criteria include sequenced 8-channel sampling capability, no pipeline delay, VDRIVE-independent parallel I/O compatibility with 3 V/5 V processors, ±1 LSB INL (differential mode), and 69 dB SINAD at 50 kHz input frequency.
Technical Context
The AD7938BCPZ-6REEL7 implements a SAR architecture with a wide-bandwidth track-and-hold amplifier capable of handling analog inputs up to 50 MHz full-power bandwidth. Its internal sequencer enables preprogrammed, automatic conversion across up to eight channels without host intervention.
Conversion is triggered by a falling edge on CONVST, with timing controlled by an external 10 MHz master clock (CLKIN); total conversion time is t₂ + 13 × tCLKIN. The device uses a flexible parallel interface with CS, RD, WR, and W/B controls, and supports both straight binary and twos complement output coding via the CODING bit in its control register.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 1 LSB = VREF/4096 quantization step for precise measurement resolution |
| Throughput Rate | 625 kSPS maximum - supports real-time sampling of fast transients in motor current or vibration sensing |
| Analog Input Channels | 8-channel with hardware sequencer - eliminates software overhead for round-robin acquisition in multichannel systems |
| Reference | On-chip 2.5 V ±0.2% (25°C), 25 ppm/°C - enables stable conversions without external reference component or layout area |
| SINAD | 69 dB min (differential mode, fIN = 50 kHz) - ensures >11.2 effective bits for high-fidelity signal reconstruction |
| Power Consumption | 3.6 mW max at 625 kSPS with 3 V supplies - enables low-power operation in battery-backed or thermally constrained modules |
| Input Configuration | Software-selectable single-ended / pseudo-differential / fully differential - adapts to diverse sensor output topologies without external signal conditioning |
| VDRIVE Range | 2.7 V to 5.25 V independent of VDD - allows direct interfacing to 3 V or 5 V microcontrollers without level shifters |
Pinout & Package
AD7938BCPZ-6REEL7 is housed in a 32-lead LFCSP (CP-32-7) package with exposed pad, requiring connection of the EPAD to AGND/DGND plane via multiple vias for thermal and electrical performance. Pin functions are validated per Analog Devices Rev. F datasheet Figure 2 and Table 5.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DB0–DB7 | Data Bits 0–7 | Three-state parallel I/O for 12-bit result or register access; voltage levels set by VDRIVE |
| DB8/HBEN | Data Bit 8 / High Byte Enable | In word mode: DB8; in byte mode: HBEN controls whether DB0–DB7 carry low byte or high nibble + channel ID |
| DB9–DB11 | Data Bits 9–11 | Complete 12-bit word transfer in word mode; unused in byte mode |
| CONVST | Conversion Start | Falling-edge-triggered sample initiation; initiates T/H hold and SAR conversion sequence |
| BUSY | Busy Indicator | Active-high open-drain output signaling conversion in progress; falls when result is latched |
| VREFIN/VREFOUT | Reference I/O | Provides 2.5 V internal reference or accepts external 0.1 V to VDD reference; requires 470 nF AGND decoupling |
| VIN0–VIN7 | Analog Inputs | Eight multiplexed inputs configurable as single-ended, pseudo-diff, or fully diff pairs via MODE bits |
| CLKIN | Master Clock Input | Drives internal timing; 10 MHz nominal yields 625 kSPS; minimum 700 kHz supported |
| W/B | Word/Byte Select | High = 12-bit word transfer on DB0–DB11; low = byte-mode with DB8/HBEN repurposed |
| CS, RD, WR | Parallel Interface Controls | Standard microprocessor bus interface: chip select, read strobe, write strobe |
| VDRIVE | Digital I/O Supply | Sets logic threshold for DBx, CS, RD, WR, CONVST, BUSY - may differ from VDD but ≤ VDD + 0.3 V |
| VDD | Analog/Digital Core Supply | 2.7 V to 5.25 V single supply powering SAR core, T/H, sequencer, and internal reference |
| AGND / DGND | Analog & Digital Grounds | Separate pins required; must be within 0.3 V potential difference to prevent noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Enables deterministic, one-shot conversion timing critical for closed-loop control where latency must be bounded and predictable |
| On-chip 2.5 V reference with ±0.2% accuracy | Eliminates need for external precision reference IC and associated PCB area, BOM cost, and calibration effort |
| Software-configurable input modes | Allows runtime reconfiguration between single-ended, pseudo-differential, and fully differential inputs to match varying sensor outputs |
| VDRIVE voltage independence | Permits direct connection to 3 V or 5 V processor buses without level-shifting circuitry, simplifying interconnect design |
| Full shutdown mode (2 μA max) | Supports ultra-low-power sleep states in portable or energy-harvesting systems without sacrificing wake-up responsiveness |
| Channel sequencer with shadow register | Enables autonomous multi-channel acquisition sequences with programmable order and repetition, reducing host CPU load |
Applications
| Industrial Process Monitoring | Motor Control Feedback |
|---|---|
Use Scenario: Continuous acquisition of temperature, pressure, and flow sensor outputs across eight field points in a distributed I/O module. IC Role / Device Role / Timing Role: Centralized 8-channel SAR ADC performing sequenced conversions with on-chip reference and no pipeline latency. Use Value: Reduces system latency and eliminates external reference drift errors, enabling tighter process control loops with <1 µs jitter in sample timing. | Use Scenario: Simultaneous sampling of three-phase motor currents and DC bus voltage in servo drives for field-oriented control (FOC). IC Role / Device Role / Timing Role: High-speed, synchronized analog front-end converting six current/voltage signals plus auxiliary sensors in fixed sequence. Use Value: Achieves 625 kSPS throughput with 69 dB SINAD, preserving harmonic content needed for accurate torque estimation and distortion analysis. |
| Programmable Logic Controller (PLC) Input Module | Test & Measurement Data Logger |
Use Scenario: Modular analog input card accepting diverse sensor types (4–20 mA, thermocouple, RTD) with configurable gain and filtering. IC Role / Device Role / Timing Role: Precision ADC providing software-selectable input ranges (0–VREF or 0–2×VREF) and coding formats (binary/twos complement). Use Value: Single-component flexibility replaces multiple fixed-function ADCs, lowering inventory complexity and board space by 35% versus discrete solutions. | Use Scenario: Portable environmental monitor logging vibration, acoustic emission, and humidity across eight channels over extended periods. IC Role / Device Role / Timing Role: Low-power SAR converter operating in autostandby mode (160 µA typ at 100 kSPS) with on-chip sequencer managing duty-cycled sampling. Use Value: Extends battery life beyond 72 hours while maintaining 12-bit resolution and <±1 LSB INL across temperature range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 12-bit, multichannel SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7938BRUZ-6 | TQFP-32 package (vs. LFCSP-32); θJA = 121°C/W (vs. 108.2°C/W); identical electrical specs and pinout | Better suited for manual assembly or prototyping; less optimal for high-density or thermally demanding layouts | Select AD7938BRUZ-6 only when LFCSP reflow capability is unavailable or thermal margin exceeds 15°C |
| AD7934-6BCPZ-REEL7 | 4-channel version (vs. 8-channel); same 12-bit resolution, 625 kSPS, LFCSP-32, and sequencer architecture | Applicable where channel count is limited and board space is constrained; shares footprint and register map | Choose AD7934-6BCPZ-REEL7 when system requires ≤4 analog inputs and pin-compatible upgrade path is valued |
Compared with AD7938BRUZ-6, AD7938BCPZ-6REEL7 offers superior thermal performance and smaller footprint; compared with AD7934-6BCPZ-REEL7, it doubles channel count without increasing interface complexity or power per channel.
Availability
AD7938BCPZ-6REEL7 is available at Aetrix Electronics and suitable for industrial automation, motor control, and test equipment applications requiring stable component supply, long-term manufacturability, and guaranteed traceability.
Supply support for AD7938BCPZ-6REEL7 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 AD7938-6 product line delivers high-speed, low-power, multichannel SAR ADCs designed for precision data acquisition in space-constrained, thermally sensitive industrial and instrumentation systems.
FAQ
What is the maximum sampling rate supported by the AD7938BCPZ-6REEL7?
The AD7938BCPZ-6REEL7 supports a maximum throughput rate of 625 kSPS, achieved with a 10 MHz CLKIN signal and confirmed across the full −40°C to +85°C operating temperature range. Conversion time is fixed at t₂ + 13 × tCLKIN, ensuring deterministic timing critical for real-time control applications. This rate is maintained regardless of input configuration (single-ended, pseudo-differential, or fully differential) or reference source (internal or external).
Does the AD7938BCPZ-6REEL7 require an external reference voltage?
No, the AD7938BCPZ-6REEL7 includes a highly accurate on-chip 2.5 V reference with ±0.2% maximum error at 25°C and 25 ppm/°C temperature coefficient, sufficient for most precision applications. However, the VREFIN/VREFOUT pin can be overdriven with an external reference from 0.1 V to VDD if higher accuracy, custom voltage, or temperature stability is required. External reference use does not degrade AC performance.
How does the channel sequencer function in the AD7938BCPZ-6REEL7?
The AD7938BCPZ-6REEL7 sequencer enables autonomous, preprogrammed conversion of up to eight analog inputs in user-defined order without host processor intervention. Sequencing is configured via the SEQ and SHDW bits in the control register and supports repeat, single-shot, or continuous modes. Channel address bits (ADD2–ADD0) determine selection order, and the sequencer automatically advances after each conversion, reducing firmware overhead and improving timing consistency in multichannel systems.
What are the supported analog input configurations for the AD7938BCPZ-6REEL7?
The AD7938BCPZ-6REEL7 supports three analog input configurations selected via MODE bits in the control register: eight single-ended inputs (VIN0–VIN7 referenced to AGND), four fully differential pairs (VIN0–VIN1, VIN2–VIN3, etc.), or four/seven pseudo-differential inputs (e.g., VIN0–VIN1 with common-mode rejection). Input range is software-selectable as 0 to VREF or 0 to 2×VREF, and output coding supports straight binary or twos complement formats.
Can the AD7938BCPZ-6REEL7 interface directly with a 3 V microcontroller?
Yes, the AD7938BCPZ-6REEL7 supports direct interfacing with 3 V microcontrollers using its VDRIVE pin. When VDRIVE is set to 3 V, all digital I/O pins (DB0–DB11, CS, RD, WR, CONVST, BUSY) operate at 3 V logic levels-even if VDD is 5 V-eliminating the need for external level shifters. This feature maintains signal integrity and simplifies PCB routing while preserving full 625 kSPS throughput and timing compliance.
AD7938BCPZ-6REEL7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad, CSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Number of Bits:
- 12
- Sampling Rate (Per Second):
- 1.5M
- Number of Inputs:
- 4, 7, 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-LFCSP-VQ (5x5)
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7938BCPZ-6REEL7 FAQ
1.How can I place an order for AD7938BCPZ-6REEL7 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7938BCPZ-6REEL7 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 AD7938BCPZ-6REEL7 reliable?
The price and inventory of AD7938BCPZ-6REEL7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7938BCPZ-6REEL7 is usually 5 days.
3.What payment methods are accepted for AD7938BCPZ-6REEL7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7938BCPZ-6REEL7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7938BCPZ-6REEL7?
AD7938BCPZ-6REEL7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7938BCPZ-6REEL7 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 AD7938BCPZ-6REEL7?
For technical support, including AD7938BCPZ-6REEL7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7938BCPZ-6REEL7 requirements.
6.How does Aetrix verify that AD7938BCPZ-6REEL7 is sourced from the original manufacturer or authorized distributors?
All AD7938BCPZ-6REEL7 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 AD7938BCPZ-6REEL7 meets industry standards.
7.What is the process for return or replacement of AD7938BCPZ-6REEL7?
All AD7938BCPZ-6REEL7 units undergo pre-shipment inspection (PSI). If there is an issue with AD7938BCPZ-6REEL7, 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 AD7938BCPZ-6REEL7 part is unused and in its original packaging.
Return procedure for AD7938BCPZ-6REEL7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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