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Analog Devices Inc. AD7938BCPZ-6
- Part No.:
- AD7938BCPZ-6
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 32-VFQFN Exposed Pad, CSP
- Datasheet:
-
AD7938BCPZ-6.pdf
- Description:
- IC ADC 12BIT SAR 32LFCSP
- Quantity:
- Payment:
- Shipping:
Inventory:4,016
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Product details
Overview
AD7938BCPZ-6 from Analog Devices is a 12-bit, 8-channel, 625 kSPS parallel successive approximation register (SAR) ADC with integrated sequencer and on-chip 2.5 V reference. It operates from a single 2.7 V to 5.25 V supply, supports software-configurable single-ended/pseudo-differential/fully differential inputs, and delivers 69 dB SINAD at 50 kHz - enabling high-fidelity data acquisition in industrial sensor interfaces and multichannel instrumentation.
For engineers reviewing the AD7938BCPZ-6 datasheet, AD7938BCPZ-6 pinout, AD7938BCPZ-6 application, or AD7938BCPZ-6 equivalent, key selection considerations include its 32-lead LFCSP package, VDRIVE-independent parallel interface, no-pipeline-delay conversion timing, and channel sequencing capability for automated multi-sensor sampling without host processor intervention.
Technical Context
The AD7938BCPZ-6 implements a SAR architecture with a differential track-and-hold amplifier supporting up to 50 MHz input bandwidth. Its sequencer operates via programmable control register bits (SEQ, SHDW), enabling preconfigured channel scan orders across all eight analog inputs without external logic.
Conversion is triggered by a falling edge on CONVST, with completion signaled by BUSY going low after exactly 13 CLKIN cycles plus t₂ setup delay. The parallel interface supports both word mode (DB0–DB11) and byte mode (DB0–DB7 + DB8/HBEN), decoupled from VDD via dedicated VDRIVE pin for mixed-voltage system interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 12-bit - delivers 4096 discrete output codes with guaranteed no missing codes in differential mode. |
| Throughput Rate | 625 kSPS maximum - enables real-time sampling of signals up to ~312 kHz Nyquist bandwidth per channel. |
| SINAD | 69 dB min (differential mode, fIN = 50 kHz) - ensures ≥11.2 effective bits for precision measurement applications. |
| On-chip Reference | 2.5 V ±0.2% at 25°C, 25 ppm/°C max - eliminates need for external reference in cost-sensitive designs while maintaining accuracy over temperature. |
| Power Dissipation | 3.6 mW max at 625 kSPS with 3 V supply - supports battery-powered or thermally constrained embedded systems. |
| Analog Input Configurations | 8 single-ended, 4 fully differential, or 4/7 pseudo-differential - selectable via MODE bits in control register for flexible sensor interface mapping. |
| Package | 32-lead LFCSP (CP-32-7), 5 mm × 5 mm, exposed pad - provides low thermal resistance (θJA = 108.2°C/W) and compact PCB footprint. |
Pinout & Package
AD7938BCPZ-6 uses a 32-lead lead-frame chip-scale package (LFCSP, CP-32-7) with an exposed thermal pad requiring connection to PCB ground plane via multiple vias.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DB0–DB7 | Data Bits 0–7 | Three-state parallel I/O for conversion results or register writes; voltage levels set by VDRIVE, not VDD. |
| 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 Bits 9–11 | Complete 12-bit word transfer in word mode; unused in byte mode and must be tied to DGND. |
| VDRIVE | Digital Interface Supply | Decouples logic interface voltage (2.7–5.25 V) from analog supply (VDD), enabling direct connection to 3 V or 5 V processors. |
| CONVST | Conversion Start | Falling-edge-triggered; initiates track-to-hold transition and starts 13-clock-cycle SAR conversion sequence. |
| BUSY | Conversion Status Output | Active-high open-drain signal indicating conversion in progress; goes low when result is latched and ready to read. |
| VIN0–VIN7 | Analog Input Channels | Multiplexed into internal T/H; configurable as single-ended, pseudo-differential, or fully differential per control register settings. |
| VREFIN/VREFOUT | Reference Input/Output | Supplies 2.5 V internal reference; can be overdriven with external reference from 0.1 V to VDD for custom full-scale ranges. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Immediate availability of conversion result after BUSY deassertion - critical for deterministic real-time control loops. |
| Software-configurable input types | Single-ended, pseudo-differential, or fully differential modes selected via MODE bits - eliminates need for external signal conditioning circuitry. |
| VDRIVE interface independence | Parallel bus operates at VDRIVE voltage level regardless of VDD - simplifies integration with mixed-supply microcontrollers and FPGAs. |
| Integrated 8-channel sequencer | Preprogrammed scan order executed autonomously - reduces host CPU overhead in multi-sensor monitoring systems. |
| Low-power shutdown mode | 2 μA max quiescent current - extends battery life in portable data loggers and wireless sensor nodes. |
Applications
| Industrial Process Monitoring | Medical Instrumentation |
|---|---|
|
Use Scenario: Simultaneous acquisition of temperature, pressure, flow, and humidity sensor outputs in PLC-based control cabinets. IC Role / Device Role / Timing Role: Central 8-channel SAR ADC performing synchronized sampling under sequencer control, feeding data to ARM Cortex-M7 MCU via parallel bus. Use Value: Eliminates external multiplexer and timing logic; 625 kSPS throughput supports >100 Hz per-channel update rates for closed-loop feedback. |
Use Scenario: Multi-lead ECG front-end capturing biopotential signals from 8 electrodes with high common-mode rejection. IC Role / Device Role / Timing Role: Fully differential ADC converting amplified electrode pairs, using internal 2.5 V reference for stable gain calibration. Use Value: 69 dB SINAD and −85 dB channel isolation suppress crosstalk between leads; low 3.6 mW power enables portable battery operation. |
| Automotive Battery Management | Test & Measurement Equipment |
|
Use Scenario: Cell voltage monitoring across 8 Li-ion battery cells in EV battery packs, with thermal sensor inputs shared via sequencer. IC Role / Device Role / Timing Role: Precision ADC measuring 0–5 V cell voltages in pseudo-differential mode, referenced to local AGND with isolated DGND. Use Value: ±1 LSB INL and ±3 LSB gain error match ensure accurate state-of-charge calculation across all cells without per-cell calibration. |
Use Scenario: Modular data acquisition module for benchtop oscilloscopes and spectrum analyzers requiring multi-channel simultaneous sampling. IC Role / Device Role / Timing Role: High-speed parallel ADC providing low-latency digitization with no pipeline latency, synchronized to system clock via CLKIN. Use Value: 50 MHz full-power bandwidth and 72 ps aperture jitter support accurate time-domain analysis of fast transients and RF signals. |
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 | Same electrical specs and functionality, but in 32-lead TQFP package (SU-32-2) instead of LFCSP. | TQFP offers easier manual soldering and prototyping; LFCSP provides superior thermal performance and smaller footprint. | Select AD7938BRUZ-6 for lab evaluation or low-volume assembly; AD7938BCPZ-6 for production-grade compact, thermally optimized designs. |
| AD7934-6BCPZ | 4-channel variant (vs. 8-channel), identical 12-bit resolution, 625 kSPS, same LFCSP package and reference architecture. | Lower channel count reduces PCB routing complexity and cost where only 4 sensors require monitoring. | Choose AD7934-6BCPZ when system requires ≤4 analog inputs and board space/power budget permits consolidation. |
Compared with AD7938BRUZ-6 and AD7934-6BCPZ, the AD7938BCPZ-6 uniquely combines 8-channel density, LFCSP thermal efficiency, and VDRIVE-level shifting - making it optimal for space-constrained, high-channel-count industrial and medical systems demanding deterministic timing and low power.
Availability
AD7938BCPZ-6 is available at Aetrix Electronics and suitable for industrial process monitoring, medical instrumentation, automotive battery management, and test & measurement equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for AD7938BCPZ-6 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 belongs to Analog Devices' precision SAR ADC product line, designed specifically for multichannel data acquisition systems requiring high speed, low power, and flexible analog input configuration without external support components.
FAQ
What is the maximum sampling rate supported by the AD7938BCPZ-6?
The AD7938BCPZ-6 supports a maximum throughput rate of 625 kSPS, achieved with a 10 MHz master clock (CLKIN) and 13-clock conversion cycle. 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). At lower clock frequencies, throughput scales linearly - e.g., 5 MHz CLKIN yields 312.5 kSPS.
Does the AD7938BCPZ-6 require an external reference voltage?
No, the AD7938BCPZ-6 includes an accurate on-chip 2.5 V reference (±0.2% max at 25°C, 25 ppm/°C tempco) that can be used directly for conversion. However, the VREFIN/VREFOUT pin is also overdrivable with an external reference from 0.1 V to VDD, allowing custom full-scale ranges such as 3.0 V or 4.096 V for enhanced system resolution or compatibility.
How does the channel sequencer in the AD7938BCPZ-6 operate?
The AD7938BCPZ-6 sequencer is controlled via SEQ and SHDW bits in the internal control register. When enabled, it automatically cycles through a user-defined subset of VIN0–VIN7 in ascending order, initiating conversions without host intervention. Channel address and configuration (single/diff/pseudo) are retained per channel in shadow registers, enabling autonomous multi-channel acquisition with minimal firmware overhead.
What is the purpose of the VDRIVE pin on the AD7938BCPZ-6?
The VDRIVE pin sets the logic voltage level for the parallel interface (DB0–DB11, RD, WR, CS, etc.), independent of the analog supply VDD. This allows the AD7938BCPZ-6 to interface directly with 3 V or 5 V microprocessors/FPGAs even when VDD is at a different voltage - eliminating level shifters and simplifying mixed-voltage system design while maintaining signal integrity.
Can the AD7938BCPZ-6 operate in both word and byte data transfer modes?
Yes, the AD7938BCPZ-6 supports both modes via the W/B pin. When W/B = high, 12-bit results are transferred across DB0–DB11 in word mode. When W/B = low, byte mode activates: DB0–DB7 carry the low byte (or top 4 bits + channel ID), and DB8 functions as HBEN. Unused DB lines in byte mode must be tied to DGND to prevent floating inputs and noise coupling.
AD7938BCPZ-6 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad, CSP
- Packaging:
- Tray
- 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-6 FAQ
1.How can I place an order for AD7938BCPZ-6 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7938BCPZ-6 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-6 reliable?
The price and inventory of AD7938BCPZ-6 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7938BCPZ-6 is usually 5 days.
3.What payment methods are accepted for AD7938BCPZ-6?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7938BCPZ-6 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7938BCPZ-6?
AD7938BCPZ-6 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7938BCPZ-6 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-6?
For technical support, including AD7938BCPZ-6 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7938BCPZ-6 requirements.
6.How does Aetrix verify that AD7938BCPZ-6 is sourced from the original manufacturer or authorized distributors?
All AD7938BCPZ-6 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-6 meets industry standards.
7.What is the process for return or replacement of AD7938BCPZ-6?
All AD7938BCPZ-6 units undergo pre-shipment inspection (PSI). If there is an issue with AD7938BCPZ-6, 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-6 part is unused and in its original packaging.
Return procedure for AD7938BCPZ-6:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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