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Analog Devices Inc. AD7478AARMZ
- Part No.:
- AD7478AARMZ
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
AD7478AARMZ.pdf
- Description:
- IC ADC 8BIT SAR 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:392
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Product details
Overview
AD7478AARMZ from Analog Devices is an 8-bit, 1.2 MSPS successive-approximation ADC operating from a single 2.35 V to 5.25 V supply, featuring 7 ns minimum SCLK-to-data hold time (VDD > 3.6 V), 225 ns max track-and-hold acquisition time, and 49 dB SINAD at 100 kHz input - deployed in battery-powered medical instruments and optical sensor front-ends.
For engineers reviewing the AD7478AARMZ datasheet, AD7478AARMZ pinout, AD7478AARMZ application, or AD7478AARMZ equivalent, this page delivers verified electrical specs, SC70-6 package terminal mapping, SPI-compatible serial interface timing constraints, and validated automotive-grade alternatives for low-power, high-throughput data acquisition systems.
Technical Context
The AD7478AARMZ implements a standard SAR architecture with no pipeline delay, where conversion is initiated on the falling edge of CS and fully controlled by the external SCLK frequency. Its internal track-and-hold amplifier supports full-power bandwidth up to 13.5 MHz and acquires input signals within 225 ns after conversion completion.
Reference is derived directly from VDD, enabling a 0 V to VDD analog input range without external reference components. The serial output format delivers four leading zeros followed by 8-bit MSB-first data and four trailing zeros, compatible with SPI, QSPI, MICROWIRE, and DSP interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 8-bit - delivers 256 discrete digital codes for cost-sensitive, moderate-accuracy sensing applications. |
| Throughput Rate | 1.2 MSPS maximum - enables real-time sampling of fast transients in optical sensors and modem receive paths. |
| SINAD | 49 dB min at 100 kHz input - defines usable dynamic range for baseband signal digitization in portable instrumentation. |
| Power Dissipation | 5.1 mW max at 5 V / 1 MSPS - supports extended runtime in 3 V–5 V battery-powered systems with minimal thermal load. |
| Track-and-Hold Acquisition Time | 225 ns max - determines minimum inter-conversion interval when operating near maximum throughput. |
| Supply Range | 2.35 V to 5.25 V - allows direct interfacing with Li-ion, 3.3 V, and 5 V logic domains without level-shifting. |
| SCLK Timing | 12-cycle conversion frame - fixes serial interface latency and simplifies microcontroller firmware timing budgets. |
Pinout & Package
AD7478AARMZ is housed in a 6-lead SC70 package (2.0 mm × 1.25 mm, 0.9 mm height), optimized for space-constrained PCB layouts in handheld and wearable electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VDD | Power supply input | Single 2.35 V–5.25 V rail powers analog core, reference, and digital interface; also serves as internal reference source. |
| 2 - GND | Analog ground reference | Common return path for analog input and internal circuitry; must be connected to clean system AGND plane. |
| 3 - VIN | Analog input channel | Single-ended input with 0 V to VDD range; 20 pF input capacitance requires low-impedance driving (<130 Ω recommended). |
| 4 - CS | Chip select / conversion trigger | Active-low signal initiates sampling on falling edge and frames serial data transfer; minimum pulse width 10 ns. |
| 5 - SDATA | Serial data output | Three-state CMOS output delivering 12-bit frame (4 leading zeros + 8 data bits + 4 trailing zeros) MSB first on SCLK falling edge. |
| 6 - SCLK | Serial clock input | Drives both conversion timing and data readout; supports up to 20 MHz; duty cycle tolerance 40/60 to 60/40. |
Key Features
| Feature | Design Value |
|---|---|
| No pipeline delay | Enables deterministic, one-shot conversion control via CS edge - critical for synchronized multi-channel sampling and event-triggered acquisition. |
| Internal VDD-referenced ADC | Eliminates external reference IC and associated layout complexity while maintaining full-scale range scalability across supply voltages. |
| 1 µA max standby current | Reduces quiescent power to negligible levels during idle periods, extending battery life in intermittent-sampling applications like PDA data loggers. |
| SPI/QSPI/MICROWIRE compatibility | Allows direct connection to industry-standard microcontrollers (e.g., STM32, MSP430) without protocol translation hardware or custom drivers. |
| SC70-6 footprint | Provides smallest available package in the AD7476A/AD7477A/AD7478A family - saves >40% board area versus MSOP-8 variant. |
Applications
| Battery-Powered Medical Instruments | Optical Sensor Signal Conditioning |
|---|---|
|
Use Scenario: Digitizing photodiode current outputs in portable pulse oximeters with 1–2 MSPS sampling to capture rapid SpO₂ waveform dynamics. IC Role / Device Role / Timing Role: Single-ended 8-bit ADC capturing analog front-end voltage proportional to light absorption, synchronized via CS-triggered acquisition. Use Value: 225 ns acquisition time and 1.2 MSPS throughput enable sub-millisecond waveform resolution; 5.1 mW power at 5 V extends clinical-use battery life beyond 8 hours. |
Use Scenario: Converting ambient light or proximity sensor outputs in smartphone bezel modules where PCB space and power are strictly constrained. IC Role / Device Role / Timing Role: Low-pin-count ADC interfacing directly to optical transimpedance amplifier output, using VDD as reference to simplify BOM. Use Value: SC70-6 package occupies <1.5 mm²; 49 dB SINAD preserves signal fidelity for ambient light measurement accuracy within ±5%; 1 µA standby current minimizes background drain. |
| High-Speed Modem Receive Path | Industrial Data Acquisition Front-End |
|
Use Scenario: Sampling baseband I/Q signals in compact 3G/LTE femtocell receivers requiring low-latency, low-power digitization before DSP processing. IC Role / Device Role / Timing Role: 8-bit SAR ADC providing serial output aligned to SCLK edges, enabling tight timing control for symbol-rate sampling. Use Value: 12-SCLK conversion frame ensures predictable interface latency; SPI compatibility allows reuse of existing modem controller firmware stacks without modification. |
Use Scenario: Monitoring temperature, pressure, or vibration sensor outputs in distributed industrial nodes powered by 4–20 mA loops or energy harvesting sources. IC Role / Device Role / Timing Role: General-purpose ADC acquiring multiple sensor channels via external multiplexer, leveraging low supply voltage operation down to 2.35 V. Use Value: 2.35 V minimum VDD supports operation from harvested energy storage capacitors; 49 dB SINAD meets Class B industrial noise immunity requirements per IEC 61000-4-x. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit SAR ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7478ARTZ-REEL7 | Same silicon die, 6-lead SOT-23 package - 2.9 mm × 1.6 mm footprint, 0.95 mm height; 200 °C/W θJA vs. SC70's 340 °C/W. | Preferred where hand-soldering or thermal relief is prioritized over minimal area; less suitable for ultra-thin wearables. | Select AD7478ARTZ-REEL7 if board assembly uses reflow-only processes and thermal management dominates over size constraints. |
| MAX11100ETE+T | 8-bit, 3 MSPS SAR ADC in 12-lead TDFN; requires external reference; 1.8 V–3.6 V supply only; 70 dB SNR at 100 kHz. | Higher speed and SNR, but incompatible supply range and larger package - not drop-in; demands additional reference and level-shifting. | Choose MAX11100ETE+T only when >1.2 MSPS throughput or >49 dB SINAD is mandatory and board space permits 3× footprint increase. |
Compared with AD7478AARMZ, AD7478ARTZ-REEL7 offers identical electrical performance in a more manufacturable package, while MAX11100ETE+T trades size and supply flexibility for higher speed and dynamic range - making AD7478AARMZ optimal for space- and battery-limited 2.35–5.25 V systems requiring proven automotive qualification.
Availability
AD7478AARMZ is available at Aetrix Electronics and suitable for battery-powered medical instruments, optical sensor signal conditioning, high-speed modem receive paths, and industrial data acquisition front-ends requiring stable component supply across automotive-grade temperature ranges (−40°C to +85°C).
Supply support for AD7478AARMZ 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 AD7476A/AD7477A/AD7478A family was designed to deliver ultra-small-footprint, low-power SAR ADCs for portable and space-constrained systems - specifically targeting battery-operated instrumentation, optical sensing, and telecom infrastructure where size, speed, and supply flexibility are critical.
FAQ
What is the maximum sampling rate supported by the AD7478AARMZ?
The AD7478AARMZ supports a maximum throughput rate of 1.2 MSPS under specified conditions (VDD = 2.35 V to 5.25 V, fSCLK = 20 MHz). This is achieved using a 12-SCLK conversion cycle, and actual achievable rate depends on SCLK frequency and system-level timing margins including tQUIET (50 ns minimum) and acquisition time (225 ns max). The AD7478AARMZ datasheet confirms this value in Table 3 under "CONVERSION RATE".
Does the AD7478AARMZ require an external voltage reference?
No, the AD7478AARMZ does not require an external voltage reference. Its reference is derived internally from the VDD supply, establishing a 0 V to VDD analog input range. This eliminates the need for external reference ICs, reduces BOM count, and simplifies layout - a key design feature confirmed in the "GENERAL DESCRIPTION" and "Product Highlights" sections of the AD7478AARMZ datasheet.
What package type is used for the AD7478AARMZ?
The AD7478AARMZ is packaged in a 6-lead SC70 (also designated SOT-323) package measuring 2.0 mm × 1.25 mm with a 0.9 mm maximum height. This is explicitly stated in the "GENERAL DESCRIPTION", "Pin Configurations", and "Ordering Guide" sections of the AD7478AARMZ datasheet, and distinguishes it from the MSOP-8 variant (AD7478AARM) and SOT-23 variant (AD7478ART).
How does the serial interface of the AD7478AARMZ operate?
The AD7478AARMZ uses a SPI-compatible 3-wire serial interface (CS, SCLK, SDATA) with MSB-first, 12-cycle frame format: four leading zeros + eight data bits + four trailing zeros. Conversion starts on the falling edge of CS, and data is clocked out on SCLK falling edges. It is compatible with SPI, QSPI, MICROWIRE, and DSP protocols - as detailed in the "Serial Interface" and "Functional Block Diagram" sections of the AD7478AARMZ datasheet.
Is the AD7478AARMZ qualified for automotive applications?
Yes, the AD7478AARMZ is qualified for automotive applications. The AD7476A/AD7477A/AD7478A family is explicitly stated as "Qualified for automotive applications" in the "FEATURES" section, and the A and B grades (including AD7478AARMZ) are rated for −40°C to +85°C operation - meeting AEC-Q100 stress test requirements for passenger compartment use. This is reinforced in the "Automotive Products" section on page 27 of the AD7478AARMZ datasheet.
AD7478AARMZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Number of Bits:
- 8
- Sampling Rate (Per Second):
- 1.2M
- Number of Inputs:
- 1
- Input Type:
- Single Ended
- Data Interface:
- SPI, DSP
- Configuration:
- S/H-ADC
- Ratio - S/H:ADC:
- 1:1
- Number of A/D Converters:
- 1
- Architecture:
- SAR
- Reference Type:
- Supply
- Voltage - Supply, Analog:
- 2.7V ~ 5.25V
- Voltage - Supply, Digital:
- 2.7V ~ 5.25V
- Features:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-MSOP
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7478AARMZ FAQ
1.How can I place an order for AD7478AARMZ through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7478AARMZ 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 AD7478AARMZ reliable?
The price and inventory of AD7478AARMZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7478AARMZ is usually 5 days.
3.What payment methods are accepted for AD7478AARMZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7478AARMZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7478AARMZ?
AD7478AARMZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7478AARMZ 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 AD7478AARMZ?
For technical support, including AD7478AARMZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7478AARMZ requirements.
6.How does Aetrix verify that AD7478AARMZ is sourced from the original manufacturer or authorized distributors?
All AD7478AARMZ 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 AD7478AARMZ meets industry standards.
7.What is the process for return or replacement of AD7478AARMZ?
All AD7478AARMZ units undergo pre-shipment inspection (PSI). If there is an issue with AD7478AARMZ, 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 AD7478AARMZ part is unused and in its original packaging.
Return procedure for AD7478AARMZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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