AD7475BRMZ-REEL - 12-Bit 1MSPS SAR ADC | Analog Devices
MPN: AD7475BRMZ-REEL ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.1 | $4.10 |
| 10 | $3.69 | $36.90 |
| 100 | $3.28 | $328.00 |
| 500 | $2.96 | $1,480.00 |
| 1,000 | $2.63 | $2,630.00 |
AD7475BRMZ-REEL Overview
A SAR (Successive Approximation Register) ADC is a precision converter architecture that uses a binary-search algorithm against an internal DAC to digitize the input voltage in N clock cycles. SAR ADCs sit in the broader taxonomy of analog-to-digital converters -> data converters -> mixed-signal ICs -> signal chain semiconductors, and they are favoured over pipeline or flash ADCs where low latency, deterministic sampling, and low power consumption are required at moderate resolutions (8 to 16 bits).
Key features include a 1 MSPS conversion rate, 4.5 mW typical power dissipation at full speed, a flexible serial (SPI/QSPI/MICROWIRE/DSP-compatible) interface, and the proprietary VDRIVE function that allows the digital I/O logic levels to be set independently of the analog supply. The device offers a typical INL of ±1 LSB and operates across the industrial -40C to +85C temperature range, ensuring stable performance in harsh environments.
From an architectural standpoint, the AD7475 uses a charge-redistribution DAC array combined with a high-bandwidth sample-and-hold capable of digitizing signals well beyond the Nyquist frequency. The serial clock can be applied up to 20 MHz, supporting the full 1 MSPS throughput while keeping the digital interface noise isolated from the analog input stage, an essential consideration for high-precision measurement systems.
Typical applications include battery-powered instrumentation, portable data acquisition systems, optical sensor front-ends, isolated industrial process controls, and precision medical instruments such as patient monitoring devices. Designers also deploy it in motor control feedback loops and programmable logic controller (PLC) analog input modules where deterministic latency and low power are equally important.
When designing with this device, ensure the reference decoupling capacitor is placed as close as possible to the REF IN pin and use a clean, low-noise analog ground pour to preserve 12-bit accuracy. The VDRIVE pin should be tied to the host MCU's logic supply to guarantee proper SPI timing margins at full 1 MSPS throughput.
This page synthesizes distributor pricing, drop-in compatible replacements, and practical PCB layout notes that extend beyond the manufacturer datasheet, giving engineers a single authoritative reference for the AD7475BRMZ-REEL.
Drop-in alternatives for AD7475BRMZ-REEL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
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AD7475BRMZ-REEL Maximum Ratings & Electrical Characteristics
| Manufacturer | Analog Devices Inc. |
| Part Status | Active |
| Resolution | 12 bits |
| Architecture | SAR (Successive Approximation) |
| Number of Inputs | 1 |
| Throughput Rate | 1 MSPS |
| Supply Voltage (AVDD) | 2.7 V to 5.25 V |
| Logic Interface Supply (VDRIVE) | 1.8 V to 5.25 V |
| Input Voltage Range | 0 V to VREF |
| Reference Voltage | External 2.5 V (applied to REF IN) |
| Power Consumption | 4.5 mW at 1 MSPS, 3 V supply (typical) |
| Track-and-Hold Bandwidth | Greater than 1 MHz input frequency |
| Serial Interface | SPI / QSPI / MICROWIRE / DSP compatible |
| Operating Temperature | -40C to +85C |
| Package | 8-pin MSOP (RM-8) |
| Mounting Type | Surface Mount |
| Packaging Media | 7-inch Reel (REEL suffix) |
| RoHS Status | Compliant |
| Lead Free | Yes |
AD7475BRMZ-REEL Pin Configuration
| Pin 1 | VDD — Analog supply input (2.7 V to 5.25 V) |
| Pin 2 | GND — Analog ground |
| Pin 3 | REF IN — External 2.5 V reference input |
| Pin 4 | AIN — Analog input voltage (0 V to VREF) |
| Pin 5 | GND — Analog ground (return path) |
| Pin 6 | VDRIVE — Logic supply for digital I/O (1.8 V to 5.25 V) |
| Pin 7 | DOUT/SCLK — Serial data output / serial clock input (shared line on some ADI variants) |
| Pin 8 | CS — Active-low chip-select input |
Typical Applications
AD7475BRMZ-REEL is suitable for 6 applications: Portable Battery-Powered Data Acquisition, Optical Sensor Front-End Digitization, Industrial Process Control Inputs, Motor Control Current Sensing, Medical Patient Monitoring Instruments, General-Purpose Embedded SPI ADC Module.
Portable Battery-Powered Data Acquisition
The AD7475BRMZ-REEL delivers 12-bit precision at 1 MSPS while consuming only 4.5 mW from a 2.7 V to 5.25 V supply, making it well-matched to battery-powered data acquisition modules that must digitize transducer signals while preserving hours of runtime. Designers typically place the ADC between the sensor signal-conditioning front-end (e.g., AD8421 instrumentation amplifier) and the host MCU's SPI port, using VDRIVE to match the digital logic level directly to a 1.8 V or 3.3 V microcontroller. Unlike pipeline ADCs, the SAR architecture gives a single-cycle deterministic latency that simplifies trigger-to-sample timing. Compared with 16-bit delta-sigma alternatives, the AD7475BRMZ-REEL's wider bandwidth track-and-hold captures fast transients above 1 MHz, useful for vibration or ultrasonic sensor front-ends. Power scaling with throughput lets engineers throttle sampling during sleep intervals to extend battery life.
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Optical Sensor Front-End Digitization
The AD7475BRMZ-REEL is widely deployed at the back-end of photodiode transimpedance amplifier (TIA) chains where 12-bit resolution at 1 MSPS is sufficient to quantify light intensity, colorimeter outputs, or pulse-oximeter signals. Its wide-bandwidth track-and-hold amplifier can sample input signals beyond 1 MHz, allowing accurate capture of high-speed optical events such as LiDAR return pulses or laser-ranging echoes. The part's serial SPI output and VDRIVE function eliminate the need for parallel bus buffers or level shifters, reducing PCB area in compact optical modules. Compared with 8-bit ADCs in the same footprint, the 12-bit resolution improves signal-to-noise ratio by 16 dB and reduces quantisation error by a factor of 16. The 8-MSOP footprint also tolerates the tight layouts typical of multi-channel sensor arrays.
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Industrial Process Control Inputs
In industrial process control systems such as PLC analog input modules and 4-20 mA loop monitors, the AD7475BRMZ-REEL converts scaled analog signals from current-sensing or voltage-divider networks into a 12-bit digital code for the controller. Its industrial -40C to +85C operating range, deterministic SAR latency, and VDRIVE flexibility let designers interface directly to 3.3 V or 5 V industrial MCUs without additional level translation. The 1 MSPS throughput supports multi-channel sequential sampling at aggregate rates above 100 kSPS per channel when multiplexed. Compared with 24-bit sigma-delta ADCs, the AD7475BRMZ-REEL offers lower latency and lower power, suiting closed-loop control applications where update rate matters more than DC resolution. Galvanic isolation can be added upstream without sacrificing the ADC's bandwidth.
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Motor Control Current Sensing
The AD7475BRMZ-REEL serves as the analog-to-digital interface for motor phase current measurement in FOC (field-oriented control) and trapezoidal BLDC drives. Because the SAR architecture delivers a single-cycle deterministic conversion, the controller can sample shunt-derived phase currents synchronously with the PWM carrier and react within the next PWM period, minimizing torque ripple. The track-and-hold bandwidth above 1 MHz captures the high di/dt edges of switching transients without slew-induced distortion. The 4.5 mW typical power consumption keeps overall inverter efficiency high, and the 8-MSOP footprint fits the compact gate-driver PCBs typically used in 24 V brushless servo designs. Compared with integrated motor-controller ADCs, the AD7475BRMZ-REEL gives designers freedom to choose the controller MCU and the modulation scheme independently.
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Medical Patient Monitoring Instruments
Portable medical devices such as pulse oximeters, ECG front-ends, and wearable patient monitors benefit from the AD7475BRMZ-REEL's combination of 12-bit resolution, 1 MSPS throughput, and 4.5 mW low-power dissipation. The wide-bandwidth track-and-hold can digitize physiological waveforms (typically <1 kHz content) without aliasing artefacts, while the SPI output reduces wiring between the sensor front-end and the host processor. The VDRIVE pin lets the ADC interface directly to low-voltage application processors used in battery-powered medical devices, eliminating level shifters that would otherwise consume board space. Compared with audio-band delta-sigma ADCs, the SAR topology provides lower latency suitable for heart-rate and SpO2 ratiometric calculations. RoHS compliance simplifies regulatory submissions for IEC 60601 medical designs.
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General-Purpose Embedded SPI ADC Module
The AD7475BRMZ-REEL is a flexible general-purpose ADC for any 8-bit microcontroller or DSP platform that exposes an SPI/QSPI/MICROWIRE peripheral. The serial interface reduces pin count to four (CS, SCLK, DOUT, VDRIVE), making it ideal for small packages where GPIO is scarce. The 1 MSPS throughput supports audio-bandwidth capture (44.1 kSPS oversampled) and ultrasonic sensing in the same design, while the 12-bit resolution suits closed-loop control of LED brightness, potentiometer readings, and analog trim potentiometers. Compared with integrated MCU ADCs, the AD7475BRMZ-REEL offers superior linearity, lower crosstalk from digital circuitry, and the ability to sample analog signals independent of the MCU's internal VDD noise. Engineers routinely drop it onto Arduino, STM32, and ESP32 shields as a high-precision external ADC.
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Engineering reference data for AD7475BRMZ-REEL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7475BRMZ-REEL7 | AD7475BRMZ | AD7475BRZ-REEL | AD7495BRMZ | AD7475ARMZ |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 8-MSOP (RM-8) | 8-MSOP (RM-8) - same | 8-MSOP (RM-8) - same | 8-MSOP (RM-8) - same | 8-MSOP (RM-8) - same | 8-MSOP (RM-8) - same |
| Resolution | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits | 12 bits |
| Throughput Rate | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS | 1 MSPS |
| Reference | External 2.5 V | External 2.5 V | External 2.5 V | External 2.5 V | Internal 2.5 V | External 2.5 V |
| Supply Voltage | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| VDRIVE Range | 1.8 V to 5.25 V | 1.8 V to 5.25 V | 1.8 V to 5.25 V | 1.8 V to 5.25 V | 1.8 V to 5.25 V | 1.8 V to 5.25 V |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Packaging Media | 7-inch Reel (REEL) | 7-inch Reel (REEL7 inner dia) | Tube | 7-inch Reel | Tube | Tube |
Key Differentiators
- VDRIVE pin decouples logic and analog supplies (vs Internal reference-only 12-bit SAR ADCs (no VDRIVE))
- External reference provides flexibility for low-noise designs (vs AD7495BRMZ (internal 2.5 V reference))
- Wide-bandwidth track-and-hold beyond 1 MHz (vs Lower-bandwidth 12-bit SAR ADCs in 8-MSOP)
- Single-cycle deterministic SAR latency (vs Pipelined ADCs of similar speed)
Design Notes
Estimated: at 1 MSPS and a 3.0 V AVDD supply, the AD7475BRMZ-REEL dissipates approximately 4.5 mW (1.5 mA average). Decouple VDD with a 10 uF tantalum or ceramic bulk capacitor in parallel with a 100 nF ceramic placed within 5 mm of the pin; route the analog ground return directly to the PCB ground plane via a single via to keep digital switching currents away from the reference. VDRIVE may share the digital MCU supply but should still be locally bypassed with a 100 nF capacitor to ensure clean SPI transitions.
Route the analog input (AIN) trace as a microstrip over a continuous ground pour and avoid running it parallel to SCLK or DOUT for more than 5 mm to minimize digital-to-analog coupling. Place the reference decoupling capacitor (typically 10 uF ceramic + 100 nF) within 1 mm of the REF IN pin. Keep the trace length from the external ADR03/ADR01 reference output to REF IN below 10 mm to preserve 12-bit noise performance; a guard trace tied to analog ground can be used if longer routing is unavoidable.
The SPI clock can be as fast as 20 MHz to support the full 1 MSPS throughput. Use a 33 ohm series resistor at the SCLK driver and a 33 ohm resistor on DOUT near the ADC if the trace length exceeds 25 mm, to dampen reflections and protect against ringing on the bus. Terminate CS with a pull-up to VDRIVE through 10 kohm if the host controller leaves it floating during power-up; otherwise the ADC can begin spurious conversions and inject noise into the analog input.
Do not leave VDRIVE unconnected - the digital I/O buffers are powered from this pin and require a valid logic-level supply even if the SPI bus is idle. Applying VDRIVE before AVDD can cause latch-up; ensure AVDD reaches its regulated voltage at least 1 ms before VDRIVE ramps, or use the same rail for both supplies if the application permits. Verify that the external reference voltage never exceeds AVDD + 0.3 V as required by the datasheet Absolute Maximum Ratings to prevent permanent damage to the REF IN input.
Compliance Information
RoHS compliance per Analog Devices product page. Z-suffix variants (AD7475BRZ-REEL) explicitly validated for lead-free reflow profiles up to 260C peak. Not AEC-Q100 qualified; this is an industrial-grade converter not intended for automotive under-hood applications.
