Analog Devices Inc. AD7495BR-REEL7

Overview

AD7495BR-REEL7 from Analog Devices is a 12-bit, 1 MSPS successive-approximation ADC with integrated 2.5 V reference, single-supply operation (2.7 V to 5.25 V), 68 dB SINAD at 300 kHz input, and SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface. It serves as the primary analog-to-digital conversion stage in portable instrumentation where precision, low power, and compact size are critical.

For engineers reviewing the AD7495BR-REEL7 datasheet, AD7495BR-REEL7 pinout, AD7495BR-REEL7 application, or AD7495BR-REEL7 equivalent, key selection considerations include on-chip 2.5 V reference accuracy (±1.5% over temperature), REF OUT impedance (10 Ω typ), full-power bandwidth (8.3 MHz @ 3 dB), no pipeline delay, and VDRIVE logic-level independence from VDD.

Technical Context

The AD7495BR-REEL7 implements a capacitive DAC-based successive-approximation architecture with track-and-hold acquisition time ≤325 ns for full-scale steps. Conversion is initiated by CS falling edge and fully completed in 800 ns (16 SCLK cycles at 20 MHz), with no pipeline latency between sampling and data availability.

Its dual-supply logic interface uses VDRIVE (2.7 V to 5.25 V) to decouple serial I/O voltage from analog VDD, enabling direct interfacing to 3 V or 5 V microcontrollers without level shifters. The on-chip 2.5 V reference provides buffered output (REF OUT) with 50 ppm/°C tempco and supports external buffering for system-level distribution.

Key Specifications

Pinout & Package

AD7495BR-REEL7 is housed in an 8-lead MSOP package (3.0 mm × 3.0 mm, 0.65 mm pitch), optimized for space-constrained PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD7475BRMZ-REEL and ADS7822U, AD7495BR-REEL7 uniquely combines 12-bit accuracy, on-chip 2.5 V reference, and VDRIVE flexibility-making it optimal for space- and power-constrained portable instrumentation where reference integration reduces calibration burden and improves long-term stability.

Availability

AD7495BR-REEL7 is available at Aetrix Electronics and suitable for portable medical instrumentation, optical sensor interfaces, mobile communications test equipment, and industrial data acquisition modules requiring stable component supply across extended temperature ranges (−40°C to +85°C).

Supply support for AD7495BR-REEL7 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7495BR-REEL7 belongs to Analog Devices' precision SAR ADC product line, designed specifically for battery-powered and space-constrained applications demanding high speed, low power, and integrated reference functionality without sacrificing DC accuracy or AC performance.

FAQ

What is the reference voltage accuracy and temperature stability of the AD7495BR-REEL7?

The AD7495BR-REEL7 features an on-chip 2.5 V reference with output voltage specified from 2.4625 V to 2.5375 V (±1.5% initial tolerance). Its temperature coefficient is 50 ppm/°C typical, ensuring reference drift remains within ±0.42% over the full −40°C to +85°C operating range. This performance eliminates the need for external trimming in many portable instrumentation applications, and the REF OUT pin must be decoupled with ≥100 nF to GND for stability. The AD7495BR-REEL7 reference is calibrated during production and does not require user adjustment.

Does the AD7495BR-REEL7 support true SPI mode, and what are its timing requirements?

Yes, the AD7495BR-REEL7 supports SPI Mode 0 (CPOL = 0, CPHA = 0) and Mode 3 (CPOL = 1, CPHA = 0), with data valid on the falling edge of SCLK. Minimum SCLK frequency is 10 kHz; maximum is 20 MHz. Conversion time is fixed at 16 SCLK cycles (800 ns at 20 MHz), and a minimum quiet time (t_QUIET) of 100 ns is required between conversions. The CS signal must remain low for the entire conversion and data readout period. The AD7495BR-REEL7 is also compatible with QSPI, MICROWIRE, and DSP serial interfaces without configuration changes.

How does the VDRIVE pin function, and why is it important for system design?

The VDRIVE pin on the AD7495BR-REEL7 sets the logic threshold voltage for all digital inputs (CS, SCLK) and defines the high/low levels for SDATA output, independent of the analog VDD supply. This allows the AD7495BR-REEL7 to interface directly with 3 V microcontrollers while powered from a 5 V analog rail-or vice versa-without external level shifters. For example, tying VDRIVE to 3.3 V enables clean communication with an ARM Cortex-M0+ MCU, even when VDD is 5 V for improved SNR. This separation simplifies mixed-voltage system architecture and improves noise immunity in noisy industrial environments.

What power-down modes does the AD7495BR-REEL7 support, and how are they controlled?

The AD7495BR-REEL7 offers three power-down states controlled entirely via the standard serial interface: Normal Mode (2 mA max at 3 V), Partial Power-Down (230 µA max, retains reference and bias), and Full Power-Down (1 µA max, reference disabled). Entry into Partial or Full Power-Down is achieved by sending specific command sequences during idle SCLK cycles-no additional control pins are required. Wake-up from Full Power-Down takes 650 µs, while Partial Power-Down resumes conversion in <100 ns. These modes enable aggressive power gating in battery-operated AD7495BR-REEL7 applications like wearable sensors.

Can the AD7495BR-REEL7's REF OUT pin drive external circuitry directly?

No, the AD7495BR-REEL7 REF OUT pin is not intended to drive external loads directly. It has a typical output impedance of 10 Ω and is specified to source/sink only ±100 µA. Driving external circuitry-such as ADC reference inputs, op-amp bias networks, or multiple channels-requires buffering with a low-noise, unity-gain stable op-amp (e.g., AD8605). The datasheet mandates a minimum 100 nF ceramic capacitor from REF OUT to GND for stability. Unbuffered use risks reference droop, increased noise, and degraded INL/DNL performance. For multi-ADC systems, buffer the AD7495BR-REEL7 REF OUT once and distribute the buffered reference.