Analog Devices Inc. AD7495ARMZ

Overview

AD7495ARMZ 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), SPI-compatible serial interface, and 68 dB SINAD at 300 kHz input - used in portable medical instruments for high-fidelity analog sensor digitization.

For engineers reviewing the AD7495ARMZ datasheet, AD7495ARMZ pinout, AD7495ARMZ application, or AD7495ARMZ equivalent, key selection considerations include on-chip reference accuracy (±1.5% over temperature), VDRIVE logic-level independence, no-pipeline-delay timing control via CS, and MSOP-8 footprint compatibility with space-constrained battery-powered systems.

Technical Context

The AD7495ARMZ implements a capacitive DAC-based successive-approximation architecture with track-and-hold acquisition time ≤325 ns for full-scale steps and aperture jitter of 50 ps typ. Conversion is initiated on the falling edge of CS and completed in exactly 16 SCLK cycles - enabling deterministic timing without pipeline latency.

It features dual power domains: VDD (2.7–5.25 V) supplies the analog core and ADC, while VDRIVE (2.7–5.25 V) independently sets logic I/O voltage levels - allowing direct interfacing to 3 V or 5 V microcontrollers without level shifters. The internal 2.5 V reference provides 50 ppm/°C tempco and 10 Ω output impedance, buffered externally for precision applications.

Key Specifications

Pinout & Package

AD7495ARMZ is housed in an 8-lead MSOP package (3.0 mm × 3.0 mm, 0.65 mm pitch), thermally optimized for compact PCB layouts with θJA = 205.9°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7475ARMZ, the AD7495ARMZ trades slightly higher operational power (6 mW vs. 4.5 mW at 3 V) for integrated reference simplicity and reduced layout risk; versus ADS7822U, it delivers superior distortion performance and logic-level flexibility at identical price point.

Availability

AD7495ARMZ is available at Aetrix Electronics and suitable for battery-powered medical instruments, optical sensor interfaces, industrial data loggers, and wireless sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for AD7495ARMZ 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, headquartered in Norwood, MA.

The AD7495ARMZ belongs to the AD7475/AD7495 family of micropower, single-supply SAR ADCs designed specifically for space- and energy-constrained portable instrumentation and sensor interface applications.

FAQ

What is the reference voltage accuracy and temperature drift of the AD7495ARMZ?

The AD7495ARMZ provides an internal 2.5 V reference with output voltage specified from 2.4625 V to 2.5375 V (±1.5%) over −40°C to +85°C, and a typical temperature coefficient of 50 ppm/°C. This is documented in Table 2 of the Rev. D datasheet under REF OUT Output Voltage and REF OUT Temperature Coefficient. The AD7495ARMZ reference is trimmed at wafer test and does not require user calibration.

Does the AD7495ARMZ support true 1 MSPS continuous sampling with no dead time between conversions?

Yes, the AD7495ARMZ achieves 1 MSPS sustained throughput with no pipeline delay: each conversion completes in exactly 16 SCLK cycles (800 ns at 20 MHz), and the minimum quiet time (t_QUIET) between conversions is only 100 ns. This allows back-to-back conversions at full rate, confirmed in Timing Specifications (Table 3) and Timing Example 1 (Page 8) of the AD7495ARMZ datasheet.

Can the AD7495ARMZ interface directly to a 3.3 V microcontroller while powered from a 5 V supply?

Yes - the AD7495ARMZ uses separate VDD (analog core supply) and VDRIVE (digital I/O supply) pins. When VDD = 5 V and VDRIVE = 3.3 V, the device operates its ADC from 5 V for optimal SNR while presenting 3.3 V–compatible logic levels on CS, SCLK, and SDATA. This is explicitly supported in the Product Highlights and Logic Inputs section of the AD7495ARMZ datasheet.

What is the maximum recommended source impedance for the VIN pin of the AD7495ARMZ?

The AD7495ARMZ VIN pin has 20 pF input capacitance and requires full settling within 325 ns (track-and-hold acquisition time for full-scale step). To meet this, Analog Devices recommends a maximum driving source impedance of 4 kΩ - verified in the Typical Connection Diagram (Figure 15) and Theory of Operation section. Higher impedances necessitate external RC filtering or buffer amplification to prevent gain error and distortion.

How does the AD7495ARMZ handle power-down sequencing and wake-up timing?

The AD7495ARMZ enters full power-down mode when CS remains high for >100 ns after conversion, drawing ≤1 µA. Wake-up occurs on the next CS falling edge, with full functionality restored in 650 µs (max) - specified in Table 3 (t_POWER-UP). This timing is independent of VDD and ensures deterministic low-power operation in battery-gated systems using the AD7495ARMZ.