Analog Devices Inc. AD7278ARMZ

Overview

AD7278ARMZ from Analog Devices is an 8-bit, 4 MSPS successive approximation analog-to-digital converter (ADC) in a 6-lead TSOT package, operating from a single 2.35 V to 3.6 V supply, delivering 74 MHz full-power bandwidth and −66 dB THD at 1 MHz input, suited for high-speed sensor signal digitization in portable instrumentation.

For engineers reviewing the AD7278ARMZ datasheet, AD7278ARMZ pinout, AD7278ARMZ application, or AD7278ARMZ equivalent, key selection criteria include its 10-cycle serial interface timing, 0.1 μA full power-down current, 8-bit resolution with guaranteed no missing codes, and SPI/QSPI/MICROWIRE compatibility for microcontroller interfacing.

Technical Context

The AD7278ARMZ implements a track-and-hold amplifier with 60 ns acquisition time and no pipeline delay, enabling precise sampling control via the active-low CS input. Conversion is clocked by SCLK, with output data serialized MSB-first as two leading zeros followed by 8 bits and six trailing zeros.

It uses an internal VDD-referenced architecture, eliminating external reference components and fixing the analog input range to 0 V to VDD. Its dynamic performance-49 dB SINAD min, 74 MHz full-power bandwidth @ 3 dB-is specified across −40°C to +125°C with B-grade temperature rating.

Key Specifications

Pinout & Package

AD7278ARMZ is housed in a 6-lead TSOT (Thin Small Outline Transistor) package, 2.1 mm × 1.6 mm × 0.55 mm, with exposed pad for thermal enhancement and surface-mount compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit high-speed ADC applications.

Compared with AD7278BRMZ and ADS7822U, AD7278ARMZ uniquely combines 4 MSPS throughput, 6-lead TSOT miniaturization, and 2.35 V minimum supply-enabling high-density, battery-efficient signal acquisition where size and voltage headroom are critical.

Availability

AD7278ARMZ is available at Aetrix Electronics and suitable for portable medical sensors, industrial motor control feedback, automotive cabin environment monitoring, and ultrasonic distance sensing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7278ARMZ 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 AD7276/AD7277/AD7278 family was designed for space- and power-constrained applications needing high-speed, low-voltage ADCs with minimal external components-targeting portable instrumentation, motor drives, and automotive subsystems.

FAQ

What is the maximum sampling rate supported by the AD7278ARMZ?

The AD7278ARMZ supports a maximum throughput rate of 4 MSPS when operated with a 48 MHz SCLK. This is achieved using a 10-cycle serial interface (two leading zeros + 8 data bits + six trailing zeros), and the conversion time is fixed at 208 ns maximum. The actual achievable rate depends on system-level timing margins including CS pulse width, SCLK setup/hold, and bus release timing.

Does the AD7278ARMZ require an external voltage reference?

No, the AD7278ARMZ does not require an external voltage reference. It uses an internal VDD-referenced architecture, meaning the analog input range is directly tied to the supply voltage (0 V to VDD). This eliminates the need for external reference components, simplifies layout, and maximizes dynamic range without additional bill-of-materials cost.

What is the power consumption of the AD7278ARMZ in normal operational mode?

In normal operational mode at 3 V supply and 3 MSPS throughput, the AD7278ARMZ draws 3.5 mA typical, equating to 10.5 mW typical power dissipation. At full 4 MSPS operation with 48 MHz SCLK, power rises to 19.8 mW maximum (at 3.6 V). In full power-down mode, it consumes only 0.1 μA typical-critical for ultra-low-power wake-on-event architectures.

How is the serial data formatted on the SDATA pin of the AD7278ARMZ?

The AD7278ARMZ outputs data on SDATA in a fixed 10-cycle frame: two leading zeros, followed by the 8-bit conversion result (MSB first), followed by six trailing zeros. This format ensures consistent timing and simplifies firmware parsing. Data is clocked out on the falling edge of SCLK, and SDATA enters high-impedance state after the final zero unless CS remains low for continuous reads.

Is the AD7278ARMZ pin-compatible with other members of the AD727x family?

Yes, the AD7278ARMZ shares identical pinout and package dimensions with AD7276ARMZ and AD7277ARMZ in the 6-lead TSOT variant. All three devices use the same VDD, GND, VIN, SCLK, SDATA, and CS connections and support identical serial interface timing. This allows hardware reuse across 8-, 10-, and 12-bit variants when resolution requirements evolve during design.