Analog Devices Inc. AD7478AWARMZ

Overview

AD7478AWARMZ from Analog Devices is an 8-bit, 1.2 MSPS successive-approximation analog-to-digital converter (ADC) operating from a single 2.35 V to 5.25 V supply in a 6-lead SC70 package. It features 7 ns minimum SCLK-to-data-valid hold time at VDD > 3.6 V, 225 ns track-and-hold acquisition time, and 49 dB SINAD at 100 kHz input - optimized for battery-powered data acquisition and optical sensor interfaces.

For engineers reviewing the AD7478AWARMZ datasheet, AD7478AWARMZ pinout, AD7478AWARMZ application, or AD7478AWARMZ equivalent, this page delivers verified electrical specs, SC70 pin mapping, real-world use cases in portable instrumentation and mobile communications, and validated alternative parts with documented functional and resolution differences.

Technical Context

The AD7478AWARMZ implements a standard SAR architecture with no pipeline delay, using CS falling edge to simultaneously sample VIN and initiate conversion. Its internal reference is derived from VDD, enabling 0 V to VDD analog input range and eliminating external reference components.

Serial interface timing is fully synchronous: SDATA outputs MSB-first with four leading zeros followed by eight data bits and four trailing zeros, clocked on SCLK falling edges; conversion completes in exactly 12 SCLK cycles at up to 20 MHz.

Key Specifications

Pinout & Package

AD7478AWARMZ is housed in a 6-lead SC70 package (2.0 mm × 1.25 mm × 0.9 mm), optimized for space-constrained PCB layouts in portable electronics. Pinout is validated per Analog Devices Rev. G datasheet Figure 5.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7478ARTZ-REEL7, AD7478AWARMZ adds guaranteed operation to +125°C and automotive qualification; compared with ADS7822U, it delivers 6× higher throughput in a 60% smaller package with identical resolution - making it optimal for space- and thermal-constrained embedded systems.

Availability

AD7478AWARMZ is available at Aetrix Electronics and suitable for battery-powered data loggers, optical sensor interfaces, mobile communication monitoring, and industrial motor control requiring stable component supply across automotive and industrial temperature ranges.

Supply support for AD7478AWARMZ 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, with design and manufacturing expertise spanning precision data conversion, power management, and RF technologies.

The AD7476A/AD7477A/AD7478A family was designed to deliver high-speed, low-power SAR ADC functionality in the smallest possible footprint - specifically targeting portable, battery-operated, and space-constrained embedded systems.

FAQ

What is the maximum sampling rate supported by the AD7478AWARMZ?

The AD7478AWARMZ supports a maximum throughput rate of 1.2 MSPS, achieved when the serial clock (SCLK) operates at 20 MHz and the conversion completes in 12 SCLK cycles. At lower SCLK frequencies, the effective sampling rate scales linearly - for example, at 10 MHz SCLK, the maximum rate is 833 kSPS. This fixed 12-cycle timing ensures deterministic latency critical for real-time control loops.

Does the AD7478AWARMZ require an external voltage reference?

No, the AD7478AWARMZ uses an internal reference derived from the VDD supply, establishing a 0 V to VDD analog input range. This eliminates the need for external reference ICs or buffers, simplifying design and reducing BOM cost and PCB area. However, input signal fidelity depends directly on VDD stability - a low-noise, well-decoupled supply is essential to maintain 49 dB SINAD performance.

What is the meaning of "WARMZ" in the AD7478AWARMZ part number?

The "WARMZ" suffix denotes the specific packaging and qualification variant: W = automotive-grade temperature range (−40°C to +125°C), A = SC70-6 package, R = tape-and-reel packaging, M = lead-free (Pb-free) finish, Z = RoHS-compliant. This distinguishes AD7478AWARMZ from commercial-grade variants like AD7478ARTZ-REEL7 (B grade, −40°C to +85°C) and confirms its suitability for automotive and harsh-environment applications.

How does the AD7478AWARMZ handle serial data framing?

The AD7478AWARMZ outputs a 12-bit serial frame on SDATA: four leading zeros, followed by the 8-bit conversion result (MSB first), followed by four trailing zeros. This consistent 12-bit structure simplifies firmware parsing across the AD7476A/AD7477A/AD7478A family. Data is clocked out on the falling edge of SCLK, with t7 hold time as low as 7 ns (VDD > 3.6 V), enabling robust timing margins even at 20 MHz.

Can the AD7478AWARMZ operate from a 2.0 V supply?

No - the absolute minimum specified VDD is 2.35 V per the datasheet. While the device may power up at 2.0 V under certain conditions, key parameters including INL (±0.3 LSB max), SINAD (49 dB min), and logic thresholds are not guaranteed below 2.35 V. Operation at 2.0 V risks increased DNL, reduced SNR, and unreliable digital interface behavior, especially with 3.3 V or 5 V microcontrollers driving CS and SCLK.