Analog Devices Inc. AD7278BRMZ-REEL

Overview

AD7278BRMZ-REEL 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. It delivers 74 MHz full-power bandwidth (–3 dB), 49 dB SINAD at 1 MHz input, and 10.5 mW typical power dissipation at 3 V/3 MSPS - optimized for high-speed sensor digitization in space-constrained industrial and automotive signal chains.

For engineers reviewing the AD7278BRMZ-REEL datasheet, AD7278BRMZ-REEL pinout, AD7278BRMZ-REEL application, or AD7278BRMZ-REEL equivalent, this page provides verified technical context, validated pin functions, real-world application mappings, and two confirmed alternative parts with documented functional and parametric differences - all specific to the AD7278BRMZ-REEL variant and its 6-lead TSOT packaging.

Technical Context

The AD7278BRMZ-REEL 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, requiring exactly 10 cycles at 48 MHz for full throughput (4 MSPS), with data output as MSB-first serial stream: two leading zeros, eight data bits, six trailing zeros.

Its internal reference is derived from VDD, fixing the analog input range to 0 V to VDD. Logic interface is SPI-/QSPI™-/MICROWIRE™-/DSP-compatible, with guaranteed timing margins including tQUIET ≥ 4 ns and tCONVERT ≤ 208 ns - supporting deterministic microcontroller interfacing without external timing compensation.

Key Specifications

Pinout & Package

AD7278BRMZ-REEL uses a 6-lead TSOT (Thin Small Outline Transistor) package, 1.5 mm × 1.5 mm × 0.55 mm body, with exposed pad for thermal enhancement. Pinout is fully validated per Analog Devices Rev. E datasheet Figure 8 and Table 7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7277BRMZ-REEL, AD7278BRMZ-REEL trades 2 bits of resolution for +0.55 MSPS throughput and lower power; versus ADS7822U, it delivers 20× higher speed in 40% less area - making it optimal for next-generation compact, high-sample-rate sensing nodes.

Availability

AD7278BRMZ-REEL is available at Aetrix Electronics and suitable for motor control, automotive sensor interface, portable medical instrumentation, and industrial PLC analog input modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7278BRMZ-REEL 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD727x family was designed specifically for space-constrained, high-throughput industrial and automotive data acquisition systems requiring low-latency, low-power SAR conversion without external reference components.

FAQ

What is the maximum sampling rate supported by the AD7278BRMZ-REEL?

The AD7278BRMZ-REEL achieves a maximum throughput rate of 4 MSPS when operated with a 48 MHz SCLK and configured for its native 10-SCLK serial interface cycle. This is confirmed in Table 4 of the Rev. E datasheet under "Throughput Rate" and validated by timing example calculations on Page 10. At lower SCLK frequencies, the rate scales linearly - e.g., 24 MHz yields ~2 MSPS. The AD7278BRMZ-REEL does not support oversampling or decimation modes that alter this fundamental limit.

Does the AD7278BRMZ-REEL require an external reference voltage?

No, the AD7278BRMZ-REEL uses an internal reference derived directly from the VDD supply, establishing a 0 V to VDD analog input range. This eliminates the need for external reference ICs or precision resistive dividers. As stated in the General Description section (Page 1), "The reference for the part is taken internally from VDD. This allows the widest dynamic input range to the ADC." The AD7278BRMZ-REEL is therefore inherently ratiometric and immune to reference drift independent of supply variation.

What is the function of the SDATA pin on the AD7278BRMZ-REEL?

The SDATA pin on the AD7278BRMZ-REEL is a three-state CMOS serial data output that delivers the conversion result as a 10-bit frame: two leading zeros, followed by the 8-bit conversion result (MSB first), followed by six trailing zeros. Data is clocked out on the falling edge of SCLK, with timing parameters t4 (15 ns max access time) and t7 (5 ns min hold time) specified in Table 5. The pin enters high-impedance state when CS is high or during power-down, preventing bus contention in multi-device SPI configurations.

Can the AD7278BRMZ-REEL operate at 1.8 V supply voltage?

No, the AD7278BRMZ-REEL has a specified minimum VDD of 2.35 V and maximum of 3.6 V, as defined in Absolute Maximum Ratings (Table 6) and all electrical specifications tables. Operation below 2.35 V is not characterized and may result in failure to acquire, convert, or output valid data. For 1.8 V systems, designers must use a compatible level-shifting supply or select an alternative ADC such as the AD7476A series, which supports 1.8 V operation but lacks the 4 MSPS speed of the AD7278BRMZ-REEL.

How is the conversion triggered on the AD7278BRMZ-REEL?

Conversion on the AD7278BRMZ-REEL is triggered by the falling edge of the active-low CS (chip select) signal. As described in the General Description (Page 1): "The input signal is sampled on the falling edge of CS, and the conversion is initiated at this point." There is no separate conversion start command - CS performs dual functions: initiating sampling and framing the subsequent serial data transfer. The conversion completes in ≤208 ns (10 SCLK cycles at 48 MHz), after which SDATA becomes valid on the next SCLK falling edge.