Analog Devices Inc. AD7278BUJZ-REEL7

Overview

AD7278BUJZ-REEL7 from Analog Devices is an 8-bit, 4 MSPS successive approximation analog-to-digital converter (ADC) in a 6-lead TSOT package, operating from 2.35 V to 3.6 V supply, delivering 49 dB SINAD at 1 MHz input and 74 MHz full-power bandwidth. It features no pipeline delay, SPI-compatible serial interface, and 0.1 μA power-down current for battery-powered data acquisition and sensor interfacing.

For engineers reviewing the AD7278BUJZ-REEL7 datasheet, AD7278BUJZ-REEL7 pinout, AD7278BUJZ-REEL7 application, or AD7278BUJZ-REEL7 equivalent, key selection criteria include throughput rate (4 MSPS), resolution (8 bits), supply voltage range (2.35–3.6 V), SNR/SINAD performance at target input frequency, and compatibility with microcontroller SPI interfaces requiring minimal external components.

Technical Context

The AD7278BUJZ-REEL7 implements a standard SAR architecture with track-and-hold amplifier enabling accurate sampling up to 74 MHz input bandwidth. Conversion is initiated by falling edge of CS, with result serialized as two leading zeros + 8-bit MSB-first data + six trailing zeros over SDATA on SCLK falling edges.

It uses internal VDD-referenced conversion, eliminating need for external reference and supporting full-scale analog input range of 0 V to VDD. Timing is fully synchronous to SCLK, with fixed 10-cycle conversion time (208 ns max at 48 MHz SCLK) and no latency between sample initiation and data availability.

Key Specifications

Pinout & Package

AD7278BUJZ-REEL7 is housed in a 6-lead TSOT (Thin Small Outline Transistor) package, measuring 1.5 mm × 1.5 mm × 0.55 mm, optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7277BUJZ-REEL7, AD7278BUJZ-REEL7 trades resolution for higher throughput and lower power; versus ADS7822U, it delivers 20× faster sampling in half the area but requires tighter layout control due to TSOT pitch and high-speed timing.

Availability

AD7278BUJZ-REEL7 is available at Aetrix Electronics and suitable for motor control feedback, portable medical sensors, industrial PLC I/O modules, and automotive battery monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7278BUJZ-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD727x family-including AD7278BUJZ-REEL7-is designed for space- and power-constrained embedded systems needing high-speed, low-latency digitization without external references or complex support circuitry.

FAQ

What is the maximum sampling rate supported by AD7278BUJZ-REEL7?

The AD7278BUJZ-REEL7 achieves a maximum throughput rate of 4 MSPS when operated with a 48 MHz SCLK and configured for its native 10-cycle serial frame. This is confirmed in Table 4 of the Rev. E datasheet under "Throughput Rate" and validated by timing specification tCONVERT = 10 × tSCLK. At lower SCLK frequencies, the rate scales linearly-for example, 24 MHz yields ~2 MSPS. The AD7278BUJZ-REEL7 does not require oversampling or decimation to reach this rate.

Does AD7278BUJZ-REEL7 require an external voltage reference?

No, AD7278BUJZ-REEL7 uses an internal reference derived from the VDD supply, enabling a full-scale analog input range of 0 V to VDD. This eliminates the need for external reference ICs, reduces BOM count, and simplifies layout-especially beneficial in compact, low-cost designs. The AD7278BUJZ-REEL7 datasheet explicitly states "Reference derived from the power supply" in Product Highlights and confirms "analog input range for the part is 0 to VDD" in the General Description section.

What are the absolute maximum ratings for AD7278BUJZ-REEL7 supply voltage?

The absolute maximum VDD rating for AD7278BUJZ-REEL7 is −0.3 V to +6 V, per Table 6 in the Rev. E datasheet. However, functional operation is strictly specified for 2.35 V to 3.6 V. Operating outside this range may cause parametric degradation or latch-up. The 6 V absolute max accommodates transient overshoots during hot-plug or power sequencing, but sustained operation above 3.6 V voids specifications and risks reliability-AD7278BUJZ-REEL7 must be powered within its rated 2.35–3.6 V window for guaranteed performance.

How does the serial interface framing work for AD7278BUJZ-REEL7?

The AD7278BUJZ-REEL7 outputs data in a fixed 16-bit frame: two leading zeros + eight data bits (MSB first) + six trailing zeros. This is documented in Table 7 ("Pin Function Descriptions") and Figure 5 timing diagram. The SDATA line is three-stated when CS is high; data becomes valid on the falling edge of each SCLK cycle starting after CS assertion. The AD7278BUJZ-REEL7 requires exactly 10 SCLK cycles to complete conversion and deliver all 8 bits-no additional clock cycles are needed for framing overhead beyond the defined pattern.

Is AD7278BUJZ-REEL7 pin-compatible with AD7276 or AD7277 in the same package?

Yes, AD7278BUJZ-REEL7 is pin-compatible with AD7276BUJZ-REEL7 and AD7277BUJZ-REEL7 in the 6-lead TSOT package, as confirmed by identical pin configurations in Figure 8 and Table 7 of the Rev. E datasheet. All three share identical VDD, GND, VIN, SCLK, SDATA, and CS pin assignments and electrical characteristics. This allows direct substitution in existing layouts when resolution or speed requirements change-no PCB revision is needed, though firmware must adjust for differing bit depth and timing frame length (10 vs. 12 vs. 14 cycles).