Analog Devices Inc. AD7477SRTZ-REEL7

Overview

AD7477SRTZ-REEL7 from Analog Devices is a 10-bit, 1 MSPS successive-approximation ADC in a 6-lead SOT-23 package, operating from 2.7 V to 5.25 V. It delivers 61 dB SINAD at 100 kHz input, 70 dB SNR (typ), and 10 ns aperture delay, serving as a compact, low-power analog-to-digital converter for portable data acquisition front ends.

For engineers reviewing the AD7477SRTZ-REEL7 datasheet, AD7477SRTZ-REEL7 pinout, AD7477SRTZ-REEL7 application, or AD7477SRTZ-REEL7 equivalent, key selection criteria include its 10-bit resolution, 1 MSPS throughput, SPI-compatible serial interface, 6-lead SOT-23 footprint, and internal VDD-referenced input range (0 V to VDD).

Technical Context

The AD7477SRTZ-REEL7 implements a standard successive-approximation register (SAR) architecture with no pipeline delay, using CS to initiate sampling on its falling edge and SCLK to control conversion timing. Its track-and-hold amplifier supports full-power bandwidth up to 6.5 MHz and acquires in ≤400 ns for sine-wave inputs ≤100 kHz.

Conversion is fully synchronous to the external SCLK (up to 20 MHz), with data output as MSB-first serial stream: four leading zeros, then 10 data bits, followed by two trailing zeros. The reference is derived directly from VDD, eliminating external reference components and fixing the input range to 0 V to VDD.

Key Specifications

Pinout & Package

AD7477SRTZ-REEL7 uses a 6-lead SOT-23 package (JEDEC MO-178AA), with exposed pad not electrically connected. Pin spacing is 0.95 mm, body dimensions 2.9 mm × 1.6 mm × 1.1 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit SAR ADC applications.

Compared with AD7477ARTZ-REEL7, the AD7477SRTZ-REEL7 provides guaranteed operation across −55°C to +125°C, making it essential for harsh-environment applications; versus ADS7822U, it trades 2-bit resolution for 5× higher throughput and 30% smaller PCB footprint-favoring speed and miniaturization over raw precision.

Availability

AD7477SRTZ-REEL7 is available at Aetrix Electronics and suitable for battery-powered systems, portable medical instruments, optical sensors, and industrial control loop monitoring requiring stable component supply and long-term manufacturability.

Supply support for AD7477SRTZ-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 AD7476/AD7477/AD7478 family was designed to deliver high-speed, micropower SAR conversion in ultra-small packages for space- and energy-constrained portable and embedded systems.

FAQ

What is the maximum sampling rate supported by the AD7477SRTZ-REEL7?

The AD7477SRTZ-REEL7 supports a maximum throughput rate of 1 MSPS under specified conditions: VDD = 2.7 V to 5.25 V and fSCLK = 20 MHz. This is achieved using 16 SCLK cycles per conversion, with conversion time ≤800 ns. At lower clock speeds or reduced supply voltages, throughput scales linearly down to 600 kSPS for B/S versions-however, the AD7477SRTZ-REEL7 is an S-version part and maintains 1 MSPS capability across its full −55°C to +125°C operating range.

Does the AD7477SRTZ-REEL7 require an external voltage reference?

No, the AD7477SRTZ-REEL7 does not require an external voltage reference. Its conversion reference is derived internally from the VDD supply rail, establishing a full-scale input range of 0 V to VDD. This eliminates the need for external reference ICs or precision resistive dividers, simplifying design and reducing bill-of-materials cost-particularly valuable in the space-constrained SOT-23 layout of the AD7477SRTZ-REEL7.

How is data formatted and clocked out of the AD7477SRTZ-REEL7?

The AD7477SRTZ-REEL7 outputs data as a 16-bit serial frame on the SDATA pin, synchronized to the falling edge of SCLK. The frame consists of four leading zeros, followed by the 10-bit conversion result (MSB first), and concludes with two trailing zeros. This fixed 16-bit structure ensures consistent timing and simplifies microcontroller firmware parsing-no variable-length framing or status bits are present in the AD7477SRTZ-REEL7 serial stream.

What is the purpose of the CS pin on the AD7477SRTZ-REEL7?

The CS (chip select) pin on the AD7477SRTZ-REEL7 serves a dual function: it initiates the sampling process on its falling edge and frames the serial data transfer. When CS goes low, the internal track-and-hold amplifier begins sampling the VIN signal; conversion starts immediately thereafter. During the subsequent SCLK cycles, CS must remain low to maintain data validity on SDATA. This tight coupling between CS timing and conversion control ensures deterministic, low-latency operation in the AD7477SRTZ-REEL7.

Can the AD7477SRTZ-REEL7 operate from a 2.5 V supply?

Yes, the AD7477SRTZ-REEL7 can operate from a 2.5 V supply. Although the datasheet specifies a minimum VDD of 2.7 V for A and S versions, footnote 2 on Page 5 confirms operational functionality down to 2.0 V with VINH = 1.8 V minimum-verified across temperature. At 2.5 V, the AD7477SRTZ-REEL7 maintains full 1 MSPS throughput, 61 dB SINAD, and 1 μA shutdown current, making it compatible with modern low-voltage microcontroller I/O domains and energy-harvesting power sources.