Analog Devices Inc. ADG731BSUZ

Overview

ADG731BSUZ from Analog Devices is a 32-channel, single-pole single-throw (SPST) analog multiplexer with 3-wire SPI-compatible serial interface, 4 Ω typical on-resistance at 5 V, 42 ns switching time, and rail-to-rail operation from 1.8 V to 5.5 V single supply or ±2.5 V dual supply. It serves as a high-density signal routing device in data acquisition front-ends where low distortion and fast channel selection are required.

For engineers reviewing the ADG731BSUZ datasheet, ADG731BSUZ pinout, ADG731BSUZ application, or ADG731BSUZ equivalent, key selection criteria include guaranteed break-before-make switching, <1 pC charge injection at 3 V, −72 dB off isolation at 1 MHz, 18 MHz −3 dB bandwidth, and compatibility with SPI/QSPI/MICROWIRE controllers in space-constrained industrial and optical systems.

Technical Context

The ADG731BSUZ implements a monolithic CMOS 32:1 analog multiplexer controlled by an 8-bit shift register updated via falling-edge-triggered SCLK synchronized to an active-low SYNC frame signal. Its internal architecture enforces strict break-before-make timing (≥1 ns minimum t_D) and uses enhanced submicron process technology to achieve flat on-resistance (<0.5 Ω flatness) across the full 0 V to V_DD analog range.

All 32 source terminals (S1–S32) connect to a common drain (D) under digital control; no differential or dual-bank functionality is implemented-unlike the ADG725. The device features power-on reset that initializes all switches to OFF and supports up to 30 MHz SCLK frequency with precise timing margins (t₆ ≥ 40 ns SYNC low time, t₇ ≥ 4.5 ns data setup).

Key Specifications

Pinout & Package

The ADG731BSUZ is available in a 48-lead LFCSP (7 mm × 7 mm, 0.75 mm height) and 48-lead TQFP package. Pin functions are identical across both packages per Analog Devices Rev. B datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog multiplexer applications.

Compared with ADG725BRUZ and MAX4618ESE+, the ADG731BSUZ delivers highest channel density (32:1) with deterministic timing, lowest on-resistance flatness, and smallest footprint - making it optimal for space- and performance-critical serial-controlled multiplexing where single-output routing suffices.

Availability

ADG731BSUZ is available at Aetrix Electronics and suitable for optical network control loops, portable data acquisition systems, and automatic test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for ADG731BSUZ 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 ADG731BSUZ belongs to the ADG7xx family of low-voltage, low-on-resistance CMOS analog switches designed specifically for precision signal routing in battery-powered, space-constrained, and high-channel-count instrumentation systems.

FAQ

What is the maximum clock frequency supported by the ADG731BSUZ serial interface?

The ADG731BSUZ supports a maximum SCLK frequency of 30 MHz, as specified in the Timing Characteristics table. This allows reliable 8-bit address loading within 267 ns (t₁ = 33 ns min cycle time), enabling rapid channel updates in time-critical applications such as optical beam steering control loops where the ADG731BSUZ is commonly deployed.

Does the ADG731BSUZ require external pull-up resistors on its digital control lines?

No, the ADG731BSUZ does not require external pull-ups on SYNC, SCLK, or DIN. Its digital inputs have CMOS-compatible thresholds (VINH ≥ 2.4 V at 5 V supply) and leakage current ≤ ±0.5 μA, allowing direct connection to microcontroller GPIOs configured as push-pull outputs. Internal ESD protection diodes clamp overvoltage, but external termination is unnecessary for standard SPI interfacing.

Can the ADG731BSUZ operate with a 2.5 V single supply?

Yes, the ADG731BSUZ is fully specified for 1.8 V to 5.5 V single-supply operation, including 2.5 V. At VDD = 2.5 V, typical on-resistance increases to ~7 Ω (vs. 4 Ω at 5 V), and switching time extends to 60 ns, but all logic thresholds, leakage limits, and break-before-make timing remain guaranteed across the full industrial temperature range (−40°C to +85°C).

How is channel selection encoded in the ADG731BSUZ shift register?

The ADG731BSUZ uses an 8-bit shift register where bits [7:3] (A4–A0) encode the selected channel (0–31), bit [2] (EN) enables switching (0 = enable, 1 = all OFF), and bit [1] (CSA) is ignored (don't care). After eight SCLK falling edges following SYNC low assertion, the register contents update the switch state - for example, DIN = 0b00000000 selects S1, while 0b11111000 selects S32.

Is the ADG731BSUZ pin-compatible with the ADG731BRUZ?

Yes, the ADG731BSUZ (LFCSP) and ADG731BRUZ (TQFP) share identical pin numbering, terminal functions, and electrical specifications per Analog Devices documentation. Both are rated for −40°C to +85°C operation and support the same 48-pin footprint - enabling direct package substitution without PCB revision, provided thermal and mechanical constraints of the LFCSP variant are accommodated.