Analog Devices Inc. AD8191AASTZ

Overview

AD8191AASTZ from Analog Devices is a 4:1 HDMI/DVI switch IC with integrated input equalization and output pre-emphasis, designed for high-speed TMDS signal routing in consumer and professional AV systems. It supports data rates up to 1.65 Gbps, pixel clocks from 25 MHz to 165 MHz, and operates with 3.3 V single-supply power. Its primary circuit role is as a unidirectional, fully buffered high-speed link selector enabling long-cable HDMI reception (up to 20 m at 1080p) in HDTV sets and A/V receivers.

For engineers reviewing the AD8191AASTZ datasheet, AD8191AASTZ pinout, AD8191AASTZ application, or AD8191AASTZ equivalent, key selection considerations include its 100-lead LQFP package, I²C/parallel dual-control interface, on-chip 50 Ω terminations, HDCP-compliant auxiliary switching, and deterministic jitter performance below 40 ps (p-p) at 1.65 Gbps.

Technical Context

The AD8191AASTZ implements a dedicated 4-input × 1-output TMDS switching core with per-channel equalization (6 dB or 12 dB boost at 825 MHz) and programmable output pre-emphasis (up to 6 dB). Its input stage uses on-chip 50 Ω single-ended terminations referenced to VTTI, while outputs feature selectable 50 Ω back-termination to VTTO and tristate disable capability for wire-OR array expansion.

It integrates an auxiliary 4×4 passive switch supporting DDC bus and two additional bidirectional signals, with 100 Ω on-resistance and 8 pF capacitance. Control is implemented via either I²C slave interface (8 configurable addresses) or parallel logic pins, with serial register writes overriding parallel settings until reset.

Key Specifications

Pinout & Package

AD8191AASTZ is housed in a 100-lead, 14 mm × 14 mm LQFP package with exposed thermal pad (not electrically connected). Pin numbering follows standard counter-clockwise orientation with pin 1 indicator at top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar HDMI/DVI switching applications.

Compared with AD8197ASTZ, AD8191AASTZ adds critical equalization for long-cable operation but shares identical pinout and control logic; compared with TPD12S016RGER, it delivers full switching functionality rather than port-level protection-making it the sole viable option for true 4:1 HDMI source aggregation.

Availability

AD8191AASTZ is available at Aetrix Electronics and suitable for HDTV sets, A/V receivers, and professional projectors requiring stable component supply, long-cable HDMI signal integrity, and HDCP-compliant auxiliary routing.

Supply support for AD8191AASTZ 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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision signal chain applications.

The AD8191AASTZ belongs to Analog Devices' high-speed video interface product line, engineered specifically for HDMI/DVI signal routing in consumer and broadcast equipment where signal integrity, cable reach, and HDCP compliance are critical.

FAQ

What is the maximum HDMI cable length supported by AD8191AASTZ at 1080p resolution?

AD8191AASTZ supports up to 20 meters of 24 AWG HDMI cable at 1080p (1.65 Gbps) when configured with maximum 12 dB input equalization. This performance is validated per HDMI 1.2a and DVI 1.0 eye diagram masks and assumes nominal signal swing and proper termination. Shorter cables (e.g., 2–5 m) may operate reliably without equalization enabled.

Does AD8191AASTZ require external termination resistors on its TMDS outputs?

AD8191AASTZ includes programmable on-chip 50 Ω output terminations referenced to VTTO, eliminating the need for external resistors in most designs. External termination is optional and only required if system-level impedance matching demands differ - in which case the internal terminations must be disabled and output current level adjusted to 10 mA via PP_OCL or register control.

Can AD8191AASTZ switch HDCP-encrypted content between sources?

Yes, AD8191AASTZ supports HDCP 1.2a-compliant operation through its auxiliary channel switch, which routes the DDC bus (including HDCP authentication handshake) and two additional bidirectional signals. The IC itself does not perform encryption/decryption but preserves HDCP signaling integrity across source selection, enabling seamless encrypted content switching.

How does the parallel control interface interact with the I²C interface on AD8191AASTZ?

On AD8191AASTZ, I²C register writes always override prior parallel control settings. Once any I²C transaction occurs, the parallel interface is disabled until the device is reset via the RESET pin. Parallel control remains fully functional only when I²C is unused - making it ideal for fixed-configuration or boot-time selection, while I²C enables dynamic runtime reconfiguration.

What power supplies are required for full operation of AD8191AASTZ?

AD8191AASTZ requires five distinct supplies: AVCC = 3.3 V (analog core), DVCC = 3.3 V (digital logic), VTTI = 3.3 V (input termination), VTTO = 3.3 V (output termination), and AMUXVCC = 5 V (auxiliary multiplexer). AVEE and DVEE are grounded (0 V). All supplies must be decoupled per the layout guidelines in the datasheet to ensure low-jitter performance.