Analog Devices Inc. AD8191ASTZ

Overview

AD8191ASTZ from Analog Devices is a 4:1 HDMI/DVI switch IC with integrated TMDS input equalization and output pre-emphasis, designed for high-fidelity video routing in long-cable applications. It supports 1.65 Gbps data rates, 165 MHz pixel clocks, 20-meter 24 AWG cable operation at 1080p, and operates from a single 3.3 V supply. Its role is to select one of four HDMI/DVI sources while preserving signal integrity across TMDS and auxiliary channels.

For engineers reviewing the AD8191ASTZ datasheet, AD8191ASTZ pinout, AD8191ASTZ application, or AD8191ASTZ equivalent, key selection considerations include its 100-lead LQFP package, I²C/parallel control interface, 12 dB receiver equalization, 6 dB transmitter pre-emphasis, and support for quad/dual/single channel bundling modes in HDMI 1.2a-compliant systems.

Technical Context

The AD8191ASTZ implements a fully buffered, unidirectional high-speed switching core with four independent TMDS link inputs (A–D), each comprising four differential pairs (clock + three data), plus bidirectional low-speed auxiliary channels for DDC and control signals. Input termination is globally or per-channel programmable via on-chip 50 Ω resistors tied to VTTI.

Its equalization architecture provides two fixed boost levels (6 dB or 12 dB) at 825 MHz, while pre-emphasis offers four selectable output drive strengths. Switching logic supports three configurable bundling modes-4:1 (default), dual 8:1, or 16:1-controlled independently for TMDS and auxiliary paths via serial (I²C slave) or parallel interfaces.

Key Specifications

Pinout & Package

AD8191ASTZ is housed in a 100-lead, 14 mm × 14 mm Pb-free LQFP package with exposed thermal pad (not electrically connected). Pin 1 is marked by a dot; pins are numbered counterclockwise. Power supplies (AVCC, DVCC, VTTI, VTTO, AVEE, DVEE, AMUXVCC) are distributed across multiple pins for low-impedance decoupling. High-speed TMDS inputs (IN_x/TP_x) and outputs (OP_x/ON_x) are arranged in complementary pairs per channel; auxiliary signals (AUX_A–D[0:3], AUX_COM[0:3]) occupy dedicated low-speed I/O banks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPD12S016 and PI3HDX1204A, the AD8191ASTZ uniquely combines input equalization, output pre-emphasis, and flexible bundling in a single 3.3 V device-enabling reliable 20-meter 1080p routing without external redrivers or level shifters.

Availability

AD8191ASTZ is available at Aetrix Electronics and suitable for HDMI switching, A/V receiver design, and projector signal routing requiring stable component supply, long-cable signal integrity, and industrial temperature operation.

Supply support for AD8191ASTZ 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.

The AD8191ASTZ belongs to Analog Devices' high-speed video interface product line, engineered specifically for HDMI/DVI signal integrity preservation in consumer and professional A/V equipment with demanding cable-length and jitter requirements.

FAQ

What is the maximum HDMI cable length supported by the AD8191ASTZ at 1080p resolution?

The AD8191ASTZ supports up to 20 meters of 24 AWG HDMI cable at 1080p resolution when configured with 12 dB input equalization. This performance is verified per HDMI 1.2a receiver eye mask requirements and assumes nominal 1.65 Gbps data rate and proper termination. Actual reach may vary with cable quality and environmental noise.

Does the AD8191ASTZ require external termination resistors on its TMDS outputs?

The AD8191ASTZ includes programmable 50 Ω on-chip output termination resistors tied to VTTO, eliminating the need for external resistors when enabled. If external termination is used instead (e.g., at the HDMI receiver), internal termination must be disabled via PP_OTO or TX_PTO register, and output current level must be set to 10 mA using PP_OCL or TX_OCL register.

Can the AD8191ASTZ switch auxiliary signals like DDC and CEC independently from the TMDS video path?

Yes-the AD8191ASTZ supports independent switching modes for TMDS and auxiliary channels via its serial (I²C) interface. In dual or single bundling modes, auxiliary signals can be routed separately from high-speed data, enabling flexible DDC arbitration and CEC command forwarding without disrupting video flow.

What is the function of the PP_EQ pin on the AD8191ASTZ?

The PP_EQ pin on the AD8191ASTZ is a parallel control input that globally enables or disables the 12 dB input equalization setting for all eight high-speed input channels. When high, it activates maximum equalization; when low, it selects the 6 dB setting. This pin is ignored when serial (I²C) configuration is active.

Is the AD8191ASTZ compatible with HDMI 2.0 or higher standards?

No-the AD8191ASTZ is specified for HDMI 1.2a and DVI 1.0 compliance, supporting maximum data rates of 1.65 Gbps per channel. It does not meet HDMI 2.0's 6 Gbps minimum requirement or support features like HDR, YCbCr 4:4:4 at 60 Hz, or HDCP 2.2. For HDMI 2.0+, consider newer switch families such as Analog Devices' ADV7611 or TI's TUSB1002.