Analog Devices Inc. AD1895YRS

Overview

AD1895YRS from Analog Devices is a 24-bit, stereo asynchronous sample rate converter (ASRC) designed for high-fidelity digital audio systems. It supports bidirectional conversion between input and output sample rates up to 192 kHz, delivers –122 dB THD+N (96 kHz:48 kHz), provides 128 dB A-weighted dynamic range, and implements a 64-tap FIR filter with 220 polyphases for precise interpolation and jitter rejection in home theater and automotive audio signal chains.

For engineers reviewing the AD1895YRS datasheet, AD1895YRS pinout, AD1895YRS application, or AD1895YRS equivalent, this page details its hardware-configurable serial interface modes (I²S, left/right-justified, TDM), bypass functionality, master/slave clock ratio selection (256/512/768 × f_S), and 28-pin SSOP package compatibility with industrial temperature operation (–40°C to +105°C).

Technical Context

The AD1895YRS employs a digital servo loop that measures input/output sample rate timing difference within ±5 ps and automatically tracks ratio changes without programming. Its core architecture combines a FIFO buffer, a 64-tap FIR filter with 220 polyphase coefficient sets stored in ROM, and a clock divider supporting MCLK frequencies up to 34 MHz.

It operates with dual supplies: 3.3 V for VDD_CORE and either 3.3 V or 5.0 V for VDD_IO, enabling 5 V-tolerant I/O while maintaining low-power core logic. Serial ports support independent master/slave configuration on input and output sides, with hardware-selectable word length (16/18/20/24 bits) and interface mode (SMODE_IN/OUT pins).

Key Specifications

Pinout & Package

AD1895YRS is housed in a 28-lead SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch, optimized for surface-mount assembly and thermal dissipation (θ_JA = 109°C/W). Pin 1 is NC; pins 7 and 22 are dedicated supply inputs; pins 4, 23, 5/6/24/25, and 20 serve serial data/clock/control functions; mute and bypass control are implemented via dedicated active-high logic inputs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar asynchronous sample rate conversion applications.

Compared with AK4128A and CS8422-CQZ, AD1895YRS offers superior jitter rejection (±5 ps servo resolution), hardware-only configuration (no SPI bus required), and TDM scalability-making it optimal for multi-channel, low-latency, and automotive-grade designs where reliability and deterministic behavior are critical.

Availability

AD1895YRS is available at Aetrix Electronics and suitable for home theater systems, automotive infotainment platforms, and professional audio equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD1895YRS 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, serving precision instrumentation, communications, and industrial markets since 1965.

The AD1895YRS belongs to Analog Devices' high-fidelity audio signal processing product line, engineered specifically for low-jitter, high-SNR asynchronous sample rate conversion in demanding consumer and automotive audio subsystems.

FAQ

What is the maximum supported input and output sample rate for AD1895YRS?

The AD1895YRS supports input and output sample rates up to 192 kHz simultaneously. This capability is confirmed in the Product Overview and Specifications sections, where "Up to 192 kHz Sample Rate" is explicitly stated and validated by test conditions showing performance at 192 kHz:48 kHz and 192 kHz:32 kHz ratios. The device achieves –122 dB THD+N and 128 dB dynamic range even at these extreme rates, making AD1895YRS suitable for next-generation high-resolution audio applications.

Does AD1895YRS require external programming or configuration registers to operate?

No, AD1895YRS operates without external programming. Its functional block diagram and Features section confirm "No Programming Required" and "Automatically Senses Sample Frequencies." Configuration is handled entirely through hardware pins (e.g., SMODE_IN_0–2, WLNGTH_OUT_0–1, MMODE_0–2), eliminating the need for SPI/I²C interfaces or firmware initialization. This makes AD1895YRS ideal for systems where deterministic startup and minimal software overhead are critical, such as automotive head units and set-top boxes.

How does the bypass mode function in AD1895YRS, and when should it be used?

In bypass mode (activated by driving Pin 9/BYPASS high), AD1895YRS routes SDATA_I directly to SDATA_O without sample rate conversion, dithering, or filtering. This mode is intended for synchronous 1:1 data pass-through, non-audio data transmission, or system diagnostics. The Product Overview confirms this behavior, stating "the AD1895 sample rate converts the data… [but] can be bypassed altogether using the bypass mode." Using bypass avoids unnecessary latency and preserves bit-perfect integrity when clock domains are already aligned.

What are the power supply requirements for AD1895YRS, and how do they affect I/O voltage tolerance?

AD1895YRS requires two supplies: VDD_CORE = 3.3 V ±5% and VDD_IO = 3.3 V or 5.0 V ±10%. When VDD_IO = 5.0 V, the device supports 5 V-tolerant digital inputs - a key specification confirmed in the Absolute Maximum Ratings and Digital I/O Characteristics tables. However, VDD_CORE must never exceed VDD_IO. This dual-supply architecture allows AD1895YRS to interface directly with both modern 3.3 V DSPs and legacy 5 V logic families without level-shifting circuitry.

Can multiple AD1895YRS devices be connected in series or parallel for multi-channel audio processing?

Yes - AD1895YRS supports TDM daisy-chaining via the TDM_IN pin (Pin 20), enabling multiple devices to share a single serial output port on a DSP. The Product Overview explicitly states "multiple AD1895s to a digital signal processor" in TDM mode, and the Pin Function Descriptions confirm TDM_IN is "Only for Daisy-Chain Mode." This architecture reduces PCB routing complexity and pin count versus discrete serial ports, making AD1895YRS scalable for 5.1, 7.1, or immersive audio systems without requiring additional DSP serial interfaces.