Analog Devices Inc. AD1835AS

Overview

AD1835AS from Analog Devices is a 24-bit, 96 kHz stereo audio codec with four independent stereo DACs (8 channels) and one stereo ADC (2 channels), operating from dual 5 V analog/digital supplies and supporting 3.3 V–tolerant digital I/O. It delivers –95 dB THD+N and 108 dB DAC SNR, features on-chip 1024-step volume control per channel, and targets high-fidelity multichannel audio systems requiring precise differential analog I/O and flexible serial interface modes.

For engineers reviewing the AD1835AS datasheet, AD1835AS pinout, AD1835AS application, or AD1835AS equivalent, key selection considerations include its 52-lead MQFP package, support for I²S/right/left-justified/DSP/TDM serial formats, 192 kHz capability on DAC1 only, differential output architecture, and industrial temperature range (–40°C to +85°C).

Technical Context

The AD1835AS integrates two 24-bit sigma-delta ADCs with decimation filters (120 dB stop-band attenuation, 48/96 kHz operation) and eight 24-bit sigma-delta DACs arranged as four stereo pairs, each with independent 1024-step linear volume control and clickless mute. Its digital architecture supports master/slave configuration via M/S pin and includes SPI-compatible control port for register programming and peak-level readback.

It employs multibit sigma-delta modulators with Analog Devices' patented differential linearity restoration, data-directed scrambling for jitter immunity, and on-chip 2.25 V reference routed to FILTR. The device accepts 24.576 MHz internal clock derived from external MCLK (scalable ×1, ×2, or ×2/3) and supports packed TDM mode for 8-in/8-out operation using a single SHARC SPORT interface.

Key Specifications

Pinout & Package

AD1835AS is housed in a 52-lead MQFP (S-52) package with exposed thermal pad, specified for industrial temperature range (–40°C to +85°C). Pin functions are validated per Analog Devices Rev. B datasheet, including dedicated differential analog I/O, dual serial data ports (ADC/DAC), SPI control interface, and configurable clock/mode pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar audio codec applications.

Compared with AK4118VN and CS42888-CQZ, the AD1835AS uniquely combines 8-channel DAC + 2-channel ADC in a single 52-pin MQFP with differential outputs, on-chip reference, and TDM packing-making it optimal for cost-sensitive, space-constrained multichannel consumer audio where 192 kHz is required only on primary DAC.

Availability

AD1835AS is available at Aetrix Electronics and suitable for DVD players, home theater receivers, and automotive infotainment systems requiring stable component supply, long-term industrial temperature support, and multichannel audio I/O integration.

Supply support for AD1835AS 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, headquartered in Norwood, MA, with over 50 years of innovation in precision signal chain solutions.

The AD1835AS belongs to Analog Devices' high-fidelity audio codec product line, designed specifically for multichannel consumer and automotive audio systems demanding low THD+N, wide dynamic range, and flexible digital interface compatibility.

FAQ

What is the maximum sample rate supported by the AD1835AS ADC?

The AD1835AS ADC supports a maximum sample rate of 96 kHz, as confirmed in the "SPECIFICATIONS" section (p.2) and "FUNCTIONAL OVERVIEW" (p.11). This applies to both stereo channels simultaneously. While DAC1 supports 192 kHz, the ADC section is limited to 96 kHz operation, with decimation filters optimized for 48 kHz and 96 kHz modes.

Does the AD1835AS support I²S serial interface mode out of the box?

Yes, the AD1835AS defaults to I²S mode for both ADC output and DAC input, as stated in the "Serial Data Ports-Data Format" section (p.12). The ADC serial output is delayed by 1 BCLK from LRCLK edge in default I²S configuration, and DAC input follows standard I²S timing unless reprogrammed via DAC Control Register 1.

How many independent volume controls does the AD1835AS provide?

The AD1835AS provides eight independent volume controls-one per DAC channel-with 1024 linear steps (0.098% step resolution) and 60 dB total attenuation range, as specified in the "FEATURES" list (p.1) and "SPECIFICATIONS" table (p.3). Each control is software-programmable via SPI and operates clicklessly.

What is the function of the FILTR pin on the AD1835AS?

The FILTR pin on the AD1835AS provides access to the internal 2.25 V voltage reference, used to bias all analog I/O pins at their common-mode voltage. As detailed on p.12 and p.7, it must be bypassed with a parallel 10 µF/100 nF capacitor and can supply <50 µA to external circuitry such as op-amp bias networks.

Is the AD1835AS pin-compatible with the AD1835ASTZ variant?

No-the AD1835AS uses a 52-lead MQFP package (S-52), while the AD1835ASTZ is a 52-lead LQFP variant with different thermal pad and lead pitch specifications. Although both share identical pin functions and electrical behavior, mechanical incompatibility prevents direct PCB substitution without layout revision.