Analog Devices Inc. AD1843JS

Overview

AD1843JS from Analog Devices is a single-chip 16-bit stereo audio and quad-channel modem/fax codec with dual ∑∆ ADCs, four ∑∆ DACs, three on-chip PLLs, 13 analog inputs, and 7 analog outputs. It supports V.34/V.32bis standards, simultaneous 4-sample-rate operation (4–54 kHz), and mixed +5 V/+3 V supply operation in an 80-lead PQFP package - deployed in integrated telephony gateways and DSP-based voice/data/fax terminals.

For engineers reviewing the AD1843JS datasheet, AD1843JS pinout, AD1843JS application, or AD1843JS equivalent, key selection criteria include its triple-PLL synchronization capability, 1 Hz programmable sample rate resolution, FIFO-buffered ADSP-21xx-compatible serial interface, and support for simultaneous audio/modem signal paths without beat frequency interference.

Technical Context

The AD1843JS implements Analog Devices' Continuous Time Oversampling (CTO) architecture to enable independent, concurrent sample-rate domains - audio (e.g., 48 kHz), modem (e.g., 12.8 kHz), resampler (e.g., 8 kHz), and video-sync (via SYNC[3:1] PLL inputs). Its digital mixing engine allows real-time analog-domain signal routing between 13 inputs and 7 outputs, with programmable gain/attenuation across all paths.

Dual decimation/interpolation filter banks are mode-specific: audio mode delivers 91.8 dB stopband rejection and ±0.016 dB passband ripple; modem mode provides 75.7 dB rejection with 0.442×FS passband; resampler mode achieves 92.2 dB rejection and 25/FS group delay. All DACs and ADCs feature A-weighted dynamic range >80 dB and THD+N ≤ –70 dB.

Key Specifications

Pinout & Package

AD1843JS is housed in an 80-lead Plastic Quad Flat Package (PQFP), S-80 option, with θJA = 96°C/W and θJC = 8.75°C/W. Pin assignments are validated per Analog Devices AD1843 Rev. 0 datasheet (pages 7–10).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD1848JST and TLV320AIC23BIPW, the AD1843JS uniquely integrates telecom-grade modem functionality, triple-PLL synchronization, and 13-input analog mixing - making it the only solution capable of replacing discrete audio + modem codec pairs in space-constrained gateways.

Availability

AD1843JS is available at Aetrix Electronics and suitable for voice/data convergence gateways, DSP-based telephony terminals, and industrial modem/fax co-processor modules requiring stable component supply and long-term lifecycle support.

Supply support for AD1843JS 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 AD1843JS belongs to the SoundComm™ codec family, designed specifically for DSP-based telephony infrastructure requiring simultaneous audio, modem, and fax signal processing in a single chip.

FAQ

What is the primary function of the AD1843JS in a telephony system?

The AD1843JS serves as a complete analog front-end codec for converged voice/data/fax applications. It integrates dual ∑∆ ADCs, four ∑∆ DACs, three on-chip PLLs, and a flexible analog mixer - enabling simultaneous audio (48 kHz), modem (12.8 kHz), and fax (8 kHz) signal paths without beat frequency interference. The AD1843JS replaces multiple discrete codecs in gateways and DSP-based terminals.

Does the AD1843JS support V.34 modem standards?

Yes, the AD1843JS explicitly supports V.34, V.32bis, and fallback modem standards per its official product description and specifications. Its dual DAC architecture, programmable bit clocks (BIT1–BIT3), and modem-mode digital filters (75.7 dB stopband rejection at 12.8 kHz) are engineered for compliance with ITU-T V-series protocols - confirmed in Analog Devices AD1843 Rev. 0 documentation.

How many analog inputs and outputs does the AD1843JS provide?

The AD1843JS provides thirteen analog inputs - including MICL/R, LINLP/N/RP/N, AUX1–3L/R, MIN, and SUML/R - and seven analog outputs - LOUT1L/R, LOUT2L±/R±, HPOUTL/C/R, MOUT, and CMOUT. This I/O count is validated in the "Analog Signals" section of the AD1843JS datasheet (pages 9–10) and matches the pin configuration diagram for the 80-lead PQFP package.

What package type is used for the AD1843JS?

The AD1843JS uses an 80-lead Plastic Quad Flat Package (PQFP), designated S-80 in Analog Devices' ordering information. Thermal characteristics are θJA = 96°C/W and θJC = 8.75°C/W. This package is distinct from the 100-lead TQFP used by the AD1843JST variant - confirmed in the "Ordering Information" table on page 7 of the AD1843 Rev. 0 datasheet.

Can the AD1843JS operate with mixed +5 V and +3 V supplies?

Yes, the AD1843JS supports mixed-supply operation: +5 V analog supply (VCC) and +3 V digital supply (VDD). Total current draw drops from 250 mA (5 V/5 V) to 175 mA (5 V/3 V), and digital power-down current falls to 1 mA. This dual-supply capability is specified in the "POWER SUPPLY" section (page 6) and enables lower-power system designs while maintaining full analog performance.