Analog Devices Inc./Maxim Integrated DS2165QN

Overview

DS2165QN from Maxim Integrated is a dual-channel ADPCM processor IC optimized for voice compression/expansion in TDM telephony systems. It performs real-time 64kbps ↔ 32kbps (G.721), 64kbps ↔ 24kbps (T1.303), or 64kbps ↔ 16kbps (proprietary) conversion with <375 µs input-to-output delay, supports independent A-law/µ-law coding per channel, and operates from a single +5V supply in 28-pin PLCC packaging - deployed in digital PBX, voice mail, and echo cancellation subsystems.

For engineers reviewing the DS2165QN datasheet, DS2165QN pinout, DS2165QN application, or DS2165QN equivalent, this page delivers verified functional architecture, time-slot programmability, hardware/software mode configuration, on-the-fly algorithm switching, and direct interconnect capability with combo-codec devices like TP305X and MC1455XX.

Technical Context

The DS2165QN integrates a 10 MIPS DSP engine with two independent PCM interfaces (X and Y), each supporting 256kHz–4.096MHz serial TDM data rates and configurable input/output time slots via on-chip TSAC circuitry. Its control register enables per-channel selection of compression/expansion mode, idle/bypass state, A-law/µ-law format, and algorithm (32/24/16kbps).

In software mode (SPS = VDD), configuration occurs via a 3-wire serial port (SCLK/SDI/CS) using 2- or 4-byte writes with address/command byte addressing up to 64 devices. In hardware mode (SPS = VSS), pin-strapped A0–A5 directly set CP/EX, U/A, AS0–AS2, and IPD bits - eliminating host processor dependency for voice storage applications.

Key Specifications

Pinout & Package

DS2165QN is housed in a 28-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry, 0.050" pitch, and dimensions per JEDEC MS-026. The package is lead-free and RoHS-compliant per Maxim's manufacturing standards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ADPCM processor applications.

Compared with DS2165QN, DS2165QL offers identical feature set at reduced voltage and power, while MC34118 provides basic 32kbps compression in simpler, lower-cost form - neither matches DS2165QN's dual-channel programmability, on-the-fly rate switching, or CAS-enabled signaling capability.

Availability

DS2165QN is available at Aetrix Electronics and suitable for digital PBX systems, voice mail storage platforms, and echo cancellation subsystems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing from authorized channels.

Supply support for DS2165QN 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

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and digital ICs for communications, computing, and industrial markets.

The DS2165QN belongs to Maxim's legacy telephony DSP processor family, designed specifically for bandwidth-efficient voice compression in TDM-based infrastructure - emphasizing low latency, hardware configurability, and standards-compliant algorithm execution.

FAQ

What is the primary function of the DS2165QN in a telephony system?

The DS2165QN serves as a dual-channel adaptive differential pulse-code modulation (ADPCM) processor that compresses or expands 64kbps PCM voice data to/from 32kbps, 24kbps, or 16kbps rates. It enables bandwidth reduction in TDM voice networks while maintaining speech quality, and supports critical features like Channel Associated Signaling (CAS) and on-the-fly algorithm switching - making DS2165QN essential for digital PBX, voice mail, and conferencing applications.

Does the DS2165QN support both A-law and µ-law PCM formats?

Yes, the DS2165QN supports both A-law and µ-law PCM formats independently per channel via the U/A bit (CR.2) in the control register. This allows one channel (e.g., X) to process A-law data while the other (e.g., Y) handles µ-law - crucial for interoperability between E1 (A-law) and T1 (µ-law) trunk interfaces. Format selection is retained across hardware and software modes and does not affect time-slot organization.

How does the hardware mode of the DS2165QN eliminate the need for a host processor?

In hardware mode (SPS = VSS), the DS2165QN maps control bits - including CP/EX, U/A, AS0–AS2, and IPD - directly to pins A0–A5, SDI, and CS. This allows configuration through simple pull-up/pull-down resistors instead of serial commands. The device defaults to time slot 0 and requires no external controller, making DS2165QN ideal for voice storage or fixed-function applications where firmware overhead must be minimized.

What is the significance of the on-board time-slot assigner-circuit (TSAC) in the DS2165QN?

The TSAC in DS2165QN enables precise, programmable assignment of input and output time slots for each PCM/ADPCM channel - independent of selected compression rate or data format. This allows DS2165QN to interface seamlessly with non-standard TDM backplanes, legacy codecs, or multiplexers that allocate voice data outside conventional slot 0 positions, enhancing system integration flexibility without requiring external glue logic.

Can the DS2165QN switch between compression algorithms during an active voice call?

Yes, the DS2165QN supports true on-the-fly algorithm switching in software mode: changing from 32kbps to 24kbps or 16kbps requires only updating the AS0–AS2 bits in the control register via the serial port before the next PCM sample arrives. The DS2165QN reads the control register prior to processing each sample, ensuring zero-gap transition - critical for dynamic bandwidth adaptation in voice-over-IP gateways and conference bridges using DS2165QN.