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Home > Products > Integrated Circuits (ICs) > Interface > Telecom

Analog Devices Inc./Maxim Integrated DS26504L+

Name: DS26504L+
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS26504L+
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS26504L+

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Telecom

Package:: 64-LQFP

Datasheet:: DS26504L+.pdf

Description:: IC TELECOM INTERFACE 64LQFP

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Product details

Overview

DS26504L+ from Maxim Integrated is a T1/E1/J1/64KCC BITS clock-recovery and rate-conversion element with integrated line interface unit (LIU), supporting 1.544MHz T1, 2.048MHz E1, 64kHz composite clock (64KCC), and 6312kHz synchronization inputs/outputs. It performs SSM recovery and transmission in both T1 (BOC) and E1 (Sa(n)) modes, operates from a 3.3V supply with 5V-tolerant I/O, and features crystal-less jitter attenuation for telecom timing applications.

For engineers reviewing the DS26504L+ datasheet, DS26504L+ pinout, DS26504L+ application, or DS26504L+ equivalent, key selection considerations include G.703 compliance across multiple sync interfaces (64kHz Option A/B, 6312kHz, 2048kHz), software-selectable 75Ω/100Ω/110Ω/120Ω/133Ω termination, dual-control port support (parallel/SPI/hardware), and IEEE 1149.1 JTAG boundary scan for production testability.

Technical Context

The DS26504L+ integrates independent transmit and receive PLLs with separate clock recovery paths for T1, E1, 64KCC, and 6312kHz interfaces. Its LIU supports CMI-coded line signaling, short- and long-haul line build-out, and automatic receive sensitivity adjustment per G.703 Section 13.

It implements full SSM handling: BOC-based SSM transmit/receive with change-of-state detection in T1 mode, and Sa(n) bit SSM processing in E1 mode including CRC4 multiframe alignment. The device accepts 8kHz and 19.44MHz reference clocks and provides dedicated 6312kHz output, while supporting 16.384MHz, 12.8MHz, 8.192MHz, 4.096MHz, 2.048MHz, and 1.544MHz master clock inputs.

Key Specifications

Parameter	Value and Actual Design Meaning
T1/E1 Support	Fully compliant with GR-378, G.703 (2048kHz, 64kHz Options A/B, 6312kHz), and ANSI T1.107 for T1/J1 (1.544MHz) and E1 (2.048MHz) line rates.
Sync Input Rates	Accepts T1 (1.544MHz), E1 (2.048MHz), 64kHz composite clock, 6312kHz, 8kHz, and 19.44MHz references - enabling flexible BITS timing source selection.
Jitter Performance	Crystal-less jitter attenuator with specified tolerance (T1: ±50ppm, E1: ±50ppm) and attenuation (T1: >30dB, E1: >30dB) per Figure 13-8/9/10/11.
Control Interface	8-bit parallel port (Intel/Motorola, multiplexed/nonmultiplexed), SPI serial port (CPOL/CPHA configurable), and hardware control mode - no external controller required.
Supply & I/O	3.3V core supply with 5V-tolerant digital and analog I/O pins - simplifies level-shifting in mixed-voltage systems.
Termination	Software-selectable internal termination: 75Ω, 100Ω, 110Ω, 120Ω, or 133Ω - eliminates external resistor networks for line impedance matching.
Diagnostic Features	Hardware LOS, AIS, LOF outputs; fast transmitter disable pin; JTAG boundary scan (IEEE 1149.1) - enables real-time fault detection and production test coverage.

Pinout & Package

DS26504L+ is housed in a 64-pin LQFP package (10mm × 10mm, 0.5mm pitch), RoHS-compliant and rated for 0°C to +70°C operation. Pin functions are defined per Table 5-1 of the official datasheet and validated for telecom line interface integrity.

Pin/Terminal	Circuit Role	Design Meaning
LOS, AIS, LOF	Hardware alarm outputs	Dedicated open-drain pins indicating loss of signal, alarm indication signal, and loss of frame - enable immediate system-level fault response without software polling.
TDIS	Transmit disable control	Active-low pin forcing fast transmitter output disable - critical for protection switching in redundant timing architectures.
MCLK	Master clock input	Accepts 1.544MHz–16.384MHz clock for T1/E1/J1 framing - determines base timing resolution and frame alignment accuracy.
REFCLK	Reference clock input	Supports 8kHz or 19.44MHz external reference - used for frequency synthesis and phase-locking when primary sync sources are unavailable.
CLK6312	Dedicated 6312kHz output	Buffered, low-jitter 6312kHz clock output - meets Japanese telecom sync requirements without external PLL or divider circuitry.
TCLK, RCLK	Transmit/receive payload clocks	Provides 8kHz, 400Hz, or 64kHz outputs in composite clock mode - directly drives downstream framer or switch fabric timing inputs.

Key Features

Feature	Design Value
G.703 Compliance	Validated against G.703 2048kHz, 64kHz Option A/B, and 6312kHz Japanese sync interfaces - ensures interoperability in global carrier networks.
SSM Handling	Full BOC-based SSM transmit/receive with change-of-state validation in T1 mode; Sa(n) bit extraction and monitoring in E1 mode - maintains traceable timing hierarchy across network elements.
Crystal-Less Jitter Attenuation	On-chip jitter filtering without external crystal or VCXO - reduces BOM count and board space while meeting GR-1244-CORE jitter specs for BITS applications.
Monitor Mode	Non-intrusive bridging capability allowing simultaneous line monitoring and active traffic forwarding - essential for network diagnostics and service assurance.
Software-Selectable Termination	Five discrete impedance options (75Ω to 133Ω) configured via register write - eliminates manual resistor changes during prototyping and field deployment.

Applications

Telecom Central Office BITS	Carrier-Grade Timing Distribution
Use Scenario: Primary timing source in central office environments requiring GR-378-compliant composite clock generation and distribution. IC Role / Device Role / Timing Role: BITS clock-recovery element sourcing stable 64kHz, 8kHz, and 400Hz composite clock outputs from diverse sync inputs. Use Value: Enables single-device synchronization of legacy TDM switches, SDH/SONET add-drop multiplexers, and modern packet-optical transport systems.	Use Scenario: Timing translation node in hierarchical telecom networks where E1-derived timing must be converted to T1-compatible format for regional equipment. IC Role / Device Role / Timing Role: Rate-conversion transceiver performing bidirectional T1↔E1 sync mapping with SSM preservation. Use Value: Maintains SSM integrity across domain boundaries, preventing timing loop formation and ensuring traceable stratum-3/4 timing delivery.
Network Element Protection Switching	Multi-Standard Sync Gateway
Use Scenario: Fast-failover timing module in redundant BITS systems where primary/backup clock sources must be seamlessly switched. IC Role / Device Role / Timing Role: Dual-input clock selector with hardware TDIS pin enabling sub-microsecond transmitter disable during switchover. Use Value: Eliminates timing glitches during protection events, satisfying ITU-T G.8262 wander and jitter limits for synchronous Ethernet migration.	Use Scenario: Edge gateway aggregating sync inputs from satellite, GPSDO, PRC, and line-derived sources into unified 64KCC output for metro aggregation nodes. IC Role / Device Role / Timing Role: Multi-interface sync translator accepting 6312kHz, 64kHz, T1, E1, and 8kHz references with programmable priority logic. Use Value: Reduces need for external muxes, dividers, and buffers - lowers system latency and improves phase noise performance in hybrid sync architectures.

Telecom Central Office BITS

Carrier-Grade Timing Distribution

Use Scenario: Primary timing source in central office environments requiring GR-378-compliant composite clock generation and distribution.

IC Role / Device Role / Timing Role: BITS clock-recovery element sourcing stable 64kHz, 8kHz, and 400Hz composite clock outputs from diverse sync inputs.

Use Value: Enables single-device synchronization of legacy TDM switches, SDH/SONET add-drop multiplexers, and modern packet-optical transport systems.

Use Scenario: Timing translation node in hierarchical telecom networks where E1-derived timing must be converted to T1-compatible format for regional equipment.

IC Role / Device Role / Timing Role: Rate-conversion transceiver performing bidirectional T1↔E1 sync mapping with SSM preservation.

Use Value: Maintains SSM integrity across domain boundaries, preventing timing loop formation and ensuring traceable stratum-3/4 timing delivery.

Network Element Protection Switching

Multi-Standard Sync Gateway

Use Scenario: Fast-failover timing module in redundant BITS systems where primary/backup clock sources must be seamlessly switched.

IC Role / Device Role / Timing Role: Dual-input clock selector with hardware TDIS pin enabling sub-microsecond transmitter disable during switchover.

Use Value: Eliminates timing glitches during protection events, satisfying ITU-T G.8262 wander and jitter limits for synchronous Ethernet migration.

Use Scenario: Edge gateway aggregating sync inputs from satellite, GPSDO, PRC, and line-derived sources into unified 64KCC output for metro aggregation nodes.

IC Role / Device Role / Timing Role: Multi-interface sync translator accepting 6312kHz, 64kHz, T1, E1, and 8kHz references with programmable priority logic.

Use Value: Reduces need for external muxes, dividers, and buffers - lowers system latency and improves phase noise performance in hybrid sync architectures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar T1/E1/J1 sync translation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS26503+	Lacks 6312kHz sync interface support and dedicated CLK6312 output; otherwise pin/software compatible.	Suitable only for North American/EMEA deployments without Japanese telecom sync requirements.	Select DS26503+ when 6312kHz compliance is unnecessary and cost optimization is prioritized.
DS26502+	Does not support 64kHz composite clock mode or SSM transmission; limited to basic T1/E1 recovery.	Applicable only in legacy TDM framer timing roles without composite clock distribution needs.	Choose DS26502+ for minimal-function clock recovery where SSM handling and multi-rate output are not required.

Compared with DS26504L+, DS26503+ omits 6312kHz functionality but retains full SSM and 64KCC support, while DS26502+ sacrifices both SSM transmission and composite clock generation - making DS26504L+ the only option for full GR-378/G.703 multi-standard BITS deployment.

Availability

DS26504L+ is available at Aetrix Electronics and suitable for telecom central office timing, carrier-grade sync distribution, network element protection switching, and multi-standard sync gateway applications requiring stable component supply and long-term lifecycle support.

Supply support for DS26504L+ 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) designs high-performance analog and mixed-signal ICs for communications, computing, and industrial markets, with deep expertise in telecom timing and interface solutions.

The DS26504L+ belongs to Maxim's BITS timing family, engineered specifically for carrier-class synchronization in T1/E1/J1 infrastructure, emphasizing G.703 compliance, SSM integrity, and jitter-controlled clock recovery.

FAQ

What telecom standards does the DS26504L+ comply with?

The DS26504L+ complies with GR-378 Composite Clock, G.703 2048kHz, G.703 64kHz Options A and B, G.703 6312kHz Japanese sync interface, and ANSI T1.107 for T1/J1 operation. It meets all referenced jitter, wander, and SSM handling requirements in those specifications - confirmed in Tables 2-1/2-2 and Figures 13-8 through 13-11 of the official datasheet.

Does the DS26504L+ support both T1 and E1 Synchronization Status Messages (SSM)?

Yes, the DS26504L+ fully supports SSM in both domains: T1-mode BOC-based SSM transmit and receive with change-of-state validation, and E1-mode Sa(n) bit extraction, transmission, and monitoring per G.707. This is implemented in dedicated hardware blocks described in Sections 11 and 12 of the datasheet and verified in Tables 11-1 and 12-1.

What master clock frequencies are supported by the DS26504L+?

The DS26504L+ accepts 1.544MHz, 2.048MHz, 4.096MHz, 8.192MHz, 12.8MHz (CPU-interface mode only), and 16.384MHz master clocks. For T1-only operation, it also supports 3.088MHz, 6.176MHz, and 12.552MHz - all explicitly listed in Table 6-1 and Section 6.1 of the datasheet.

How is line termination configured on the DS26504L+?

Line termination on the DS26504L+ is software-selectable via internal registers: 75Ω, 100Ω, 110Ω, 120Ω, or 133Ω options are available for both transmit and receive sides, eliminating external resistors. Configuration is detailed in Table 6-2 and Section 6.2 of the datasheet, with real-time reconfiguration supported.

Is the DS26504L+ pin-compatible with other devices in the DS2650x family?

Yes, the DS26504L+ is pin and software compatible with the DS26502+ and DS26503+, as stated in the Features section of the datasheet. This allows drop-in replacement in existing designs - though functional differences (e.g., missing 6312kHz support in DS26503+) must be verified per application requirements.

DS26504L+ Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 64-LQFP

Packaging:: Tray

Product Status:: Obsolete

Function:: BITS Element

Interface:: 64KCC, E1, T1

Number of Circuits:: 1

Voltage - Supply:: 3.14V ~ 3.47V

Current - Supply:: 150mA

Power (Watts):: -

Operating Temperature:: 0°C ~ 70°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 64-LQFP (10x10)

DS26504L+ FAQ

1.How can I place an order for DS26504L+ through Aetrix?

Please submit a Request for Quotation (RFQ) for DS26504L+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for DS26504L+ reliable?

The price and inventory of DS26504L+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS26504L+ is usually 5 days.

3.What payment methods are accepted for DS26504L+?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS26504L+ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS26504L+?

DS26504L+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS26504L+ order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for DS26504L+?

For technical support, including DS26504L+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS26504L+ requirements.

6.How does Aetrix verify that DS26504L+ is sourced from the original manufacturer or authorized distributors?

All DS26504L+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS26504L+ meets industry standards.

7.What is the process for return or replacement of DS26504L+?

All DS26504L+ units undergo pre-shipment inspection (PSI). If there is an issue with DS26504L+, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The DS26504L+ part is unused and in its original packaging.

Return procedure for DS26504L+:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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