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

Analog Devices Inc./Maxim Integrated DS2187S/T&R

Name: DS2187S/T&R
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS2187S/T&R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS2187S/T&R

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Telecom

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: DS2187S/T&R.pdf

Description:: IC TELECOM INTERFACE 20SOIC

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Product details

Overview

DS2187S/T&R from Maxim Integrated (now Analog Devices) is a T1/CEPT receive line interface IC that extracts clock and data from twisted-pair or coaxial transmission lines. It supports 1.544 MHz (T1) and 2.048 MHz (CEPT) primary-rate networks, features on-chip precision PLL with laser-trimmed VCO, decodes AMI/B8ZS/HDB3, and operates from a single 5V supply.

For engineers reviewing the DS2187S/T&R datasheet, DS2187S/T&R pinout, DS2187S/T&R application, or DS2187S/T&R equivalent, key selection considerations include its dual-standard support, integrated jitter-tolerant clock recovery, alarm reporting (AIS/RCL/BPV), and compatibility with DS2180A/DS2181A transceivers and DS2186/DS2188 companion devices.

Technical Context

The DS2187S/T&R implements a hybrid clock recovery architecture combining a high-Q frequency-locked loop (FLL) and digital phase-locked loop (DPLL). The FLL tracks average input frequency using a laser-trimmed on-chip VCO (18.528 MHz for T1, 24.576 MHz for CEPT), minimizing output jitter; the DPLL provides fine-phase alignment and delivers extracted clock at RCLK.

It accepts bipolar line signals via RTIP/RRING inputs with ±7V tolerance, uses internal peak detection and 50% threshold slicing, and supports zero-code suppression (ZCSEN) to replace B8ZS/HDB3 codewords with all-zeros - configurable per standard via RCLKSEL. Alarm logic monitors AIS, RCL, and BPV in real time.

Key Specifications

Parameter	Value and Actual Design Meaning
T1 Data Rate	1.544 MHz - supports North American primary-rate digital transmission with full compliance to TR 62411 and PUB 43801.
CEPT Data Rate	2.048 MHz - meets European E1 standard requirements including CCITT G.823 timing specifications.
Input Sensitivity	0.4–0.6 V_pk - enables reliable signal acquisition from transformer-coupled lines without external amplification.
Input Jitter Tolerance	200 UI - handles severe line jitter while maintaining lock, critical for short-loop terminal equipment applications.
Supply Voltage	4.75–5.25 V - single 5V rail simplifies power design and eliminates need for multiple supplies or regulators.
Lock Acquisition Time	50 ms - ensures rapid synchronization after signal reacquisition, reducing downtime in CSU/DACS systems.
FLL Loop Bandwidth	50 Hz - suppresses low-frequency jitter components, preserving clean RCLK output for downstream timing circuits.

Pinout & Package

DS2187S/T&R is packaged in a 20-pin SOIC (300-mil) with exposed pad not present; pin 1 marked by notch or dot. Power separation (AVDD/AVSS/DVDD/DVSS) enables analog-digital noise isolation on PCB layout.

Pin/Terminal	Circuit Role	Design Meaning
1 AVDD	Analog Positive Supply	5.0 V analog rail for internal analog front-end and PLL circuitry; requires local 0.1 µF + 10 µF decoupling.
2 RAIS	Alarm Timing Input	Defines AIS detection window period; every other low pulse sets two-cycle monitoring interval for zero-count analysis.
3 ZCSEN	Code Suppression Control	Active-high enables replacement of B8ZS (T1) or HDB3 (CEPT) codewords with all-zero sequences at RPOS/RNEG outputs.
4 LCAP	Loop Filter Capacitor	Connects external 10 µF capacitor to AVSS; sets FLL loop dynamics and stability for jitter tracking performance.
5 RCLKSEL	Standard Selection Input	Grounded for T1 (1.544 MHz); tied to DVDD for CEPT (2.048 MHz); configures internal clock dividers and decoding logic.
6–7 RTIP/RRING	Differential Line Inputs	Accept ±7 V bipolar line signals via center-tapped transformer; support negative excursions below AVSS for proper AMI waveform capture.
8 LOCK	Frequency Lock Indicator	Open-drain output goes high when FLL achieves frequency lock and valid RCLK/RPOS/RNEG are stable.
9–10 AVSS/DVSS	Analog/Digital Ground	Separate ground pins reduce coupling between sensitive analog recovery circuitry and noisy digital outputs.
11 RCLK	Recovered Clock Output	Buffered DPLL output clock synchronized to incoming line rate; rise/fall time ≤20 ns, duty cycle 45–55%.
12–13 RNEG/RPOS	Recovered Data Outputs	Complementary NRZ data updated on rising edge of RCLK; meet TTL logic thresholds with 4 mA sink capability.
14 NC	No Connect	Not internally bonded; must remain unconnected to avoid parasitic coupling or latch-up risk.
15 BPV	Bipolar Violation Flag	Asserts high for full bit period on detection of bipolar violation; disabled during ZCSEN=1 in CEPT mode.
16 AIS	Alarm Indication Signal	Indicates loss of framing or remote alarm condition; remains asserted for two RAIS periods after detection.
17 RCL	Receive Carrier Loss	Asserts after 192 consecutive zeros at RPOS/RNEG; resets on next '1' bit - detects complete signal loss.
18 DVDD	Digital Positive Supply	5.0 V rail for digital logic, output drivers, and control circuitry; shares voltage with AVDD but routed separately.

Key Features

Feature	Design Value
Integrated FLL + DPLL Architecture	Combines high-Q analog frequency lock with digital phase alignment to deliver low-jitter RCLK (<50 Hz loop bandwidth) while meeting AT&T TR 62411 jitter specs.
Laser-Trimmed On-Chip VCO	Eliminates external crystal or LC tank components and manual tuning, reducing BOM count and board area in CSU and channel bank designs.
Programmable Code Suppression (ZCSEN)	Enables transparent pass-through or zero-substitution of B8ZS/HDB3 codewords - essential for interoperability with DS2180A/DS2181A transceivers.
Real-Time Alarm Monitoring	Dedicated open-drain outputs (AIS, RCL, BPV) provide immediate visibility into network health without requiring host processor polling or firmware overhead.
Transformer-Coupled Input Interface	RTIP/RRING accept ±7 V differential signals with internal peak detection and adaptive 50% slicing - supports legacy T1/E1 line transformers without external biasing.

Applications

Channel Service Unit (CSU)	Digital Access and Cross-Connect System (DACS)
Use Scenario: Installed in telco demarcation points to terminate T1/E1 lines and regenerate clean clock/data for customer premises equipment. IC Role / Device Role / Timing Role: Primary receive line interface performing clock recovery, code decoding, and alarm reporting for physical layer termination. Use Value: Enables compact, low-power CSU designs with no external crystal or tuning components while meeting stringent TR 62411 jitter requirements.	Use Scenario: Embedded in carrier-grade DACS platforms to monitor and switch T1/E1 traffic across multiple ports with real-time fault detection. IC Role / Device Role / Timing Role: Line receiver providing synchronized RCLK and RPOS/RNEG outputs plus AIS/RCL/BPV status flags for system-level supervision. Use Value: Reduces FPGA or microcontroller I/O burden by offloading alarm logic and delivering deterministic timing outputs for cross-connect switching.
Customer Premises Equipment (CPE)	PABX-to-Computer Interface (DMI/CPI)
Use Scenario: Integrated into T1/E1 WAN interface cards for enterprise routers and firewalls to connect to service provider lines. IC Role / Device Role / Timing Role: Physical-layer receiver converting raw line signals into synchronous digital streams usable by MAC or framer ICs. Use Value: Supports both T1 and CEPT standards via RCLKSEL pin, enabling single-hardware SKUs for global deployment without redesign.	Use Scenario: Used in legacy PBX-to-host computer gateways (e.g., DMI, CPI) to interface telephony signaling with data processing systems. IC Role / Device Role / Timing Role: Receive interface extracting clock and data from E1/T1 trunks for protocol translation and call-control processing. Use Value: Provides precise RCLK timing and error flags required for time-sensitive DMI frame alignment and CPI message parsing.

Channel Service Unit (CSU)

Digital Access and Cross-Connect System (DACS)

Use Scenario: Installed in telco demarcation points to terminate T1/E1 lines and regenerate clean clock/data for customer premises equipment.

IC Role / Device Role / Timing Role: Primary receive line interface performing clock recovery, code decoding, and alarm reporting for physical layer termination.

Use Value: Enables compact, low-power CSU designs with no external crystal or tuning components while meeting stringent TR 62411 jitter requirements.

Use Scenario: Embedded in carrier-grade DACS platforms to monitor and switch T1/E1 traffic across multiple ports with real-time fault detection.

IC Role / Device Role / Timing Role: Line receiver providing synchronized RCLK and RPOS/RNEG outputs plus AIS/RCL/BPV status flags for system-level supervision.

Use Value: Reduces FPGA or microcontroller I/O burden by offloading alarm logic and delivering deterministic timing outputs for cross-connect switching.

Customer Premises Equipment (CPE)

PABX-to-Computer Interface (DMI/CPI)

Use Scenario: Integrated into T1/E1 WAN interface cards for enterprise routers and firewalls to connect to service provider lines.

IC Role / Device Role / Timing Role: Physical-layer receiver converting raw line signals into synchronous digital streams usable by MAC or framer ICs.

Use Value: Supports both T1 and CEPT standards via RCLKSEL pin, enabling single-hardware SKUs for global deployment without redesign.

Use Scenario: Used in legacy PBX-to-host computer gateways (e.g., DMI, CPI) to interface telephony signaling with data processing systems.

IC Role / Device Role / Timing Role: Receive interface extracting clock and data from E1/T1 trunks for protocol translation and call-control processing.

Use Value: Provides precise RCLK timing and error flags required for time-sensitive DMI frame alignment and CPI message parsing.

Equivalent & Alternatives

The following parts are listed as comparable options for similar T1/CEPT receive line interface applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS2187N+	Same die, 18-pin DIP package; lacks SOIC thermal and mounting advantages; identical electrical specs and pinout mapping.	Suitable for through-hole prototyping or legacy board upgrades where SOIC footprint is unavailable.	Select DS2187N+ only when DIP assembly is mandated; DS2187S/T&R preferred for automated SMT production and thermal performance.
DS2155	Single-chip T1/E1 transceiver (transmit + receive); higher integration but no ZCSEN control or independent alarm flag granularity.	Applicable where bidirectional line interface is needed and space constraints favor monolithic solution over discrete Tx/Rx pairing.	Choose DS2155 if transmit functionality is also required; DS2187S/T&R remains optimal for dedicated receive-only, high-alarm-visibility designs.

Compared with DS2187N+, DS2187S/T&R offers superior thermal dissipation and SMT manufacturability; compared with DS2155, it delivers finer-grained alarm reporting and independent receive optimization - making it ideal for CSU, DACS, and CPE applications demanding reliability and diagnostic transparency.

Availability

DS2187S/T&R is available at Aetrix Electronics and suitable for channel service units, digital access and cross-connect systems, and customer premises equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for DS2187S/T&R 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 semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for communications, industrial, and computing markets.

The DS2187S/T&R belongs to Maxim's telecom line interface product line, designed specifically for robust, low-jitter clock and data recovery in T1/E1 terminal equipment operating in short-loop environments such as CSU, DACS, and PABX interfaces.

FAQ

What is the primary function of the DS2187S/T&R in a T1/CEPT system?

The DS2187S/T&R serves as a dedicated receive line interface IC that extracts clock and data from bipolar-encoded T1 (1.544 MHz) or CEPT (2.048 MHz) transmission lines. It performs clock recovery using an integrated FLL/DPLL architecture, decodes AMI/B8ZS/HDB3 signals, and reports alarms (AIS, RCL, BPV) - all within a single 5V CMOS device. Its role is strictly receive-side physical layer termination.

Does the DS2187S/T&R require an external crystal or oscillator?

No, the DS2187S/T&R does not require an external crystal or oscillator. It incorporates a laser-trimmed on-chip voltage-controlled oscillator (VCO) generating 18.528 MHz for T1 and 24.576 MHz for CEPT modes, eliminating external timing components and manual tuning - a key differentiator confirmed in its official features list and block diagram.

How does the DS2187S/T&R handle B8ZS and HDB3 line coding?

The DS2187S/T&R natively decodes both B8ZS (for T1, when RCLKSEL = 0) and HDB3 (for CEPT, when RCLKSEL = 1). When ZCSEN is high, it replaces decoded codewords with all-zero sequences at RPOS/RNEG outputs; when ZCSEN is low, codewords pass through unchanged - a behavior explicitly defined in Pin Description Table 1 and the 0 Code Suppression section.

What are the power supply requirements for the DS2187S/T&R?

The DS2187S/T&R requires a single 5V supply with tight regulation: 4.75 V to 5.25 V across both AVDD and DVDD pins. It separates analog (AVDD/AVSS) and digital (DVDD/DVSS) supplies to minimize noise coupling, and draws 18–25 mA typical supply current - values verified in the Recommended DC Operating Conditions and DC Electrical Characteristics tables.

Can the DS2187S/T&R be used in both T1 and CEPT applications without hardware change?

Yes, the DS2187S/T&R supports both standards via the RCLKSEL pin: grounding it selects T1 (1.544 MHz) mode, tying it to DVDD selects CEPT (2.048 MHz) mode. All core functions - clock recovery, decoding, alarm reporting - adapt automatically, enabling one hardware design to serve global deployments, as stated in the Features and Pin Description sections.

DS2187S/T&R Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Receive Line Interface

Interface:: T1

Number of Circuits:: 1

Voltage - Supply:: 4.75V ~ 5.25V

Current - Supply:: 18mA

Power (Watts):: -

Operating Temperature:: 0°C ~ 70°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

DS2187S/T&R FAQ

1.How can I place an order for DS2187S/T&R through Aetrix?

Please submit a Request for Quotation (RFQ) for DS2187S/T&R 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 DS2187S/T&R reliable?

The price and inventory of DS2187S/T&R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2187S/T&R is usually 5 days.

3.What payment methods are accepted for DS2187S/T&R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2187S/T&R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS2187S/T&R?

DS2187S/T&R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS2187S/T&R 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 DS2187S/T&R?

For technical support, including DS2187S/T&R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2187S/T&R requirements.

6.How does Aetrix verify that DS2187S/T&R is sourced from the original manufacturer or authorized distributors?

All DS2187S/T&R 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 DS2187S/T&R meets industry standards.

7.What is the process for return or replacement of DS2187S/T&R?

All DS2187S/T&R units undergo pre-shipment inspection (PSI). If there is an issue with DS2187S/T&R, 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 DS2187S/T&R part is unused and in its original packaging.

Return procedure for DS2187S/T&R:

1.Submit a request within 90 days.

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

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