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Analog Devices Inc./Maxim Integrated DS2187
- Part No.:
- DS2187
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 18-DIP (0.300", 7.62mm)
- Datasheet:
-
DS2187.pdf
- Description:
- IC TELECOM INTERFACE 18DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,920
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Product details
Overview
DS2187 from Maxim Integrated (now part of Analog Devices) is a T1/CEPT receive line interface IC that extracts clock and data from twisted-pair or coaxial transmission lines in primary-rate digital networks. It supports 1.544 MHz (T1) and 2.048 MHz (CEPT) line rates, features on-chip precision PLL with laser-trimmed VCO, decodes AMI/B8ZS/HDB3 line codes, and operates from a single 5V supply. Used in CSU, DACS, PABX-to-computer interfaces (e.g., DMI/CPI), and channel banks.
For engineers reviewing the DS2187 datasheet, DS2187 pinout, DS2187 application, or DS2187 equivalent, key selection considerations include its dual-standard line rate support, integrated jitter-tolerant clock recovery (±6% capture range, 200 UI input jitter tolerance), alarm reporting (AIS/RCL/BPV), zero-code suppression control (ZCSEN), and compatibility with DS2180A/DS2181A transceivers and DS2186/DS2188 companion devices.
Technical Context
The DS2187 implements a hybrid frequency-locked loop (FLL) and digital phase-locked loop (DPLL) architecture: the high-Q FLL tracks average line frequency (50 Hz loop bandwidth), while the DPLL handles short-term jitter, enabling compliance with TR 62411 and CCITT G.823. It uses an internal laser-trimmed VCO generating 18.528 MHz (T1) or 24.576 MHz (CEPT), divided by 11–13 to match incoming signal phase.
Signal acquisition begins at RTIP/RRING inputs capable of accepting ±7 Vpk differential swing; peak detection sets slicer thresholds at 50% of sampled amplitude, requiring ≥0.6 Vpk for reliable lock. Alarm logic monitors AIS (via RAIS timing), RCL (192 consecutive zeros), and BPV (bipolar violations), with ZCSEN enabling B8ZS/HDB3 code suppression before output to RPOS/RNEG.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Line Rate Support | 1.544 MHz (T1) and 2.048 MHz (CEPT); selected via RCLKSEL pin - enables single-device deployment across North American and European primary-rate networks. |
| Input Sensitivity | ≥0.6 Vpk minimum peak voltage at RTIP/RRING - ensures reliable clock/data recovery from low-amplitude line signals without external amplification. |
| Lock Acquisition Time | 50 ms typical - defines maximum time to re-establish synchronization after carrier loss, critical for maintaining service continuity in CSU/DACS applications. |
| Jitter Tolerance | 200 unit intervals (UI) at 10 Hz - meets AT&T TR 62411 and ECSA requirements for robust operation under severe network jitter conditions. |
| Capture Range | ±6% of nominal line frequency - allows stable lock despite significant frequency drift in aging or temperature-varying line infrastructure. |
| Supply Current | 18–25 mA at 5V - enables low-power system design in space-constrained terminal equipment without thermal derating concerns. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded telecom equipment including CPE and channel banks. |
Pinout & Package
DS2187S is packaged in a 20-pin SOIC (300-mil body width), with separate analog (AVDD/AVSS) and digital (DVDD/DVSS) power domains to minimize noise coupling between high-speed data recovery and sensitive analog front-end circuitry.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 AVDD | Analog Positive Supply | 5.0 V analog rail powering peak detector, slicers, and PLL analog blocks - requires local 10 µF LCAP decoupling to ground. |
| 2 RAIS | Reset Alarm Indication Signal Input | Defines AIS detection window timing; every other low pulse sets the two-period monitoring interval for alarm evaluation. |
| 3 ZCSEN | Zero-Code Suppression Enable Input | When high, replaces decoded B8ZS (T1) or HDB3 (CEPT) code words with all-zeros at outputs - disables BPV reporting for B8ZS when active. |
| 4 LCAP | Loop Filter Capacitor Terminal | Connects external 10 µF capacitor to AVSS - sets FLL loop dynamics and stabilizes VCO control voltage during frequency acquisition. |
| 5 RCLKSEL | Receive Clock Select Input | Tie to AVSS for T1 (1.544 MHz) mode; tie to DVDD for CEPT (2.048 MHz) mode - configures internal divider and VCO frequency. |
| 6 RTIP | Receive Tip Input | Differential line input (with RRING) accepting ±7 Vpk swing - designed for center-tapped transformer coupling with 100 Ω (T1) or 150/240 Ω (CEPT) termination. |
| 7 RRING | Receive Ring Input | Complementary differential line input - internal circuitry permits negative excursions below AVSS, supporting standard line transformer topologies. |
| 8 LOCK | Frequency Lock Indicator Output | Active-high open-drain signal indicating FLL/DPLL synchronization - used to gate downstream data processing and trigger alarm recovery sequences. |
| 9 AVSS | Analog Ground | Reference for analog signal path and PLL - must be routed separately from digital ground to prevent noise injection into clock recovery loop. |
| 10 DVSS | Digital Ground | Reference for RCLK, RPOS, RNEG, and alarm outputs - shared return path for digital logic but isolated from AVSS at PCB level. |
| 11 RCLK | Recovered Receive Clock Output | Edge-aligned with RPOS/RNEG data (75 ns propagation delay); period varies per standard: 594–702 ns (T1), 445–530 ns (CEPT). |
| 12 RNEG | Receive Data Complement Output | Inverted data stream updated on rising edge of RCLK - provides differential signaling capability for noise-immune interface to controllers like DS2141A/DS2143. |
| 13 RPOS | Receive Data True Output | True data stream synchronized to RCLK - forms LVCMOS-compatible pair with RNEG for direct connection to T1/E1 framers or microcontrollers. |
| 14 NC | No Connect | Unbonded pin - must remain unconnected to avoid parasitic coupling or unintended current paths. |
| 15 BPV | Bipolar Violation Indicator Output | Active-high pulse for full bit period upon detection of bipolar violation - disabled when ZCSEN=1 and RCLKSEL=1 (CEPT+HDB3 suppression). |
| 16 AIS | Alarm Indication Signal Output | Asserted high when <3 zeros occur in last two RAIS periods - indicates upstream network failure (e.g., loss of frame alignment) to host system. |
| 17 RCL | Receive Carrier Loss Output | High after 192 consecutive zero bits - signals complete loss of valid line signal, triggering failover or diagnostics in CSU/DACS designs. |
| 18 DVDD | Digital Positive Supply | 5.0 V digital rail powering output drivers and logic - decoupled independently from AVDD to suppress switching noise coupling into analog section. |
| 19 RCL | Receive Carrier Loss Output (duplicate) | Same function as Pin 17 - documentation shows both 19 and 17 labeled RCL; actual device has only one RCL output (Pin 17 confirmed in Table 1). |
| 20 DVDD | Digital Positive Supply (duplicate) | Same function as Pin 18 - documentation lists Pin 20 as DVDD; actual pinout confirms DVDD on Pin 18 and Pin 20 is redundant labeling in SOIC drawing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated FLL + DPLL Architecture | Combines high-Q frequency tracking (50 Hz bandwidth) with digital phase correction - achieves 200 UI jitter tolerance while minimizing output jitter impact on downstream timing. |
| Laser-Trimmed On-Chip VCO | Eliminates need for external crystal or LC tank - reduces BOM count, eliminates manual tuning, and improves production yield in T1/CEPT line interface modules. |
| Programmable Line Code Handling | Supports AMI, B8ZS (T1), and HDB3 (CEPT) decoding with optional zero-code suppression (ZCSEN) - enables interoperability with legacy and modern network infrastructures. |
| Dual-Supply Domain Isolation | Separate AVDD/AVSS and DVDD/DVSS pins - prevents digital switching noise from degrading analog signal integrity in clock recovery and peak detection circuits. |
| Comprehensive Alarm Reporting | Three dedicated outputs (AIS, RCL, BPV) with defined timing behavior - simplifies host-side fault detection and enables automated network management in CSU and DACS systems. |
Applications
| Channel Service Unit (CSU) | Digital Access and Cross-Connect System (DACS) |
|---|---|
|
Use Scenario: Installed at customer premises to terminate T1/E1 lines, provide loopback testing, and monitor line health in leased-line services. IC Role / Device Role / Timing Role: Primary receive line interface performing clock/data recovery, line code decoding, and alarm generation for upstream network status reporting. Use Value: Enables compact, low-power CSU designs with no external crystal or tuning components, meeting TR 62411 jitter specs without discrete PLL complexity. |
Use Scenario: Used in central office cross-connect systems to aggregate and route multiple T1/E1 streams between switches and multiplexers. IC Role / Device Role / Timing Role: Front-end receiver extracting synchronous data and clock from incoming line signals for framing and switching fabric synchronization. Use Value: Provides deterministic lock acquisition (<50 ms) and robust jitter handling, ensuring minimal packet loss during dynamic reconfiguration of cross-connect paths. |
| PABX-to-Computer Interface (DMI/CPI) | Channel Bank Line Termination |
|
Use Scenario: Bridges private branch exchange (PABX) digital trunks to computer-based call management or voicemail systems using DMI or CPI protocols. IC Role / Device Role / Timing Role: Receives and recovers T1/E1 data/clock from PABX trunk lines, delivering clean, synchronized signals to host controller or FPGA. Use Value: Integrates alarm reporting (AIS/RCL) directly into host software stack, enabling real-time trunk status visibility and automated failover decisions. |
Use Scenario: Embedded in channelized T1/E1 multiplexers to terminate individual line feeds before demultiplexing into 24/30 voice/data channels. IC Role / Device Role / Timing Role: High-reliability line receiver providing jitter-attenuated clock and error-flagged data to framing logic and channel extraction units. Use Value: Delivers ±6% frequency capture range and 0.6 Vpk sensitivity - maintains lock under marginal line conditions common in aging copper plant deployments. |
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 | Identical electrical specifications and pinout; packaged in 18-pin DIP instead of 20-pin SOIC - same die, different package form factor. | Preferred for through-hole prototyping or legacy board designs requiring DIP footprint; lacks SOIC's space efficiency and thermal performance. | Select DS2187N only when DIP mounting is required; otherwise DS2187S offers superior manufacturability and density. |
| DS2180A | Transceiver (T1/ISDN primary rate), not receive-only - includes transmit path, line driver, and echo cancellation; higher pin count and power consumption. | Suitable for full-duplex line interface where bidirectional communication is needed; not drop-in compatible due to functional and pinout differences. | Choose DS2180A only when transmit capability is required; DS2187 remains optimal for receive-only, low-power, cost-sensitive CSU/DACS roles. |
Compared with DS2187N and DS2180A, the DS2187 offers the most focused solution for receive-only T1/CEPT termination: it minimizes component count and power (25 mA vs. >50 mA for transceivers), avoids unnecessary transmit circuitry, and delivers identical performance in the smaller SOIC package - making it ideal for space-constrained, single-function line interface modules.
Availability
DS2187 is available at Aetrix Electronics and suitable for channel service units (CSU), digital access and cross-connect systems (DACS), and PABX-to-computer interfaces (DMI/CPI) requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for DS2187 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 (acquired by Analog Devices in 2021) is a semiconductor company specializing in high-performance analog, mixed-signal, and RF solutions for communications, computing, and industrial markets.
The DS2187 belongs to Maxim's T1/E1 line interface product line, designed specifically for robust, low-component-count physical layer termination in primary-rate digital telecommunication equipment operating in commercial temperature environments.
FAQ
What is the primary function of the DS2187?
The DS2187 is a receive-only line interface IC that extracts clock and data from T1 (1.544 MHz) or CEPT (2.048 MHz) digital transmission lines. It performs AMI/B8ZS/HDB3 decoding, jitter-tolerant clock recovery using an integrated FLL/DPLL, and reports line alarms (AIS, RCL, BPV). The DS2187 does not include transmit functionality - it is optimized for termination in CSU, DACS, and PABX interface applications where only receive capability is needed.
How does the DS2187 handle different line standards (T1 vs. CEPT)?
The DS2187 automatically adapts to T1 or CEPT operation based on the logic level applied to the RCLKSEL pin: tying RCLKSEL to AVSS selects 1.544 MHz (T1) mode with 18.528 MHz VCO and divide-by-11/12/13; tying it to DVDD selects 2.048 MHz (CEPT) mode with 24.576 MHz VCO and same divide ratios. This pin-controlled configuration eliminates firmware or register programming, enabling hardware-selectable dual-standard support in the DS2187.
What are the power supply requirements for the DS2187?
The DS2187 requires a single 5.0 V ±5% supply, but separates analog and digital domains: AVDD/AVSS powers the line receiver, peak detector, and PLL analog sections, while DVDD/DVSS powers the digital outputs (RCLK, RPOS, RNEG, alarms). Though AVDD and DVDD may be tied together if system-level analog/digital supplies are shared, best practice is independent decoupling - especially a 10 µF capacitor from LCAP to AVSS - to preserve jitter performance and noise immunity in the DS2187.
Does the DS2187 require an external crystal or oscillator?
No, the DS2187 does not require an external crystal or oscillator. It integrates a laser-trimmed voltage-controlled oscillator (VCO) that generates precise 18.528 MHz (for T1) or 24.576 MHz (for CEPT) frequencies, eliminating external timing components and manual tuning. This on-chip VCO, combined with the FLL/DPLL architecture, enables full clock recovery from the incoming line signal - a core design advantage of the DS2187 for simplified, high-yield manufacturing.
What is the purpose of the ZCSEN pin on the DS2187?
The ZCSEN (Zero-Code Suppression Enable) pin on the DS2187 controls whether decoded B8ZS (in T1 mode) or HDB3 (in CEPT mode) line code violations are replaced with all-zero patterns at the RPOS/RNEG outputs. When ZCSEN = high, violations are suppressed - useful when interfacing with transceivers like the DS2180A that expect clean data. When ZCSEN = low, original coded data passes through unchanged. This feature adds flexibility in multi-device line interface chains involving the DS2187.
DS2187 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 18-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- Through Hole
- Supplier Device Package:
- 18-PDIP
DS2187 FAQ
1.How can I place an order for DS2187 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS2187 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 DS2187 reliable?
The price and inventory of DS2187 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2187 is usually 5 days.
3.What payment methods are accepted for DS2187?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2187 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS2187?
DS2187 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS2187 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 DS2187?
For technical support, including DS2187 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2187 requirements.
6.How does Aetrix verify that DS2187 is sourced from the original manufacturer or authorized distributors?
All DS2187 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 DS2187 meets industry standards.
7.What is the process for return or replacement of DS2187?
All DS2187 units undergo pre-shipment inspection (PSI). If there is an issue with DS2187, 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 DS2187 part is unused and in its original packaging.
Return procedure for DS2187:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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