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Analog Devices Inc./Maxim Integrated DS2149Q+
- Part No.:
- DS2149Q+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 28-LCC (J-Lead)
- Datasheet:
-
DS2149Q+.pdf
- Description:
- IC TELECOM INTERFACE 28PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,629
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Product details
Overview
DS2149Q+ from Maxim Integrated is a fully integrated T1 Line Interface Unit (LIU) for long-haul and short-haul twisted-pair applications, supporting ANSI T1.102/T1.403/T1.408 and AT&T 62411 standards, with crystal-less jitter attenuation, programmable line build-out (0dB to –22.5dB), and bipolar/NRZ interface capability - deployed in DSUs, CSUs, and T1 test equipment.
For engineers reviewing the DS2149Q+ datasheet, DS2149Q+ pinout, DS2149Q+ application, or DS2149Q+ equivalent, this page delivers verified technical context, real-world timing role definitions, confirmed pin functions per hardware/software mode, and validated alternatives for T1 LIU selection in carrier-grade telecom infrastructure.
Technical Context
The DS2149Q+ implements a dual-path analog front-end with independent transmit driver (TTIP/TRING) and receive equalizer (RTIP/RRING), supporting automatic receive sensitivity adjustment across –18dB, –26dB, and –36dB thresholds. Its on-chip crystal-less jitter attenuator operates at 1.544MHz reference clock input and offers selectable 32-bit or 128-bit FIFO depth.
Control is implemented via either hardware mode (dedicated pins for LBO, loopback, and jitter path selection) or serial port mode (SCLK/SDI/SDO/CS), with register-mapped diagnostics including QRSS generation/detection, in-band loop-up/down code handling, and real-time status reporting via RCL, DFMO, and NLOOP outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| T1 Data Rate | 1.544MHz - precisely matches DS1 framing; requires MCLK input at this frequency for PLL lock and jitter attenuation. |
| Jitter Attenuator Path | Programmable to transmit or receive path - selected via JASEL pin or CR1[7:6]; enables flexible clock cleanup placement in system timing architecture. |
| Receive Sensitivity Range | 0dB to –36dB - supports operation over 6k ft of 22AWG cable; gain settings configurable via EQZMON20/EQZMON26 bits. |
| Line Build-Out Options | Five discrete settings (0dB, –7.5dB, –15dB, –22.5dB, 6V) - maps directly to DSX-1 and D4 short-haul/long-haul cable lengths per Table 4-E. |
| CSU Filter Attenuation | 0dB to –22.5dB in 7.5dB steps - provides precise impedance matching and signal shaping for legacy T1 network interfaces. |
| Diagnostic Outputs | Driver-Fail (DFMO), Monitor-Open (RCL), Loss-of-Signal (NLOOP) - active-high TTL-level signals for real-time fault isolation without host CPU polling. |
| Interface Mode Support | Bipolar (AMI) or NRZ - selected via ENCENB/UNIENB bits; B8ZS encoding/decoding enabled independently for NRZ operation. |
Pinout & Package
DS2149Q+ is housed in a 28-pin Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, rated for 0°C to +70°C operation and compatible with standard PLCC socketing and reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (MCLK) | Master Clock Input | 1.544MHz TTL-level reference for internal PLL and jitter attenuator; required for all operational modes. |
| 3 (TPOS)/4 (TNEG) | Transmit Bipolar Data Inputs | Sampled on falling edge of TCLK; drive line formatter for AMI output on TTIP/TRING. |
| 6 (RNEG)/7 (RPOS) | Receive Bipolar Data Outputs | Updated on rising/falling edge of RCLK per CCR2.0; provide recovered bipolar data stream post-equalization. |
| 11 (JASEL) | Jitter Attenuator Path Select | Hardware-mode control: 0 = transmit path, 1 = receive path, float = disabled - no software register override. |
| 13/16 (TTIP/TRING) | Transmit Analog Outputs | Differential line driver outputs; connect via step-up transformer to twisted-pair; support up to 6V peak-to-peak swing. |
| 19/20 (RTIP/RRING) | Receive Analog Inputs | Differential line receiver inputs; connect via 1:1 transformer; enable automatic sensitivity adaptation from 0dB to –36dB. |
| 26 (RLB) | Remote Loopback Control | Hardware-activated: high = route inbound RTIP/RRING data to TTIP/TRING at recovered clock rate - used for network diagnostics. |
| 27 (LLB) | Local Loopback Control | Hardware-activated: high = digital loopback of TPOS/TNEG to RPOS/RNEG; float = analog loopback (TTIP/TRING → RTIP/RRING). |
Key Features
| Feature | Design Value |
|---|---|
| Crystal-less jitter attenuation | Eliminates external crystal oscillator requirement while meeting T1 jitter tolerance (Figure 11-3) and attenuation (Figure 11-4) specs at 1.544MHz. |
| Programmable line build-out | Five discrete settings map directly to T1 cable length segments (0–655 ft for short-haul, up to 6k ft for long-haul), enabling single-device deployment across multiple field configurations. |
| In-band loop-up/down detection | Hardware-accelerated recognition of AT&T 62411-defined 00001 (loop-up) and 001 (loop-down) codes - triggers NLOOP output and IR.LUP/LDN flags without host intervention. |
| QRSS pattern generation & detection | On-chip quasirandom signal source and detector enable bit-error-rate testing with no external pattern generator; QPD output pulses on error detection. |
| Dual-mode control interface | Pin-strapped hardware mode allows standalone operation in headless systems; serial port mode (SCLK/SDI/SDO/CS) enables full register access and dynamic reconfiguration. |
Applications
| Data Service Unit (DSU) | Channel Service Unit (CSU) |
|---|---|
Use Scenario: Aggregating customer premise data into T1 trunks for telco handoff. IC Role / Device Role / Timing Role: DS2149Q+ serves as the physical layer line interface, providing T1 framing alignment, jitter cleanup, and line drive/receive conditioning. Use Value: Meets ANSI T1.403 long-haul requirements and supports automatic receive sensitivity adaptation across varying loop lengths - reducing field calibration effort. |
Use Scenario: Providing T1 termination, monitoring, and alarm signaling at central office demarcation points. IC Role / Device Role / Timing Role: DS2149Q+ acts as the CSU's analog front-end, delivering CSU filter attenuation (0dB to –22.5dB), AIS generation, and RCL detection. Use Value: Four programmable CSU filters and integrated driver-fail/monitor-open outputs enable compliance with AT&T 62411 CSU specifications without external comparators. |
| T1/E1 Test Equipment | Routers with T1 WAN Interfaces |
Use Scenario: Field-portable T1 bit-error and loopback validation in telecom maintenance. IC Role / Device Role / Timing Role: DS2149Q+ provides local/remote/analog/network loopbacks, QRSS generation/detection, and in-band code handling - all under hardware or serial control. Use Value: Eliminates need for external loopback switches or pattern generators; NLOOP, RCL, and QPD outputs feed directly into pass/fail logic. |
Use Scenario: Embedded T1 WAN interface on enterprise or service-provider routers. IC Role / Device Role / Timing Role: DS2149Q+ functions as the line-side PHY, interfacing FPGA/MCU to twisted-pair, managing jitter, and reporting alarms (AIS, RCL, DFMO) to host. Use Value: Serial register interface enables runtime configuration of line code (AMI/B8ZS), build-out, and diagnostic modes - supporting multi-region T1 deployments from one BOM. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar T1 line interface unit applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS2155Q+ | Successor device with enhanced jitter performance (±50ppm vs. ±32ppm), extended temperature range (–40°C to +85°C), and added E1 support - not pin-compatible; requires PCB redesign. | Required for new designs targeting E1 compatibility or wider industrial temp range; unsuitable for drop-in DS2149Q+ replacement. | Select DS2155Q+ only when E1 support or extended temperature is mandatory; retains same register map and software interface. |
| MC145508P | Legacy Motorola LIU with fixed –15dB build-out, no crystal-less jitter attenuation, and no serial interface - requires external clock, comparator, and loopback switches. | Suitable only for cost-sensitive, low-feature legacy replacements where diagnostics and flexibility are secondary. | Choose MC145508P only for brownfield repairs with identical footprint constraints; lacks DS2149Q+'s diagnostic automation and configurability. |
Compared with DS2149Q+, DS2155Q+ adds E1 capability and tighter clock accuracy but demands layout changes, while MC145508P offers basic T1 functionality at lower integration - making DS2149Q+ the optimal balance of feature depth, field adaptability, and design maturity for mid-life telecom infrastructure.
Availability
DS2149Q+ is available at Aetrix Electronics and suitable for data service units, channel service units, and T1 test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for DS2149Q+ 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 precision analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.
The DS2149Q+ belongs to Maxim's T1/E1 line interface portfolio, designed specifically for carrier-class telecom infrastructure requiring ANSI/AT&T-compliant physical layer performance, robust diagnostics, and field-deployable flexibility.
FAQ
What is the operating temperature range for DS2149Q+?
The DS2149Q+ is specified for operation from 0°C to +70°C ambient temperature. This grade corresponds to commercial temperature range and is validated per the DS2149Q ordering option (distinct from DS2149QN, which supports –40°C to +85°C). All electrical characteristics, including jitter attenuation, receive sensitivity, and line build-out accuracy, are guaranteed within this range.
Does DS2149Q+ require an external crystal oscillator?
No, DS2149Q+ does not require an external crystal oscillator. It features a crystal-less jitter attenuator that uses the 1.544MHz MCLK input as its reference - eliminating crystal BOM cost, board space, and aging-related drift. The jitter attenuator meets ANSI T1.102 and AT&T 62411 requirements without external timing components.
How is the jitter attenuator path selected on DS2149Q+?
The jitter attenuator path on DS2149Q+ is selected via the JASEL pin (Pin 11) in hardware mode: logic low places it in the transmit path, logic high places it in the receive path, and floating disables it. In serial port mode, the same function is controlled by CR1[7:6] (JASEL1/JASEL0 bits), with values 01 for transmit and 11 for receive per Table 4-C.
Can DS2149Q+ support both AMI and B8ZS line coding?
Yes, DS2149Q+ supports both AMI and B8ZS line coding. AMI is used in bipolar mode (ENCENB=0, UNIENB=0); B8ZS is enabled in NRZ mode (ENCENB=1). The B8ZS encoder/decoder is fully integrated - no external logic required - and operates at 1.544MHz with compliant pulse shapes per Figure 11-2.
What diagnostic loopback modes are available on DS2149Q+?
DS2149Q+ supports five diagnostic loopback modes: local (LLB pin), remote (RLB pin), analog (LLB float), network (in-band loop-up code), and dual (simultaneous local + remote). Each mode routes signal paths differently - e.g., analog loopback connects TTIP/TRING directly to RTIP/RRING - enabling isolation of transmitter, receiver, and transformer faults without external cabling.
DS2149Q+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Line Interface Unit (LIU)
- Interface:
- LIU
- Number of Circuits:
- 1
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-PLCC (11.51x11.51)
DS2149Q+ FAQ
1.How can I place an order for DS2149Q+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS2149Q+ 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 DS2149Q+ reliable?
The price and inventory of DS2149Q+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2149Q+ is usually 5 days.
3.What payment methods are accepted for DS2149Q+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2149Q+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS2149Q+?
DS2149Q+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS2149Q+ 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 DS2149Q+?
For technical support, including DS2149Q+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2149Q+ requirements.
6.How does Aetrix verify that DS2149Q+ is sourced from the original manufacturer or authorized distributors?
All DS2149Q+ 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 DS2149Q+ meets industry standards.
7.What is the process for return or replacement of DS2149Q+?
All DS2149Q+ units undergo pre-shipment inspection (PSI). If there is an issue with DS2149Q+, 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 DS2149Q+ part is unused and in its original packaging.
Return procedure for DS2149Q+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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