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Analog Devices Inc./Maxim Integrated DS2148T
- Part No.:
- DS2148T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 44-TQFP
- Datasheet:
-
DS2148T.pdf
- Description:
- IC TELECOM INTERFACE 44TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,526
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Product details
Overview
DS2148T from Maxim Integrated is a single-channel, 5V E1/T1/J1 Line Interface Unit (LIU) supporting both short- and long-haul trunks, with software-selectable 75Ω/100Ω/120Ω receive termination, crystal-less jitter attenuation (32-bit or 128-bit FIFO), and AMI/HDB3/B8ZS encoding/decoding - deployed in telecom access equipment for E1/T1 line termination.
For engineers reviewing the DS2148T datasheet, DS2148T pinout, DS2148T application, or DS2148T equivalent, key selection considerations include hardware-mode configuration support, 44-pin TQFP package compatibility, 5V-only operation, G.703/G.775 compliance, and dual-path jitter attenuator placement flexibility in transmit or receive data paths.
Technical Context
The DS2148T implements full E1 (2.048MHz) and T1 (1.544MHz) physical layer functions including clock/data recovery, bipolar-to-NRZ conversion, line build-out synthesis (0dB to –22.5dB), and G.775-compliant Receive Carrier Loss detection. Its analog front-end accepts transformer-coupled RTIP/RRING inputs and drives TTIP/TRING outputs via external step-up transformers.
It supports three control interfaces - parallel (muxed/non-muxed Intel/Motorola), serial (SPI-like), and hardware mode - with dedicated pins for BIS0/BIS1, PBTS, and HRST. The jitter attenuator uses MCLK-derived timing and synthesizes BPCLK outputs at 2.048MHz, 4.096MHz, 8.192MHz, or 16.384MHz referenced to RCLK.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 5.0V ±5% - requires single-rail 5V supply; VSM pin must be tied high for valid operation. |
| Operating Temperature | 0°C to +70°C - commercial-grade thermal range suitable for indoor telecom infrastructure. |
| Package | 44-pin TQFP - surface-mount, lead-free RoHS-compliant package with 0.8mm pitch. |
| Jitter Attenuation Depth | 32-bit or 128-bit FIFO - selectable depth determines jitter filtering bandwidth and latency trade-off. |
| Line Build-Out Range | E1: 0dB to –22.5dB (75Ω/120Ω); T1: 0dB to –22.5dB (DSX-1/CSU) - programmable analog output shaping per ITU/ANSI standards. |
| Encoding Standards | AMI, HDB3 (E1), B8ZS (T1) - fully compliant encoding/decoding with automatic protocol detection. |
| Receive Sensitivity | E1: 0dB to –43dB; T1: 0dB to –36dB - enables operation over 2.5km E1 cable or 6k ft T1 cable. |
Pinout & Package
DS2148T is housed in a 44-pin Thin Quad Flat Package (TQFP), measuring 10mm × 10mm × 1.4mm, with exposed thermal pad and RoHS-compliant lead finish. Pin assignments are validated for Hardware Mode (BIS1=1, BIS0=1) per Table 2-7 of the datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RTIP / RRING | Analog Receive Inputs | Transformer-coupled differential inputs for E1/T1 waveform acquisition; support internal 75Ω/100Ω/120Ω termination selection. |
| TTIP / TRING | Analog Transmit Outputs | Differential line driver outputs requiring external step-up transformer; support CSU/DSX-1/E1 waveshaping per G.703. |
| RPOS / RNEG | Bipolar/NRZ Data Outputs | Recovered data outputs synchronized to RCLK; configurable edge-triggered sampling and NRZ mode via CCR1.6. |
| TPOS / TNEG | Bipolar/NRZ Data Inputs | Transmit data inputs sampled on TCLK edges; polarity and timing controlled by CCR2.1. |
| RCLK | Recovered Clock Output | Buffered line-recovered clock; used as reference for BPCLK synthesis and system synchronization. |
| MCLK | Master Clock Input | 2.048MHz (±50ppm) TTL-level input for clock/data recovery and jitter attenuation; 1.544MHz optional for T1. |
| BIS0 / BIS1 | Bus Interface Select | Hardware-mode enable (BIS1=1, BIS0=1); defines fixed-function pin behavior without register programming. |
| HRST | Hardware Reset Input | Active-low asynchronous reset that forces all control registers to default state (all zeros). |
Key Features
| Feature | Design Value |
|---|---|
| Crystal-less jitter attenuation | Eliminates need for external crystal oscillator; uses only 2.048MHz MCLK for E1/T1 operation with selectable 32/128-bit FIFO depth. |
| Software-selectable receive termination | Enables field-configurable impedance matching (75Ω/100Ω/120Ω) without hardware changes or external components. |
| G.775-compliant RCL detection | Provides standardized Receive Carrier Loss flagging with 5µs ±2µs timeout on RCL/LOTC pin for system alarm integration. |
| Multi-standard encoding/decoding | Single device supports AMI (E1/T1), HDB3 (E1), and B8ZS (T1) - reduces BOM count in multi-region deployments. |
| Hardware mode operation | Fixed-function configuration via BIS0/BIS1 pins eliminates firmware dependency for basic LIU functionality. |
| PRBS generation/detection | On-chip 2¹⁵–1 and 2²⁰–1 pattern support with PBEO pulse output and error counter registers for link integrity testing. |
Applications
| DSLAM Line Card | TDM Access Gateway |
|---|---|
|
Use Scenario: Aggregating multiple E1/T1 lines from copper loops into a packet-switched backhaul network. IC Role / Device Role / Timing Role: Physical layer line interface unit performing clock recovery, signal conditioning, and G.703-compliant waveform generation. Use Value: Enables interoperability with legacy telco infrastructure while supporting hardware-mode bootstrapping for rapid deployment. |
Use Scenario: Providing T1/E1 connectivity in enterprise-class VoIP gateways with integrated channelized TDM switching. IC Role / Device Role / Timing Role: Dual-role LIU handling both transmit waveform shaping and receive sensitivity adaptation across mixed E1/T1 environments. Use Value: Reduces external component count with integrated line build-out, termination, and jitter attenuation - lowering PCB area and bill-of-materials cost. |
| Remote Terminal Unit (RTU) | Cell Site Synchronization Unit |
|
Use Scenario: Deploying in outdoor cabinets for last-mile T1/E1 demarcation with minimal power and thermal overhead. IC Role / Device Role / Timing Role: Standalone line interface with hardware-mode configuration and 5V-only supply simplifying power design. Use Value: Eliminates need for voltage translation or clock synthesis ICs - streamlines design for temperature-limited industrial enclosures. |
Use Scenario: Delivering precise timing reference from E1/T1 lines to baseband processors in macrocell BTS systems. IC Role / Device Role / Timing Role: Jitter-attenuated RCLK and synthesized BPCLK outputs serve as low-jitter system clocks for FPGA/DSP timing domains. Use Value: Provides traceable, standards-compliant timing derived directly from line sync - avoiding external PLLs or jitter cleaners. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar line interface unit applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS2148TN | Same silicon, –40°C to +85°C extended temperature grade; identical pinout and electrical specs. | Suitable for outdoor or industrial environments where ambient exceeds +70°C. | Select DS2148TN when operating temperature range must cover –40°C to +85°C; otherwise DS2148T suffices for commercial indoor use. |
| DS21Q48 | Quad-channel version in 144-ball CSBGA; shares core LIU architecture but differs in pin count, package, and channel density. | Targeted at high-density line cards requiring four independent E1/T1 ports on one IC. | Choose DS21Q48 only when multi-channel integration justifies larger footprint and higher complexity; not a drop-in replacement. |
Compared with DS2148TN and DS21Q48, the DS2148T offers optimal cost and thermal performance for single-channel commercial-grade E1/T1 line termination, with no compromise on jitter attenuation, encoding compliance, or hardware-mode configurability.
Availability
DS2148T is available at Aetrix Electronics and suitable for DSLAM line cards, TDM access gateways, remote terminal units, cell site synchronization units, and telecom demarcation equipment requiring stable component supply and long-term lifecycle support.
Supply support for DS2148T 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 communications, industrial, and computing markets.
The DS2148T belongs to Maxim's legacy telecom line interface portfolio, designed specifically for E1/T1/J1 physical layer termination in carrier-grade access equipment with emphasis on jitter resilience, standard compliance, and hardware configurability.
FAQ
What is the operating voltage requirement for the DS2148T?
The DS2148T requires a single 5.0V ±5% supply. The VSM pin must be tied high to enable 5V operation; operation outside this range or with VSM low is undefined and nonfunctional. No 3V or dual-supply capability exists - confirmed in revision history note #8 (082504) which removed all 3V references.
Does the DS2148T support both E1 and T1 standards simultaneously?
Yes, the DS2148T supports both E1 (2.048MHz) and T1 (1.544MHz) standards in a single device. It auto-adapts encoding (HDB3 for E1, B8ZS for T1), line build-out profiles, and receive sensitivity ranges based on configuration bits (ETS bit in CCR1.7). MCLK can be either 2.048MHz (default) or 1.544MHz for T1-only use.
Can the DS2148T operate without firmware initialization?
Yes - the DS2148T supports hardware mode (BIS1=1, BIS0=1), where pin-strapped configuration enables fixed-function operation without register writes. In this mode, default settings apply for termination, encoding, and loopback control, making it suitable for boot-time line interface functionality before host processor initialization.
What is the purpose of the RCL/LOTC pin on the DS2148T?
The RCL/LOTC pin on the DS2148T serves dual functions: when CCR2.7 = 0 (default in hardware mode), it asserts high during Receive Carrier Loss per ITU-T G.775; when CCR2.7 = 1, it toggles high if TCLK remains inactive for 5µs ±2µs, indicating Loss of Transmit Clock. This dual-mode alarm output simplifies integration with system monitoring logic.
Is the DS2148T pin-compatible with other variants like DS2148GN?
No - the DS2148T (44-pin TQFP) is not pin-compatible with DS2148GN (49-ball CSBGA). They share functional equivalence and register mapping but differ in package type, pin count, thermal pad configuration, and mechanical layout. Board redesign is required to substitute between TQFP and CSBGA variants; migration must account for routing, decoupling, and thermal management differences.
DS2148T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 44-TQFP
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Line Interface Unit (LIU)
- Interface:
- LIU
- Number of Circuits:
- 1
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Supply:
- 95mA
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 44-TQFP (10x10)
DS2148T FAQ
1.How can I place an order for DS2148T through Aetrix?
Please submit a Request for Quotation (RFQ) for DS2148T 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 DS2148T reliable?
The price and inventory of DS2148T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2148T is usually 5 days.
3.What payment methods are accepted for DS2148T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2148T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS2148T?
DS2148T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS2148T 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 DS2148T?
For technical support, including DS2148T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2148T requirements.
6.How does Aetrix verify that DS2148T is sourced from the original manufacturer or authorized distributors?
All DS2148T 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 DS2148T meets industry standards.
7.What is the process for return or replacement of DS2148T?
All DS2148T units undergo pre-shipment inspection (PSI). If there is an issue with DS2148T, 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 DS2148T part is unused and in its original packaging.
Return procedure for DS2148T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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