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Analog Devices Inc./Maxim Integrated DS21448
- Part No.:
- DS21448
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 144-BGA
- Datasheet:
-
DS21448.pdf
- Description:
- IC TELECOM INTERFACE 144BGA
- Quantity:
- Payment:
- Shipping:
Inventory:2,100
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Product details
Overview
DS21448 from Maxim Integrated is a quad-port E1/T1/J1 line interface unit (LIU) supporting simultaneous short-haul and long-haul trunk operation. It integrates four independent transmitters and receivers, delivers programmable line build-outs (0dB to –22.5dB), supports AMI/HDB3/B8ZS encoding/decoding, and operates from a single 3.3V supply - deployed in multiservice access platforms and central-office switches.
For engineers reviewing the DS21448 datasheet, DS21448 pinout, DS21448 application, or DS21448 equivalent, key selection considerations include its dual-standard E1/T1/J1 compatibility, crystal-less jitter attenuator with 2.048MHz/1.544MHz master clock support, software-selectable 75Ω/100Ω/120Ω receive termination, and JTAG boundary-scan compliance per IEEE 1149.1.
Technical Context
The DS21448 implements four fully independent LIU channels, each with integrated clock/data recovery, bipolar-to-NRZ conversion, and programmable transmit pulse shaping compliant with ITU G.703 (E1) and ANSI T1.403 (T1). Each channel features dedicated RCLK, TCLK, RPOS/RNEG, and TTIP/TRING I/O paths with configurable edge alignment and polarity control via CCR2.0 and CCR1.6.
Its jitter attenuator uses a 32-bit or 128-bit PLL-based architecture synchronized to MCLK, synthesizing backplane clocks at 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz - all phase-locked to recovered RCLK. The device supports hardware-mode configuration for critical timing functions and includes PRBS generation/detection, in-band loop-code handling (1–16 bits), and AIS alarm detection per G.775.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| E1/T1/J1 Support | Fully independent quad-channel operation with selectable standard per channel via ETS bit; no shared resources between ports. |
| Line Build-Out Range | E1: G.703-compliant waveshapes for 75Ω or 120Ω; T1: DSX-1/CSU outputs at 0dB, –7.5dB, –15dB, –22.5dB with return-loss compensation. |
| Jitter Attenuation | Crystal-less 32-/128-bit PLL-based attenuator; accepts 2.048MHz (E1) or 1.544MHz (T1) master clock; recovers and cleans line-recovered clock. |
| Encoding/Decoding | AMI, HDB3 (E1), and B8ZS (T1) encoding/decoding per channel; real-time BPV/CV/EXZ error detection and reporting. |
| Receive Termination | Software-selectable internal termination: 75Ω, 100Ω, or 120Ω - eliminates need for external resistors in most line-interface configurations. |
| Interface Options | 8-bit parallel (Intel/Motorola timing, multiplexed/nonmultiplexed), serial SPI-compatible, or hardware mode - all sharing same physical pins via BIS0/BIS1. |
| Alarm & Diagnostics | Detects/generates Blue (AIS) alarms per G.775; provides RCL/LOTC outputs; supports local/remote/analog/dual loopbacks and PRBS pattern testing. |
Pinout & Package
DS21448 is available in two RoHS-compliant packages: 144-ball TE-PBGA (56-G6020-001) and 128-pin LQFP (56-G4011-001), both rated for 3.3V operation. Pin assignments differ between packages and depend on selected bus interface mode (parallel, serial, or hardware).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RTIP1–RTIP4 / RRING1–RRING4 | Analog receive inputs | Differential bipolar inputs for clock/data recovery; connect via 1:1 transformer to E1/T1 line; support internal 75Ω/100Ω/120Ω termination. |
| TTIP1–TTIP4 / TRING1–TRING4 | Analog transmit outputs | Differential bipolar line drivers; output G.703/T1-compliant pulses; include open-circuit detection and 50mARMS current limiting. |
| RPOS1–RPOS4 / RNEG1–RNEG4 | Recovered data outputs | NRZ or bipolar data aligned to RCLK edge (configurable); RNEG pulses indicate BPV/CV/EXZ errors synchronously with RCLK. |
| TPOS1–TPOS4 / TNEG1–TNEG4 | Transmit data inputs | Accept NRZ or bipolar data synchronized to TCLK; support hardware-mode framing and monitor gain control. |
| RCLK1–RCLK4 / TCLK1–TCLK4 | Recovered/transmit clocks | RCLK is buffered line-recovered clock; TCLK is host-provided transmit reference; both used for timing alignment and loopback control. |
| CS1–CS4 | Channel select enables | Active-low chip selects enabling register access to individual LIU channels; allow independent configuration without bus contention. |
| BIS0/BIS1 | Bus interface mode selector | Configures pin function mapping: parallel (multiplexed/nonmultiplexed), serial, or hardware mode - determines whether A0–A4/D0–D7 are address/data or control signals. |
| JTMS/JTCLK/JTDI/JTDO/JTRST | JTAG boundary-scan interface | Fully compliant with IEEE 1149.1; enables production test, interconnect verification, and in-system diagnostics without requiring functional firmware. |
Key Features
| Feature | Design Value |
|---|---|
| Quad independent E1/T1/J1 LIUs | Four isolated signal chains eliminate crosstalk and enable mixed-standard operation (e.g., two E1 + two T1 ports) on one die. |
| Crystal-less jitter attenuator | Eliminates external VCXO/TCXO; synthesizes stable backplane clocks from low-jitter 2.048MHz/1.544MHz input - reduces BOM count and layout area. |
| Programmable line build-out | Digitally selects precise T1 DSX-1/CSU or E1 G.703 output levels - avoids manual resistor networks and supports field reconfiguration. |
| Multi-mode bus interface | Single pinout supports Intel/Motorola parallel, SPI-like serial, or fixed-function hardware mode - simplifies host controller integration across product generations. |
| Comprehensive loopback suite | Local, remote, analog, and dual loopbacks per channel - enables full PHY-layer validation without external test equipment or line connection. |
| G.775-compliant AIS detection | Automatically detects Blue alarms on all four ports and asserts RCL/LOTC outputs - ensures interoperability with legacy telecom infrastructure. |
Applications
| Integrated Multiservice Access Platforms | T1/E1 Cross-Connects & Multiplexers |
|---|---|
Use Scenario: Aggregating legacy TDM traffic from multiple E1/T1 lines into packet-switched backhaul networks. IC Role / Device Role / Timing Role: Line interface unit providing physical layer termination, clock recovery, and jitter cleaning for four concurrent E1 or T1 trunks. Use Value: Enables deterministic latency and sub-50ppm frequency accuracy required for CESoPSN and SAToP transport over IP/MPLS. |
Use Scenario: Reconfigurable digital cross-connect systems routing DS1/E1 signals between central office switches and remote terminals. IC Role / Device Role / Timing Role: Quad-port LIU serving as physical interface for both ingress and egress TDM streams, with independent timing domains per port. Use Value: Supports hitless reconfiguration of line build-out and encoding schemes without service interruption - critical for maintenance windows. |
| Central-Office Switch Interfaces | Wireless Base Station Backhaul |
Use Scenario: Interfacing Class 5 switches with legacy PBX and channel banks using E1/T1 trunks. IC Role / Device Role / Timing Role: Physical layer bridge converting switch backplane NRZ data to G.703/T1 line signals with embedded AIS/alarm handling. Use Value: Meets ANSI T1.403 and ITU G.703 compliance out-of-box - eliminates need for custom analog front-end design and qualification. |
Use Scenario: Connecting BTS controllers to microwave or fiber backhaul links carrying E1/T1 Abis or Iub interfaces. IC Role / Device Role / Timing Role: Line interface providing robust clock recovery under variable jitter conditions and PRBS-based link integrity monitoring. Use Value: Built-in jitter attenuator maintains <1.5UI peak-to-peak jitter on recovered clock - satisfies 3GPP TS 25.423 timing stability requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad E1/T1 line interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS21Q348 | Pin-compatible upgrade with enhanced jitter performance (±50ppm vs ±100ppm), added J1 support, and improved ESD rating (±8kV HBM). | Targeted at new designs requiring tighter jitter tolerance and extended temperature range (–40°C to +85°C standard). | Select DS21Q348 for next-generation deployments where long-term lifecycle assurance and higher reliability are prioritized. |
| MAX3005 | Single-port E1/T1 LIU; lacks jitter attenuator, PRBS generator, and JTAG; supports only 128-pin LQFP package. | Suitable for cost-sensitive, low-density applications where quad integration is unnecessary and external clock clean-up is acceptable. | Choose MAX3005 only when scaling down to single-port requirement and accepting increased system-level jitter management overhead. |
Compared with DS21448, DS21Q348 offers superior jitter specs and broader environmental qualification but requires identical PCB layout; MAX3005 reduces integration density and removes on-chip jitter attenuation - increasing dependency on external clock conditioning circuitry.
Availability
DS21448 is available at Aetrix Electronics and suitable for integrated multiservice access platforms, T1/E1 cross-connects, and wireless base station backhaul systems requiring stable component supply across industrial temperature grades and long-lifecycle programs.
Supply support for DS21448 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 applications.
The DS21448 belongs to Maxim's telecom line interface portfolio, engineered specifically for carrier-grade TDM infrastructure requiring multi-standard E1/T1/J1 support, low-power 3.3V operation, and comprehensive diagnostic capabilities.
FAQ
What standards does the DS21448 comply with?
The DS21448 complies with ANSI T1.403-1999, ANSI T1.408, ITU-T G.703, G.704, G.706, G.736, G.775, G.823, I.431, O.151, O.161, ETSI ETS 300 166, and JTG.703. These cover physical layer signaling, framing, alarm handling, and jitter performance for E1 and T1 applications - ensuring interoperability with global telecom infrastructure.
Does the DS21448 require an external crystal oscillator?
No, the DS21448 does not require an external crystal oscillator. Its integrated 32-bit or 128-bit crystal-less jitter attenuator accepts a 2.048MHz master clock for E1 operation or a 1.544MHz clock for T1 operation - both referenced to TTL-level inputs. This eliminates the need for external VCXOs or TCXOs in most deployments.
How many independent line interfaces does the DS21448 provide?
The DS21448 provides four completely independent E1/T1/J1 line interfaces. Each channel has dedicated transmit and receive paths, separate RCLK/TCLK domains, individual CSx controls, and autonomous configuration registers - enabling mixed-standard operation (e.g., E1 on ports 1–2, T1 on ports 3–4) without resource sharing.
What package options are available for the DS21448?
The DS21448 is offered in two package variants: 144-ball TE-PBGA (56-G6020-001) and 128-pin LQFP (56-G4011-001). Both support industrial temperature ranges (0°C to +70°C and –40°C to +85°C), are RoHS-compliant, and operate from a single 3.3V supply. Pinouts differ between packages and must be verified per datasheet Section 11.
Can the DS21448 perform in-band loopback testing?
Yes, the DS21448 supports in-band loopback testing with programmable code lengths from 1 to 16 bits, including full CSU loop code compatibility. Loop codes are generated and detected per channel, with status reported via interrupt and status registers - enabling automated link validation without external test gear or physical loopback cables.
DS21448 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 144-BGA
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Line Interface Unit (LIU)
- Interface:
- -
- Number of Circuits:
- 4
- Voltage - Supply:
- 3.135V ~ 3.465V
- Current - Supply:
- 320mA
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 144-TEPBGA (17x17)
DS21448 FAQ
1.How can I place an order for DS21448 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS21448 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 DS21448 reliable?
The price and inventory of DS21448 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS21448 is usually 5 days.
3.What payment methods are accepted for DS21448?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS21448 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS21448?
DS21448 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS21448 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 DS21448?
For technical support, including DS21448 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS21448 requirements.
6.How does Aetrix verify that DS21448 is sourced from the original manufacturer or authorized distributors?
All DS21448 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 DS21448 meets industry standards.
7.What is the process for return or replacement of DS21448?
All DS21448 units undergo pre-shipment inspection (PSI). If there is an issue with DS21448, 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 DS21448 part is unused and in its original packaging.
Return procedure for DS21448:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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