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Analog Devices Inc./Maxim Integrated DS21349Q+T&R
- Part No.:
- DS21349Q+T&R
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 28-LCC (J-Lead)
- Datasheet:
-
DS21349Q+T&R.pdf
- Description:
- IC TELECOM INTERFACE 28PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,852
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Product details
Overview
DS21349Q+T&R from Maxim Integrated is a fully integrated 3.3V 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 compliance, with crystal-less jitter attenuation, programmable B8ZS/NRZ interface, and five line build-out settings - deployed in DSUs, CSUs, and T1 test equipment.
For engineers reviewing the DS21349Q+T&R datasheet, DS21349Q+T&R pinout, DS21349Q+T&R application, or DS21349Q+T&R equivalent, key selection considerations include jitter attenuator path placement (TX/RX), receive sensitivity range (0dB to –36dB), PLCC-28 hardware/software mode configuration, and bipolar/NRZ data interface support.
Technical Context
The DS21349Q+T&R integrates full T1 physical-layer functionality: a digitally controlled line driver with four selectable CSU filters (0dB to –22.5dB), adaptive receive equalization with 20dB/26dB gain boost options, and a 1.544MHz reference-driven crystal-less jitter attenuator configurable for 32-bit or 128-bit FIFO depth and 3Hz/6Hz bandwidth.
It supports dual operating modes: hardware mode using dedicated control pins (MODE0/MODE1/JASEL/L0–L3), and serial port mode via SPI-compatible interface (SCLK/SDI/SDO/CS), with diagnostic features including local/remote/analog loopbacks, QRSS generation/detection, and in-band loop-up/down code handling per AT&T 62411.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 3.3V ±5% - powers both transmitter (TVDD) and core logic (VDD) blocks independently. |
| Data Rate | 1.544Mbps T1 - matches standard DS1 framing; requires 1.544MHz MCLK for PLL and jitter attenuation. |
| Receive Sensitivity | 0dB to –36dB - enables operation over 0.63mm (22AWG) cables up to 6k feet in length. |
| Jitter Attenuator | Crystal-less, programmable TX/RX path placement - eliminates external crystal requirement while meeting T1 jitter tolerance specs. |
| Line Build-Out | Five settings: 0dB, –7.5dB, –15dB, –22.5dB, and 6V - supports both long-haul (T1) and short-haul (D4/DSX-1) cable lengths. |
| CSU Filters | Four selectable: 0dB, –7.5dB, –15dB, –22.5dB - compensates for line loss in channel service unit applications. |
| Interface Mode | Bipolar (AMI) or NRZ - selected via ENCENB/UNIENB bits; supports B8ZS encoding/decoding when enabled. |
Pinout & Package
DS21349Q+T&R is housed in a 28-pin Plastic Leaded Chip Carrier (PLCC) package, RoHS-compliant and lead-free, with 11.43mm × 11.43mm body size and 1.27mm pitch. Pin functions differ between hardware and serial port modes - full mapping validated per Maxim DS21349 datasheet Rev 011206.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| MCLK | Master Clock Input | 1.544MHz TTL-level reference clock for PLL and jitter attenuator; required for all operational modes. |
| TPOS/TNEG | Transmit Data Outputs | Differential bipolar transmit data sampled on falling edge of TCLK; drive TTIP/TRING through transformer. |
| RPOS/RNEG | Receive Data Inputs | Differential bipolar data recovered from RTIP/RRING; output synchronized to RCLK rising/falling edge per CLKE setting. |
| JASEL | Jitter Attenuator Path Select | Hardware-mode control: 0 = TX path, 1 = RX path, float = disabled - determines where jitter cleanup occurs. |
| L0–L3 | Line Build-Out Control | 4-bit input selecting one of five output pulse shapes/gain settings for short-haul or long-haul transmission. |
| MODE0/MODE1 | Operating Mode Select | MODE1 = 0 → hardware mode; MODE1 = 1 → serial port mode; MODE0 = 1 disables all outputs for board testing. |
| TTIP/TRING | Analog Transmit Outputs | Transformer-coupled analog line drivers delivering compliant T1 pulses to twisted-pair medium. |
| RTIP/RRING | Analog Receive Inputs | Differential analog inputs from line transformer; feed clock/data recovery and equalization circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Fully integrated LIU | Eliminates need for external line drivers, equalizers, encoders, and jitter cleaners - reduces BOM count and PCB area. |
| Crystal-less jitter attenuation | Removes crystal oscillator requirement while meeting ANSI T1.403 jitter tolerance; supports 32/128-bit FIFO depth and 3/6Hz bandwidth. |
| Programmable TX/RX path placement | Enables system-level jitter cleanup optimization - e.g., place attenuator in receive path for noisy lines or transmit path for timing-critical outputs. |
| Five line build-out settings | Supports deployment across diverse cable lengths (0–6k ft) and standards (T1 long-haul, D4, DSX-1 short-haul) without hardware change. |
| Comprehensive diagnostics | Includes QRSS pattern gen/detect, in-band loop-up/down, local/remote/analog loopbacks, and real-time status reporting via interrupt/status registers. |
Applications
| Data Service Units (DSUs) | Channel Service Units (CSUs) |
|---|---|
|
Use Scenario: DSU connecting customer premises equipment to T1 carrier network over twisted-pair. IC Role / Device Role / Timing Role: Physical-layer line interface handling signal conditioning, jitter cleanup, and AMI/B8ZS encoding for DS1 framing. Use Value: Enables reliable long-haul operation up to 6k ft on 22AWG cable with automatic receive sensitivity adjustment and programmable line build-out. |
Use Scenario: CSU providing line termination, monitoring, and alarm reporting in central office or enterprise demarcation points. IC Role / Device Role / Timing Role: T1 line driver and receiver with CSU filter bank (0dB to –22.5dB) and RCL/AIS/DFMO alarm outputs. Use Value: Delivers precise line build-out and real-time fault detection (driver-fail, monitor-open, loss-of-signal) required for carrier-grade CSU compliance. |
| T1/E1 Test Equipment | Routers with T1 WAN Interfaces |
|
Use Scenario: Portable field tester verifying T1 line integrity, jitter, loopback response, and in-band signaling. IC Role / Device Role / Timing Role: Programmable LIU supporting QRSS generation, remote/local/analog loopbacks, and in-band loop-up/down code detection. Use Value: Provides full diagnostic coverage per AT&T 62411 - including pattern generation, error insertion/detection, and jitter tolerance validation. |
Use Scenario: Enterprise router adding T1 WAN connectivity via modular interface card or onboard PHY. IC Role / Device Role / Timing Role: T1 physical-layer transceiver interfacing FPGA or MAC controller via bipolar/NRZ digital interface and 1.544MHz clock domain. Use Value: Integrates all analog front-end functions - eliminating discrete op-amps, filters, and clock cleaners - while supporting hardware or SPI-based configuration. |
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+T&R | Higher integration: includes T1 framer + LIU in single chip; requires external 1.544MHz clock but adds HDLC/transparent framing. | Replaces separate framer + LIU designs; not drop-in - requires register map and interface redesign. | Select when needing embedded framing logic and reduced component count; avoid if only LIU functionality is required. |
| MAX3273EUP+ | Single-supply 3.3V LIU with integrated transformer driver; no crystal-less jitter attenuator; supports only short-haul (≤133ft) per DSX-1 spec. | Limited to very short cable runs; lacks programmable jitter attenuation, B8ZS, and multi-build-out flexibility. | Choose for cost-sensitive, space-constrained short-haul applications where jitter attenuation is handled upstream. |
Compared with DS21349Q+T&R, DS2155Q+T&R adds framer functionality at the cost of design complexity, while MAX3273EUP+ simplifies layout for ultra-short-haul use but sacrifices jitter control, long-haul capability, and protocol flexibility.
Availability
DS21349Q+T&R is available at Aetrix Electronics and suitable for T1 line interface applications in data service units, channel service units, telecom test equipment, and industrial routers requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for DS21349Q+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 DS21349Q+T&R belongs to Maxim's T1/E1 line interface product line, designed specifically for robust, standards-compliant physical-layer interfacing in carrier-class and enterprise telecom infrastructure.
FAQ
What is the operating temperature range for DS21349Q+T&R?
The DS21349Q+T&R is rated for 0°C to +70°C ambient operation, matching the 'Q' grade designation in Maxim's ordering nomenclature. This commercial temperature range suits indoor telecom equipment, enterprise routers, and benchtop test instruments where environmental control is maintained. The device's thermal design ensures stable jitter attenuation and line build-out performance across this full range without derating.
Does DS21349Q+T&R require an external crystal oscillator?
No, DS21349Q+T&R does not require an external crystal oscillator because it incorporates a crystal-less jitter attenuator that uses the 1.544MHz MCLK input as its timing reference. This eliminates crystal-related BOM cost, board space, and aging/calibration concerns while still meeting ANSI T1.403 jitter tolerance requirements - a key differentiator versus legacy LIUs.
How is the jitter attenuator configured in DS21349Q+T&R?
The jitter attenuator in DS21349Q+T&R is configured via the JASEL pin in hardware mode (0 = TX path, 1 = RX path, float = disabled) or CR1[7:6] bits in software mode. Its depth (32-bit or 128-bit) and bandwidth (3Hz or 6Hz) are set via CR3[2] and CR3[7], respectively. All settings are confirmed in the DS21349 datasheet Rev 011206 Section 4 and Table 4-C.
Can DS21349Q+T&R operate in both bipolar (AMI) and NRZ modes?
Yes, DS21349Q+T&R supports both bipolar (AMI) and NRZ interfaces. Mode selection is controlled by ENCENB and UNIENB bits in Control Register 1 (CR1), with B8ZS encoding/decoding enabled when ENCENB = 1. The device handles NRZ data on TDATA/RDATA pins and bipolar data on TPOS/TNEG/RPOS/RNEG - verified in Table 4-D and Section 5.1/6.3 of the datasheet.
What package type and lead finish does DS21349Q+T&R use?
DS21349Q+T&R uses a 28-pin Plastic Leaded Chip Carrier (PLCC) package (56-G4001-001), with lead-free, RoHS-compliant finish indicated by the '+' suffix in the part number. The PLCC format provides robust mechanical mounting and thermal performance suitable for telecom-grade PCBs, and is explicitly listed in the Ordering Information table on page 5 of the DS21349 datasheet.
DS21349Q+T&R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 28-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Line Interface Unit (LIU)
- Interface:
- -
- Number of Circuits:
- -
- Voltage - Supply:
- 3.135V ~ 3.465V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-PLCC (11.51x11.51)
DS21349Q+T&R FAQ
1.How can I place an order for DS21349Q+T&R through Aetrix?
Please submit a Request for Quotation (RFQ) for DS21349Q+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 DS21349Q+T&R reliable?
The price and inventory of DS21349Q+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 DS21349Q+T&R is usually 5 days.
3.What payment methods are accepted for DS21349Q+T&R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS21349Q+T&R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS21349Q+T&R?
DS21349Q+T&R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS21349Q+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 DS21349Q+T&R?
For technical support, including DS21349Q+T&R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS21349Q+T&R requirements.
6.How does Aetrix verify that DS21349Q+T&R is sourced from the original manufacturer or authorized distributors?
All DS21349Q+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 DS21349Q+T&R meets industry standards.
7.What is the process for return or replacement of DS21349Q+T&R?
All DS21349Q+T&R units undergo pre-shipment inspection (PSI). If there is an issue with DS21349Q+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 DS21349Q+T&R part is unused and in its original packaging.
Return procedure for DS21349Q+T&R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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