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Analog Devices Inc./Maxim Integrated DS21Q48C
- Part No.:
- DS21Q48C
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 144-BBGA, CSPBGA
- Datasheet:
-
DS21Q48C.pdf
- Description:
- 5V E1/T1/J1 LINE INTERFACE
- Quantity:
- Payment:
- Shipping:
Inventory:3,536
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Product details
Overview
DS21Q48C from Maxim Integrated is a quad-channel 5V E1/T1/J1 Line Interface Unit (LIU) supporting simultaneous long- and short-haul trunk operation, internal 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 multiplexers and channel bank line cards.
For engineers reviewing the DS21Q48C datasheet, DS21Q48C pinout, DS21Q48C application, or DS21Q48C equivalent, key selection criteria include quad-channel LIU integration, 5V-only operation, 144-ball CSBGA package (17mm × 17mm), G.703/G.775 compliance, and hardware/serial/parallel interface flexibility for TDM backplane synchronization.
Technical Context
The DS21Q48C implements four independent LIU channels sharing a common 5V supply and control interface, each with full analog front-end (RTIP/RRING input, TTIP/TRING output), clock/data recovery PLL, programmable line build-out (E1: 0dB to -22.5dB; T1: DSX-1/CSU), and dual-mode jitter attenuator configurable in transmit or receive path.
It supports three bus modes - serial (SDI/SDO/SCLK), parallel (muxed/non-muxed Intel/Motorola), and hardware mode - with register-mapped diagnostics including PRBS generation/detection, in-band loop code handling (1–16 bits), remote/local/analog loopbacks, and real-time alarm reporting (RCL, AIS, LOS) per channel.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | Four independent E1/T1/J1 LIUs - enables single-chip replacement of four discrete line interfaces in multi-port access nodes. |
| Supply Voltage | 5.0V ±5% - requires dedicated 5V rail; no 3V operation supported per revision history. |
| Jitter Attenuation | Crystal-less 32-bit or 128-bit FIFO - accepts only 2.048MHz (E1/T1) or optional 1.544MHz (T1) MCLK; eliminates external crystal dependency. |
| Receive Sensitivity | E1: 0dB to –43dB; T1: 0dB to –36dB - supports operation over 2.5km E1 cable (0.63mm) and 6k ft T1 cable without repeaters. |
| Encoding Support | AMI, HDB3 (E1), B8ZS (T1) - fully compliant with ITU G.703, ANSI T1.403-1999, and ETSI ETS 300 166 standards. |
| Package | 144-ball CSBGA (17mm × 17mm) - thermal resistance θJA = 22.5°C/W at 200 LFM airflow per Table 9-4. |
| Operating Temp | 0°C to +70°C - commercial temperature grade; DS21Q48N variant supports –40°C to +85°C. |
Pinout & Package
DS21Q48C uses a 144-ball CSBGA package (17mm × 17mm, 0.8mm pitch) with exposed thermal pad. Pin assignments are defined in Section 8 (page 55) and Figure 8-1 of the datasheet, supporting parallel, serial, and hardware interface configurations via BIS0/BIS1 pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RTIP / RRING | Analog receive inputs | Differential transformer-coupled inputs per channel; support internal 75Ω/100Ω/120Ω termination selection via CCR registers. |
| TTIP / TRING | Analog transmit outputs | Differential line driver outputs per channel; generate G.703-compliant E1 waveshapes or DSX-1/CSU T1 line build-outs. |
| RPOS / RNEG | Bipolar/NRZ receive data | Output recovered data synchronized to RCLK; NRZ mode enabled via CCR1.6; error pulses on RNEG in NRZ mode. |
| TPOS / TNEG | Bipolar/NRZ transmit data | Input data sampled on TCLK edge (configurable via CCR2.1); fed into HDB3/B8ZS encoder and line driver. |
| MCLK | Master clock input | 2.048MHz (±50ppm) TTL-level input for clock/data recovery and jitter attenuation; 1.544MHz optional for T1-only use. |
| RCLK | Recovered receive clock | Buffered line-recovered clock output; used as reference for backplane clock synthesis (BPCLK) and system timing. |
| BPCLK | Synthesized backplane clock | 16.384MHz/8.192MHz/4.096MHz/2.048MHz output derived from RCLK; selectable via CCR5.7/CCR5.6. |
| INT* | Active-low interrupt | Open-drain status change flag per channel; asserts on alarm conditions (AIS, RCL, LOS) or diagnostic events. |
Key Features
| Feature | Design Value |
|---|---|
| Quad LIU integration | Four fully independent E1/T1/J1 line interfaces in one 144-ball CSBGA - reduces board area by ~75% vs. four DS2148 devices. |
| Software-selectable termination | Per-channel 75Ω/100Ω/120Ω receive termination controlled via CCR register - eliminates external resistor networks and layout variants. |
| Crystal-less jitter attenuation | 32-bit or 128-bit FIFO with MCLK-only requirement - removes crystal oscillator BOM cost and layout sensitivity while meeting G.823 jitter specs. |
| G.703/G.775 compliance | Full support for E1 pulse templates (Figure 7-4), T1 pulse templates (Figure 7-5), and Receive Carrier Loss detection per ITU G.775 - ensures interoperability with legacy telco infrastructure. |
| Multi-mode interface | Hardware, serial (3-wire), or parallel (8-bit muxed/non-muxed Intel/Motorola) control - enables flexible host processor integration without protocol translation. |
Applications
| DSLAM Line Card | Wireless Backhaul Radio |
|---|---|
Use Scenario: Aggregating multiple E1/T1 feeds from remote DSLAMs into a central office switch via TDM over fiber. IC Role / Device Role / Timing Role: Quad LIU provides physical layer framing, clock recovery, and line drive for four simultaneous E1 trunks; RCLK feeds timing to upstream framer. Use Value: Enables single-board 4×E1 aggregation with <2.5dB insertion loss and <0.01% BPV error rate under G.703 template compliance. | Use Scenario: Connecting microwave radio units to legacy TDM switching centers using T1 leased lines. IC Role / Device Role / Timing Role: DS21Q48C acts as T1 line interface with DSX-1 line build-out and B8ZS encoding; monitors RCL and AIS for link health. Use Value: Supports 6k-ft T1 reach with –36dB receive sensitivity and automatic carrier loss detection per G.775, reducing field maintenance calls. |
| Channel Bank Shelf | Enterprise PBX Gateway |
Use Scenario: Providing 24-channel T1 connectivity in modular channel banks serving business telephony systems. IC Role / Device Role / Timing Role: Four DS21Q48C channels handle 4×T1 (96 DS0s); BPCLK supplies 8.192MHz backplane clock to time-slot interchange (TSI) matrix. Use Value: Eliminates need for external clock synthesizers and reduces power per T1 port by 35% vs. discrete LIU solutions. | Use Scenario: Bridging legacy T1 PRI circuits from PSTN to VoIP gateways in enterprise communications infrastructure. IC Role / Device Role / Timing Role: DS21Q48C terminates T1 PRI signaling (D-channel), performs B8ZS decoding, and delivers framed data to DSP subsystem. Use Value: Maintains D-channel bit integrity with <10⁻⁹ BER under PRBS-2¹⁵ testing and supports in-band loop codes for remote diagnostics. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar line interface unit applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS21Q48N | Same functionality and pinout; extended temperature range (–40°C to +85°C) and lead-free RoHS-compliant packaging. | Required for industrial outdoor cabinets or base station environments with wide ambient swings. | Select DS21Q48N when operating outside 0°C–70°C or requiring RoHS compliance; otherwise DS21Q48C suffices for commercial indoor use. |
| DS2148GN | Single-channel version in 49-ball CSBGA; identical core architecture but no quad integration or shared backplane clock synthesis. | Suitable for low-port-count applications where space and channel density are not constrained. | Choose DS2148GN only for designs needing ≤1 LIU channel; DS21Q48C offers 4× density and shared resources like BPCLK. |
Compared with DS21Q48N, DS21Q48C trades extended temperature and RoHS compliance for lower cost and standard commercial qualification; compared with DS2148GN, it delivers 4× channel integration and unified clock distribution at the expense of higher pin count and PCB routing complexity.
Availability
DS21Q48C is available at Aetrix Electronics and suitable for telecom access equipment, wireless backhaul radios, channel bank shelves, and enterprise TDM gateways requiring stable component supply across multi-year production cycles.
Supply support for DS21Q48C 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 RF ICs for communications, computing, and industrial markets.
The DS21Q48C belongs to Maxim's T1/E1/J1 LIU product line, designed specifically for carrier-grade line interface consolidation in space-constrained telecom infrastructure equipment.
FAQ
What is the maximum cable length supported by DS21Q48C in E1 mode?
The DS21Q48C supports up to 2.5km of 0.63mm (22AWG) copper cable in E1 mode, enabled by its –43dB receive sensitivity and integrated active filter compensation for nonlinear transmission losses. This performance meets ITU G.703 E1 pulse template requirements and is validated per Figure 7-4 in the datasheet. DS21Q48C achieves this without external equalization circuitry.
Does DS21Q48C support both E1 and T1 protocols simultaneously on different channels?
Yes, DS21Q48C supports independent E1 and T1 operation per channel - each of the four LIUs can be configured separately for E1 (HDB3, 2.048MHz) or T1 (B8ZS, 1.544MHz) via register settings in CCR1 and CCR4. The device does not require global mode selection; channel-specific ETS bits enable mixed-mode deployment in multi-standard access nodes.
Is an external crystal required for DS21Q48C jitter attenuation?
No, DS21Q48C implements a crystal-less jitter attenuator that operates solely from the 2.048MHz (or optional 1.544MHz) master clock applied to the MCLK pin. The 32-bit or 128-bit FIFO-based attenuation meets G.823 jitter transfer and tolerance specifications without any external crystal or VCXO, simplifying BOM and layout.
What package type and dimensions does DS21Q48C use?
DS21Q48C uses a 144-ball CSBGA package measuring 17mm × 17mm with 0.8mm ball pitch and an exposed thermal pad. Mechanical details are specified in section 11.3 (page 72) of the datasheet under part number 56-G6011-001. The package supports standard reflow profiles and provides θJA = 22.5°C/W at 200 LFM airflow.
Can DS21Q48C generate and detect in-band loop codes for remote diagnostics?
Yes, DS21Q48C supports generation and detection of in-band loop codes from 1 to 16 bits, including CSU-specific loop codes, as documented in Section 6.1. Loop code length and pattern are programmable via CCR registers, and detection status is reported in status registers - enabling standardized remote line testing per ANSI T1.403 and ITU G.704.
DS21Q48C Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 144-BBGA, CSPBGA
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Line Interface Unit (LIU)
- Interface:
- E1, J1, T1
- Number of Circuits:
- 1
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Supply:
- 125mA
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 144-CSBGA (17x17)
DS21Q48C FAQ
1.How can I place an order for DS21Q48C through Aetrix?
Please submit a Request for Quotation (RFQ) for DS21Q48C 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 DS21Q48C reliable?
The price and inventory of DS21Q48C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS21Q48C is usually 5 days.
3.What payment methods are accepted for DS21Q48C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS21Q48C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS21Q48C?
DS21Q48C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS21Q48C 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 DS21Q48C?
For technical support, including DS21Q48C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS21Q48C requirements.
6.How does Aetrix verify that DS21Q48C is sourced from the original manufacturer or authorized distributors?
All DS21Q48C 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 DS21Q48C meets industry standards.
7.What is the process for return or replacement of DS21Q48C?
All DS21Q48C units undergo pre-shipment inspection (PSI). If there is an issue with DS21Q48C, 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 DS21Q48C part is unused and in its original packaging.
Return procedure for DS21Q48C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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