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Analog Devices Inc./Maxim Integrated DS21FT42
- Part No.:
- DS21FT42
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 300-BBGA
- Datasheet:
-
DS21FT42.pdf
- Description:
- IC TELECOM INTERFACE 300BGA
- Quantity:
- Payment:
- Shipping:
Inventory:2,620
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Product details
Overview
DS21FT42 from Maxim Integrated is a 12-channel T1 framer multichip module (MCM) implementing three DS21Q42 quad-framer die in a single 300-pin, 27mm × 27mm BGA package. It supports IEEE 1149.1 JTAG boundary scan, operates at 3.3V with 5V-tolerant I/O, and delivers full T1 framing functionality across 12 independent channels for high-density line card applications.
For engineers reviewing the DS21FT42 datasheet, DS21FT42 pinout, DS21FT42 application, or DS21FT42 equivalent, this device serves as a cost-optimized 12-channel alternative to the 16-channel DS21FF42-enabling precise framer count matching in T3 systems without over-provisioning power or silicon area.
Technical Context
The DS21FT42 implements a 4×3 MCM architecture containing three DS21Q42 die, each handling four T1 channels. All core DS21Q42 functions-including HDLC control, FDL/FS extraction/insertion, elastic store operation, and per-channel code generation-are retained, though signal consolidation reduces pin count versus discrete quad framers.
TSYSCLK and RSYSCLK are internally tied; signals absent in the 4×3 configuration-including RFSYNC, RLCLK, RCHCLK, RMSYNC, RLOS, LOTC, TLCLK, TCHCLK, and TCHBLK-are explicitly marked NC. The fourth quad framer is unpopulated, eliminating all associated I/Os.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channel Count | 12 independent T1 framers-exactly matches DS21Q42-based 4×3 MCM architecture, avoiding unused channel overhead. |
| Package | 300-pin BGA, 27mm × 27mm, 1.27mm pitch-standardized footprint shared with DS21FF42 and DS21FT44 for layout reuse. |
| Supply Voltage | 3.3V digital supply with 5V-tolerant I/O-enables direct interfacing to legacy 5V logic without level shifters. |
| Operating Temperature | 0°C to +70°C-qualified for commercial-grade telecom infrastructure line cards and DSLAMs. |
| JTAG Support | IEEE 1149.1 boundary scan-provides full interconnect testability and debug access across all 300 pins. |
| System Clock Input | CLKSI reference input drives internal 8.192MHz clock synthesizer (8MCLK output)-eliminates need for external T1 clock source. |
Pinout & Package
DS21FT42 uses a 300-pin, 27mm × 27mm, 1.27mm pitch BGA package. Pin assignments follow the DS21FT42-specific land pattern (Figure 4-1), with 12-channel signal mapping and explicit NC designations for unpopulated fourth quad framer signals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A7 | Address bus inputs | 8-bit address decoding for parallel port register access across all 12 framers. |
| D0–D7 | Data bus I/O | Bidirectional 8-bit data path supporting register read/write and status polling. |
| CS1*–CS3* | Quad framer chip selects | Selects individual 4-channel framer blocks (1–3); CS4* is NC on DS21FT42. |
| RCLK1–RCLK12 | Receive clock inputs | Dedicated 1.544MHz T1 receive clocks per channel-no shared clock domain required. |
| TCLK1–TCLK12 | Transmit clock inputs | Independent 1.544MHz transmit clocks per channel-supports asynchronous T1 line timing. |
| RPOS1/RNEG1–RPOS12/RNEG12 | Differential receive data inputs | 12 pairs of balanced T1 line inputs compliant with ANSI T1.403 electrical specs. |
| TPOS1/TNEG1–TPOS12/TNEG12 | Differential transmit data outputs | 12 differential T1 outputs meeting jitter and rise/fall time requirements for central office interface. |
| INT* | Open-drain interrupt output | Active-low aggregated interrupt signaling frame loss, alarm, or register event across all 12 channels. |
Key Features
| Feature | Design Value |
|---|---|
| 12-channel T1 framing | Exact match to DS21Q42 functional block-no feature reduction versus quad-framer die, enabling drop-in replacement in 4×3 designs. |
| JTAG boundary scan | Full IEEE 1149.1 compliance with dedicated JTMS/JTCLK/JTDI/JTDO pins-enables board-level interconnect test without external test fixtures. |
| 8.192MHz backplane stream | Concatenated output from all 12 channels forms a single 8.192MHz data stream-simplifies backplane routing in multiplexer/demultiplexer systems. |
| Pin-compatible with DS21FT44 | Same 300-pin BGA footprint and signal mapping-allows same PCB to support T1 (DS21FT42) or E1 (DS21FT44) applications via firmware change only. |
| Low-power 3.3V CMOS | Reduces thermal load in high-density line cards-meets telecom power budget constraints without forced air cooling. |
Applications
| DSLAM Line Card | Multiplexer/Demultiplexer |
|---|---|
Use Scenario: Aggregating 12 T1 lines from remote terminals into a high-speed backplane interface. IC Role / Device Role / Timing Role: Primary T1 framer handling line termination, frame alignment, CRC validation, and HDLC signaling for all 12 channels. Use Value: Eliminates need for four discrete quad framers-reducing BOM count, PCB area, and power by ~30% versus discrete implementation. |
Use Scenario: Converting between T1 tributaries and OC-3/STM-1 SONET/SDH payloads in edge multiplexers. IC Role / Device Role / Timing Role: Framing engine extracting DS0 channels, performing bit-stuffing removal, and generating structured T1 frames for transport. Use Value: Native 8.192MHz concatenated output aligns directly with SONET STS-1 payload rate-avoiding additional clock domain crossing logic. |
| High-Density Switch Fabric | T3 Transport Interface |
Use Scenario: Providing T1 interface capability on modular switch blades with strict thermal and space constraints. IC Role / Device Role / Timing Role: Channelized T1 framer supporting per-DS0 signaling, FDL/FS insertion, and loopback diagnostics across 12 ports. Use Value: JTAG boundary scan enables in-system verification of all 300 BGA connections-critical for field-replaceable modules requiring zero rework. |
Use Scenario: Building T3 (44.736Mbps) interfaces using two devices: one DS21FF42 (16 ch) and one DS21FT42 (12 ch). IC Role / Device Role / Timing Role: Cost-optimized framer providing exactly 12 T1 channels-no wasted silicon or power versus octal or hexadecagonal alternatives. Use Value: Enables 28-channel T3 solution with minimal component count-reducing total system cost and power vs. over-specified 32-channel approaches. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar T1 framer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS21FF42 | 16-channel version with identical 300-pin BGA package and pinout; includes fourth quad framer die and associated signals (e.g., CS4*, RCLK13–16). | Supports higher channel density in same footprint-used where 16 T1 lines are required or future scalability is needed. | Select DS21FF42 when full 16-channel capacity is required; DS21FT42 avoids paying for unused channels in 12-line systems. |
| DS21FT44 | Pin-compatible 12-channel E1 framer (2.048MHz) with identical package and control interface; replaces T1-specific timing and framing logic with E1-compliant functions. | Designed for European/E1 infrastructure-supports E1 framing, CAS signaling, and G.704/G.706 compliance instead of ANSI T1.403. | Choose DS21FT44 for E1 deployments; DS21FT42 is strictly T1-optimized and not interoperable with E1 line rates or protocols. |
Compared with DS21FF42 and DS21FT44, the DS21FT42 uniquely balances channel count, cost, and T1-specific feature fidelity-making it the optimal choice for fixed 12-T1 line cards where over-provisioning or regional protocol mismatch must be avoided.
Availability
DS21FT42 is available at Aetrix Electronics and suitable for DSLAMs, multiplexers/demultiplexers, and high-density line cards requiring stable component supply, long-term lifecycle support, and verified telecom-grade reliability.
Supply support for DS21FT42 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 high-reliability interface solutions for communications, industrial, and automotive markets.
The DS21FT42 belongs to Maxim's T1/E1 framer product line, designed specifically for high-density telecom infrastructure requiring multi-channel framing, low-power operation, and JTAG-testable packaging in compact BGA formats.
FAQ
What is the exact channel count and framer architecture of the DS21FT42?
The DS21FT42 implements exactly 12 independent T1 framers arranged as three DS21Q42 quad-framer die in a 4×3 multichip module. The fourth quad framer position is unpopulated, and all associated signals (e.g., RCLK13–16, CS4*) are designated No Connect (NC). This architecture delivers precise 12-channel capability without redundant silicon or power consumption.
Is the DS21FT42 pin-compatible with other devices in the same family?
Yes, the DS21FT42 is pin-compatible with DS21FF42 (16-channel) and DS21FT44 (12-channel E1), sharing the identical 300-pin, 27mm × 27mm BGA package and signal mapping. This allows a single PCB footprint to support T1 or E1 variants-or scale from 12 to 16 channels-via firmware and BOM changes only, with no layout revision required.
Does the DS21FT42 support JTAG boundary scan, and how is it implemented?
Yes, the DS21FT42 fully supports IEEE 1149.1 JTAG boundary scan using dedicated pins: JTCLK, JTMS, JTDI, JTDO (T17), and JTRST*. The boundary scan chain covers all 300 pins, enabling comprehensive interconnect testing, fault isolation, and in-system programming-critical for high-reliability telecom line cards where physical probe access is impractical.
What clocking resources does the DS21FT42 provide for T1 line interfacing?
The DS21FT42 accepts a single CLKSI reference input to generate an internal 8.192MHz clock (8MCLK output) for backplane streaming. Each of the 12 T1 channels has dedicated RCLK and TCLK inputs for line-synchronized 1.544MHz operation. TSYSCLK and RSYSCLK are internally tied, simplifying clock distribution while maintaining full per-channel timing independence.
How does the DS21FT42 differ from the DS21Q42 quad-framer die?
The DS21FT42 integrates three DS21Q42 die into a single MCM but consolidates signals to minimize pin count: TSYSCLK/RSYSCLK are tied, and signals like RFSYNC, RLCLK, RCHCLK, RLOS, TLCLK, and TCHCLK are omitted and marked NC. All core DS21Q42 functions-including HDLC, FDL/FS, elastic stores, and per-channel code generation-remain fully operational across the 12 active channels.
DS21FT42 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 300-BBGA
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- -
- Interface:
- Parallel/Serial
- Number of Circuits:
- -
- Voltage - Supply:
- 2.97V ~ 3.63V
- Current - Supply:
- 225mA
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 300-PBGA (27x27)
DS21FT42 FAQ
1.How can I place an order for DS21FT42 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS21FT42 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 DS21FT42 reliable?
The price and inventory of DS21FT42 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS21FT42 is usually 5 days.
3.What payment methods are accepted for DS21FT42?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS21FT42 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS21FT42?
DS21FT42 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS21FT42 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 DS21FT42?
For technical support, including DS21FT42 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS21FT42 requirements.
6.How does Aetrix verify that DS21FT42 is sourced from the original manufacturer or authorized distributors?
All DS21FT42 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 DS21FT42 meets industry standards.
7.What is the process for return or replacement of DS21FT42?
All DS21FT42 units undergo pre-shipment inspection (PSI). If there is an issue with DS21FT42, 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 DS21FT42 part is unused and in its original packaging.
Return procedure for DS21FT42:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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