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Microchip Technology LE79Q2281DVCT
- Part No.:
- LE79Q2281DVCT
- Manufacturer:
- Microchip Technology
- Category:
- Telecom
- Package:
- 64-TQFP
- Datasheet:
-
LE79Q2281DVCT.pdf
- Description:
- IC TELECOM INTERFACE 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,485
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Product details
Overview
LE79Q2281DVCT from Zarlink Semiconductor is a quad-channel intelligent subscriber line audio-processing circuit (ISLAC™) designed for BORSCHT implementation in voice-over-x line cards. It provides full programmable A-law/µ-law/linear codec, transhybrid balance, DC loop feeding, ring-trip detection, and tone generation (DTMF/FSK/metering) across four channels. Operates at +3.3 V and interfaces via PCM/MPI or GCI with master clock support from 512 kHz to 8.192 MHz.
For engineers reviewing the LE79Q2281DVCT datasheet, LE79Q2281DVCT pinout, LE79Q2281DVCT application, or LE79Q2281DVCT equivalent, this device serves as the digital signal processing core in dual-chip ISLAC+ISLIC voice interface solutions-requiring precise coordination with VE790-series ISLIC devices for loop supervision, ringing control, and analog front-end management.
Technical Context
The LE79Q2281DVCT implements a four-channel DSP-based architecture with dedicated converter blocks per channel, supporting simultaneous A/D and D/A conversion, programmable digital filtering (gain, impedance, equalization), and adaptive transhybrid balancing. It integrates microprocessor/GCI/PCM interface logic and generates control signals (VHLi, VLBi, LDi, P1–P3) to manage external VE790-series ISLIC devices.
Its internal block diagram confirms independent channel processing paths with shared clock and reference circuits, plus configurable interrupt generation (INT), tri-level load signaling (LD1–LD4), and analog sense inputs (VILG/VIMT/VSAB) for metallic/longitudinal current and voltage monitoring-enabling real-time loop diagnostics including leakage, capacitance, and resistance measurement per channel.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 4 independent subscriber line processing channels with fully separate analog I/O and digital control paths. |
| Supply Voltage | +3.3 V DC for both analog (VCCA1–VCCA4) and digital (VCCD) sections-no 5 V required except for 5-V-tolerant I/O pins. |
| Digital Interface | Selectable PCM/MPI or GCI; supports 8 kHz frame sync, 256 kHz–8.192 MHz master clock, and 2/4 MHz downstream clock in GCI mode. |
| Codec Format | Programmable 8-bit A-law/µ-law or 16-bit linear two's-complement PCM-enables global or per-channel companding selection. |
| Line Supervision | Programmable off-hook debounce, ground-key detection, ring-trip filtering, and polarity reversal (smooth or abrupt) per channel. |
| Tone Generation | On-chip DTMF, FSK, random noise, arbitrary tone, and 12/16 kHz metering signal generation with envelope shaping. |
| Diagnostic Capability | Built-in AC/DC line testing per channel meeting GR-909/GR-844; measures longitudinal/metallic resistance, capacitance, and leakage. |
Pinout & Package
LE79Q2281DVCT is housed in a 64-pin Thin Quad Flat Pack (TQFP), RoHS-compliant green package, tray-packed. Pin functions are validated per Zarlink Document #081256 (Rev G, Sep 2007), with all analog and digital I/O mapped to specific channel roles and interface protocols.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN1–VIN4 | Analog input (voice receive) | Four-wire analog voice input per channel; connects to ISLIC output for digitization by on-chip ADC. |
| VOUT1–VOUT4 | Analog output (voice transmit) | Reconstructed analog voice output per channel; drives ISLIC input for line transmission. |
| VHL1–VHL4 | ISLIC high-level control | Generates DC feed current, internal ringing, and metering signals for corresponding VE790 ISLIC channel. |
| VILG1–VILG4 / VIMT1–VIMT4 | Analog sense inputs | Monitor longitudinal (ILG) and metallic (IMT) loop currents from ISLIC for real-time supervision and diagnostics. |
| LD1–LD4 | Tri-level load select | 3-state outputs (0 V / VCC / VREF) that route P1–P3 control bits to ISLIC relay latches or mode latches per channel. |
| DXA/DU, DRA/DD | PCM transmit/receive data | Primary serial PCM data path (MSB-first, 8/16-bit bursts); supports independent timeslot assignment for signaling data. |
| CS/RST, DIO/S1 | MPI control & bidirectional data | Chip-select/reset and serial control I/O for configuration registers; 5-V tolerant, used only in 64-pin TQFP variant. |
| FS/DCL, PCLK/FS | Frame sync & clock input | Dual-function pins: FS in PCM mode (8 kHz), DCL in GCI mode (2/4 MHz); PCLK/FS serves as PCM clock or GCI frame sync. |
Key Features
| Feature | Design Value |
|---|---|
| Quad-channel BORSCHT engine | Fully software-configurable battery feed, ringing, supervision, coding, hybrid, and testing across four lines-eliminates need for discrete analog components. |
| Adaptive transhybrid balance | Continuous or "adapt-and-freeze" digital echo cancellation per channel, programmable impedance matching for variable loop lengths and impedances. |
| Integrated line diagnostics | Per-channel measurement of loop resistance, capacitance, and leakage without external test equipment-meets GR-909/GR-844 compliance requirements. |
| Programmable signaling modes | Supports loop-start and ground-start operation with configurable off-hook debounce, ring-trip thresholds, and polarity reversal timing per channel. |
| Flexible digital interface | Single hardware design supports PCM highway or GCI backplane via pin-strapping and register configuration-enables reuse across carrier-grade and residential platforms. |
Applications
| Voice over IP Integrated Access Device (IAD) | Cable Telephony Node Interface Unit (NIU) |
|---|---|
Use Scenario: Residential gateway aggregating four POTS lines into VoIP trunk using SIP or MGCP signaling. IC Role / Device Role / Timing Role: LE79Q2281DVCT performs full BORSCHT processing per line, synchronizing with VE790 ISLIC for analog line conditioning and supervisory state reporting. Use Value: Enables single-board, software-defined line card supporting multiple country-specific ringing frequencies, loop feed profiles, and regulatory tone standards without hardware change. |
Use Scenario: Cable operator NIU deployed in street cabinets serving up to four subscriber lines over HFC infrastructure. IC Role / Device Role / Timing Role: LE79Q2281DVCT handles voice digitization, DTMF detection, and metering generation while coordinating with ISLIC for battery backup and fault isolation during power loss. Use Value: Provides GR-909-compliant line testing and remote diagnostics-reducing truck rolls by identifying open/short/capacitive faults via embedded measurement routines. |
| Fiber-to-the-Home (FTTH) Optical Network Terminal (ONT) | Intelligent PBX Line Card |
Use Scenario: ONT providing POTS service alongside broadband, requiring low-power, compact line interface with earth-backed ringing support. IC Role / Device Role / Timing Role: LE79Q2281DVCT manages four independent subscriber lines with external ringing generator control, zero-crossing synchronized relay drive, and programmable ring-trip sensitivity. Use Value: Supports both internal and external ringing topologies via software-selectable modes-enabling flexible bill-of-materials across deployment variants. |
Use Scenario: Enterprise PBX line card delivering analog station ports with caller ID (CID) tone generation and adaptive hybrid balance for echo suppression. IC Role / Device Role / Timing Role: LE79Q2281DVCT generates CID tones, performs real-time transhybrid adaptation per line, and reports off-hook/ring-trip events via INT pin to host controller. Use Value: Delivers CCITT-compliant voice quality and signaling reliability while enabling feature differentiation (e.g., custom ring patterns, multi-frequency tone sets) through firmware updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad-channel ISLAC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LE79Q2284MVC | 80-pin LQFP package with additional I/O pins (I/O1–I/O4, DIN/S1, DOUT, GS11–GS14), no DIO/S1 or DXA/DU pins. | Supports higher pin-count system integration, external gain switching, and expanded general-purpose I/O control not available on LE79Q2281DVCT. | Select LE79Q2284MVC when board layout requires extra GPIOs or analog gain control nodes; LE79Q2281DVCT remains optimal for space-constrained 64-pin designs. |
| LE79228-AB | Same die, different ordering suffix; identical electrical specs and pinout-but packaged in tape-and-reel (T-suffix) and marked with alternate revision labeling. | No functional or application difference; used interchangeably where packaging format (tray vs. tape) aligns with assembly requirements. | Choose LE79228-AB only for volume SMT production requiring automated pick-and-place; LE79Q2281DVCT is tray-packed for prototyping and low-volume builds. |
Compared with LE79Q2284MVC, LE79Q2281DVCT offers identical core ISLAC functionality in a smaller 64-pin TQFP footprint but omits auxiliary I/O and analog gain control pins-making it ideal for cost- and area-sensitive line cards. Versus LE79228-AB, it differs solely in packaging format and orderable part number, with no electrical or functional distinction.
Availability
LE79Q2281DVCT is available at Aetrix Electronics and suitable for Voice over IP IADs, Cable Telephony NIUs, FTTH ONTs, and Intelligent PBX line cards requiring stable component supply, long-term lifecycle support, and traceable sourcing for carrier-grade deployments.
Supply support for LE79Q2281DVCT 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
Zarlink Semiconductor was a fabless provider of high-performance analog and mixed-signal ICs for communications infrastructure, acquired by Microsemi in 2011 and later integrated into Microchip Technology. It specialized in voice, timing, and RF solutions for telecom and enterprise networks.
The LE79Q2281DVCT belongs to Zarlink's VE790-series intelligent line interface chipset, designed specifically for software-programmable, multi-country BORSCHT implementation in carrier-class and residential voice access equipment-emphasizing diagnostic capability, regulatory compliance, and ISLIC co-processor interoperability.
FAQ
What is the primary function of the LE79Q2281DVCT in a voice line card?
The LE79Q2281DVCT serves as the quad-channel intelligent subscriber line audio-processing circuit (ISLAC™), executing all digital signal processing tasks for BORSCHT functions-including codec, transhybrid balance, DC feed control, ring-trip detection, and line diagnostics-while coordinating with external VE790-series ISLIC devices for analog line driving and supervision. Its role is central to enabling software-defined, multi-country voice line interfaces.
Does the LE79Q2281DVCT integrate a microcontroller or require external firmware?
No, the LE79Q2281DVCT does not contain an embedded microcontroller. It relies on an external host processor (e.g., ARM or DSP) to configure its registers via MPI, PCM, or GCI interface. Firmware resides externally and controls all programmable parameters-including filter coefficients, supervision thresholds, and ringing waveforms-using tools like WinSLAC™ for coefficient generation.
Can the LE79Q2281DVCT operate without a companion ISLIC device?
No, the LE79Q2281DVCT is designed exclusively for use with VE790-series ISLIC devices. It lacks high-voltage analog drivers and cannot directly interface with telephone lines. Its analog I/O pins (VIN/VOUT/VHL/VILG/VIMT) are intended to connect to the ISLIC's corresponding terminals-making the dual-chip architecture mandatory for full BORSCHT functionality.
What clock frequencies does the LE79Q2281DVCT support for PCM and GCI interfaces?
The LE79Q2281DVCT supports master clock frequencies from 512 kHz to 8.192 MHz for PCM/MPI operation, with minimum PCLK of 256 kHz for linear/companded data plus signaling. In GCI mode, it accepts 2 MHz or 4 MHz downstream clock (DCL) on FS/DCL and requires 8 kHz frame sync on PCLK/FS-ensuring compatibility with standard telecom backplane timing architectures.
How does the LE79Q2281DVCT handle ring-trip detection in external ringing configurations?
The LE79Q2281DVCT supports both automatic and manual ring-trip modes with integrated filtering. In external ringing setups, it monitors the ring-trip sense resistors (RSHB/RSLB/RSPB) via SHB/SLB/SPB pins and uses programmable thresholds to detect ring-trip events. The INT pin asserts upon detection, and status is readable via signaling registers-enabling precise synchronization with relay control via LD/P1–P3 signals.
LE79Q2281DVCT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 64-TQFP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- ISLAC DEVICE
- Interface:
- PCM
- Number of Circuits:
- 4
- Voltage - Supply:
- 3.3V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (10x10)
LE79Q2281DVCT FAQ
1.How can I place an order for LE79Q2281DVCT through Aetrix?
Please submit a Request for Quotation (RFQ) for LE79Q2281DVCT 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 LE79Q2281DVCT reliable?
The price and inventory of LE79Q2281DVCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE79Q2281DVCT is usually 5 days.
3.What payment methods are accepted for LE79Q2281DVCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE79Q2281DVCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE79Q2281DVCT?
LE79Q2281DVCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE79Q2281DVCT 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 LE79Q2281DVCT?
For technical support, including LE79Q2281DVCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE79Q2281DVCT requirements.
6.How does Aetrix verify that LE79Q2281DVCT is sourced from the original manufacturer or authorized distributors?
All LE79Q2281DVCT 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 LE79Q2281DVCT meets industry standards.
7.What is the process for return or replacement of LE79Q2281DVCT?
All LE79Q2281DVCT units undergo pre-shipment inspection (PSI). If there is an issue with LE79Q2281DVCT, 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 LE79Q2281DVCT part is unused and in its original packaging.
Return procedure for LE79Q2281DVCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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