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Microchip Technology LE79R241DJCT
- Part No.:
- LE79R241DJCT
- Manufacturer:
- Microchip Technology
- Category:
- Telecom
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
LE79R241DJCT.pdf
- Description:
- IC TELECOM INTERFACE 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,961
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Product details
Overview
LE79R241DJCT from Zarlink Semiconductor is an Intelligent Subscriber Line Interface Circuit (ISLIC™) designed for telephony line cards in central office, DLC, and PBX systems. It delivers programmable DC feed (25 mA current limit, 500 Ω feed resistance), dual battery operation (–42.5 V to –99 V VBH), integrated relay drivers (R1–R3), and subscriber line diagnostics including loop resistance, leakage, and capacitance measurement. It operates across –40°C to +85°C and supports internal/external ringing per US and European standards.
For engineers reviewing the LE79R241DJCT datasheet, LE79R241DJCT pinout, LE79R241DJCT application, or LE79R241DJCT equivalent, this device serves as a high-voltage bipolar interface for BORSCHT functions-requiring precise coordination with VE790-series ISLAC controllers, thermal management resistor selection (e.g., 1 kΩ on TMP/TMS), and PLCC-32 layout compliance for longitudinal balance and fault detection.
Technical Context
The LE79R241DJCT implements linear loop-current feeding with intelligent thermal management, offloading power dissipation via external resistors (TMP–TMS, TMN–VBL) rather than on-die regulation. Its analog sensing architecture feeds metallic (IMT) and longitudinal (ILG) loop currents, plus scaled AC (VTX) and DC (VSAB) voltages, to a companion VE790-series ISLAC for full software control of feed, supervision, and diagnostics.
It uses tri-level LD/P1–P3 control signaling to switch between operating mode decoding and relay driver control. The device supports both loop-start and ground-start signaling, smooth polarity reversal, tip-open state for ground start, and metering at 12 kHz or 16 kHz-enabling full BORSCHT implementation without external DACs or high-voltage transistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temp | –40°C to +85°C industrial range; validated for telecom equipment reliability per GR-357-CORE. |
| Battery Supply | VBH: –42.5 V to –99 V; VBL: –15 V to VBH; enables dual-battery operation for power savings. |
| DC Feed Current Limit | 25 mA typical; programmable via IRSN = 50 µA; independent of battery voltage. |
| Feed Resistance | 500 Ω typical; fully software configurable through VE790 ISLAC interface. |
| Ringing Drive | Supports US standard: up to 4.4 kft (26 AWG) or 7 kft (24 AWG); EU: up to 1.7 km (0.5 mm Cu). |
| Thermal Management | On-chip thermal shutdown at ~165°C; external resistor network (TMP/TMS/TMN/VBL) required for safe long-loop operation. |
| Line Diagnostics | Measures leakage resistance, loop resistance, line capacitance, bell capacitance, and foreign voltage. |
Pinout & Package
LE79R241DJCT is housed in a 32-pin Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, RoHS-compliant green finish, and thermal performance rated at 45°C/W (junction-to-air, free convection). Pin 1 is marked for orientation; reserved pins (RSVD) must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AD / BD | Subscriber line drive outputs | High-voltage bipolar outputs driving A/B leads; support ±150 mA continuous; require external fuse resistors. |
| SA / SB | Line voltage sense inputs | Protected inputs sensing voltages across fuse resistors; referenced to VREF; tolerate ±12.5 mA transient surges. |
| IMT / ILG | Analog diagnostic outputs | IMT ∝ differential loop current (IAD + IBD); ILG ∝ common-mode current (IAD – IBD); pulled to CREF during thermal overload. |
| VTX / VSAB | AC/DC line voltage outputs | VTX = scaled AC component (voice path); VSAB = scaled DC voltage (VSAB = 0.01 × VSA–SB); both referenced to VREF. |
| P1 / P2 / P3 / LD | Tri-level control interface | LD selects function mode: logic 1 → mode decode (P1–P3), logic 0 → relay control (RD1–RD3), mid-level → latch lock. |
| R1 / R2 / R3 / RYE | Relay driver outputs | R1 emitter tied to BGND; R2/R3 emitters tied to RYE; supports up to three mechanical relays or test load switches. |
| VBH / VBL / BGND | High/low battery supplies | VBH powers ringing/long loops (–42.5 V to –99 V); VBL powers short loops; BGND is shared return for both batteries. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable DC feed | Current limit and feed resistance set independently of battery voltage-enables stable loop current across varying line lengths and battery aging. |
| Integrated line diagnostics | On-chip measurement of leakage resistance, loop resistance, line/bell capacitance, and foreign voltage-eliminates need for external test hardware in remote deployments. |
| Intelligent thermal management | External resistor network (TMP/TMS/TMN/VBL) diverts >90% of dissipated power-reduces junction temperature rise and extends reliability in high-power ringing modes. |
| Smooth polarity reversal | Controlled transition between battery polarities avoids transients that could trigger false off-hook or ring-trip detection in legacy POTS systems. |
| Tip-open ground-start support | Dedicated tip-open state allows reliable ground-start signaling-required for compatibility with British Telecom and other European CO exchanges. |
Applications
| CO Line Card | DLC Remote Terminal |
|---|---|
Use Scenario: Central office line card serving 16–32 analog subscribers with mixed loop lengths and regulatory requirements. IC Role / Device Role / Timing Role: Primary high-voltage line interface IC providing BORSCHT functions under VE790 ISLAC control; handles battery switching, ringing, and diagnostics. Use Value: Enables single-hardware design compliant with US (LSSGR) and EU (ETSI) standards via software configuration-reducing inventory and certification effort. |
Use Scenario: Distributed digital loop carrier terminal deployed in rural areas with long loops (>5 km) and limited maintenance access. IC Role / Device Role / Timing Role: ISLIC managing DC feed, thermal protection, and automated line testing without field technician intervention. Use Value: Integrated leakage and capacitance measurement identifies corroded cables or faulty telephones remotely-cutting truck rolls by >40%. |
| PBX/KTS System | Pair Gain Multiplexer |
Use Scenario: Enterprise PBX supporting analog extensions with metering, caller ID, and selective ringing. IC Role / Device Role / Timing Role: Line interface delivering 12/16 kHz metering signals, ring-trip detection, and programmable off-hook thresholds per extension. Use Value: Metering capability meets FCC Part 68 billing requirements; ground-key detection enables feature access codes without extra hardware. |
Use Scenario: Pair gain system consolidating 4–8 voice channels onto one copper pair using time-division multiplexing. IC Role / Device Role / Timing Role: ISLIC providing per-channel loop supervision, battery feed, and relay-controlled test access points. Use Value: Three integrated relay drivers (R1–R3) allow automatic switching between live lines and test loads-enabling in-service diagnostics without service interruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar subscriber line interface applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LE79R251QC | QFN-32 package (vs. PLCC-32); higher thermal efficiency (25°C/W vs. 45°C/W); identical electrical specs and pinout mapping. | Preferred for space-constrained, high-density line cards requiring improved thermal performance without layout redesign. | Select LE79R251QC when board area is limited and thermal headroom is critical; verify PCB pad layout matches QFN footprint and exposed pad soldering. |
| LE79231JC | Lower maximum VBH (–75 V vs. –99 V); no RYE pin; single relay driver (R1 only); reduced diagnostic scope (no bell capacitance measurement). | Suitable for short-loop, low-cost DLC or PBX applications where full long-loop ringing and multi-relay control are unnecessary. | Choose LE79231JC for cost-sensitive, short-loop (<3 km) deployments; not recommended for CO or EU-standard long-loop use. |
Compared with LE79R241DJCT, LE79R251QC offers superior thermal handling in compact form, while LE79231JC sacrifices voltage range and relay count for lower BOM cost-making LE79R241DJCT the balanced choice for full-featured, globally compliant line cards.
Availability
LE79R241DJCT is available at Aetrix Electronics and suitable for central office line cards, remote DLC terminals, enterprise PBX systems, and pair gain multiplexers requiring stable component supply across extended product lifecycles and global regulatory updates.
Supply support for LE79R241DJCT 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 semiconductor company specializing in voice, timing, and communications ICs, acquired by Microsemi in 2011. Its products targeted carrier-grade telephony infrastructure with emphasis on reliability and standards compliance.
The LE79R241DJCT belongs to Zarlink's ISLIC™ family-designed specifically for software-programmable BORSCHT implementation in telecom line cards, enabling global interoperability through VE790-series ISLAC co-control and eliminating discrete high-voltage component dependencies.
FAQ
What is the primary function of the LE79R241DJCT in a telephony line card?
The LE79R241DJCT serves as the high-voltage bipolar Intelligent Subscriber Line Interface Circuit (ISLIC™) responsible for BORSCHT functions-including battery feed, overvoltage protection, ringing, supervision, coding, hybrid, and testing. It interfaces exclusively with VE790-series ISLAC devices for full software control of DC feed, diagnostics, and signaling, and requires external fuse resistors and thermal management resistors for safe operation.
Does the LE79R241DJCT support both US and European telephone line standards?
Yes, the LE79R241DJCT supports both US and European standards. For US applications, it drives ringing up to 4.4 kft (26 AWG) or 7 kft (24 AWG) cable; for European (British) standards, it supports up to 1.7 km of 0.5 mm copper cable. These capabilities are enabled via software configuration through the VE790 ISLAC controller-not hardware changes-and comply with LSSGR and ETSI requirements.
How does thermal management work in the LE79R241DJCT?
The LE79R241DJCT uses intelligent thermal management by routing excess power dissipation through external resistors connected between TMP–TMS and TMN–VBL, rather than dissipating heat on-die. This reduces junction temperature rise and prevents thermal shutdown during long-loop ringing. The device includes on-chip thermal shutdown at ~165°C and reports overload by pulling IMT to CREF, allowing the VE790 ISLAC to initiate corrective action.
Can the LE79R241DJCT operate with a single battery supply?
Yes, the LE79R241DJCT supports single-battery operation: VBH and VBL can be tied together when only one battery is available. In this configuration, the device uses the same supply for both long-loop (ringing) and short-loop (standby) operation. Dual-battery operation remains optional to reduce power consumption during standby-VBH remains active for ringing while VBL is disabled.
What diagnostic measurements does the LE79R241DJCT perform autonomously?
The LE79R241DJCT performs autonomous subscriber line diagnostics including leakage resistance, loop resistance, line capacitance, bell capacitance, and foreign voltage detection. These measurements are derived from analog outputs (IMT, ILG, VTX, VSAB) fed to the VE790 ISLAC, which applies programmable thresholds and reports pass/fail status or raw data via PCM channel-enabling remote fault isolation without external test equipment.
LE79R241DJCT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Subscriber Line Interface Concept (SLIC)
- Interface:
- 2-Wire
- Number of Circuits:
- 1
- Voltage - Supply:
- 5V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (11.43x13.97)
LE79R241DJCT FAQ
1.How can I place an order for LE79R241DJCT through Aetrix?
Please submit a Request for Quotation (RFQ) for LE79R241DJCT 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 LE79R241DJCT reliable?
The price and inventory of LE79R241DJCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE79R241DJCT is usually 5 days.
3.What payment methods are accepted for LE79R241DJCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE79R241DJCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE79R241DJCT?
LE79R241DJCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE79R241DJCT 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 LE79R241DJCT?
For technical support, including LE79R241DJCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE79R241DJCT requirements.
6.How does Aetrix verify that LE79R241DJCT is sourced from the original manufacturer or authorized distributors?
All LE79R241DJCT 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 LE79R241DJCT meets industry standards.
7.What is the process for return or replacement of LE79R241DJCT?
All LE79R241DJCT units undergo pre-shipment inspection (PSI). If there is an issue with LE79R241DJCT, 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 LE79R241DJCT part is unused and in its original packaging.
Return procedure for LE79R241DJCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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