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Microchip Technology LE7920-1DJC
- Part No.:
- LE7920-1DJC
- Manufacturer:
- Microchip Technology
- Category:
- Telecom
- Package:
- 32-LCC (J-Lead)
- Datasheet:
-
LE7920-1DJC.pdf
- Description:
- IC TELECOM INTERFACE 32PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,994
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Product details
Overview
LE7920-1DJC from Zarlink Semiconductor is a Subscriber Line Interface Circuit (SLIC) implementing POTS line interface functions including active, ringing, standby, and disconnect control states; supports –19 V to –58 V battery operation; delivers 500× current gain; features on-chip thermal management; and enables low-cost, high-performance line card designs for telephony infrastructure.
For engineers reviewing the LE7920-1DJC datasheet, LE7920-1DJC pinout, LE7920-1DJC application, or LE7920-1DJC equivalent, this page provides verified technical context, confirmed pin functions, real-world SLIC operating parameters, and validated alternative options for POTS line interface design.
Technical Context
The LE7920-1DJC integrates dual power amplifiers (A/TIP and B/RING), a receive summing node (RSN) with 500× current gain, programmable DC feed via RDC network, and independent loop-detect and ring-trip comparators with user-set thresholds. It operates without a –5 V supply and uses external impedance networks to set two-wire AC input impedance and receive gain.
It includes four open-collector relay drivers (RINGOUT, RYOUT1–3), all referenced to BGND, and an on-chip thermal management (TMG) circuit that offloads power via an external resistor to VBAT. Control logic decodes C2/C1 inputs to select among four operational states, while DET output signals detector events with built-in 15 kΩ pull-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Battery Range | –19 V to –58 V: Enables compatibility with global POTS central office battery voltages. |
| Current Gain | 500× at RSN: Defines metallic current as 500× current injected into RSN pin for precise loop-current programming. |
| Standby Power | 35 mW typical: Minimizes heat generation during idle line state in multi-channel line cards. |
| Longitudinal Balance | 63 dB (–2 grade): Meets stringent Bellcore GR-357-CORE requirements for noise immunity in 200 Hz–1 kHz band. |
| Loop Detect Threshold | Programmable via RD: Adjustable trip point (e.g., 11.5–17.3 mA on threshold) for reliable off-hook detection across loop lengths. |
| Ring-Trip Threshold | Programmable via DA/DB: Differential input allows configurable AC ring signal detection independent of DC bias. |
| Thermal Management | TMG pin with external RTMG resistor: Offloads up to ~400 mW from die in Active/Disconnect states to extend reliability. |
Pinout & Package
LE7920-1DJC is housed in a 32-pin Plastic Leaded Chip Carrier (PLCC) package, RoHS-compliant (green package), with standard JEDEC MS-016 footprint (D = 0.490", E = 0.590"). Pin 1 is marked for orientation; NC pins are not internally connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A(TIP) | Power amplifier output | Drives TIP line with programmable constant-current feed; connects to external line transformer or hybrid. |
| B(RING) | Power amplifier output | Drives RING line; complements A(TIP) for full metallic interface; shares same feed programming network. |
| RSN | Receive summing node | Input where 500× current gain is applied; all impedance, gain, and feed networks tie here. |
| RDC | DC feed programming | Connection point for RDC1/RDC2 network that sets loop current in constant-current region. |
| DET | Switchhook detector output | Open-collector logic output with 15 kΩ internal pull-up; indicates loop/ring-trip event per C2/C1 state decode. |
| RYOUT1–3 | Relay drivers | Open-collector outputs (emitter to BGND); drive external relays for line supervision, test access, or battery reversal. |
| RINGOUT | Ringing relay driver | Dedicated open-collector output for ringing generator control; separate from general-purpose RYOUTs. |
| TMG | Thermal management | Connects external resistor to VBAT to shunt power away from die during high-power states. |
Key Features
| Feature | Design Value |
|---|---|
| Four integrated relay drivers | Eliminates need for four discrete driver ICs or transistors; reduces BOM count and PCB area in line cards. |
| On-hook transmission | Enables audio path monitoring (e.g., dial tone, busy signal) while line remains electrically off-hook-critical for call progress analysis. |
| Single external impedance for two-wire Z | Allows precise 600 Ω (or other) AC termination using one external network tied to VTX and RSN-simplifies impedance matching. |
| No –5 V supply required | Reduces system power supply complexity and cost; eliminates dedicated negative rail generation and regulation circuitry. |
| Programmable constant-current feed | Supports compliance with regional loop current standards (e.g., 20–35 mA) via resistor selection on RDC pin. |
Applications
| Central Office Line Card | Digital Loop Carrier (DLC) |
|---|---|
Use Scenario: High-density analog line interface in Class 5 telephone switches handling thousands of subscriber lines. IC Role / Device Role / Timing Role: Primary SLIC providing battery feed, loop supervision, ringing, and 2-wire/4-wire conversion. Use Value: 63 dB longitudinal balance ensures minimal crosstalk and noise coupling in dense backplane environments. | Use Scenario: Remote terminal unit serving rural or suburban subscribers via fiber-fed DLC architecture. IC Role / Device Role / Timing Role: Line interface element enabling long-loop (>10 km) operation with programmable feed current and robust ring-trip detection. Use Value: Programmable loop-detect threshold adapts to varying line resistance, ensuring reliable off-hook detection over extended distances. |
| VoIP Gateway FXS Port | Test & Maintenance System |
Use Scenario: Analog telephony adapter (ATA) or enterprise VoIP gateway providing FXS ports for legacy phone support. IC Role / Device Role / Timing Role: SLIC bridging VoIP media processing ASIC to PSTN copper pair; handles battery feed, hook state, and ringing. Use Value: Low 35 mW standby power minimizes thermal load in fanless, compact gateway enclosures. | Use Scenario: Centralized line testing platform performing continuity, insulation, and fault location on deployed copper plant. IC Role / Device Role / Timing Role: Programmable line interface enabling controlled battery reversal, loop closure, and signal injection for diagnostics. Use Value: Four independent relay drivers (RYOUT1–3 + RINGOUT) allow simultaneous control of multiple test functions without external logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SLIC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LE7920-2DJC | Higher longitudinal balance (63 dB vs. 53 dB for –1 grade) across full 200 Hz–3.4 kHz band; identical pinout, package, and functional spec. | Required for systems demanding stricter noise rejection in high-interference environments (e.g., co-located DSLAMs). | Select LE7920-2DJC when longitudinal balance >60 dB is mandated by system-level EMC or voice quality specs. |
| SLIC26020DZ | Lower standby power (25 mW), integrated DC-DC converter, but no on-chip relay drivers; 32-pin QFN vs. PLCC. | Suitable for space-constrained, low-power VoIP endpoints-but requires external drivers for relay control. | Choose SLIC26020DZ only if board area and power budget are critical and relay functionality is implemented externally. |
Compared with LE7920-1DJC, LE7920-2DJC offers superior noise immunity without layout or firmware changes, while SLIC26020DZ trades integrated supervision for smaller size and lower quiescent draw-making it viable only when relay control is handled elsewhere.
Availability
LE7920-1DJC is available at Aetrix Electronics and suitable for central office line cards, VoIP gateways, digital loop carriers, and telecom test equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant green packaging.
Supply support for LE7920-1DJC 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 broadband communications ICs, acquired by Microsemi in 2011 and later integrated into Microchip Technology.
The LE7920-1DJC belongs to the VE580 Series SLIC family, designed specifically for cost-sensitive, high-reliability POTS line interface applications in carrier-grade and enterprise telephony infrastructure.
FAQ
What is the operating temperature range for the LE7920-1DJC?
The LE7920-1DJC is rated for commercial operation from 0°C to +70°C. Its electrical characteristics-including loop current accuracy, longitudinal balance, and THD-are guaranteed across this ambient range per Bellcore GR-357-CORE requirements. The device also supports industrial characterization down to –40°C, though full spec compliance at extremes requires verification against the –2 performance grade variant.
Does the LE7920-1DJC require an external –5 V supply?
No, the LE7920-1DJC does not require a –5 V supply. It operates from a single +5 V VCC rail and a negative battery voltage (–19 V to –58 V) applied to VBAT. This eliminates the need for a dedicated negative regulator, simplifying power system design and reducing bill-of-materials cost in line card applications.
How is loop current programmed on the LE7920-1DJC?
Loop current is programmed via the RDC pin using a resistor network (RDC1 and RDC2) connected between RDC and AGND/DGND. The total resistance RDC = RDC1 + RDC2 sets the constant-current region value: ILOOP ≈ 1250 / RDC (kΩ). For example, 54.34 kΩ yields ~23 mA-within the 18–30 mA active-state specification.
What is the function of the TMG pin on the LE7920-1DJC?
The TMG pin on the LE7920-1DJC connects to an external resistor (RTMG) tied to VBAT to implement on-chip thermal management. During high-power states (Active/Disconnect), RTMG diverts power away from the die, reducing junction temperature rise. For VBAT = –48 V and ILOOP = 23 mA, RTMG ≥ 1.8 kΩ is recommended to maintain safe thermal operation of the LE7920-1DJC.
Can the LE7920-1DJC drive standard electromechanical relays directly?
Yes, the LE7920-1DJC can drive standard electromechanical relays directly via its open-collector relay drivers (RINGOUT, RYOUT1–3), each rated for 50 mA sink current and capable of withstanding 7.2 V zener breakover. When driving a 12 V relay coil, an external flyback diode must be used; the internal 15 kΩ pull-up on DET does not apply to relay outputs, which require external pull-up resistors to VBAT or VCC depending on relay logic polarity.
LE7920-1DJC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 32-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Subscriber Line Interface Concept (SLIC)
- Interface:
- 2-Wire
- Number of Circuits:
- 1
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-PLCC (11.43x13.97)
LE7920-1DJC FAQ
1.How can I place an order for LE7920-1DJC through Aetrix?
Please submit a Request for Quotation (RFQ) for LE7920-1DJC 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 LE7920-1DJC reliable?
The price and inventory of LE7920-1DJC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE7920-1DJC is usually 5 days.
3.What payment methods are accepted for LE7920-1DJC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE7920-1DJC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE7920-1DJC?
LE7920-1DJC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE7920-1DJC 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 LE7920-1DJC?
For technical support, including LE7920-1DJC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE7920-1DJC requirements.
6.How does Aetrix verify that LE7920-1DJC is sourced from the original manufacturer or authorized distributors?
All LE7920-1DJC 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 LE7920-1DJC meets industry standards.
7.What is the process for return or replacement of LE7920-1DJC?
All LE7920-1DJC units undergo pre-shipment inspection (PSI). If there is an issue with LE7920-1DJC, 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 LE7920-1DJC part is unused and in its original packaging.
Return procedure for LE7920-1DJC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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