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Microchip Technology LE75181BBSC
- Part No.:
- LE75181BBSC
- Manufacturer:
- Microchip Technology
- Category:
- Telecom
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LE75181BBSC.pdf
- Description:
- IC TELECOM INTERFACE 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,023
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Product details
Overview
LE75181BBSC from Zarlink Semiconductor is a monolithic solid-state Line Card Access Switch (LCAS) designed for analog telephony line cards. It provides dual-function switching: line break (SW1/SW2) and ringing access (SW4), with integrated protection, 5 V-only operation, −48 V battery reference, and break-before-make/make-before-break logic control. Used in central office, DLC, and PBX systems for power ringing and test access.
For engineers reviewing the LE75181BBSC datasheet, LE75181BBSC pinout, LE75181BBSC application, or LE75181BBSC equivalent, this page delivers verified technical context, exact pin functions, real-world switching behavior (including zero-cross turn-off for SW4), thermal shutdown response, and precise isolation ratings - all validated against Zarlink's VE750 series documentation and ordering data.
Technical Context
The LE75181BBSC implements four independent solid-state switches: two low-ON-resistance line break switches (SW1/SW2, RON ≤ 31 Ω), one ring return switch (SW3), and one AC-coupled ringing access switch (SW4) with >480 V pole-to-pole isolation and mandatory zero-current turn-off. Its B-version architecture omits the SCR clamping circuit present in A/C variants, routing negative faults to battery instead of ground.
Switching state is controlled via TTL-compatible INPUT and LATCH pins, with TSD serving as both thermal flag output and logic input for mode selection. The device draws only 0.56–2.1 mA IDD in idle/talk and power ringing states, operates across −40°C to +85°C, and enters all-OFF upon battery loss (VBAT > −10 V) or thermal shutdown (>110°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 5 V only (VDD = 4.5–5.5 V); eliminates need for multi-rail power design |
| Line Break ON-Resistance | ≤31 Ω at −40°C; matched within 1.0 Ω - ensures balanced tip/ring conduction in analog voice paths |
| Ringing Access Isolation | >480 V pole-to-pole; withstands transient surges during ring cadence without external crowbar |
| Thermal Shutdown Threshold | Activates ≥110°C; forces all-OFF state and pulls TSD LOW - protects SLIC and line interface |
| Battery Monitoring | Enters all-OFF if VBAT rises above −10 V; remains off until VBAT drops below −15 V - prevents fault propagation during battery failure |
| Dynamic Current Limit | 2.5 A peak (<0.5 µs) under 10/1000 µs lightning pulse - limits stress on secondary protector and SLIC |
| Logic Compatibility | TTL-level INPUT/LATCH (VIL ≤ 0.8 V, VIH ≥ 2.2 V); no driver circuitry required |
Pinout & Package
LE75181BBSC is housed in a 16-pin plastic SOIC (GULL) package, RoHS-compliant, with matte-tin lead finish. Pin 1 is FGND; pin 16 is VBAT. Thermal pad not present. Standard JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DGND | Digital ground reference | Separate from FGND to isolate logic noise from fault current return path |
| FGND | Fault ground return | Primary sink for positive lightning events via internal diode bridge |
| INPUT | Switch state control input | Active-high; 75 kΩ internal pull-down - enables direct MCU GPIO connection |
| LATCH | Data latch enable | Transparent-low; holds state when high - supports synchronous control in multi-device systems |
| TBAT / RBAT | TIP/RING on SLIC side | Connects to SLIC outputs; referenced to battery for protection circuit activation |
| TLINE / RLINE | TIP/RING on line side | Interfaces directly to telephone line; rated for ±330 V isolation |
| RRINGING / TRINGING | Ringing generator interface | SW4 connects between these pins; requires AC source for zero-cross turn-off |
| VDD | 5 V power supply | Only supply powering logic and switch bias - enables ultra-low idle power (0.56 mA) |
| VBAT | Battery voltage reference | Not a power rail; used solely by protection circuit - monitors −48 V battery health |
| TSD | Thermal shutdown flag | Open-drain output (HIGH normal, LOW in shutdown); can also serve as logic input for mode control |
Key Features
| Feature | Design Value |
|---|---|
| Break-before-make & make-before-break switching | Configurable via INPUT/TSD logic sequences - avoids transient arcs during ring-to-talk transitions |
| Clean, bounce-free switching | No mechanical contacts; eliminates relay chatter and associated EMI in voice band |
| Integrated protection (B-version) | Diode bridge + current limiting + thermal shutdown - negative faults routed to battery, not ground |
| Zero-cross turn-off for ringing switch (SW4) | Forces turn-off at next AC current zero - prevents voltage transients during ring generator disconnection |
| Low impulse noise | Eliminates need for external zero-cross circuitry - reduces BOM count and board area in CO/DLC line cards |
Applications
| Central Office Line Card | Digital Loop Carrier (DLC) |
|---|---|
Use Scenario: Power ringing delivery and test access switching on Class 5 switch line cards supporting POTS subscribers. IC Role / Device Role / Timing Role: Solid-state replacement for electromechanical relays; manages tip/ring continuity and ringing generator connection under microcontroller control. Use Value: Enables hot-swap maintenance, eliminates contact wear, and meets ITU-T K.20 surge immunity with proper secondary protection. |
Use Scenario: Remote terminal line cards in rural or distributed DSLAM deployments requiring low-power, high-reliability switching. IC Role / Device Role / Timing Role: Provides isolated line break and ringing access while operating from −48 V battery backup with minimal idle draw (0.56 mA). Use Value: Extends battery runtime in FOC/FITL applications and satisfies Bellcore TA-909 remote power constraints. |
| PBX Analog Interface | HFC/FITL Node |
Use Scenario: Analog station port switching in enterprise PBX systems needing clean talk/ring state transitions. IC Role / Device Role / Timing Role: Controls line continuity and ringing injection using TTL inputs; supports make-before-break to prevent audio dropouts. Use Value: Delivers bounce-free switching and <1 µA OFF-state leakage - preserves signal integrity in multi-channel voice paths. |
Use Scenario: Hybrid fiber-coax node line cards delivering POTS over coaxial distribution networks. IC Role / Device Role / Timing Role: Interfaces SLIC to outside plant; handles lightning transients via integrated diode bridge and thermal shutdown. Use Value: Reduces external protection components by 30% vs. discrete solutions - lowers cost and improves surge test pass rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar line card access switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Zarlink LE75181ABSC | Includes SCR clamping circuit; routes negative faults to ground instead of battery | Required where SLIC-side fault grounding is mandated by system architecture | Select ABSC if your design uses SCR-based secondary protectors and requires symmetric fault handling |
| Zarlink LE75181CBSC | Pin-compatible with L8581A; higher SCR hold current (110 mA vs. 80 mA in A/B) | Suitable for high-holding-current SLICs where latching risk must be minimized | Choose CBSC when deploying with Le5712 or other high-current SLICs in extended power cross scenarios |
Compared with LE75181ABSC and LE75181CBSC, the LE75181BBSC offers distinct fault routing (negative events to battery), lower SCR-related latch risk, and identical pinout - making it optimal for battery-grounded architectures where asymmetric protection suffices and layout reuse is critical.
Availability
LE75181BBSC is available at Aetrix Electronics and suitable for central office, digital loop carrier, and PBX analog line card designs requiring stable component supply, long lifecycle support, and RoHS-compliant surface-mount packaging.
Supply support for LE75181BBSC 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 mixed-signal ICs for communications infrastructure, specializing in voice, timing, and protection solutions before its acquisition by Microsemi in 2011.
The LE75181BBSC belongs to the VE750 series Line Card Access Switch family, engineered specifically for solid-state replacement of electromechanical relays in analog telephony line cards - emphasizing low power, high isolation, and integrated fault protection.
FAQ
What is the key functional difference between LE75181BBSC and LE75181ABSC?
The LE75181BBSC lacks the integrated SCR clamping circuit found in the LE75181ABSC. As a result, during negative lightning or power cross events, the BBSC routes fault current to the battery rail, whereas the ABSC routes it to ground via the SCR. This makes the BBSC suitable for battery-grounded architectures but incompatible with systems requiring SCR-based crowbar protection.
Does LE75181BBSC require external zero-cross switching circuitry?
No. The LE75181BBSC's ringing access switch (SW4) is designed to turn off automatically at the next zero-current crossing of the AC ringing signal. This eliminates the need for external zero-cross detection and control circuitry - reducing component count and simplifying design in central office and DLC line cards.
How does LE75181BBSC respond to loss of battery voltage?
The LE75181BBSC continuously monitors VBAT. If battery voltage rises above approximately −10 V (indicating loss of −48 V), it enters an all-OFF state and remains there until VBAT drops below −15 V. This behavior prevents fault propagation and ensures fail-safe operation during battery failure in remote terminal applications.
What is the maximum allowable voltage across TLINE/RLINE terminals?
The LE75181BBSC guarantees ≥330 V pole-to-pole isolation for its line break switches (SW1/SW2) and ring return switch (SW3). For the ringing access switch (SW4), the rating is >480 V. However, a secondary protector must limit tip/ring voltage to avoid exceeding these breakdown limits - especially during lightning transients per LSSGR or ITU-T K.20.
Can LE75181BBSC operate without a battery connection?
No. Although the LE75181BBSC is powered solely by its 5 V VDD supply, the VBAT pin must be connected to the −48 V battery rail. VBAT serves as the reference for the internal protection circuit and battery-loss detection. Leaving VBAT unconnected will cause the device to enter and remain in the all-OFF state.
LE75181BBSC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Switch
- Interface:
- -
- Number of Circuits:
- 1
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
LE75181BBSC FAQ
1.How can I place an order for LE75181BBSC through Aetrix?
Please submit a Request for Quotation (RFQ) for LE75181BBSC 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 LE75181BBSC reliable?
The price and inventory of LE75181BBSC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE75181BBSC is usually 5 days.
3.What payment methods are accepted for LE75181BBSC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE75181BBSC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE75181BBSC?
LE75181BBSC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE75181BBSC 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 LE75181BBSC?
For technical support, including LE75181BBSC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE75181BBSC requirements.
6.How does Aetrix verify that LE75181BBSC is sourced from the original manufacturer or authorized distributors?
All LE75181BBSC 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 LE75181BBSC meets industry standards.
7.What is the process for return or replacement of LE75181BBSC?
All LE75181BBSC units undergo pre-shipment inspection (PSI). If there is an issue with LE75181BBSC, 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 LE75181BBSC part is unused and in its original packaging.
Return procedure for LE75181BBSC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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