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Vishay Semiconductor Opto Division LH1529BAC
- Part No.:
- LH1529BAC
- Manufacturer:
- Vishay Semiconductor Opto Division
- Category:
- Solid State Relays (SSR)
- Package:
- 8-SMD (0.300", 7.62mm)
- Datasheet:
-
LH1529BAC.pdf
- Description:
- SSR RELAY SPST-NO 120MA 0-350V
- Quantity:
- Payment:
- Shipping:
Inventory:4,239
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Product details
Overview
LH1529BAC from Vishay Semiconductors is a surface-mount telecom switch integrating a solid-state relay (SSR) and a bidirectional optocoupler in one SMD-8 package. It delivers 5300 VRMS input/output isolation, 100 % minimum CTR, 20 Ω typical on-resistance, 350 V load voltage, and 120 mA continuous load current - enabling reliable on/off hook control and ring detection in legacy telephony systems.
For engineers reviewing the LH1529BAC datasheet, LH1529BAC pinout, LH1529BAC application, or LH1529BAC equivalent, key selection criteria include verified SSR RON, optocoupler CTR ≥100 %, isolation voltage compliance, turn-on/turn-off timing (1.3–2.5 ms), and SMD-8 footprint compatibility with telecom line interface cards.
Technical Context
The LH1529BAC implements dual functional blocks: a zero-crossing-capable SSR for clean bounce-free switching of analog telecom signals, and a bidirectional phototransistor optocoupler for loop current sensing and ring detection. Both share a common 5300 VRMS isolation barrier and operate across –40 °C to +85 °C ambient.
Its SSR section features current-limit protection (210 mA typical), low power consumption (<600 mW total dissipation), and clean switching without contact wear. The optocoupler provides bidirectional current detection with CTRDC ≥100 % at IF = 6 mA and VCE = 0.5 V, supporting accurate DC loop monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5300 VRMS - meets reinforced insulation requirements for telecom line-side safety |
| SSR On-Resistance | 20 Ω typical - ensures minimal signal attenuation and voltage drop in 350 V AC/DC load paths |
| Optocoupler CTR | ≥100 % min. - enables robust loop current sensing under low-drive conditions (IF = 6 mA) |
| Load Voltage Rating | 350 V - supports operation across global POTS line voltages including ringing (≈90 V RMS) and off-hook DC (≈−48 V) |
| Turn-On/Off Time | 1.3–2.5 ms - matches telecom dial-pulse timing and prevents false hook-state transitions |
| Package | SMD-8 - surface-mount compatible with automated assembly; footprint matches JEDEC MS-012 |
| Ambient Temp Range | –40 °C to +85 °C - qualified for industrial-grade telecom equipment operating in uncontrolled environments |
Pinout & Package
SMD-8 package with 2.54 mm lead pitch, 7.62 mm body width, and gull-wing leads. Pin 1 marked by notch or dot; coplanarity ≤0.1 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | SSR Input Anode/Cathode | Drive LED to activate SSR; bidirectional capability allows polarity-insensitive connection |
| 4, 6 | SSR Output (Load Terminals) | Switched AC/DC path; pins 4 and 6 are interchangeable ± terminals for symmetrical load connection |
| 7, 8 | Optocoupler Collector/Emitter | Bidirectional phototransistor output; supports loop current sensing in either direction |
| 3, 5 | Internal Tie / No Connect | Internally connected to substrate; must be left floating or tied to ground per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Integrated SSR + Optocoupler | Reduces BOM count and PCB area vs. discrete solutions while maintaining 5300 VRMS isolation between both functions |
| Current-Limit Protection | 210 mA typical trip threshold prevents latch-up during surge events on telecom lines |
| Bidirectional Optocoupler | Enables single-device ring detection and loop current monitoring without external polarity-reversal circuitry |
| Clean Bounce-Free Switching | Eliminates mechanical contact chatter, critical for accurate pulse dialing and hook-state reporting |
| Low Power Consumption | ≤600 mW total dissipation allows use in thermally constrained line card designs without heatsinking |
Applications
| On/Off Hook Control | Dial Pulse Switching |
|---|---|
Use Scenario: Detecting and controlling subscriber line state in analog telephone interfaces. IC Role / Device Role / Timing Role: LH1529BAC SSR acts as isolated line switch; optocoupler monitors loop closure for hook detection. Use Value: Enables precise, galvanically isolated hook-state reporting with <2.5 ms response - compliant with ITU-T Q.931 timing. | Use Scenario: Generating standardized pulse trains for rotary-dial telephone signaling. IC Role / Device Role / Timing Role: LH1529BAC SSR performs clean make/break switching of the local loop; optocoupler verifies pulse integrity. Use Value: 1.3 ms turn-on ensures accurate 10-pulse-per-second generation without timing jitter or contact bounce artifacts. |
| Ringing Current Detection | Loop Current Sensing |
Use Scenario: Identifying incoming call alerts via high-voltage AC ringing signals (≈20 Hz, 90 V RMS). IC Role / Device Role / Timing Role: LH1529BAC optocoupler detects bidirectional ring current flow; SSR remains off until answered. Use Value: ≥100 % CTR ensures reliable ring detection even with aged line impedances and low LED drive currents. | Use Scenario: Monitoring DC loop current to determine off-hook status and detect line faults. IC Role / Device Role / Timing Role: LH1529BAC optocoupler provides isolated feedback of loop current magnitude and direction. Use Value: Bidirectional capability eliminates need for external diodes or H-bridge sensing, reducing component count by 3+ parts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar telecom switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Vishay LH1529BB | DIP-8 package; identical electrical specs (CTR ≥100 %, RON = 20 Ω, 5300 VRMS) | Through-hole mounting only; not suitable for SMT production lines | Select LH1529BB only when legacy DIP-8 footprint or manual assembly is required |
| Vishay LH1529GPTR | SMD-8 package; higher CTR (min. 165 %); same SSR specs; RoHS-compliant, halogen-free | Designed for new designs requiring extended CTR margin and modern environmental compliance | Choose LH1529GPTR for new telecom hardware where enhanced CTR and green compliance are mandatory |
Compared with LH1529BAC, LH1529BB offers identical performance in a through-hole format but requires PCB redesign for SMT migration, while LH1529GPTR provides superior CTR and environmental compliance at no footprint cost - making it the preferred upgrade path for new designs.
Availability
LH1529BAC is available at Aetrix Electronics and suitable for telecom line interface cards, analog PBX modules, and legacy telephone test equipment requiring stable component supply despite its End-of-Life status (January 2018).
Supply support for LH1529BAC 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
Vishay Semiconductors is a global leader in discrete semiconductors and passive components, specializing in high-reliability optoelectronics, power MOSFETs, and precision resistors.
The LH1529 family was developed specifically for analog telecom infrastructure, delivering integrated SSR/optocoupler functionality with certified safety isolation to replace electromechanical relays in POTS line cards.
FAQ
What is the isolation voltage rating of the LH1529BAC and how is it validated?
The LH1529BAC is rated for 5300 VRMS input-to-output isolation, tested for 60 seconds per UL1577 and FIMKO standards. This value is confirmed in the Vishay datasheet (Document Number 83827, Rev. 1.5) and applies to both the SSR and optocoupler sections. The LH1529BAC achieves this via internal double-molded construction and creepage/clearance distances exceeding 8 mm, ensuring compliance with IEC 60950-1 for telecom safety.
Does the LH1529BAC support bidirectional current detection in the optocoupler section?
Yes, the LH1529BAC optocoupler supports true bidirectional current detection - its phototransistor output responds identically to current flow in either direction across pins 7 and 8. This is explicitly stated in the Vishay datasheet under "Optocoupler" features and verified in the electrical characteristics table, enabling single-device ring detection and loop monitoring without external polarity logic.
What is the typical on-resistance of the LH1529BAC SSR and why does it matter for telecom applications?
The LH1529BAC SSR has a typical on-resistance of 20 Ω, with a maximum of 25 Ω. This low RON minimizes voltage drop across the switched path - critical for maintaining sufficient loop current (>20 mA) during off-hook conditions in POTS systems. At 120 mA load current, the drop is only ~2.4 V, preserving line voltage headroom for signaling and battery feed.
Is the LH1529BAC still in production, and what support is available for legacy designs?
No - the LH1529BAC reached End of Life in January 2018 per Vishay documentation. However, Aetrix Electronics maintains verified legacy stock with full traceability and offers lifecycle coordination services. For designs using LH1529BAC, we provide last-time-buy planning, cross-reference validation to LH1529GPTR, and engineering support for migration paths.
How does the current-limit protection function in the LH1529BAC SSR section?
The LH1529BAC SSR incorporates internal current-limit protection that activates at 210 mA typical (170–250 mA range). When load current exceeds this threshold, the device clamps current to prevent thermal runaway - essential for surviving lightning-induced surges and short-circuit transients on telecom lines. This behavior is documented in the "Electrical Characteristics" table under "Current limit" for LH1529BAC/LH1529BACTR variants.
LH1529BAC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Semiconductor Opto Division
- Series:
- LH1529
- Packaging:
- Tube
- Product Status:
- Obsolete
- Mounting Type:
- Surface Mount
- Circuit:
- SPST-NO (1 Form A)
- Output Type:
- AC, DC
- Voltage - Input:
- 1.26VDC
- Voltage - Load:
- 0 V ~ 350 V
- Load Current:
- 120 mA
- On-State Resistance (Max):
- 20 Ohms
- Termination Style:
- Gull Wing
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-SMD
- Approval Agency:
- BSI, FIMKO, UL
- Grade:
- -
- Qualification:
- -
LH1529BAC FAQ
1.How can I place an order for LH1529BAC through Aetrix?
Please submit a Request for Quotation (RFQ) for LH1529BAC 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 LH1529BAC reliable?
The price and inventory of LH1529BAC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LH1529BAC is usually 5 days.
3.What payment methods are accepted for LH1529BAC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LH1529BAC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LH1529BAC?
LH1529BAC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LH1529BAC 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 LH1529BAC?
For technical support, including LH1529BAC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LH1529BAC requirements.
6.How does Aetrix verify that LH1529BAC is sourced from the original manufacturer or authorized distributors?
All LH1529BAC 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 LH1529BAC meets industry standards.
7.What is the process for return or replacement of LH1529BAC?
All LH1529BAC units undergo pre-shipment inspection (PSI). If there is an issue with LH1529BAC, 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 LH1529BAC part is unused and in its original packaging.
Return procedure for LH1529BAC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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