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Vishay Semiconductor Opto Division LH1529BB
- Part No.:
- LH1529BB
- Manufacturer:
- Vishay Semiconductor Opto Division
- Category:
- Solid State Relays (SSR)
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LH1529BB.pdf
- Description:
- SSR RELAY SPST-NO 120MA 0-350V
- Quantity:
- Payment:
- Shipping:
Inventory:2,915
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Product details
Overview
LH1529BB from Vishay Semiconductors is a telecom switch solid-state relay (SSR) with integrated bidirectional optocoupler in a DIP-8 package, featuring 5300 VRMS isolation, 100 % minimum CTR, 20 Ω typical on-resistance, 350 V load voltage, and 120 mA continuous load current - used for on/off hook control and ring detection in legacy telephone line interface circuits.
For engineers reviewing the LH1529BB datasheet, LH1529BB pinout, LH1529BB application, or LH1529BB equivalent, key selection criteria include its 100 % CTR min., 1.3 ms typical turn-on time, DIP-8 through-hole mounting, 210 mA current limit, and dual-function integration of SSR switching and loop current sensing in a single isolated package.
Technical Context
The LH1529BB integrates two optically isolated functional blocks: a solid-state relay (pins 4–6) with MOSFET-based output stage enabling clean bounce-free switching up to 350 V AC/DC, and a bidirectional phototransistor optocoupler (pins 1–2, 7–8) supporting ring detection and loop current sensing via symmetric current conduction.
Its internal architecture provides galvanic isolation between input LED and both output sections, with guaranteed ≥10¹² Ω isolation resistance at 25 °C and 1.3 pF input-to-output capacitance - critical for maintaining signal integrity and noise immunity in telecom line interface units (LIUs) operating under stringent EMI requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5300 VRMS - enables safe interfacing between subscriber line (high-voltage analog) and low-voltage logic/controller domains |
| CTR (min) | 100 % - ensures reliable optocoupler output drive under worst-case aging and temperature conditions without external gain compensation |
| RON (typ) | 20 Ω - limits I²R power loss and voltage drop during 120 mA DC load switching in hook-switch applications |
| Turn-on Time (typ) | 1.3 ms - supports dial-pulse timing compliance and fast on-hook detection in PSTN line cards |
| Current Limit (typ) | 210 mA - protects SSR output stage during transient overloads such as lightning-induced surges on telephone lines |
| Load Voltage (max) | 350 V - accommodates peak ringing voltage (≈170 V RMS × √2 ≈ 240 V) plus safety margin for telecom line transients |
| Off-state Leakage (max) | 1 μA at ±350 V - maintains high impedance in open-circuit state to prevent false loop closure detection |
Pinout & Package
DIP-8 through-hole package with 2.54 mm lead pitch, 9.77 mm body width, and 0.75 mm lead thickness - compatible with standard wave-soldering profiles per Vishay document 83827.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | LED Anode/Cathode | Input side of optocoupler; bidirectional operation enabled by internal anti-parallel LED configuration |
| 4, 6 | SSR Output Terminals | AC/DC load switch terminals; pins 4 and 6 are interchangeable polarity inputs for SSR channel |
| 7, 8 | Phototransistor Collector/Emitter | Output side of optocoupler; supports bidirectional current sensing via external bias network |
| 3, 5 | No Connect | Internally unconnected; must remain floating per datasheet to avoid parasitic coupling or latch-up |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional optocoupler | Enables ring detection and loop current monitoring using same device without polarity-sensitive external circuitry |
| Current limit protection | 210 mA typical trip threshold prevents thermal runaway during short-circuit or surge events on telephone line |
| Clean bounce-free switching | Eliminates mechanical contact chatter artifacts in hook-switch control, ensuring deterministic state transitions |
| Low power consumption | 0.7 mA typical LED turn-on current reduces drive circuit loading and heat generation in dense line-card designs |
| High surge capability | Withstands telecom line transients per ITU-T K.20/21 without external clamping components |
Applications
| On/Off Hook Control | Dial Pulse Switching |
|---|---|
Use Scenario: Detecting and controlling subscriber line connection state in analog telephone interface cards. IC Role / Device Role / Timing Role: LH1529BB SSR acts as isolated electronic hook switch; optocoupler monitors loop current to confirm off-hook condition. Use Value: Replaces electromechanical relays with 1.3 ms response time, eliminating wear-out and contact bounce in high-cycle-count systems. | Use Scenario: Generating pulse-coded dial signals for rotary-dial telephones connected to modern PBX or VoIP gateways. IC Role / Device Role / Timing Role: LH1529BB SSR performs rapid make/break switching of line current; optocoupler verifies pulse timing via feedback. Use Value: Achieves precise 10–20 pulses/sec timing with <2.5 ms max turn-off time, meeting ANSI/TIA-968-B pulse specifications. |
| Ring Current Detection | Loop Current Sensing |
Use Scenario: Identifying incoming call ring signals (20 Hz, 90 V RMS) on POTS lines without disturbing line impedance. IC Role / Device Role / Timing Role: LH1529BB optocoupler detects bidirectional ring current flow; SSR remains inactive until ring-stop confirmation. Use Value: Enables zero-crossing synchronized ring detection with <1 μA leakage, preventing false triggers during idle line conditions. | Use Scenario: Monitoring DC loop current (20–60 mA) to verify line integrity and detect faults like open or short circuits. IC Role / Device Role / Timing Role: LH1529BB phototransistor provides isolated current-proportional output; SSR may be used for fault isolation. Use Value: Delivers linear CTR (100–165 %) across temperature, enabling accurate current measurement without calibration drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar telecom switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Vishay LH1529BAC | SMD-8 package; identical electrical specs including 100 % CTR min. and 210 mA current limit | Requires rework of PCB layout for surface-mount assembly; no change in functional behavior or timing | Select when automated SMT production is preferred and board space constraints favor compact footprint |
| Toshiba TLP3558 | Single-channel SSR only (no integrated optocoupler); 400 V load rating; 0.5 A current limit; SOIC-8 package | Requires external optocoupler for ring/loop sensing; higher load capacity but no bidirectional sensing capability | Select when higher load current is required and separate sensing circuitry is acceptable |
Compared with LH1529BAC and TLP3558, the LH1529BB uniquely combines DIP-8 through-hole mountability, integrated bidirectional sensing, and telecom-optimized timing - making it optimal for legacy line card upgrades where mechanical reliability and minimal BOM count are prioritized.
Availability
LH1529BB is available at Aetrix Electronics and suitable for telecom line interface units, analog telephone adapters, and PSTN gateway designs requiring stable component supply and long-term obsolescence management support.
Supply support for LH1529BB 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 Intertechnology is a global manufacturer of discrete semiconductors and passive components, specializing in high-reliability optoelectronics, power management, and precision sensing solutions.
The LH1529 family was designed specifically for telecom infrastructure applications requiring galvanically isolated switching and bidirectional current monitoring in analog subscriber line interfaces.
FAQ
What is the isolation voltage rating of the LH1529BB and how is it validated?
The LH1529BB has a 5300 VRMS isolation test voltage rated for 60 seconds per UL1577 and FIMKO pending certification. This value is measured between input (LED) and output (SSR + optocoupler) sides under standardized dielectric withstand testing. The LH1529BB achieves this rating via internal mold compound and physical spacing compliant with reinforced insulation requirements for telecom equipment.
Does the LH1529BB support bidirectional current detection, and how is it implemented?
Yes, the LH1529BB supports bidirectional current detection via its integrated optocoupler section (pins 1–2 and 7–8), which uses an anti-parallel LED configuration enabling conduction in both directions. This allows the same device to sense ring current polarity and loop current direction without external diode networks - a feature confirmed in Vishay document 83827 for the LH1529BB variant.
What is the maximum continuous load current the LH1529BB SSR can switch, and what limits it?
The LH1529BB SSR supports 120 mA continuous DC load current, limited by internal thermal design and power dissipation (600 mW total). Its 210 mA current limit threshold activates during transient overloads to protect the output MOSFET. This specification is explicitly listed in the Electrical Characteristics table of Vishay document 83827 for LH1529BB.
Is the LH1529BB still in production, and what is its lifecycle status?
The LH1529BB reached End of Life in January 2018 per Vishay document 83827 Rev. 1.5. It is no longer manufactured, but Aetrix Electronics maintains legacy inventory and offers obsolescence mitigation services including cross-reference support and last-time buy coordination for ongoing production needs.
How does the LH1529BB's 100 % minimum CTR compare to the LH1529AAC variant?
The LH1529BB specifies 100 % minimum DC current transfer ratio (CTR) at IF = 6 mA and VCE = 0.5 V, whereas the LH1529AAC specifies only 33 % min. This higher CTR ensures stronger phototransistor output drive, reducing sensitivity to LED aging and temperature drift - a key differentiator confirmed in the Electrical Characteristics table of Vishay document 83827 for the LH1529BB part number.
LH1529BB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Semiconductor Opto Division
- Series:
- LH1529
- Packaging:
- Tube
- Product Status:
- Obsolete
- Mounting Type:
- Through Hole
- 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:
- PC Pin
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 8-DIP
- Approval Agency:
- BSI, FIMKO, UL
- Grade:
- -
- Qualification:
- -
LH1529BB FAQ
1.How can I place an order for LH1529BB through Aetrix?
Please submit a Request for Quotation (RFQ) for LH1529BB 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 LH1529BB reliable?
The price and inventory of LH1529BB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LH1529BB is usually 5 days.
3.What payment methods are accepted for LH1529BB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LH1529BB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LH1529BB?
LH1529BB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LH1529BB 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 LH1529BB?
For technical support, including LH1529BB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LH1529BB requirements.
6.How does Aetrix verify that LH1529BB is sourced from the original manufacturer or authorized distributors?
All LH1529BB 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 LH1529BB meets industry standards.
7.What is the process for return or replacement of LH1529BB?
All LH1529BB units undergo pre-shipment inspection (PSI). If there is an issue with LH1529BB, 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 LH1529BB part is unused and in its original packaging.
Return procedure for LH1529BB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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