SD68C128K-12

High-voltage phototransistor optocoupler, 80V VCEO, 200-400% CTR (K grade), 5000V isolation, SMD

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Manufacturer Part：

SD68C128K-12

Package：

SOP-4

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Description

Product Overview

The SD68C128K-12 is a high-voltage phototransistor optocoupler featuring an 80V collector-emitter voltage rating and high current transfer ratio (CTR). This surface-mount device provides 5000Vrms electrical isolation between input and output circuits, making it suitable for high-voltage power supply feedback and industrial control applications. The K-12 grade designation indicates a specific CTR binning range optimized for consistent performance across temperature variations. Packaged in a compact SMD form factor, it is ideal for dense PCB designs requiring reliable galvanic isolation with high output voltage capability.

Key Specifications

Type High-Voltage Phototransistor Optocoupler
Input Side GaAs Infrared LED
Output Side High-Voltage NPN Phototransistor
Isolation Voltage (VISO) 5000 Vrms (1 min)
Current Transfer Ratio (CTR) 200-400% at IF=5mA, VCE=5V (K grade)
Collector-Emitter Voltage (VCEO) 80 V min
Saturation Voltage (VCE(sat)) 0.3 V max
Collector Dark Current (ICEO) 100 nA max
Rise Time (tr) 6 µs typical
Fall Time (tf) 10 µs typical
Package SOP-4 / SOP-5 (SMD)
Operating Temperature -55°C ~ +110°C

Features

  • High VCEO: 80V minimum rating
  • High CTR range: 200% to 400% (K grade)
  • 5000Vrms isolation voltage
  • Surface-mount package (SMD)
  • Enhanced temperature stability
  • UL recognized (UL1577)
  • VDE certified (DIN EN 60747-5-5)
  • RoHS compliant and halogen-free
  • Low coupling capacitance
  • High common-mode rejection

Applications

  • Offline switch-mode power supplies
  • Flyback and forward converter feedback
  • High-voltage sensing circuits
  • Industrial automation and control
  • Telecom power systems (48V)
  • Battery management systems
  • Solid state relays
  • Medical equipment isolation

The SD68C128K-12 is a K-grade high-voltage phototransistor optocoupler offering an 80V collector-emitter voltage rating with a current transfer ratio (CTR) specified between 200% and 400%. This higher CTR grade (compared to the TJ-15 variant) provides increased output sensitivity, making it ideal for applications where drive current is limited or where higher noise margin is desired. The device consists of a gallium arsenide infrared emitting diode optically coupled to a high-voltage silicon NPN phototransistor, all enclosed in a surface-mount package. The 5000Vrms isolation barrier provides robust galvanic separation between input and output circuits, essential for safety isolation in offline power supplies and industrial control systems. The high VCEO rating of 80V allows direct interfacing with higher voltage buses such as 48V telecom rails or auxiliary power supplies without the need for additional voltage regulation on the output side. The SMD package enables compact, automated assembly, making it suitable for high-volume manufacturing. This device meets major international safety standards including UL1577 and VDE (DIN EN 60747-5-5), and is RoHS compliant. It finds widespread use in offline flyback converters, high-voltage monitoring circuits, telecom power systems, and industrial I/O modules.

The SD68C128K-12 optocoupler operates by converting an electrical input signal into light, transmitting it across an insulating barrier, and converting it back to an electrical signal on the output side — providing complete galvanic isolation. The input side infrared LED (IRED) emits light proportional to the forward current (IF). This light travels through a transparent insulating medium (the isolation barrier) and strikes the base-collector junction of the high-voltage phototransistor on the output side. Photons absorbed in the depletion region generate electron-hole pairs that create a photocurrent, which acts as the base current for the NPN transistor. The collector current (IC) is then approximately CTR × IF, where CTR for the K grade is 200-400%. The higher CTR of the K grade means more output current per unit of LED drive current, enabling operation with lower input currents or providing higher output drive capability. The high-voltage phototransistor (80V VCEO) is designed with a thicker collector drift region to support higher voltage breakdown, using optimized doping profiles to maintain current gain at elevated voltages. In switching applications, the device transitions between saturation (low VCE, high current) when LED current is applied, and cutoff (high VCE, near-zero current) when the LED is off. The isolation barrier (5000Vrms) is designed to withstand high differential voltages between input and output sides indefinitely at normal operating levels, and can sustain much higher voltages for short durations. This isolation prevents ground loops, eliminates common-mode noise, and provides operator safety protection.

Pin Number Pin Name Type Description
1 Anode Input LED anode (positive terminal)
2 Cathode Input LED cathode (negative terminal)
3 Emitter Output Phototransistor emitter
4 Collector Output Phototransistor collector
  • AC-DC converter feedback circuits
  • Flyback transformer primary-secondary isolation
  • 48V telecom power supply modules
  • High-voltage battery monitoring
  • Industrial PLC analog I/O
  • Solid state relay construction
  • Medical device patient protection circuits
  • Motor drive fault detection
Manufacturer Part Number Description
Vishay VO619A-9 80V VCEO optocoupler, 200-400% CTR, SMD
Everlight EL357N-C Phototransistor optocoupler, 35V, SOP-4
Sharp PC817C Phototransistor optocoupler, 35V, DIP-4
ON Semiconductor FODM817C Phototransistor optocoupler, 35V, SMD
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Quality Assurance

Quality is the core foundation of our long-term global cooperation. With over 20 years of experience in the electronic component industry, Materialparts has built a strict and standardized quality management system covering component sourcing, incoming inspection, full-batch testing, packaging and delivery. We are committed to delivering 100% genuine, high-reliability electronic components for industrial control, automotive electronics, consumer electronics and medical device industries, and fully safeguarding your production and R&D projects.

1. Authorized & Genuine Sourcing Promise

All of our electronic components are procured from official authorized distributors and original manufacturers. We strictly reject counterfeits, refurbished parts, disassembled components and gray-market goods. Every product is guaranteed to be brand-new original parts and fully consistent with the original technical parameters. For branded products such as NXP IC series, we maintain complete supply channel documents to realize full product traceability.

2. Strict Full-batch Quality Inspection

We implement 100% full-batch quality control for all goods before shipment. Our professional QC team conducts multi-dimensional tests including appearance inspection, electrical parameter testing, performance verification and packaging check. Each batch of components is attached with complete inspection reports and batch records. We stick to zero-tolerance standards for defective products to ensure every piece of component meets industrial application requirements.

3. Industry Standard Compliance

Our products comply with a variety of international industry quality standards to adapt to high-standard application scenarios:
  • Automotive Electronics: All automotive-grade components pass AEC-Q series certification, featuring excellent stability and durability to adapt to complex vehicle operating environments.
  • Medical Devices: High-reliability components meet medical industry safety and compliance regulations, ensuring stable operation for medical equipment.
  • Industrial Control & Consumer Electronics: Products conform to universal international electronic industry standards, suitable for long-term continuous operation of various equipment.

4. Professional Reliability Control

For static-sensitive, moisture-sensitive and precision components such as ICs, PCBs, sensors and connectors, we carry out reliability screening in advance. Combined with standardized ESD anti-static packaging and vacuum moisture-proof packaging, we avoid component damage caused by static electricity, dampness or collision during storage and transportation, and retain the original performance of products.

5. Traceability Management System

We establish a complete product traceability system. Each batch of goods corresponds to independent batch number, sourcing record, inspection record and delivery record. Customers can query the whole lifecycle information of components at any time. This system effectively solves quality risks and facilitates after-sales handling and production quality control for your company.

6. After-sales Quality Guarantee

If any product is confirmed to have non-conformity quality problems due to our reasons after receipt, we provide free return, exchange and supplementary delivery services. Our professional quality team will also conduct root cause analysis to optimize our quality control process. We respond to quality feedback within 24 hours to resolve your worries efficiently.

Contact Us

If you have inquiries about our quality standards, inspection procedures or product certification documents, please feel free to contact us:

 

Email: info@ic-vendor.com
Tel / WhatsApp: +86 13760382860
Address: Room 2919, Guoli Building, Huaqiang North, Futian District, Shenzhen, Guangdong, China

 

Shipping & Payment

Materialparts is a professional global supplier of electronic components with over 20 years of industry experience. We provide one-stop supply of passive components, integrated circuits, as well as parts for industrial control, automotive electronics, consumer electronics and medical devices. Below are the unified shipping and payment policies applicable to all orders, samples and bulk purchases worldwide.

1. Payment Terms

We offer a variety of secure and convenient payment methods to meet diverse business cooperation needs. Details are as follows:
  1. Accepted Payment Methods
  • T/T (Bank Wire Transfer): The primary settlement method for bulk orders and a widely used international payment channel.
  • PayPal: Ideal for small orders, sample orders and quick payments.

  1. Settlement Currency

     

    US Dollar (USD) is the default settlement currency. RMB is available for domestic customers.

  2. Bank Charges

     

    All transfer fees, intermediary bank charges and other remittance-related expenses shall be borne by the buyer.

  3. Payment Requirements
  • Sample and small orders: Shipment will be arranged upon full payment.
  • In-stock bulk orders: Goods will be delivered within 2 to 3 working days after full payment.

2. Shipping & Delivery

We partner with leading global logistics providers to ensure safe and fast delivery worldwide. Relevant details are listed below:
  1. Logistics Partners
  • International Express: DHL, FedEx, UPS, TNT
  • Economy Logistics: Air freight and sea freight for large-volume cargo
  • Domestic Delivery: SF Express, Yunda Express
  1. Order Processing Time
  • In-stock items: Orders confirmed and fully paid before 14:00 (GMT+8) will be shipped on the same day. All other orders will be dispatched within 1 to 2 working days.
  • Out-of-stock or sourced items: The delivery lead time will be confirmed separately according to brand and inventory status.
  1. Estimated Transit Time
  • International Express: 3 – 7 working days globally
  • Air Freight: 7 – 12 working days
  • Sea Freight: 25 – 40 working days for heavy and large bulk cargo
  1. Shipping Fee Rules
  • Shipping cost is calculated based on package weight, volume, destination and delivery method.
  • Both freight prepaid and freight collect are available. Please provide your courier account number in advance if you choose freight collect.
  • Free international express delivery is offered for large orders. Terms for long-term partners can be negotiated separately.
  1. Shipment Tracking
     

    Within 24 hours after dispatch, we will send the tracking number, commercial invoice, packing list and other documents to your email or communication account. You may check the shipment status online in real time.

3. General Order Rules & Notes

  1. MOQ & Sample Service

     

    We support flexible minimum order quantities for samples, small-batch and large-batch orders. All sample orders shall comply with the above shipping and payment policies.

  2. Packaging Standard

     

    All electronic components are packed with professional anti-static and shockproof materials. Original factory packaging is available for branded chips and integrated circuits.

4. Customs & Liability Statement

  1. Import Duties & Taxes

     

    All import duties, customs clearance fees and local taxes incurred for international shipments shall be borne by the buyer. We will provide complete customs documents to assist you with clearance procedures.

  2. Handling of Lost or Damaged Goods
  • In case of loss or severe damage during transit, please contact us within 48 hours after receiving the tracking information. We will assist you in filing a claim with the logistics provider.
  • We shall not be liable for any losses caused by incorrect delivery address, wrong contact information or the buyer’s refusal to complete customs clearance.

5. Local Pickup in Shenzhen

Local pickup service is available for customers in Shenzhen and surrounding areas:
  • Address: Room 2919, Guoli Building, Huaqiang North, Futian District, Shenzhen, Guangdong Province, China
  • Business Hours: 09:00 – 18:00, Monday to Friday. Closed on weekends and official public holidays.
  • Notice: Please make an appointment via email or communication tools one day in advance, and present your order information upon pickup.

Contact Information

Email: info@ic-vendor.com

Tel / WhatsApp: +86 13760382860

Service & Packaging

Materialparts is a professional electronic component supplier based in Shenzhen, China, with over 20 years of global trading experience. We integrate component procurement, quality inspection, technical support, customized packaging, and global delivery services to provide one-stop supply chain solutions. Our business covers industrial control, automotive electronics, consumer electronics, medical devices and other industries. We always adhere to genuine sources, stable supply and considerate after-sales service.

Core Services

1. One-stop Sourcing & BOM Support

We specialize in a full range of passive and active electronic components, including SMD resistors, power resistors, connectors, aviation connectors, LED beads, flexible circuit boards, printed circuit boards, and integrated circuits. Our professional team provides BOM list consolidation, component matching, and alternative model recommendation services. We support sample orders, small-batch trial production, and mass production orders with flexible MOQs to meet diverse procurement needs.

2. Genuine Product Guarantee & Full-process Quality Inspection

All products are sourced from official authorized channels and are 100% original genuine parts. Every batch of goods undergoes strict full-process quality inspection before delivery, with complete batch records and traceability documents provided. Our products comply with AEC-Q standards for automotive electronics and high-reliability specifications for medical devices. We eliminate counterfeits, refurbished parts and defective products from the source to secure your project production.

3. Fast Quotation & Order Processing

Our customer service team responds promptly to inquiries and quotation requests. All in-stock orders will be processed within one working day. We provide stocking reservation services for long-term cooperative customers, effectively solving problems such as component shortages and unstable supply chains.

4. Professional Technical Support

Our senior engineer team provides free technical consultation, model selection guidance and original manufacturer datasheets. We assist customers in solving problems related to product R&D, circuit design and component application, providing reliable technical support for project progress.

5. Sourcing for Special Components

Relying on our global supply chain network, we professionally source scarce components, obsolete parts and customized special components to efficiently solve your procurement difficulties.

6. Global Logistics & Document Services

We cooperate with mainstream international logistics providers including DHL, FedEx, UPS and TNT to achieve fast global delivery. We can provide complete export documents such as customs declaration files, commercial invoices and packing lists to ensure smooth customs clearance for international shipments. Local pickup is also available for customers in Shenzhen, China.

Professional Packaging Standards

Electronic components are sensitive to static electricity, collision, moisture and dust. We adopt industry-standard anti-static packaging solutions to fully ensure the integrity of goods during transportation and storage.

1. General Packaging Specifications

  • All components are packed separately to avoid damage caused by friction and collision;
  • Shockproof buffer materials are added for fragile products to ensure transportation safety;
  • Each package is clearly marked with part number, quantity, batch number and specifications for easy inventory counting and management.

2. Classified Professional Packaging

  • Anti-static Packaging: Static-sensitive components such as chips, circuit boards and sensors are packaged with anti-static bags, shielding boxes and conductive foam in strict accordance with international anti-static standards to prevent static damage.
  • Vacuum Moisture-proof Packaging: Moisture-sensitive components are vacuum-sealed with desiccants to isolate humid air, suitable for ocean transportation and long-term storage.
  • Original Factory Packaging: Integrated circuits of brands such as NXP are delivered with original reels, trays or tubes by default, retaining complete original packaging and adapting to automated SMT production lines.
  • Discrete Device Packaging: Discrete devices such as SMD resistors, power resistors and LEDs are quantitatively and classifiedly packaged with accurate quantity and clear marking.
  • Connector / Aviation Connector Packaging: Hard outer packaging is adopted to prevent pin bending and structural deformation.

3. Custom Packaging Services

We provide value-added services including personalized packaging, custom labeling and re-reeling according to customer requirements, fully matching your production and warehouse management standards.

Contact Information

For service consultation or packaging customization, please feel free to contact us:
Email: info@ic-vendor.com
Tel / WhatsApp: +86 13760382860
Address: Room 2919, Guoli Building, Huaqiang North, Futian District, Shenzhen, Guangdong, China
 

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