Diodes Incorporated

Frequently Asked Questions

Search our knowledge base of commonly asked questions to find answers to your questions about our products and services.

Most Commonly Asked Questions

Are Diodes' dual transistor devices, such as the MMDT series, made with monolithic die?

Diodes manufactures its dual transistor products using separate die which are wire bonded to the lead frames. They are not monolithic devices.

Are Diodes' dual transistors made with matched pairs of dice?

Diodes manufactures both matched and non-matched dual transistor products.

  • The DMMT series are matched products made with adjacent die from a single wafer.
  • The IMX8, IMT4, BC847BS, and MMDT series are not made with matched dice.

Please see the appropriate Data Sheets for Diodes' specific matching specifications.

Are Diodes' products UL Certified?

Basically, UL Listings (Certification) are for assemblies or certain Discretes (Power Semiconductors) designed to go on power mains such as TVSs (Transient Voltage Suppressors) and Bridge Rectifiers. Most of our Bridge Rectifiers, and TVS in SMB and SMC are listed. SMA TVS are not listed. For all other discretes, UL has no listing program for them.

Can Diodes provide Spice model for simulation?

Spice model for simulation is available upon request. Please contact Diodes Customer Support.

Can I Continue to Buy Product with the Old SnPb Lead Finish After the Conversion Date?

Customers may continue to buy products that have not been "converted" subject to availability in either format, with SnPb Lead Finish or Lead Free. If other products are converted, advanced notification will be given. Should a major customer require product with SnPb plating after a general product conversion, a Customer Special Part Number may have to be generated. The length of time the old product will remain available to you will be by special agreement. (Pricing may then be reviewed.) A Lifetime buy may be offered on a package / Customer basis.

Green molding compound changes are by date code. Once stock is exhausted, the device will not be available in the old compound even if SnPb finish.

Can I plug this board in a PCI-X slot?

Yes you can, the PCI-X specification is backward compatible with this bridge, and it will work at 66 MHz speed.

Can Products with New Lead Free Finishes Be Used with Pb Containing Solders?

The lead-free solder finishes are backwards compatible with Pb-containing solders. Soldering profiles may need to be adjusted slightly depending on the many design and usage variables.

Can you provide a brief overview of the Diodes Incorporated Rectifier Die Glass Passivation Process (GPP)?

The Diodes Glass Passivation Process (GPP) for Rectifier Dice occurs in the wafer form after the Wafer Diffusion (P+) Process.

Immediately after the Diffusion Process, the wafer is masked with a photoresist film and the dice are pattern etched through the junction plane, this operation is called mesa etching.

The exposed p-n junction surface is then passivated in a two-layer process.

  • First, an oxygen doped, Semi-Insulating Poly Crystalline Silicon (SIPOS) layer is deposited onto the silicon junction surface by Low Pressure Chemical Vapor Deposition (LPCVD) to stabilize the region.
  • Second, a thick layer of fired - on, high temperature glass is deposited over the SIPOS layer and protects the junction from ambient contamination and mechanical damage.

The wafers are then masked with a photoresist film and the top (Anode) Contact Metallization Layer of sintered nickel is applied (see figure 1).

Figure 1. Cross Section of GPP Die

product faq16

Note: This process is typical to our GPP rectifier die; however, particular processes and materials used may vary depending on the specific device. Please contact a Diodes Incorporated Applications Engineer for more detailed information regarding a specific device.

Can You Provide Details on Product Availability?

Products with SnPb solder finishes are no longer available.

External links to some of the ASSPXO/VCXO datasheets are missing, where can I go to access them?

Please go to the Media & Downloads page. From there please click on the tab called "FCP Support Documents".
In that section, you should be able to access all the links related to each product, in terms of reflow, test circuits and tape and reel information. We apologize for the inconvenience.

Has Testing Been Done to Qualify Diodes Incorporated's Lead Free Finishes for Use in Standard SMT/Through-Hole Assembly Processes?

Each product family where the Lead Finish is being converted to Pb Free has been or will be re-qualified by subjecting a family sample to the following tests (typical):

Preconditioning (PC) followed by:

  • Highly Accelerated Stress Testing (HAST)
  • Autoclave (AC)
  • Temperature Cycling (TC)
  • Solderability
  • With SnCuAg Solder
  • With SnPb Solder
  • Resistance to Solder Heat (RSH)
How can I contact sales?

Diodes Incorporated's sales representatives and distributors can be found in the Contact Us section of our site.

How compatible is your part to the 21152? Will Intel drivers work with this device?

The PI7C8152B was intended to be a pin compatible drop-in replacement to the Intel 21152. The drivers that currently work for the Intel device will function with our device as well. The PI7C8152B does not require any external drivers, but instead utilizes the embedded drivers in Windows. The only issue that may come up is that if your software is looking specifically for the Intel device and vendor ID's, it will need to be modified. The PI7C8152B has an added feature, it can work at 66 MHz. our device ID and vendor ID are different from Intel's.

How compatible is your part to the Intel 21150? Will Intel drivers work with this device?

The PI7C8150B was intended to be a pin compatible drop-in replacement to the Intel 21150. The drivers that currently work for the Intel device will function with our device as well. The PI7C8150B does not require any external drivers, but instead utilizes the embedded drivers in Windows. The only issue that may come up is that if your software is looking specifically for the Intel device and vendor ID's, it will need to be modified. Our device and vendor ID's are different from Intel's.

How Does Diodes Define "Green" Products?

Diodes defines "Green" products as those which are RoHS compliant and contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br Cl) and <1000ppm antimony compounds. Further information about Diodes' "Green" Policy can be found on our website.

How does Pericom identify and mark its manufacturing date codes?

Please see the Pericom Date Code Policy.

How Will I Be Able to Distinguish Between Finishes on the Product?

Product package labeling clearly states the status of the parts. Please see Document AP02006.pdf for complete labeling information.

The sheen of Matte Tin vs. SnPb Finish is visibly different. It is not possible to tell Green from non-Green products once put into use.

To which version of the Intel 21154 is the PI7C8154 pin compatible?

This bridge is designed to Intel 21154BE capabilities (power management support at pin D11, 2KV ESD rating, 0.35 micron process, and more robust tolerances for 3.3V/5V power start up sequence.) The bridge also can be used in designs intended for 21154 versions AC, AE, and BC also.

What do the Diodes' Data Sheet Banners and Watermarks indicate?


Banner and/or WatermarkQualification StatusSample StatusWebsite Location
"New Product Banner" Must be Qualified Production Catalog and Search
"Not Recommended For New Design, Use XXXXX" Watermark
(See Note 1)
Qualified Limited Distribution Inactive Data Sheet Archive Only
"Discontinued (Date) Use XXXXX" Watermark (See Note 1) N/A No Distribution Inactive Data Sheet Archive Only
  1. "Use XXXXX" is included when applicable and is a Diodes, Inc. part number or series part number.
What does "TCXO" mean?

TCXO means "Temperature Compensated Crystal Oscillator" A TCXO is essentially a quartz crystal integrated with compensation electronic circuitry sensitive to temperature variation. The compensation circuitry helps TCXO maintain high frequency stability over temperature (0.5ppm - 5ppm)


What Does Diodes Incorporated Mean by "Removal of Halogens and Antimony Compounds"?

Removal of halogens and antimony compounds is brought about by a change of molding compounds only. No electrical or performance changes are made for this conversion. All these ratings remain the same.

What Is Diodes Incorporated's Definition of "Lead Free"?

Diodes Incorporated's products defined as "Lead Free" contain no purposefully added Lead either internally or externally. Only trace elements may remain.

What Is Diodes Incorporated's Definition of Products with a "Lead Free Finish" ?

These products will have no external Lead, but will still contain internal Lead in the form of high temperature die bonding solder, glass encapsulation or glass die passivation. Lead in these types of materials are currently RoHS exempt.

When suffixes are appended to part numbers, what do they signify?

At Diodes Incorporated, dash numbers / letters are appended to our product part numbers (example: ZMM5250B-7) to indicate package type and reel size, as listed below.

A = Ammo Pack
B = Bulk Packaging
T = Tape & Reel
U = Tube Packaging
7 = 7-inch Reel
13 = 13-inch Reel
F = Pb Free or Pb Free Lead Finish (as noted on associated data sheets)
L = (Analog) Pb Free
G = (Analog) Pb Free and Green
TA, TC = Refers to the tape and reel option of the part. Note: These suffixes are not shown on our Data Sheets and other marketing materials. They are not needed for part number searches on our website.

Where can I find plastic package thermal data for Pericom parts?

Package Thermal Data can be found under Packaging section. Please refer to the Packaging Mechanicals & Thermal Characteristics table.

Where can I find the latest information on Pericom's Product and Package Reliability data?

Please see Pericom's Product Quality & Reliability Page.

Where can Pericom silicon revision (PCN - process change notice) information be found?

Silicon revision information can be found under the Quality section of our site. Please refer to the Product Change Notices

Where can Theta J and Theta C data be found?

Theta J and Theta C can be found in the Packaging section of our site. Please refer to the Packaging Mechanicals & Thermal Characteristics Table.

Where do I find a listing of Inactive (Non-Active) and Obsolete devices for Diodes Incorporated?

To find Inactive (Non-active) and Obsolete devices on our website, go to our Products pulldown menu and select:


Where do I find Diodes Incorporated's Cross from Other Vendors' Parts?

At the top right of our Diodes' homepage, you will see the Cross Reference part number-entry field. 


You will also find CROSS REFERENCE listed in our homepage Design Tools box and in our Site Index.

Where do I find information on Pad Layouts for Diodes' parts?

On our Package Outlines page, you may view "Suggest Pad Layout" specifications for each Surface Mount package [Package Outlines].

Where do I find information on Reflow and Soldering of Diodes' parts?

At our Design Tools box, select "Application Notes" and, at the bottom of the Application Notes list, choose "Recommended Soldering Techniques"

Where do I find Packaging (as in Boxes) information?

At our Products pulldown menu, select "Product Packaging" and choose "Product Carton Specification" [AP02005]

Where do I find Product Change Notifications (PCN) for Diodes' parts?

At our Quality pulldown menu, select "PCN" to locate PCNs, the most recent are listed at the top; you may select them by year at right.

Where do I find Spice Models?

On our website, you will find SPICE MODELS listed in our homepage Design Tools box, on our Products pulldown menu, and in our Site Index.

Where do I find Tape and Reel Specifications?

Please see our "Package Outlines" page in the Design section and view our package dimensions for

Where do I find the device Package Dimensional Drawing?

You may dimensional drawings for our packages in the "Package Outlines" page

You will also find Part Search By Package in our Design Tools, as well as in our site map.

Why do I need a PCI-to-PCI-Bridge?

There are many uses for this chip including:

1) To alleviate the excessive loading on the motherboard. This chip can be used on a server board, or a main board in a system that needs many I/O cards connected to it; these I/O cards can be Ethernet, Fiberchannel, SCSI, or any other PCI I/O cards. PCI specification rev 2.2 allows you to have as many as 4 slots @ 33 MHz slots and two 66 MHz slots. If your system requires more then 4 slots, then you need to add a PCI-to-PCI Bridge. This bridge will take one load only, but it will allow you to add four additional slots on the other side. See Figure 1 of Application Note 55 available on the web.

2) If you have more than one PCI interface chip on an add-in card. If you are designing an intelligent add-in card that requires a CPU and an I/O chip like Ethernet, SCSI, or Fiberchannel, then you will have two or more PCI loads, in this case you must have a PCI-to-PCI bridge on the card. The PCI specification rev 2.2 allows only one PCI Load connected to the PCI Edge connector. See Figure 3 of Application Note 55 available on the web.

3) If you have many types of interfaces, and you would like to isolate each application’s traffic to a specific bus (example: you have couple of Ethernet chips on your system that need to be 32-bit and 66 MHz and have two low-performance 32-bit applications like modem cards running at 33 MHz). In this case, to isolate the two distinct applications you would add one bridge for the 66 MHz high-speed I/O interfaces, and another bridge for the low-speed applications. The benefit is that the high speed I/O card does not have to wait for the low-speed application to finish its transfer. You will also have one bus running at 66 MHz and another slow bus running at 33 MHz.

Will Data Sheets Indicate the Change?

Data Sheets will contain ordering information for each version of a component where more than one version is available. Also, the Features Section will indicate when a Lead Free Version of a product is available or if a product is Lead Free by design, and it is Green. The Mechanical Data Section will have a notation regarding the type of Lead Finish plating.

Will Electrical or Mechanical Specification of the Product Change to Reflect Lead Finish & Molding Compound?

There will not be any specification changes other than to reflect the Lead Free and Molding Compound. Products will continue to be qualified to 260ºC solder re-flow profiles. Moisture Sensitivity Level (MSL) will remain 1 unless specifically announced otherwise on an individual product. Reliability and Qualification Testing will remain as is before with the exception of additional Solderability Testing using Pb Free solders. No major changes should be necessary in customer's processes except for solder profile adjustments.

Will Part Numbers Change?

Yes, part numbers have changed in most cases for Lead Free. A part number suffix is used to designate Lead Free or Lead Free Finish versions of a product when there was a former version containing Lead. The suffix used is an "-F." Part numbers have not changed to indicate Green status.

Examples: To order a Dual Surface Mount Switching Diode in a SOT-323 package (BAV99W) with SnPb Lead Finish on a 7" reel, you would formerly order a "BAV99W-7". To order the Lead Free Version of this device on a 7" reel, you would order a "BAV99W-7-F".

To order a 1 Amp, 400 Volt Standard Recovery Rectifier in an SMA package (S1G) on Tape and Reel (13" reel), you would formerly order an "S1GT-13". To order the same product with Lead Free Lead Finish, you would order "S1GT-13-F".

Please see our data sheets for specific product ordering information and to determine the Green conversion.