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FAQ: Common

Q. Are there any mounting manuals?

Common: 000


“Package Manuals” are available on the following page. The manual refers to recommended mounting conditions, precautions, package information, etc. Use the manual with the product datasheet.

Q. Tell me about thermal resistance (θja / ψjt) of packages.

Common: 001


Thermal resistance values of the main packages are suggested below.

Packages θja (°C/W) ψjt (°C/W)
HSOP-6J 37 7
HSOP-8E 34.5 10
HSOP-18 32 8
TO-252-5 26 7
SOT-89-5 38 13

Thermal resistance is mentioned in PDFs of Package List.

Q. Tell me the definitions of θja, ψjt and θjc.

Common: 002


The definitions are as follows:

θja: Thermal Resistance between Tj and Ta

ψjt: Thermal Resistance between Tj and Tt

θjc: Thermal Resistance between Tj and the Bottom Surface of the Package

Definitions of θja, ψjt and θjc

Q. Where does junction temperature refer to?

Common: 003


Junction temperature refers to the temperature of a chip inside a package. Temperatures around a package are called as follows:

Ta: Ambient Temperature

Tt: Temperature of the Top Surface

Tj: Junction Temperature

Temperatures around a package

Q. What does maximum junction temperature refer to?

Common: 004


Maximum junction temperature refers to the allowable maximum temperature during operation of a chip. Temperature momentarily exceeding the allowable value may cause permanent damage and may degrade reliability and safety of both the device and the system containing it. Operation at or over the rated temperature is not assured. See the item "Tj" in Absolute Maximum Ratings on datasheets to obtain information about operating temperature of each product.

Q. Is there any difference between the squared values/characters and those not squared, both of which appear in outline drawings of packages?

Common: 005


In some package outlines, geometrical dimensioning and tolerancing is used to indicate shape tolerance, in addition to size tolerance. Geometrical tolerancing is defined by ISO, JIS, ASME, etc. For example, JIS defines it from JISB0021. Squares only containing values represent theoretically-accurate measurements.

ex. DFN(PLP)1010-4

Q. What do the characters on the surface of a package represent?

Common: 006


The characters represent product codes (output voltage, detector threshold, etc.) and lot numbers. See the part markings in product specifications for more details.

ex. RP201K

ex. RP201K

Q. Tell me about recommended landing patterns.

Common: 007


Recommended landing patterns are mentioned on PDF files in Package Information.
See the PDF on the linked page here.

Q. How should the tab on the bottom surface of DFN (PLP) packages be connected?

Common: 008


The tab (thermal pad) is at the ground level. The tab is better to be connected to the GND in order to ensure heat dissipation and mounting strength, but leaving it open is also acceptable.

Q. Tell me about packing outlines.

Common: 009


The packing outlines are below:





Q. Tell me about packing materials.

Common: 010


Packing materials are as follows:

  • Emboss Carrier Tape: APET/ PS/ PC + Carbon (conductive)
  • Top Cover Tape: PET or Polyester (antistatic)
  • Tape Reel: PS + Carbon (conductive)

Q. Give me information about the feed direction of tape-and-reel packed products.

Common: 011


Feed direction is contained in the product name, like -E2, -TR, -TL, and -T1. The directions of each are suggested below:

User Direction of Feed









Q. Tell me about the information on product labels.

Common: 012


The following information is included in the product label.

ex. Barcode labels (code 39) with a QR code

ex. Barcode labels

  • 1.Product Formal Name, Number of the Product
  • 2.Mark Lot No., Company Code (Fixed)
  • 3.Product Formal Name
  • 4.Number of the Product
  • 5.Manufacturing Lot No.
  • 6.Wafer Lot No.
  • 7.Quality Approved Date

Explanation about Lot No.

Mark Lot No. A lot number marked on the product
Manufacturing Lot No. The lot number at assembly process
Wafer Lot No. The lot number at wafer process

Data Included in the QR code

The QR code includes the following data:

"Product Name", "Number of the Product", "QC LOT (Manufacturing Lot No.)", "Wafer Lot No."

Q. Tell me about your contribution to lead (Pb) free and halogen free.

Common: 013


We have complied with RoHS Directive by introducing lead (Pb) free since April 1st, 2006.

Also, we have shipped out halogen-free products only, since April 1st, 2012.

See the following page for more information about Ricoh Environment Policy.

Q. How can I find out the production status of your products?

Common: 014


The products in the page below are under production.

Q. How can I get to the information about alternatives for non-promotion/limited/discontinued products?

Common: 015


You can obtain the information from the page below.

Q. Show reliability data, such as MTTF or MTBF, FITs, and FIT, and failure rate.

Common: 016


Product reliability is indicated by Mean Time Between Failure (MTBF) for repairable, Mean Time To Failure (MTTF) for unrepairable, and Failures in Time (FITs). MTTF is applied for semiconductor devices because they are unrepairable.

MTTF and failure rates of Ricoh electronic products are suggested in the PDF below.

FIT is calculated by the following formula:

1FIT = 10-9 (Failure/Time) = 10-4 (%/1000h)

The data is obtained from test results with 110 samples and zero defects.
This is calculated as follows:

FIT value = (number of defects) / (number of tests × test time × acceleration factor)

As the number of tests increases, the FIT value decreases.

In Ricoh electronic devices, data is calculated with 110 pieces, due to the cost and man-hours required for the test.