UL Certification Requirement Decision for UL 864

ULCertification: UL Certification Requirement Decision for UL 864

UL Certification Requirement Decision for UL 864

UNDERWRITERS LABORATORIES CERTIFICATION REQUIREMENT DECISION

This UL Certification Requirement Decision is prepared and published by Underwriters Laboratories (UL). It is normative for the applicable UL Product Certification Program(s); however, it is currently not part of the UL Standard(s) referenced below.

Product Category (CCN): UOXX or UOJZ
Standard Number: UL 864

Edition Date: September 30, 2003

Edition Number: 9

Section / Paragraph Reference: Table 62.1

Subject: Component Temperature for Solid-State Devices

DECISION:
Include specifics for utilizing the option indicated in the exception stipulated for Paragarph 62.1 for determining component temperature compliance.

Table 62.1
Maximum temperature rises - electronic components
Component or device  Normal standby (continuous),  Alarm condition (constant temperatures), 
�F  (�C)  �F  (�C) 
A. COMPONENTS         
  1. Capacitorsa 45  25  72  40 
  2. Resistorsb        
    Carbon  45  25  45  25 
    Wire-wound  90  50  585  325 
B. SOLID-STATE DEVICES  See note (c) 
a In lieu of complying with these temperature limits, a component shall meet the derating parameters specified in Table 53.1 or the component reliability assessment specified in paragraph 53.2, exception b) or c)..
b In lieu of complying with these temperature limits, a resistor shall not dissipate more than one-half of its maximum power rating under the test conditions specified.
c The temperature of a solid-state device (such as a transistor, SCR, or integrated circuit) shall comply with one of the following:
  1) Not exceed: 
    a) 50 percent of its rated junction temperature, or storage temperature when not rated for junction temperature, during the normal standby condition or 
    b) 75 percent of its rated junction temperature, or storage temperature when not rated for junction temperature, under the alarm condition or any other condition of operation which produces the maximum temperature dissipation of the component. 
For reference purposes, 32�F (0�C) shall be determined as 0 percent. For integrated circuits, the loading factor shall not exceed 50 percent of its rating under the normal standby condition and 75 percent under any condition of operation. 
  2) Not exceed 100 percent of its rating under any condition of normal use and the component is subjected to one of the following: 
    a) The component complies with the requirements of MIL-STD 883E;
    b) A quality control program established by the manufacturer consisting of inspection and testing of all pertinent parameters of 100 percent of components either on an individual basis, as part of an assembly, or the equivalent. 
    c) Each assembled production unit is subjected to a burn-in test under the condition which results in the maximum temperatures for 24 hours, while connected to a source of rated voltage and frequency in an ambient of at least 120�F (49�C), followed by an operation test for normal signaling performances. 
    d) Component reliability data based on actual performance in a similar application, or the Military Handbook "Electronic Reliability Design Handbook, MIL-HDBK-338," such that the failure rate is equal to or less than 0.5 failures per million hours of operation.

RATIONALE FOR DECISION:
Currently, the exception to paragraph 62.1 indicates that a component with a temperature exceeding that indicated in Table 62.1 is not prohibited from being used when reliability data at the higher temperature is provided by the manufacturer to justify its use. Paragraph 53.2 established an acceptable maximum failure rate of 0.5 failures per million hours of operation, based upon actual performance in a similar application or upon Military handbook "Electronic Reliability Design Handbook, MIL-HDBK-338." This decision extends the same principle of validating the reliability of a component under the exibited higher temperatures than that permitted in Table 62.1, to solid state components.

The decision also includes an revison to Note A to correctly reference paragraph 53.2 rather than only the option provided in Table 53.1.