Lot Acceptance Testing (LAT)

Advantages

Lot Acceptance Testing provides screening and qualification tests to enable the use of Exxelia Ohmcraft’s standard parts in flight applications (Aerospace/Space). Exxelia Ohmcraft can screen and qualify its resistor products to MIL-PRF-55342, MIL-PRF-49462, NASA EEE-INST-002 (Level 1 or Level 2) or a custom test plan. LAT Testing includes but is not limited to:

  • Thermal Shock
  • Power Conditioning
  • High Temperature Exposure
  • Solderability
  • TCR
  • Load Life
  • Short Term Overload
  • Terminal Strength
  • Resistance to Solvents
Value R R Ω Resistance Value in kΩs, MΩs, GΩs, or TΩs
Tolerance ± X% at V Resistance Tolerance measured at specified voltage
TCR < [Ordering Coder TCR] ppm/ºC (Hot to TmaxºC, Cold to TminºC)
< 2*[Ordering Coder TCR] ppm/ºC (Hot to 125ºC, Cold to -55ºC)
TCR referenced to 25ºC
Working Voltage V Voltage across the resistor during application operation
Max Voltage Rating V Maximum Voltage based on resistance value or case rating
Max Power Rating W Maximum Wattage based on resistance value or case rating

Pre-Cap Visual Inspection

Prior to Conformance Test 13 pcs

Conformance Test – 100% Screening

Visual Inspection

  • Magnification: 30x to 60x
100%
Mechanical Inspection 3 pcs. (minimum)
DC Resistance

  • Per MIL-STD-202, Method 303
  • Measured at specified test voltage for resistance tolerance
100%
Thermal Shock

  • Per-MIL-STD-202. Method 107, Test Condition B (modified)
  • 5 cycles (MIL-PRF-55342), 10 cycles ( NASA level 2) or 25 cycles (NASA level 1)
  • Min. temp -55ºC, Max temp 125ºC
100%
High Temperature Exposure (SMT)

  • 100 hours at 125ºC
100%
Power Conditioning (Leaded)

  • 100 hours at Working Voltgage at 25ºC
100%
Final DC Resistance

  • Per MIL-STD-202, Method 303
  • Measured at specified test voltage for resistance tolerance
100%

Conformance PDA: 5% (NASA Level 1 or MIL-PRF-55342), 10% (MIL-PRF-49462) or 15% (NASA Level 2)

Group

NASA Sample Size (Level 1 / Level 2)

Group 1

  • Conformance Testing: Basic Screening
100%
Group 2

  • Solderability
    • MIL-STD-202, Method 208
  • Resistance to Solvents (Leaded)
    • MIL-STD-202, Method 215
3 pcs / 3 pcs
Group 3

  • Temperature Coefficient (TCR)
    • Per MIL-STD-202, Method 304
    • Reference Temperature: 25ºC
  • Low Temperature Storage
    • -65ºC no load dwell for 24±4 hours
    • +25ºC ambient no load dwell for 2-8 hours
  • Low Temperature Operation
    • -65ºC no load dwell for 1 hour
    • Working Voltage for 54 minutes
    • +25ºC no load dwell for 24±4 hours
  • Short Time Overload
    • 2X Working Voltage for 5 seconds
10 pcs / 6 pcs
Group 4

  • Resistance to soldering heat
    • MIL-STD-202, Method 210, Test Condition B (modified)
    • 260ºC for 20 seconds
  • Terminal Strength (Leaded)
  • MIL-STD-202, Method 211 Test Condition C
  • 16 ounces ± 1 ounce for 10 seconds
9 pcs / 6 pcs
Group 5

  • Shock (Leaded)
    • MIL-STD-202, Method 213B, Test Condition I
  • Vibration (Leaded)
    • Per MIL-STD-202, Method 204, Test Condition D
9 pcs / 6 pcs
Group 6

  • Load Life
    • Per MIL-STD-202, Method 108
    • Working Voltage for 1000 or 2000 hours at 25ºC
12 pcs / 9 pcs
Group 7

  • Resistance to Bonding Exposure (SMT)
    • Solder mounted to a ceramic test plate
    • 4-12 hours stabilization at 25ºC
10 pcs / 5 pcs
Group 8

  • No Applicable Tests
Group 9

  • High Temperature Exposure
    • 125ºC for 100 hours
5 pcs

Custom Configurations Available Upon Request

Please consult with our knowledgeable sales staff for help specifying custom parts to meet your needs.

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