www.vishay.com

79

VHZ Hermetic

Vishay Foil Resistors

Document Number: 63063

Revision 12-Dec-05

For technical questions, contact: foil@vishay.com

SALES

• AMERICAS: foilsales.usa@vishay.com

• ASIA/JAPAN: foilsales.asia@vishay.com

• UK/HOLLAND/SCANDINAVIA: foilsales.eunorth@vishay.com

• GERMANY/CZECH REPUBLIC/AUSTRIA: foilsales.eucentral@vishay.com

• FRANCE/SWITZERLAND/SOUTHERN EUROPE: foilsales.eusouth@vishay.com

• ISRAEL: foilsales.israel@vishay.com

FIGURE 2 - POWER DERATING CURVE

NOTES:

1. Standard Resistance Tolerance: ± 0.005%; ± 0.01%;

± 0.02%; ± 0.05%; ± 0.1%; ± 0.25%; ± 0.5%; ± 1.0%.

2. Not to exceed power rating of resistor.

3. See Figure 2 below.

4. 0.200" (5.08 mm) lead spacing available for VH102Z,

specify VH102ZL.

5. Maximum is 1.0% A.Q.L. standard for all specifications

except TCR. (For TCR information see notes 6 -8.)

Typical is a designers reference which represents that

85% of the units supplied, over a long period of time, will

be at least the figure shown or better.

6. Vishay Nominal TCR is defined as the chord slopes of

the relative change of resistance/temperature, expressed

in ppm (parts per million), called (RT) curve from 0°C to

+ 25°C and + 25°C to + 60°C (“Instrument” Range); and

from – 55°C to + 25°C and + 25°C to + 125°C (“Military”

Range). These specifications and the definition of

Nominal TCR apply to all resistance values including

low-value resistors.

7. Selected TCR Tracking is available for specially ordered

lots of resistors. The selected TCR tracking can be 3, 2,

1 and as close as 0.5ppm/°C throughout the full

temperature range.

Bulk Metal

Hermetically Sealed Resistors, Aerospace

8

TCR tracking is a measure of the similarity of resistance

value change in two or more resistors which are

undergoing the same temperature changes. Tracking

could be expressed a s the dif ference in the

temperature coefficients of the resistors, expressed in

ppm/°C as (∆R

1

/R

1

– ∆R

2

/R

2

) x 10

of resistors are referenced to a nominal TCR, the spread

or envelope around the nominal would be the

difference. If the spread is ± 1.5ppm/°C about a nominal,

the tracking, as defined above, will be 3ppm/°C.

9. Load life ∆R Maximum can be reduced through in-

house procedures.

10. Inductance (L) due mainly to the leads.

11. The resolution limit of existing test equipment (within

the

measurement capability of the equipment, or

“essentially zero.”)

12. µV/°C relates to EMF due to lead temperature difference

and µV/watt due to power applied to the resistor.

+100

+75

+50

+25

0

–75 –50

–25

0

+25 +50

+75 +100 +125 +150 +175 +200

Ambient Temperature (°C)

–55°C

+200

+70°C Double Rated Power

Rated Power

+175

+150

+125