V5X5P, V15X5P, V15X10P

with TCR of 2 ppm/°C and Tolerance to 0.005 %

for use in Hybrid Circuits

www.vishay.com

For any questions, contact: foil@vishay.com

Document Number: 63024

6

Revision: 25-Oct-07

EFFECTS OF GOLD WIRE

The bonding of the gold wires to the chip has an effect on the overall resistance and on the temperature coefficient, according to

the length of wire used.

The nomogram below shows the effect on both parameters with varying lengths of 0.001" (0.0254 mm) diameter gold wire.

NOMOGRAM

Change of resistance and TCR due to a length L of gold wire added at wire bonding.

500

360

250

160

120

90

62.5

40

22.5

10

50

23

16

10.5

6

4

2.25

1.40

0.82

0.47

0.30

0.16

0.11

600

350

225

130

85

41

25

16

10

6

1900

1100

610

400

230

150

85

53

31

18

11

6.1

4.2

2.3

1.5

0.85

0.50

0.32

0.15

0.10

0.06

0.04

0.02

1

1.4

2.2

3.2

4

6.2

9

12.2

16

25

36

49

64

81

100

144

225

324

400

625

900

1.2K

1.6K

2.5K

3.6K

4.9K

6.4K

8.1K

10K

14.4K

22.5K

32.4K

40K

ppm

%

A

B

R

Δ TCR

ppm/°C

ΔR

R

L

thousandths of an inch

total length of 2 gold

wires of 0.001" diameter

nominal resistance of

chip as measured on its

pads (

Ω)

EXAMPLE:

Total length of wires L = 0.100" (point A on left scale)

Resistance of chip R = 200

Ω (point B on right scale)

Read on intersection of line as with central scale:

On left side - change of resistance:

ΔR

R

On right side - change of TCR:

ΔTCR = ± 2.3 ppm

Nomogram based on the following specs for gold wire:

• Conductivity 72 % of copper

• 1.2

Ω/inch for 0.001" (0.0254 mm) diameter wire

• TCR 3900 ppm/°C

= 600 ppm