Document Number: 63140

For any questions, contact: foil@vishay.com

www.vishay.com

Revision: 12-Feb-08

1

VAR (Vishay Audio Resistor)

Vishay Foil Resistors

Ultra High Precision, High Resolution Z-Foil Audio Resistor,

with TCR of ± 0.2 ppm/°C, Tolerance to ± 0.01 %

and Noise < - 40 dB

Any value at any tolerance available within resistance range

INTRODUCTION

technology, with improved sound quality, provides a

combination of low noise and low inductance/capacitance,

making it unrivalled for applications requiring low noise and

distortion-free properties.

While

the

regular

foil

resistors

are

already

widely

acknowledged as the leading resistors for audio applications,

the special “naked Z-foil resistor” design without mold or

encapsulation, adds an additional dimension for reducing

signal distortion and increasing clarity in signal processing.

Our application engineering department is available to

advise and to make recommendations. For non-standard

technical requirements and special applications, please

contact us.

FEATURES

• Temperature coefficient of resistance (TCR):

- 55 °C to + 125 °C, 25 °C ref.

± 0.2 ppm/°C typical (see table 1)

• Rated power: to 0.4 W at + 70 °C

• Tolerance: to ± 0.01 %

• Load life stability: to ± 0.01 % at 70 °C, 2000 h at rated

power

• Resistance range: 10 Ω to 100 kΩ (higher or lower values

of resistance are available)

• Electrostatic discharge (ESD) above 25 000 V

• Non inductive, non capacitive design

• Rise time: 1 ns without ringing

• Current noise: < - 40 dB

• Thermal EMF: 0.05 µV/°C typical

• Voltage coefficient: < 0.1 ppm/V

• Low inductance: < 0.08 µH typical

• Non hot spot design

• Terminal finishes available:

lead (Pb)-free

tin/lead alloy

APPLICATIONS

• High precision amplifiers

• High-end speaker system

• High-end audio circuit

• Transducer

• High fidelity audio amplifier

Note:

• For other values and tighter tolerances, please contact application engineering using the footer below

* Pb containing terminations are not RoHS compliant, exemptions may apply

FIGURE 1 - TYPICAL TCR CURVE Z-FOIL

+ 500

+ 200

+ 100

0

- 100

- 200

- 300

- 500

- 55

- 25

+ 25

+ 60

+ 75

+ 100

+ 125

Ambient Temperature (°C)

ΔR

R

(ppm)

0

0.05 ppm/°C

- 0.1 ppm/°C

0.1 ppm/°C

0.14 ppm/°C

0.2 ppm/°C

- 0.16 ppm/°C

- 400

+ 300

+ 400

Available

Pb-free

RoHS*

COMPLIANT

TABLE 1 - RESISTANCE VERSUS TCR (- 55 °C to + 125 °C, + 25 °C Ref.)

RESISTOR

RESISTANCE VALUE

(

Ω)

TYPICAL TCR AND MAXIMUM SPREAD

(ppm/°C)

TIGHTEST TOLERANCE

(%)

VAR

100 to < 100K

± 0.2 ± 1.8

0.01

50 to < 100

± 0.2 ± 2.8

0.01

10 to < 50

± 0.2 ± 3.8

0.02