-600

-400

-200

0

200

400

600

Tem perature (°C)

+5 ppm/K

-5 ppm/K

+2,2 ppm/K

-1,8 ppm/K

-50

-25

025

50

75

100

125

No minal-dR/R

No minal-Spread

+/-2,3 ppm/K

No minal-Spread

+/-2,3 ppm/K

USR UNR 4-T220 4-T220B 4-T221

USS UNS 4-T220

••••• Near Temperature

Independent

••••• Lowest Tolerances

••••• Low Capacitance and

Inductance

••••• High Power

••••• Available also 2-pin version

SPECIFICATIONS

ELEKTRICAL

USR 4-T220

UNR 4-T220

Resistance range

:

0R2...80R

0R2...80R

Nominal power

:

1.5 W (70°C) without heatsink

10 W*

15 W*

* with heatsink

Thermal Resistance Rthj-c :

10.8 K/W

6.8 K/W

Tolerances

:

from 0R5

:

0.1%, 0.25%, 0.5%, 1%

from 10R

:

0.05%, 0.1%, 0.25%, 0.5%, 1%

from 50R

:

0.01%, 0.02%, 0.05%, 0.1%, 0.25%, 0.5%, 1%

Stability

:

0.01%

Temperature coefficient :

max. ±5 ppm/K (-55...155)°C

typ. ±3 ppm/K (-55...125)°C

upon request ±1 ppm/K (0...60)°C

Voltage Proof

:

1 kVDC

Thermal EMF

:

< 1 µV/K

ENVIRONMENTAL

Operating Temperature Range

:

-55°C...155°C

:

NiCr-Foil

Substrate

:

Al

AlN

Housing

:

Epoxy + heatsink Cu nickel plated

Connector Material

:

Cu, tinned, 4-pin

Max. torque backplate

:

1.0 Nm

TEMPERATURE COEFFICIENT

Willow Technologies Ltd. Shawlands Court, Newchapel Road, Lingfield, Surrey, RH7 6BL, UK