Document Number: 63102

For any questions, contact: foil@vishay.com

www.vishay.com

Revision: 14-Nov-07

3

SMR1D/SMR3D

Resistor with TCR down to ± 2 ppm/°C, Flexible

Terminations, and Load Life Stability of ± 0.005 % (50 ppm)

Vishay Foil Resistors

FIGURE 2 - DIMENSIONS in inches (millimeters)

MODEL

L

W

H

P

TW

TH (minimum)

SMR1D

0.236 ± 0.012

(5.99 ± 0.30)

0.126 ± 0.012

(3.20 ± 0.30)

0.098 ± 0.012

(2.49 ± 0.30)

0.051 ± 0.012

(1.30 ± 0.30)

0.087 ± 0.004

(2.21 ± 0.10)

0.039

(0.99)

SMR3D

0.287 ± 0.012

(7.29 ± 0.30)

0.170 ± 0.012

(4.32 ± 0.30)

0.110 ± 0.012

(2.79 ± 0.30)

0.051 ± 0.012

(1.30 ± 0.30)

0.095 ± 0.004

(2.41 ± 0.10)

0.039

(0.99)

TH Minimum

Side View

Stand Off

W

Bottom View

L

P

P

End View

H

TW

Top View

100R0T

(DATE CODE)

-

V

TOLERANCE

LEAD (Pb)-FREE INDICATOR

VALUE (5 DIGITS)

FIGURE 3 - RECOMMENDED MOUNTING PAD GEOMETRIES in inches (millimeters)

MODEL

METHOD

A

MIN.

B

REF

C

REF

D

± 0.04 (± 1.02)

E

REF

SMR1D

Reflow

0.110

(2.79)

0.106

(2.69)

0.124

(3.15)

0.337

(8.55)

0.050

(1.27)

SMR3D

Reflow

0.118

(3.00)

0.106

(2.69)

0.175

(4.45)

0.388

(9.86)

0.050

(1.27)

Per IPC-SM-782 Rev. A

E

A

C

B

D

Reflow Solder Pads

FIGURE 4 - TRIMMING TO VALUES

(Conceptual Illustration)

Mutual Inductance

Reduction due

to Change in

Current Direction

Current Path

Before Trimming

Trimming Process

Removes this Material

from Shorting Strip Area

Changing Current Path

and Increasing

Resistance

NOTE: Foil shown in black, etched spaces in white

Current Path

After Trimming

Interloop Capacitance

Reduction in Series

FIGURE 5 - TYPICAL TCR CURVE

(For more details, see table 2)

Note: The TCR values for < 80

Ω are influenced by the

termination composition and the result in deviation from this curve

- 50

- 25

0

+ 25

+ 50

+ 75

+ 100

+ 125

- 55

± 2 ppm/°C

(+ 25 °C Reference)

+ 150

+ 100

+ 50

0

- 50

- 100

- 150

- 200

R

(ppm)

Ambient Temperature (°C)