www.vishayfoilresistors.com
3
SMR1DZ / SMR3DZ (Z-Foil)
For any questions, contact
foil@vpgsensors.com
4151-EN
Rev 13-Aug-2020
Figure 2—Dimensions in Inches (Millimeters)
TH Minimum
Stand Off
W
Bottom View
L
PP
End View
TW
Top View
100R0T
(DATE CODE) -V
z
TOLERANCE
Z-FOIL
INDICATOR
LEAD (Pb)-FREE INDICATOR
V
ALUE (5 DIGITS)
Model L W H P TW TH (Minimum)
SMR1DZ
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)
SMR3DZ
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)
Figure 3—Recommended Mounting Pad Geometries in Inches (Millimeters)
E
A
C
B
D
Model Method A Min B Ref C Ref D ±0.04 (±1.02) E Ref
SMR1DZ
Reflow
0.110 (2.79)
0.106
(2.69)
0.124 (3.15) 0.337 (8.55)
0.050
(1.27)
SMR3DZ 0.118 (3.00) 0.175 (4.45) 0.388 (9.86)
Per IPC-SM-782 Rev A
Figure 4—Trimming to Values
(conceptual illustration)
Mutual
inductance
reduction
due to change
in current
direction
Current path
before trimming
Foil shown in black, etched spaces in white
Interloop
capacitance
reduction
in series
Trimming process
removes this material
from shorting strip area
changing current path
and increasing
resistance
Current path after trimming
Note
To acquire a precision resistance value, the Bulk Metal Foil
chip is trimmed by selectively removing built-in “shorting bars.”
To increase the resistance in known increments, marked
areas are cut, producing progressively smaller increases in
resistance. This method reduces the effect of “hot spots” and
improves the long-term stability of VFR resistors.
Figure 5—Typical TCR Curve Z-Foil
+500
+200
+100
0
–100
–200
–300
–500
∆R
R
(ppm)
0.05 ppm/°C
–0.1 ppm/°C0.1 ppm/°C
0.14 ppm/°C
0.2 ppm/°C –0.16 ppm/°C
–400
+300
+400
Ambient Temperature (°C)
TCR Values for Different Temperature Ranges
–25+250+60 +75+100+125–55
Notes
• For more details, see Table 1.
• The TCR values for <80 Ω are influenced by the
termination composition and the result is deviation from
this curve.
