Post on 24-Jun-2015
description
I. Specification Comparison
II. Appearance Observations
III. Manufacturing Processes
IV. Characteristic Analysis
V. Summary
Benchmark of Metal Strip
Current Sensing Resistors
I. Specification Comparison
Company
Model WMCS series WSL series LR series RL series RLM series
Power
Rating
2W (1mW≦R≦100mW) 2W (R≦10mΩ) 2W (0.5mΩ≦R≦75mΩ) 2W (R≦2mΩ) 2W (R≦10mW)
1W (1mW≦R≦200mW) 1W (R>10mΩ) 1W (0.5mΩ≦R≦100mΩ) 1W (R>2mΩ) 1W (R>10mW)
TCR±50ppm/°C
(1mW≦R≦200mΩ)
275ppm/°C
(R≦2.9mΩ)
50ppm/°C
(0.5mΩ≦R≦3mΩ)
200ppm/°C
(R≦2.9mΩ)
275ppm/°C
(R≦2mΩ)
150ppm/°C
(2.9mΩ<R≦4.9mΩ)
-25ppm/°C
(3.1mΩ<R≦6.9mΩ)
100ppm/°C
(3mΩ<R≦10mΩ)
100ppm/°C
(2mΩ<R≦10mΩ)
110ppm/°C
(4.9mΩ<R≦6.9mΩ)
-15ppm/°C
(7mΩ≦R>10mΩ)
50ppm/°C
(R>10mΩ)
75ppm/°C
(R>10mΩ)
75ppm/°C
(R>6.9mΩ)
Resistance
Range1mΩ~200mΩ 1mΩ~500mΩ 0.5mΩ~100mΩ 1mΩ~50mΩ 1mΩ~100mΩ
Operating
Temp. Range-55°C~+170°C -65°C~+170°C -65°C~+275°C -55°C~+170°C -55°C~+170°C
Company
Top View
Bottom View
Side View
II. Appearance Observations
Metal foil/substrate
laminationCu electrode
formation
Resistance
trimming
Over-coating Marking Cu/Ni/Sn Plating
III. Manufacturing Processes
Wellcomp WMCS series
III. Manufacturing Processes
Vishay WSL series
NiCr foil Cu electrode welding Trimming Over-coating
Marking Terminal plating
010Resistance
formationMolding Marking
Cu electrode
combination
III. Manufacturing Processes
GTC LR series
010
Terminal Plating
010
III. Manufacturing Processes
Cyntec RL series
Substrate Metal foil/substrate
lamination
Trimming
Over-coating Marking Terminal plating
III. Manufacturing Processes
TA-I RLM series
Resistance
formationMolding Marking Cu plating
Cutting and Sn
platingSorting
IV. Characteristic Analysis
TCR (Temperature Coefficient of Resistance)
Company
ItemWMCS2512
R010
WSL2512
R010
LR2512
R010
RL3264
R010
RLM2512
R010
R1 at 25°C (mW) 9.98 9.96 9.97 10.02 10.02
R2 at 125°C (mW) 9.97 9.98 9.96 10.03 9.99
TCR (ppm/°C) -10.02 20.08 -10.03 9.98 -29.94
STOL (short time over load) test
Test condition:
Power:5W Current:22.4A Loading Time:5 seconds
IV. Characteristic Analysis
Power 5W
Company
Res
ista
nce
Va
ria
tio
n
MAX 0.02% 0.04% 0.03% 0.08% 0.03%
MIN 0.01% 0.01% 0.01% 0.02% 0.01%
AVG 0.011% 0.023% 0.02% 0.05% 0.013%
IV. Characteristic Analysis
STOL (short time over load) test
Test condition:
Power:10W Current:31.6A Loading Time:5 seconds
Power 10W
Company
Res
ista
nce
Va
ria
tio
n
MAX 0.06% 0.32% 0.28% 0.26% 0.15%
MIN 0.01% 0.11% 0.13% 0.02% 0.02%
AVG 0.038% 0.243% 0.178% 0.133% 0.092%
Device Surface Temperature
Test Condition: Current:10A Loading Time:10min
Wellcomp Vishay
CyntecTA-I
IV. Characteristic Analysis
GTC
V. Summary
Company Wellcomp Vishay GTC Cyntec TA-I
ModelWMCS
seriesWSL series LR Seroes RL series RLM Series
Construction
Metal foil on ceramic
substrate
Combination of the
metal foil and the
electrode material
Combination of the
metal foil and the
electrode material
Metal foil on
ceramic substrate
Metal foil body with
copper plating
electrodes
Advantage
1.High chip size
ability
(From 0805~2512)
2. Low device
working temperature
3. Lead-free product
4. High thermal
stability
1. Lower terminal
resistance
2. Lead-free
product
1. Lead-free
product
2. Lower terminal
resistance
1. Low device
working
temperature
2. Lead-free product
3. High device
thermal stability
1. Well mass
production ability
2. Lead-free product
Disadvantage
1. Not well known
yet
1. High material
cost
2. High human
source request
for the assembling
1. High material
cost
2. High human
source request
for the assembling
3. Weak overcoating
1. High process
control cost
2. Longer lead time
1. High device
working temperature
2. Poor soldering
especially at small
size device.