www.yageo.com
Current Sensing
Chip Resistors
About Yageo
Founded in 1977, the Yageo Corporation has become a
world-class provider of passive component services with
capabilities on a global scale, including production and sales
facilities in Asia, Europe and the Americas.
Yageo currently ranks as the world No.1 in chip-resistors,
No. 3 in MLCCs and No. 4 in ferrite products, with a
strong global presence: 21 sales offices in 15 countries, 9
production sites, 8 JIT logistic hubs, and 2 R&D centers
worldwide. Ferroxcube and Vitrohm, who produce ferrites
and leaded resistors, are also a part of the Yageo group.
We support our customers with extensive literature
including datasheets, brochures and application notes, which
are also available electronically on our website at:
www.yageo.com
Table of Contents
Introduction..............................................................3
Current-Sensing Circuit Applications..........4
Market Applications..............................................6
Product Portfolio....................................................7
Product Selection Tables................................. 10
2
Introduction
Low Resistance, High Power for Current Sensing Applications
Current Sensing Chip Resistors
Current measurement is very important in power and instrumentation systems for circuit control, protection,
monitoring, and performance enhancement. Engineers in power supply and battery circuit designs need to consider
a give-and-take strategy between low resistance values to minimize power losses and sufficient voltage supplies to
avoid noises generated from the environments or particularly in switch mode power supplies.
Yageo’s current-sensing chip resistors are also fully compatible with today’s high volume pick-and-place assembly
systems. As such, they offer attractive, cost-effective solutions to designers of low voltage power supplies and
battery management systems. Featuring a comprehensive resistance range of 0.5 milli-ohms to 1 ohm (low-ohmic),
and available from 0.05 to 5 watts, they are not only applicable to battery packs, power supplies and converters, but
also suitable for use in diverse power control circuits of tablets, notebook computers and hard disks.
Introduction
Yageo now offers three types of surface-mount (SMT) current-sensing chip resistors based on thick film, metal foil,
and metal plate technologies, with scalable product portfolios to meet the various demands of customers and their
applications.
Main Features of Yageo’s Current-Sensing Chip Resistors
•
•
•
•
Low resistance value from 1mΩ to 20 mΩ for minimizing power losses.
High power-rating from 0.05 to 5 watts.
Tight tolerance within 2% to exhibit actual current via voltage reading.
Low TCR to avoid measurement distortions. TCR ranges from 50 to 100ppm/ºC
for metal and 100 to 1500ppm/ºC for thick film current sensors.
• Scalable off-the-shelf products in standard case sizes.
• Compatibility with surface-mount assembly process.
• RoHS/REACH-compliant & Halogen-free.
The low temperature coefficient of resistance (TCR) of Yageo's current-sensing chip resistors minimizes the
resistance change caused by self-heating and high temperature environments.
Thermal electromotive force (EMF) is also an important consideration. Thermal EMF is an important parameter of
the metal foil series of battery management circuits, and of current-sensor resistors. Thermal electromotive force
(EMF) of an Mn-Cu alloy is especially optimal with low EMF below µ0.03 uV/oC.
3
Current-Sensing Circuit Applications
Low-Ohmic Resistors in Power-Sensing
Current-sensor resistors are used in power sensing applications
such as sensing output current in power supplies and
automotive engine management systems. As shown in Figure 1, a
typical function for a current-sensor chip resistor is as a currentsensor (Rsense). This generates the sensing voltage (Vs) for a
feedback control network through which an output current (Io)
passes. The sensing voltage triggers MOSFET switches, switching
them ON and OFF to regulate the duty factor of the current
passing through a choke (L).
The sensing voltage (Vs) is given by the simple relation:
Figure 1 Current sensor chip resistor in current
sensing application
Vs = Io x Rsense
This sensing voltage is generally set at around 100 mV both to save power and maintain satisfactory noise
immunity. To sense a 5 A average output current, Rsense must be 100 mV/5 A = 20 mΩ. The power dissipation will
then be:
P = Io2Rsense = 5 A x 5 A x 20 mΩ = 0.5 W
A current-sensor chip resistor with a power rating 1.0 W would then be recommended for this application to
provide an adequate safety margin.
Over-Current Detection
As a means to detect the current passing through the
transistor (see Figure 2), a resistor in series is added
between an emitter and a ground. This resistor shouldn't
emit smoke or catch fire even when the switching transistor,
subjected to a larger current, breaks down. In addition,
reduced parasitic inductance is required, particularly for high
frequency switching control. Recommended resistors with
low resistance are metal-plate types, like the PE-series.
DC/DC converter
Figure 3 on the right shows the current-detecting circuit
of a DC/DC converter. The voltage across the currentdetecting resistor is fed back to control the output power.
The resistance should be low to reduce power dissipation,
and the resistor should withstand a repeated rush current.
Furthermore, the self-inductance should be low for highfrequency applications. Recommended types are PE-series
chip resistors. As for high frequency DC/DC converters,
metal-plate chip resistor, PE-series are the best fit.
4
Figure 2 Over-current protection circuit
Figure 3 DC/DC converter circuit
Tight Tolerance in Sensing Resistance
2
Current Sensing Chip Resistors
The magnitude of the output ripple depends on the
inductance of the choke - the higher the inductance,
the lower the ripple. A high inductance choke, however,
reduces the ability of the circuit to respond to high
frequency transients. Such a choke will also be physically
large, limiting the possibilities for miniaturization so
essential to modern mobile equipment.
0.04 = 4
Figure 4 Relationship between average output current and
Introduction
A trade-off is therefore necessary between choke
peak current with a ripple of 0.04
volume and output current ripple. Experience indicates
that a ripple of 0.04 provides a good compromise in
this area. With this ripple value, the peak output current (Ipeak) is 2% greater than the average current (Iavg): Ipeak
= 1.02 x Iavg (Figure 4).
The voltage generated across the sensing resistor is used in a feedback network to trigger the power-switching
IC.To allow for variation in the characteristics of the power-switching IC, a safety margin for the sensing-voltage is
necessary. A -2% margin on sensing-voltage is usually taken for general applications.
As mentioned earlier, the relation between current sensor resistance, feedback sensing voltage and output
current is given given by the formula: Rsense = Vs/Io. With an output ripple of of 0.04, a 4% (± 2%) deviation
on output current and a safety margin on the sensing voltage of -2%, the allowable deviation on (Rsense) is:
0.98 x Vs
0.98 x 1o
Vs
0.85 x 1o
If Vs= 100 mV and Io= 5 A, the allowable current sensor sensing resistance must lie in the range 19.2mΩ to 20.4mΩ.
Excellent Low TCR Values for Precision Applications
The above discussion does not, of course, take into account the effects of the temperature coefficient of
resistance (TCR) on current sensing applications. With a maximum deviation of 4% on output current and a safety
margin of 2% on sensing voltage, the maximum allowable deviation on sensing resistance is 6%. The limit on TCR
is then given by:
T.C.R.
So
TCR
1.06 Rsense
0.06
Figure 3 plots the allowable T.C.R. values required to maintain tolerance on sensing resistance within the
specified limit. TCR values of Yageo’s current-sensor chip resistors fall well within these allowed limits over the
temperature range 25°C to 155°C.
5
Market Applications
Yageo’s current sensor chip resistors are optimized for current sensing control. The current sensor current sensors,
available from 0.05 to 5 watts, are applicable to battery pack, power supply and converter, and are suitable for use in
diverse power control circuit of notebook computer or the hard disk of other compact portable devices that have
current sensing and over current protection requirements. Featuring a comprehensive resistance range of 0.5 milliohms to 1 ohm and superior temperature coefficient (T.C.R.) performance is able to meet various customer demands
and applications.
Application
Segment
Consumer
Automotive
Industrial
Telecom
Medical
Device & Computing
Home Appliances
v
Air Conditioners
v
v
Diagnostic Equipment
Infotainment System
v
v
v
Smart Meters
v
Smartphones & Tablets
v
v
Notebooks
v
v
Wearable Devices
v
v
Networking
v
v
v
Batteries
Battery Chargers
v
v
v
v
v
Battery Life Indicators
v
v
v
v
v
Battery Packs
v
v
v
v
v
Motor Controls
v
v
v
Motor Drives
v
v
v
v
v
v
v
v
Motors
Power Supplies
DC/DC Converters
v
Switch Mode Power Supplies
v
v
v
LED Drivers
v
v
v
v
Ballasts
v
v
v
v
LED Lighting
Storage & Cloud Computing
6
Disk Drives (HDD &SSD)
v
Servers
v
Product Portfolio
Thick Film Current-Sensing Chip Resistors
(RL & PT Series)
marking layer
overcoat
protective coat
Based on thick film technology, these products exhibit far low parasitic
inductance than wirewound and leaded counter parts. Yageo’s thick
film RL/PT low-ohmic current sensing chip resistors is low cost,
capable of providing low TCR down to ±75ppm/°C, resistance value
down to 50mΩ with power up to 2 watts of power dissipation.
resistive layer
termination (Ni / matte tin)
inner electrode
ceramic substrate
Cross section of RL / PT series
Metal Foil Current-Sensing Chip Resistors
(PE & PF Series)
Metal Plate Current-Sensing Chip Resistors
(PA & PR Series)
A related simple construction without multiple cuts, metal plate
current-sensing resistors provide low TCR down to ±25ppm/°C,
high power rating up to 3W, high frequency performance and low
resistance down to 0.5mΩ.
marking layer
protective coat
end termination
H
inner electrode
I2
protective coat
ceramic substrate
resistive layer (metal foil)
Cross section of PE / PF series
metal substrate
H
end termination
I2
protective coat
Cross section of PA / PR series
marking layer
protective coat
Wide Terminal Current-Sensing Chip
Resistors
Using the wider side as connection in the mounting plate, wide
terminal current-sensing chip resistors strengthen solder joints,
holding reliably to achieve higher power rating needs. With an ideal
structure to suppress heat generation, wide terminal type currentsensors save space, and reduce resistor numbers in high-density
circuit board designs.
Market Applications / Product Portfolio
Metal foil current-sensing resistors made of Mn-Cu alloy are
developed with substrates to provide a better thermal dissipation
and with a wider resistance range up to 300mΩ. Metal foil PE series
feature low EMF below conditions of temperature changes.
µ0.03 uV/ºC is more likely to endure harsh conditions. In the metal
foil type, TCR ranges from 50 to 100ppm/ºC, power rates up to 3W,
and resistance value is available as low as 0.5mΩ.
Current Sensing Chip Resistors
inner electrode
resistive layer
inner electrode
H
termination (Ni/matte tin)
I2
ceramic substrate
Cross section of wide terminal series
Four-Terminal, Current-Sensing Chip Resistors
Design of accurate measurement circuitry, lower power consumption, higher accuracy, and smaller space
requirements are important features for electronic control units. To minimize power losses, a large current across
the (Rsense) resistor needs to be measured, and high-side, current-sense amplifier ICs have to monitor the current
accurately. Four-terminal, current-sensing resistors separating current-carry from voltage-sensing terminals are
able to improve voltage and current measurement accuracy from the ideal Kelvin configuration. They also improve
interference and thermoelectric effects at higher applied power.
7
Dimensions
Wide terminal
I1
I1
I1
I1
H
H
W
I2
I2
L
Type
I2
I2
W
L
unit: mm
unit: mm
Resistance range
L
W
H
I1
I2
50mΩ ≤ R < 1Ω
RL0402
(1)
1.00 ±0.10
0.50 ±0.05
0.35 ±0.05
0.20 ±0.10
0.25 ±0.10
RL0603
(1)
1.60 ±0.10
0.80 ±0.10
0.45 ±0.10
0.25 ±0.15
0.25 ±0.15
RL0805
(1)
2.00 ±0.10
1.25 ±0.10
0.50 ±0.10
0.35 ±0.20
0.35 ±0.20
RL1206
(1)
3.10 ±0.10
1.60 ±0.10
0.55 ±0.10
0.45 ±0.20
0.45 ±0.20
3.10 ±0.10
2.60 ±0.15
0.55 ±0.10
0.50 ±0.20
0.50 ±0.20
RL1218
(1)
3.05 ±0.15
4.60 ±0.20
0.55 ±0.10
0.45 ±0.25
0.50 ±0.25
RL2010
(1)
5.00 ±0.10
2.50 ±0.15
0.55 ±0.10
0.60 ±0.20
0.50 ±0.20
RL2512
(1)
6.35 ±0.10
3.20 ±0.15
0.55 ±0.10
0.60 ±0.20
0.50 ±0.20
PT0402
(1)
1.00 ±0.10
0.50 ±0.05
0.35 ±0.05
0.20 ±0.10
0.25 ±0.10
PT0603
(1)
1.60 ±0.10
0.80 ±0.10
0.45 ±0.10
0.25 ±0.15
0.25 ±0.15
PT0805
(1)
RL1210 (1)
PT1206 (1)
10mΩ ≤ R < 1Ω
50mΩ ≤R < 1Ω
2.00 ±0.10
1.25 ±0.10
0.55 ±0.10
0.35 ±0.20
0.35 ±0.20
50mΩ ≤ R < 75mΩ
& 91mΩ ≤ R < 1Ω
3.10 ±0.10
1.60 ±0.10
0.55 ±0.10
0.45 ±0.20
0.45 ±0.20
75mΩ ≤ R < 91mΩ
3.10±0.10
1.60±0.10
0.55±0.10
0.75±0.20
0.45±0.20
5.00 ±0.10
2.50 ±0.15
0.55 ±0.10
0.60 ±0.20
0.50 ±0.20
6.35 ±0.10
3.20 ±0.15
0.55 ±0.10
0.60 ±0.20
0.50 ±0.20
0.25 ± 0.10
PT2010
(1)
PT2512
(1)
PE0402
(2)
10mΩ ≤ R ≤ 50mΩ
1.00 ± 0.30
0.50 ± 0.20
0.45 ± 0.20
---
PE0603
(2)
5mΩ ≤ R < 100mΩ
1.60 ± 0.25
0.80 ± 0.25
0.60 ± 0.25
---
100mΩ ≤ R < 1Ω
4mΩ
PE0805 (2)
PE1206
(2)
5mΩ
6mΩ
2.00 ± 0.25
1.25 ± 0.25
0.60 ± 0.25
---
PE2512
4mΩ
1.20 ± 0.25
5mΩ ≤ R ≤ 8mΩ
5mΩ ≤ R ≤ 9mΩ
10mΩ ≤ R < 100mΩ
9mΩ ≤ R < 99mΩ
100mΩ
3.20 ± 0.25
1.60 ± 0.25
0.60 ± 0.25
1.15 ± 0.25
0.58 ± 0.25
5.00 ± 0.25
2.50 ± 0.25
0.60 ± 0.25
---
6.30 ± 0.25
3.10 ± 0.25
0.60 ± 0.25
---
6.45 ± 0.25
3.25 ± 0.25
0.70 ± 0.25
---
Note: 1. Apply to ordering codes ending in “L”
2. Apply to ordering codes ending in “Z”
Please contact sales offices, distributors and representatives in your region before ordering
8
0.55 ± 0.25
0.40 ± 0.25
6mΩ ≤ R ≤ 8mΩ
(2)
0.63 ± 0.25
7mΩ ≤ R < 100mΩ
9mΩ ≤ R < 100mΩ
PE2010 (2)
0.30 ± 0.25
0.70 ± 0.25
1.50 ± 0.25
0.60 ± 0.25
1.90 ± 0.25
0.95 ± 0.25
0.60 ± 0.25
Type
Resistance range
5mΩ
PE4527 (2)
PR1206
6mΩ ≤ R < 910mΩ
(2)
1mΩ ≤ R ≤ 4mΩ
PR2010 (2)
W
H
I1
I2
11.50 ± 0.25
7.00 ± 0.25
0.60 ± 0.25
---
3.20 ± 0.25
1.60 ± 0.25
0.64 ± 0.25
0.50 ± 0.25
0.50 ± 0.25
2.90 ± 0.25
2.60 ± 0.25
1mΩ ≤ R ≤ 3mΩ
5.10 ± 0.25
2.54 ± 0.25
0.80 ± 0.25
1.30 ± 0.25
1.30 ± 0.25
4mΩ
5.10 ± 0.25
2.54 ± 0.25
0.64 ± 0.25
0.80 ± 0.25
0.80 ±0.25
1mΩ ≤ R ≤ 5mΩ
6.50 ± 0.20
3.20 ± 0.20
0.65 ± 0.15
0.90 ± 0.20
0.90 ± 0.20
Current Sensing Chip Resistors
PA2512
(1)
L
Wide terminal
Resistance range
L
W
H
I1
I2
PE0306
(2)
5mΩ ≤ R ≤ 100mΩ
0.90 ± 0.20
1.70 ± 0.20
0.65 ± 0.20
0.25 ± 0.15
0.25 ± 0.15
PE0508
(2)
3mΩ ≤ R ≤ 100mΩ
1.35 ± 0.20
2.10 ± 0.20
0.65 ± 0.20
0.43 ± 0.15
0.43 ± 0.15
1mΩ
1.60 ± 0.20
3.20 ± 0.20
0.60 ± 0.15
0.55 ± 0.20
0.55 ± 0.20
PE0612
(2)
2mΩ ≤ R ≤ 4mΩ
1.60 ± 0.20
3.20 ± 0.20
0.60 ± 0.15
0.40 ± 0.20
0.40 ± 0.20
5mΩ ≤ R ≤ 300mΩ
1.60 ± 0.20
3.20 ± 0.20
0.60 ± 0.15
0.30 ± 0.20
0.30 ± 0.20
1mΩ
2.50 ± 0.20
3.70 ± 0.20
0.60 ± 0.15
0.95 ± 0.20
0.95 ± 0.20
2mΩ
2.50 ± 0.20
3.70 ± 0.20
0.60 ± 0.15
0.75 ± 0.20
0.75 ± 0.20
3mΩ ≤ R ≤ 100mΩ
2.50 ± 0.20
3.70 ± 0.20
0.60 ± 0.15
0.60 ± 0.20
0.60 ± 0.20
6 / 8 / 10mΩ
2.00 ± 0.20
7.50 ± 0.30
0.60 ± 0.15
0.60 ± 0.15
0.60 ± 0.15
1mΩ ≤ R ≤ 100mΩ (except 6/8/10mΩ) 2.50 ± 0.20
7.50 ± 0.30
0.60 ± 0.15
0.58 ± 0.15
0.58 ± 0.15
PE0815
(2)
PE0830 (2)
PE1225 (2)
1mΩ
3.10 ± 0.20
6.30 ± 0.20
0.60 ± 0.15
1.15 ± 0.20
1.15 ± 0.20
2mΩ ≤ R ≤ 100mΩ
3.10 ± 0.20
6.30 ± 0.20
0.60 ± 0.15
0.50 ± 0.20
0.50 ± 0.20
Product Portfolio
Type
4 terminal
D
W
C
PS0306 / PS0508 / PS0612
A
L
A
C
C
PS1225
A
H
A
unit: mm
Type
Resistance range
L
W
A
D
C
H
PS0306
10mΩ ≤ R ≤ 50mΩ
0.80 ± 0.20
1.60 ± 0.20
0.25 ± 0.20
0.30 ± 0.15
0.30 ± 0.15
0.55 ± 0.20
PS0508
10mΩ ≤ R ≤ 50mΩ
1.25 ± 0.20
2.00 ± 0.20
0.25 ± 0.20
0.20 ± 0.15
0.30 ± 0.20
0.55 ± 0.20
PS0612
(2)
0.5mΩ ≤ R ≤ 100mΩ
1.60 ± 0.20
3.20 ± 0.20
0.45 ± 0.20
0.50 ± 0.20
0.65 ± 0.20
0.60 ± 0.20
PS1225
(2)
3mΩ ≤ R ≤ 100mΩ
3.10 ± 0.20
6.30 ± 0.20
0.80 ± 0.20
---
2.20 ± 0.20
0.60 ± 0.15
Note: 1. Apply to ordering codes ending in “L”
2. Apply to ordering codes ending in “Z”
Please contact sales offices, distributors and representatives in your region before ordering
9
Product Selection Tables
T. C. R. - RL series
Type
T.C.R
RL0402
RL0603
RL0805 / RL1206 / RL2010
50mΩ≤R
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