1206 High Precision Chip Current Sensing Resistor 3mohm 4mohm 5mohm
6mohm 7mohm 8mohm 9mohm 10mohm
Introduction of Current Sensing Resistors
The precision current sensing resistor is a fixed resistor with
very low resistance error value, can flow a large amount of
current, good weather resistance and mechanical strength, and high
operating ambient temperature. At the same time, the resistance
value drifts with temperature changes. Low; In addition, its
electrical characteristics are stable, CSR is a resistor product
with extremely high stability among fixed resistors
According to different materials and processes, there are four main
resistance technologies: wirewound resistors, thick film resistors,
thin film resistors, and metal foil resistors.
Specification sheet of TCS1206003S1W0
Terminal Pad Solderability: Meets EIA Specification RS186-9E And
ANSI/J-STD-002 Category 3.
Terminal Pad Materials: Tin-plated Nickel-Copper
Lead-Free, RoHS Compliant
TABLE Ⅰ. Construction And Dimension (Unit:mm)
| P/N | Marking | L | W | T | A |
| TCS1206003S1W0 | R003 | 3.20±0.2 | 1.60±0.2 | 0.40±0.2 | 0.58±0.2 |
TABLE Ⅱ. Performance Specification
| P/N | Marking | Prat 70℃(Watt) | Ro(mΩ) | Rt(±%) | Vmax (V) | TCR(ppm) | Ri(MΩ) | Ta(℃) |
| TCS1206003S1W0 | R003 | 1.00 | 3.00 | 1,2,3,5 | (P*R)1/2 | ±70 | >100 | 70.00 |
TABLE Ⅲ. Temperature and heat derating curve.
Rated power refers to the term that can be used continuously at
full power within 70 C.
The following figure shows the usable power attenuation curve when
the operating temperature is higher than 70 C.
TABLE Ⅳ. Tape And Reel Specifications (mm)
TABLE Ⅴ. Recommended Solder Reflow Conditions
‧Recommended reflow methods:IR, vapor phase oven, hot air oven.
‧Devices are not designed to be wave soldered to the bottom side of
the board.
‧Recommended maximum paste thickness is 0.15 mm (0.006 inch).
‧Devices can be cleaned using standard method and solvents. Note:If
reflow temperatures exceed the recommended profile, devices may not
meet the performance requirements.
‧In case of special use, please contact our engineer
TABLE VI. Recommended Pad Layout (mm)
Order Information & Packaging
| TCS1206 | 003 | Tape & Reel Quantity |
Product name Size 3216 mm / 1206 mils SMD:surface mount device | R 3mΩ | 5000 pcs/reel |
Types of Current Sensing Resistors
| Wirewound Precision Resistors | The earliest precision resistor technology, high-precision
wirewound resistor TCR can achieve ±1ppm/°C, the best precision
wirewound resistor can achieve a resistance value close to 50M, and
the resistance value accuracy can achieve ±0.001%, suitable for
ultra-high Precision high resistance applications. Due to the
development of other resistor technologies, precision wirewound
resistors tend to be on the verge of being eliminated because of
their high price and disadvantages such as inductance |
| Thick Film Precision Resistors | Realized by printing and sintering of resistor paste, the most
precise thick film resistor technology TCR can achieve ±50ppm/°C;
the highest resistance value accuracy can reach ±0.1%; it is mainly
used in the requirements of high voltage, high resistance value and
high precision.
The disadvantage of thick film resistors is that it is difficult to
achieve high precision and low TCR in the low resistance part, the
noise index is not good, and the long-term stability is generally
worse than other precision resistors. |
| Thin Film Precision Resistors | Thin film precision resistors are realized by depositing resistive
materials on a carrier; it is the most popular precision resistor
technology at present. Through long-term multilayer film
deposition, high-precision resistance adjustment and later
screening, the optimal precision thin-film resistor can achieve a
TCR of ±2ppm/°C, an accuracy of ±0.01%, and good long-term
stability. The disadvantage is that the power is not large, the low
resistance part is not good, it is not antistatic, the power
coefficient is poor, it is difficult to meet the supply of small
batches, and the consistency of different batches is not good. |
| Metal foil precision resistors | By sticking the alloy foil on the carrier for stress balance, the
temperature drift close to zero can be obtained. By etching the
resistance pattern and adjusting the resistance, an accuracy of up
to ±0.001% can be obtained. The best foil resistors have a 6-year
storage resistance drift of only ±2ppm, antistatic, non-inductive
and non-capacitive, no hot spot design, low noise, and low voltage
coefficient. The disadvantage of foil resistors is that the
resistance value cannot be very high. The maximum size of the chip
resistor can only be up to 150K, and the maximum size of the pin
resistance can only be up to 2M. In addition, due to the process
and customer base, the unit price of the foil resistor is high
cost. |
Advantages and disadvantages of different types of precision
resistors
| Features | Resistance tolerance | TCR | Size miniaturi zation | Withstand power | Usable temperature range | Power decay temperature point | Thermoelectro motive force | Long electrode polarization | Surface temperature | Carrier cracks affect electrical characteristics | Resistance breadth | Product stability |
| Thin Film Precision Resistors | High | High | Yes | Low | Low | Low | High | Without | High | Yes | Small | Low |
| Thick Film Precision Resistors | High | High | Yes | Low | Low | Low | High | Without | High | Yes | Small | Low |
| Metal foil process | High | Low | Yes | High | High | High | Low | Yes | Low | No | Big | High |
Explanation of current sensing resistor
1. Resistance accuracy: resistance error range (D=0.5%, F=±1%,
G=±2%, H=±3%, J=±5%)
2. Temperature Coefficient (TCR) : Resistance Drift Coefficient
with Temperature
3. Rated power: At room temperature, the element can withstand the
maximum power of the current flowing
4. Operating temperature range: the temperature range in which the
element can operate
5. Power decay temperature point: the highest temperature at which
the element produces power decay
6. Thermoelectromotive force : The error voltage coefficient of the
element due to the Seebeck effect (thermoelectric effect)
7. Self-inductance: the error voltage coefficient of the component
due to the magnetoelectric effect
General characteristic test
1.R0 (installed resistance value)
2. TCR (Temperature Coefficient of Resistance)
3.Power (rated power)
4.Stature between Electrode and Paint (height difference between
electrode and solder mask)
5.Ri (insulation resistance test)
6.Solderability (solderability test)
Reliability (long-term) test
7.Short Time Overload
8.Intensity of Plating
9.Substrate Bending (bending test)
10.Current Stability Test
11.Resistance to Solder Heat
12.The Surface Temperature Test
13.High Temperature Load Life (high temperature test)
14.Low Temperature Load Life (low temperature test)
15. Moisture Load Life (high humidity test)
16. Thermal Shock
17. Load Life at 70°C (70°C environmental test)
18. Pulse Test
Product structure
| Section | Material |
| Coating | Ink |
| Electrode | Cu,Ni |
| Element | Alloy metal |
| Bonding Sheet | Prepreg |
| Support plate | Metal |
| Marking | Ink |
Process description
Pressing (alloy and carrier are pressed together by bonding sheet)
=> Lines (make line graphics according to the required
specifications)=> Electroplating (electrode thickened and
electroplated with copper nickel tin)=> Measure and repair the
resistance (according to the specification requirements, repair the
resistance to the specified resistance value range)=> Cut (cut
to a fixed size)=>Test package (finished product resistance test
and carrier tape packaging).
Application field of Current Sensing Resistors
* Power industry: adaptor/converter/inverter/transducer/charger
* Home appliance industry: white goods (air conditioners/washing
machines/refrigerators/microwave ovens...etc.)/black home
appliances (LCD TVs, plasma TVs...etc.)
* Battery Industry: Battery Protection Board/Control Board
(Batteries for Electric Vehicles, Motors, Pedal Vehicles/Power
Tools/3C Industry, etc.)
* Automotive Electronics Industry: Vehicle Power Conversion
* Equipment/Audio/Micro-motor equipment (electric, window electric
chair, electric side central locking/rearview mirror...etc.)
* Network Communication Industry: Central Office Switch/Security
Unit (MDF)/Client Switch/Modem/Router/Hub
* Computer Industry : NB/Desktop/Tablet/Server/Monitor
* Computer Peripheral Industry: Hard Disk
Drive/CD-ROM/Keyboard/Mouse/Scanner/Printer/Card Reader
(POS)/Audio-Video, Visualization Module/Audio-Video, Video, Video
Network
* Membrane identification module
* Consumer Electronics Industry: Car DVD/Satellite Navigation/Smart
Phone/Talkie/Digital Camera/Digital Video Recorder/Portable
DVD/Audio Equipment/MP3/MP4/Game console
* Lighting Industry : LED/HID/CCFL/HALOGEN LAMP/Ballast
* Industrial Electronics (Equipment) Industry: Security
Alarm/Anti-theft System/Instrument/Equipment Electronic Control
System/Motor/Inverter
* Office equipment industry: copiers/fax machines/office machines
Basic circuit application
CSR is a current sensing element
Its function is to transmit the measured information to the IC
comparator to determine subsequent actions (PWM/PFC/OCP/OPP), so
the accuracy of CSR is very important
High precision (△R＜1%), high power load (P＞2W), small size (D＜0805)
Basic principles of product selection
The selection of CSR shall take into account the following
parameters:
1.Shape: SMD or DIP
2.Size: 0603/0805/1206/2512/3921......
3. Resistance value R and resistance error value △R
4. Maximum steady state operating current Imax
5. Thermoelectromotive force TEMF
6. Power attenuation value and safety attenuation value
Selection Method
Step 1: Confirm circuit related parameters
Step 2: Select the desired resistance value in the loop.
Step 3: Select the required accuracy of the resistance value, that
is, the minimum error value.
Step 4 : Confirm the maximum current flowing through the element
regularly in the loop
Step 5: Calculate the minimum rated power required for the
component at this current
1. Temperature (power) decay rate
2. Safe decay rate
Step 6: Select the required size according to the design space.
Step 7: With or without thermal electromotive force (EMF)
considerations.
Step 8: Actual installation test.
