The Fundamental Technical Knowledge of Passive Components

The Fundamental Technical Knowledge
of Passive Components
for Windows version
http://www.ty-top.com
- Chapter 1-
Capacitor
Impedance Characteristics of Capacitor
Impedance equivalent circuit with capacitor is the same as the RLC series model.
Changes in Frequency
ESR: Increase
Impedance
Frequency
Frequency
ESL: Decrease
Frequency
Impedance
Impedance
ESL increases
Capacitance
Frequency
Impedance
ESR is constant
ESL
Changes in Element
Impedance
ESR
Impedance
Elements in Capacitor
Cap. : Increase
Frequency
Capacitance decreases
Frequency
What happens to the impedance level when connected in series?
Impedance Characteristics of Capacitor
Impedance for series connection
Impedance with different elements
100
100
10
インピーダンス　[Ω]
Impedance
インピーダンス　[Ω]
Impedance
10
Impedance
depends on ESL
Impedance depends
on capacitance
1
0.1
Resonance
Point
0.01
0.001
0.001
0.01
0.1
Impedance
depends on
ESR
1
10
0.1
0.01
100
周波数　[MHz]
Frequency
• At resonance point, no impedance
for Capacitor & ESL
(Impedance for ESR only)
• The frequency at resonance point depends
on Capacitor & ESL
Cap. : Increase
1
0.001
0.001
Resonance Point
→Cap. : Increase,
ESL: Increase
0.01
0.1
1
Frequency
周波数　[MHz]
ESL:
Decrease
ESR:
Decrease
10
Impedance characteristics vary
depended on each element.
100
Impedance Characteristics of Capacitor
ESR varies depended
on frequency
Frequency characteristics for
different type of capacitors
Impedance,ESR Freq.-Temperature Characteristic
100
1000
R
100
10
Z
インピーダンス・ESR　[Ω]
Impedance
Impedance,ESR[Ω]
Ta　47μF　ESR
Ta　47μF　Z
NEO 47μF　ESR
NEO 47μF　Z
SPCAP 47μF ESR
SPCAP 47μF Z
MLCC47μF　ESR
JM432BJ476MM　ESR
MLCC47μF　Z
JM432BJ476MM　Z
SDK47μF　ESR
SDK47μF　Z
10
1
0.1
1
0.1
0.01
0.01
0.001
0.1
1
10
100
1000
Frequency[KHz]
10000
100000
0.001
1
10
100
1000
周波数　[kHz]
Frequency
10000
100000
RLC Series Model→ ESR independent
from frequency
RLC varies depended on capacitor’s
material, structure and case size
ESR actually varies.
Frequency characteristic varies depended
on the type of capacitor,
especially on ESR.
Reliabilities of Multi-Layered Ceramic Capacitor
1. Operational condition comparison chart for Circuit
Polarity De-rating
MLCC
Ta Cap.
No
◎
Ripple CU.
Solvent
Heat
Limitation Resistance Resistance
◎
◎
Al Capacitor
《Leaded》
What’s Electrolytic Capacitor?
Loading
Test
◎
Al
foil
Al foil
◎
Al
foil
×
△
×
△
Al foil
Electrolytic paper
Dielectric
<Surface mounted>
Yes
Electrolytic paper
（Al2O3 )
Vertical style
×
Electrolysis solution
La
Da
Dk
Ca
Ck
Ra
Al Cap.
Horizontal style
Yes
∗Layout
Application
Problems
×
∗Operational
∗Polarity exam
limitation for rated
voltage
When mounting
(70～50%level)
×
∗Have margin
capacity for
ripple current
∗Less reliable
associated from
self heating
∗Reverse voltage
Consideration
△
∗Limitation
for reflow
molding and
degrading
advancement
×
△
∗Liquid solution
flooding except
block structure
MLCC
∗Al capacitor:
decreasing in
capacitance from
electrolysis loss
Ta Capacitor
《Leaded》
∗Ta capacitor:
diffusion of Ag,
short circuit from
degrading of
insulating layer
Rk
Ca, Ck: positive/negative pole cap.
Da,Dk: rectification from negative
pole’s oxidization coating
La,Lk: Inductance for +,- leads
R: resistance of electrolsis solution
and paper
Ra,Rk: Inside resistance of forward
direction from +,-poles’ oxidization
coating
<Surface mounted>
Dielectric
（Ta2O５）
MnO2
Graphite
Ceramic Capacitor
Tantal
Argentum paste
Solder
Da
La
Dielectric：
Barium Titanate
Lx
Ca
Lx
Ra
Breakdown Voltage (V)
500
Breakdown voltage level comparison: rated voltage 10V
MLCC
400
300
200
100
0
Electrode: Ni
Ta Capacitor
Backward
direction
Forward
direction
１０uF
212F475
4.7uF
316Ｆ１０６
１０uF
212ＢＪ１０５
１uF
316ＢＪ２２５
2.2uF
Characteristics Comparison for the Different Type of Capacitors
Frequency Characteristics
100
Ta　47μF　ESR
Ta　47μF　Z
NEO 47μF　ESR
NEO 47μF　Z
SPCAP 47μF ESR
SPCAP 47μF Z
MLCC47μF　ESR
JM432BJ476MM　ESR
MLCC47μF　Z
JM432BJ476MM　Z
SDK47μF　ESR
SDK47μF　Z
インピーダンス・ESR　[Ω]
Impedance
10
1
ESR varies greatly depended
on each type of capacitors.
Al>Ta>Functional Ta>Functional Al>ML
0.1
The lower ESR becomes, the lower
the impedance for high frequency gets.
0.01
0.001
1
10
100
1000
Frequency
周波数　[kHz]
10000
100000
Al>Ta>Functional Ta>Functional Al>ML
MLCC has superior frequency characteristics.
The most competitive merit
Characteristics Comparison for the Different Type of Capacitors
Ripple Current Characteristics
Ripple current characteristics
for the different type of capacitors
リップル電流対部品温度上昇の比較
Temperature rise characteristic due to ripple current
Heat
Capacitor
Ripple
current
Heat
ESR
ESL
Temperature rise (degree)
Electrical energy is converted to heat
when current goes through resistance.
100
M LCC47uF
積層コン４７μF
Tant.Cap47uF
タンタル４７μF
POSCAP100uF
POSCAP１００μF
10
1
0.1
0
Capacitor
0.5
1
1.5
2
2.5
3
リップル電流（Aｒｍｓ）
Ripple
current(Arms)
3.5
4
Given the same amount of calorific power,
ripple current goes through MLCC
the most because of its low ESR.
Electrical energy is converted
to heat when ripple current
(AC) goes through capacitor.
(DC does not go through it)
Operational recommendation of heat release
value for MLCC is within 10℃.
There is no limitation of allowed ripple current for MLCC.
Heat shortens capacitor’s
durability.
Operational recommendation of heat release
value for electrolytic capacitor is within 5℃.
Allowed ripple current is regulated by makers.
The Basic Knowledge of
Circuits
The Functions of Bypass (decoupling) Capacitor
The Role of Bypass Capacitor
Noise + Load current
Power supply line
Necessary Characteristics for Bypass Capacitor
It has low impedance.
Load
Current
Noise
Current
(low prevention of an electric current)
IC
To connect
the noise
current to
the earth
(grounding)
It electrifies an electric current well.
It efficiently grounds the noise current.
It effectively decreases the noise current.
The principle of operation for Bypass Capacitor
DC does not go through the capacitor
(Impedance:∞)
DC is supplied directly to IC
Noise: more
Noise: less
Low Impedance
High Impedance
AC (noise) does go through the capacitor
AC (noise) is grounded
Noise Suppression → Stabilize IC operation
Impedance
Low
High
Noise effect of
decreasing
More
effective
Less
effective
The Functions of Bypass (decoupling) Capacitor
Replacement of Ta capacitor
by Bypass Capacitor
Selection Criteria for Capacitor
1000
Increasing in noise
suppression effectiveness
Impedance,ESR[Ω]
100
R
Z
10
Decreasing in noise
suppression effectiveness
1
Impedance(Ω）
Change
product name
100
to MLCC +
capacitance
10
Impedance,ESR Freq.-Temperature Characteristic
インピーダンスの比較
Impedance Comparison
タンタル１０μF
Ta10uF
タンタル４７μF
Ta47uF
LMK212F475ZG
LMK316F106ZL
LMK212BJ225KG
EMK325BJ106KN
1
0.1
0.01
0.001
10
0.1
0.01
0.001
0.1
1
Maximum level for noise
suppression effectiveness
10
100
1000
Frequency[KHz]
10000
100
1000
Frequency(kHz
10000
100000
When the frequency is over 10kHz,
the impedance of MLCC is lower than
that of Ta capacitor.
100000
Several kinds of Noise Frequencies
Effectiveness of reduction in high
frequency noise for MLCC is more
superior than that of Ta capacitor.
Select a Capacitor based on noise
frequency needs to be eliminated
It enables to replace Ta capacitor
with a smaller value of MLCC.
The Functions of Backup Capacitor
Load current doesn’t stay constant.
Load current:
small
IC
Operating
at low-speed
Load current:
large
IC
Operating
at high-speed
High-speed load change
Load current
When IC’s operational speed changes rapidly,
large load current is quickly needed.
Low-speed
operation
High-speed
operation
Power line for high-speed load changing
The current can’t flow
Large load current is
to IC quickly enough.
quickly needed.
Line
voltage
IC
Line
voltage
Line voltage can’t be
maintained, therefore
voltage is dropped.
Voltage
dropped
Line
voltage
IC
Low-speed
operation
IC
High-speed
operation
Circuit voltage,
Load current
Load current to IC
Minimum
required
operational
voltage
for IC
Time
Line voltage decreases below the required
operational voltage for IC.
Time
The IC stops its operation.
The Functions of Backup Capacitor
Capacitor’s actual
(considering equivalent circuit)
The Role of Backup Capacitor
Electric current delays
IC
Line
voltage
Line voltage,
needed load current,
Discharge current from
Capacitor
Voltage dropped
by electric current
ESR
Low-speed
operation
Maintaining
Line
voltage
IC
Capacitor
Minimum required
operational voltage
for IC
Voltage dropped
by discharge
current
Line voltage
dropped
Voltage fluctuation occurs
when capacitor charging
High-speed
operation
Line voltage
Voltage
dropped
∗This is a simplified version, so disregard ESL
Making up for electric
current shortage
Voltage dropped
by ESR
Voltage dropped
by electric
discharge
Voltage risen by
capacitor charging
Voltage risen by ESR
Time
Keeping the minimum required
operational voltage for IC
Maintaining
stable operation
Capacitor and ESR decide the amount
of voltage dropped
The Functions of Backup Capacitor
Experimental
circuit
To oscilloscope
R = 1Ω
Power
Supply
Voltage=
5V
Experimental result for Capacitance and ESR
Load
resistance
R=5Ω
LMK432BJ226MMのリップル電圧
Ripple
Voltage of LMK432BJ226MM
タンタル１００μFのリップル電圧
Ripple
Voltage of 100uF Ta Cap
ESR による電圧変動
Voltage
fluctuation by ESR
Pulse generator
1945 (NF)
MLCC
47µF∗7
２０ｍV／Div
Rating
Capacitor
２０ｍV／Div
2SK2684
Current
probe
Voltage
fluctuation
容量による電圧変動
by capacitance
Switching frequency =
1000KHz
１μS／Div
ESR comparison
１μS／Div
ＥＳＲの比較
10
MLCC
22uF
積層コン２２μＦ
Ta Cap
100uF
タンタル１００μＦ
ＥＳＲ（Ω）
1
High Value
Low ESR
The fluctuation band of
line becomes narrower.
0.1
Merits of MLCC
0.01
It enables to replace Ta capacitor with a
smaller value of MLCC.
0.001
0.1
1
10
100
1000
周波数（ＫＨｚ）
Frequency (KHz)
10000
100000
The effectiveness of MLCC’s voltage fluctuation
depressing effect is greater than that of Ta capacitor.
Application Examples for Backup Capacitor
22uF
LMK432BJ226MM(積層コン デン サ２２μF）
タン Ta
タルコン
デン
サ１０μF
Cap
10uF
OSコン １０μF
２．５μS／Div
5０ｍV／Div
OSコン ４７μF
OS-CON 22uF
OSコン １００μF
OS-CON 47uF
５０ｍV／Div
２．５μS／Div
Ta Cap 100uF
２．５μS／Div
OSコン２２μF
５０ｍV／Div
２．５μS／Div
タン タルコン デン サ１００μF
Ta Cap 47uF
２．５μS／Div
OS-CON 10uF
５０ｍV／Div
OSOS-CON
２．５μS／Div
タン タルコン デン サ４７μF
Ta Cap 22uF
２．５μS／Div
JMK550BJ107MM(100uF)
２．５μS／Div
タン タルコン デン サ２２μF
５０ｍV／Div
5０ｍV／Div
Ta Cap
JMK550BJ107MM（積層コン デン サ１００μF）
JMK432BJ476MM(47uF)
２．５μS／Div
２．５μS／Div
JMK432BJ476MM（積層コン デン サ４７μF）
５０ｍV／Div
5０ｍV／Div
５０ｍV／Div
JMK325BJ226MM(22uF)
５０ｍV／Div
JMK316BJ106ML(10uF)
100uF
５０ｍV／Div
MLCC
LMK325BJ106MN（積層コン デン サ１０μF）
47uF
OS-CON 100uF
５０ｍV／Div
10uF
２．５μS／Div
２．５μS／Div
The Basic Knowledge of Power
Supply Circuit
Series Regulator (3 Terminal Regulator)
Load current fluctuation
Load
current
Producing output voltage by
lowering certain amount of input
voltage
Step-down power supply
Controlling element
(transistor)
Input
voltage
Output
voltage
Input
voltage
Controlling element
(transistor)
Output
voltage
Circuit operation (water gate model)
Load
current
Controlling water gate to keep
the water level constant
Controlling load current with transistor
Output voltage stays constant.
Series Regulator (3 Terminal Regulator)
Circuit structure
Effects of input capacitor
Input voltage > Output voltage
Regulator
Add alternate current to input voltage
purposely to measure input current
amount with or without input capacitor
IC
Input Capacitor
IC
Output Capacitor
IC
Consisting of IC, input and output capacitors.
Function of input capacitor
Noise current
Without capacitors
IC
Connecting the line
noise to the ground.
Input Voltage　Vin
Noise + Load current
Load
current
With capacitors (MLCC)
2000
2000
1000
1000
0
0
-1000
-1000
-2000
-2000
-1
0
1
-1
Vertical: mV
Same as the function of
Bypass Capacitor
0
1
Horizontal: u sec
Input voltage is stabilized as
input capacitor is connected.
Series Regulator (3 Terminal Regulator)
Effects of output capacitor
Unable to supply
current immediately
IC
Voltage
dropped
Cover the current
shortage
IC
Line
voltage
Measuring the voltage fluctuation when load change
is occurred with/without output capacitor.
Load Current Iout
Function of output capacitor
Keeping line
voltage
200
150
100
50
0
-10
-5
0
IC
Same as the function of
Backup Capacitor
10
IC
Without capacitors
Output fluctuation
ΔVout
Supply current to control voltage
fluctuation for rapid load change
5
With capacitors (MLCC)
1000
1000
0
0
-1000
-1000
-2000
-2000
-2
-1
0
1
2
-10
-5
0
5
10
Output voltage is stabilized as output
capacitor is connected.
Step-Down Converter
Transistor for switching power supply
has only ON or OFF signal.
Circuit operation (water gate model)
Output
voltage
Controlling element
(transistor)
Load current
Controlling element
(transistor)
Output
voltage
Input
voltage
Input
voltage
Producing output voltage by lowering
input voltage with transistor
Load current
Switching operation
Controlling output voltage
by switching
Turn-on cycle
Constant
Time to be ON
Changes
Turn-on cycle
Constant
Time to be ON
Constant
Turn-on cycle of the switch
Control
ON
PWM
method
PFM
method
Switching frequency
Control
ON
PWM
ON
Time
ON
ON
PFM
ON
Time
Step-Down Converter
Operation of input capacitor
Circuit structure
Choke coil
FET1
Control IC
FET2
heat
heat
Heat generated by ESR
FET
(2)
Necessary characteristics of input capacitor
Input
capacitor
Output
capacitor
Input side current
Input
current
Ripple current flows
into input capacitor.
Ripple current
High tolerance for ripple current
Example: Permissible ripple current of a capacitor is 1A.
Ripple current: 6A
6
capacitors
1A
FET1
FET1
FET1
ON
ON
ON
Time
Large amount of alternating current
(ripple current) flows.
1A
1A
1A
1A
1A
Reduced
Example: Permissible ripple current of a
capacitor is 2A.
Ripple current: 6A
3
2A
2A
2A
capacitors
Step-Down Converter
Points of output voltage to remember
Output side operation
Choke coil
Keeping higher voltage than the lowest operating
voltage of load IC.
Ripple voltage
Rated output voltage
Voltage
Voltage
Output
capacitor
Input voltage
ON
ON
Output
voltage
ON
The lowest
operating voltage
Keep the band of
ripple voltage within
the rated value.
Rapid load voltage fluctuation
Time
Input voltage is controlled
by an on-off switching.
Time
Rated output voltage
It is smoothed with a
choke coil and an output
capacitor.
The lowest
operating voltage
Ripple voltage is included.
Control voltage drop by
rapid load voltage
fluctuation
Step-Down Converter
Factor for determining voltage drop by
rapid load voltage fluctuation
Factor for determining ripple voltage
Repeating an on-off switching signal
Operation at rapid load change
Charge and discharge are repeated with
output capacitor.
Voltage is fluctuated by current flowing in
and out.
Same as Backup Capacitor
Necessary characteristics for capacitor
when rapid load fluctuation occurred
Ripple voltage
High capacitance
Supply capacitor of high electronic charge
When discharging
When charging
Charging
Current
ESR
Low ESR
Voltage rise
Discharging
current
Repeat
ESR
Voltage drop
Charging
Reducing voltage drop when supplying
electronic charge
Capacity
Capacity
Voltage rise
High Value MLCC
Suitable
High capacitance and low ESR
reduce ripple voltage.
Discharging
Voltage drop
Charge Pump (Boost)
Circuitry of charge pump
(example: double boost)
Operation of charge pump (image)
Charging 2 capacitors separately
Charging
C1
V
In
Charging
V
V
C2
V
Output capacitor
(smoothing capacitor)
C1
C2
IC
Output
capacitor
Capacitors for charging
Required characteristics of capacitor
V
Connect
Input
capacitor
Out
2V
Load
V
Connecting charged capacitors
Charging capacitor and output capacitor
Lowering voltage fluctuation
occurred by charging/discharging
Backup Capacitor
Same as step-down output capacitor
Output double amount of voltage than input
Smoothing with output capacitor (Switching)
Output voltage is determined by the number of
capacitors connected. (integral multiple)
High capacitance and low ESR
are required.
Comparison of Various Input Capacitors
Summary
Vertical mV, Horizontal µsec
Without Capacitor
コンデンサ未挿入
Input
fluctuation
Output
fluctuation
入力変動　ΔVin
出力変動　ΔVout
100
Measuring the noise absorption and the output voltage
fluctuation by adding sine wave on input line
2000
Z1
Regulator
Vs:1Vrms
Vs Z2
7.5V
IC
ΔVin
0
0
-1000
-50
-2000
ΔVout
-100
-1
0
1
-1
Input fluctuation of 1Vrms
ΔVin =
Z2
Vs
Z1 + Z 2
Capacitor (Z2) has low impedance.
Effect of noise suppression: large
Vertical mV, Horizontal µsec
250
250
0
0
0
-250
-250
-250
250
-500
-500
-1
0
-500
-1
1
0
1
-1
1000
With Capacitor
入力コンデンサ挿入時の出力変動　ΔVout
AlAl電解1μＦ
Cap
積層1μＦ
MLCC
Ta
Cap
Ｔａ電解1μＦ
20
20
20
100
10
10
10
10
0
0
0
-10
-10
-10
ML　R
ML　Z
Ta　R
Ta　Z
Al　R
Al　Z
0.1
0.01
1
Vertical mV, Horizontal µsec
各種コンデンサ周波数特性（1μF)
Frequency
Characteristics
1
0
MLCC is excellent in noise suppression (low impedance).
Constant IC input voltage
10000
1
入力コンデンサ挿入時の入力変動　ΔVin
With Capacitor
Al
Cap
Ta
Cap
Al電解1μＦ
Ｔａ電解1μＦ
MLCC
積層1μＦ
500
500
500
(Z1:Line impedance)
0
Output fluctuation of 35Vrms
Input capacitor inserted
IC used:NJM78L05(JRC)
Capacitor used:LMK212BJ105KG, Ta1uF, A11uF
Z・ESR　[Ω]
50
1000
-20
-20
-20
-1
0
1
-1
0
1
-1
0
1
Output fluctuation becomes smaller as IC input voltage stays constant.
0.001
1
10
100
1000
Freq.　[kHz]
10000
100000
MLCC has lower impedance than that of Ta for a wide range of frequency.
MLCC is suitable for input capacitor.
Summary Operation Analysis of Output Capacitor
Vout
150
100
50
0
-10
-5
0
5
時間　μsec
Time
Waveform observation: Iout, Vout
(Observing by the type of output capacitors)
IC used: R1112N331B (Ricoh)
Input Cap: LMK212BJ225KG
Input V: 5V
Switching frequency: 100Hz
Load current: 150mA
Taコンと積層コンのESR-周波数特性比較
Frequency
Characteristics Comparison
1000
JMK212BJ475KG
Ta4.7μF
ESR　[Ω]
100
10
Vout
Fluctuation
出力電圧変動　ΔV　mV
Regulator
IC
200
負荷電流　Iout　mA
Load
Current
Iout
Vout Fluctuation
出力電圧変動
Load負荷電流波形
Current Waveform
Observation of output voltage fluctuation
2000
Without
Capacitor
未挿入
Ta 4.7uF
Ta　4.7μF
JMK212B475KG
JMK212B475KG
0
-2000
-4000
-10
-5
0
5
時間　μsec
Time
10
Vout
Fluctuation
出力電圧変動　Δ
V
Ta　4.7μF
JMK212BJ475KG
50
50
0
0
-50
-50
-100
-100
-150
-150
-10
-5
0
5
Variable
ESR: Large
ESRの変動分：大
ESR：Large
10
-10
-5
0
5
10
Variable
ESR: Small
ESRの変動分：小
ESR：Small
Vertical mV, Horizontal µsec
10
Using output capacitor with low ESR
reduces the output voltage drop
when load fluctuation occurred.
1
0.1
0.01
0.001
1
10
100
1000
Freq.　[kHz]
10000 100000
MLCC with low ESR is well-suitable for output capacitor.
Development Method Direction for ML Lineups and Proposals
Market demand
Circuit segment
Digital circuit
Analog circuit
Capacitor application segment
Required performance
Focusing on impedance and
ESR characteristics
It is for circuit noise suppression and often used
in digital circuits.
Low Impedance, Low ESR
MLCC with Y5V characteristic and 0.1-10uF is best
suited
Decoupling
Backup
Smoothing
Amplifier
It may also be used for a circuit with large load
change (CPU), stability of power line and
protection of IC.
Low ESR, Low ESL, Low Impedance
MLCC with characteristics of Y5V,X5R,X7R
and 0.1-10uF is best suited.
Arithmetic
Oscillation
High pressure
Modem
Logic
Digital
High frequency
Power supply
Power supply
Audio
Others
Filter
Coupling
Time constant,
Resonance
Focusing on the stability of real
capacitance, temperature and bias
It is for in/output of power supply circuit and more
used as the miniaturization of equipment.
Real capacitance, Low ESR, Low ESL, Low Impedance
Rated Voltage and Reliability
MLCC with characteristics of X5R, X7R
and 1- tens of uF is best suited.
It is for amplifier, arithmetic, modem and
filter circuits.
Stability of capacitance temperature and bias
is important.
Temperature compensating dielectric type
MLCC is best suited.
(CFCAP, TC type multilayer)
Proposal for Bypass Capacitor
Common Case Example
Ta or
Electrolysis
Multilayer
0.1uF
電解コン22μF＋積層0.1μFのインピーダンス特性
Impedance Characteristics
10000
Impedance
インピーダンス　[Ω]
Replacement proposal for high capacitance Ta
or Al electrolysis with ML 0.1uF
電解コン22μＦ＋積層0.1μＦ
Electrolytic
cap 22uF + MLCC 0.1uF
電解コン22μＦ
Electrolytic
cap 22uF
積層0.1μＦ
MLCC
0.1uF
1000
100
10
1
0.1
0.01
0.001
1
10
100
1000
10000 100000
周波数　[ＫＨｚ]
Frequency
Impedance for high frequency decreases.
High frequency characteristic is advanced.
大容量積層コンデンサのインピーダンス特性
Impedance Characteristics
High Value
MLCC
10000
Impedance
インピーダンス　[Ω]
Replaced only by a single High
Value MLCC
積層０．１μＦ
電解コン２２μＦ＋
Electrolytic
cap 22uF + MLCC
0.1uF
積層コンＦ特４．７μＦ
MLCC 4.7uF
積層コンF 特１０μF
MLCC 10uF
1000
100
10
1
0.1
0.01
0.001
Replaced only by a single MLCC
1
10
100
1000
10000 100000
Frequency
周波数　[ＫＨｚ]
Wider low impedance range compared with parallel use.
- Chapter 2-
Inductor
Impedance of Inductor and Capacitor “Inductive Reactance & Capacitive Reactance”
Ohm’s law：　（Alternate voltage）＝（Impedance）×（Alternate current）
Impedance of pure inductor: inductive reactance: it increases as frequency increases.
Alternate
power supply
Frequency : ｆ
Voltage magnitude : VO
V=V0・exp(jωｔ)
According to the Ohm’s law, the
impedance of pure inductor is
proportional to frequency and
inductance.
V=L・di/dt
Solving for V: V0=j2πf・L
Impedance is equal to:Z=XL=2πf・L
Inductance:
High
Inductance:
Medium
インピーダンス
Impedance
Inductance： L
Inductance:
Low
Frequency
周波数
Frequency : ｆ
Voltage magnitude : VO
Ｖ=V0・exp(jωｔ)
According to the Ohm’s law, the
impedance of pure capacitor is
inversely proportional to
frequency and capacitance.
Alternate
power supply
Capacitance :C
V=1/C・∫idt
Solving for V: V0 = 1/(ｊ2πf・C)
Impedance is equal to: Z = Xc = 1/(2πf・C)
インピーダンス
Impedance
Impedance of pure capacitor: capacitive reactance: it decreases as frequency decreases.
Capacitance:
Medium
Capacitance:
High
Frequency
周波数
Capacitance:
Low
Usage of Inductor and Capacitor: “Low-pass Filter and High-pass Filter”
Impedance of inductor: It increases as frequency increases.
Impedance of capacitor: It decreases as frequency increases.
Typical characteristic of
low-pass filter
GND
In case of high frequency,
inductor’s high Z:
blocked
capacitor’s low Z:
dropping to the ground
Gain
Gain
IN
OUT
In case of low frequency,
inductor’s low Z:
passing-through
capacitor’s high Z:
passing-through instead
of dropping to the ground
Frequency
周波数
OUT
In case of low frequency,
inductor’s low Z:
dropping to the ground
capacitor’s high Z:
blocked
Ｇａｉｎ
Gain
IN
Typical characteristic of
high-pass filter
GND
In case of high frequency,
inductor’s high Z:
passing-through instead of
dropping to the ground
capacitor’s low Z:
passing-through
Frequency
周波数
Series Circuit・Series Resonance and Parallel Circuit・Parallel Resonance of Inductor and Capacitor
Impedance of inductor: It increases as frequency increases.
Impedance of capacitor: It decreases as frequency increases.
Series circuit of pure
inductor and capacitor:
Series resonance
Parallel circuit of pure
Inductor and capacitor:
Parallel resonance
Parallel circuit:
Basically an electric
current flows in
lower impedance.
Series circuit:
Basically addition
At resonant
frequency:
zero
Impedance of
series circuit
Inductor’s
impedance
Frequency
周波数
Impedance of
parallel circuit
Capacitor’s
impedance
インピーダンス
Impedance
インピーダンス
Impedance
Capacitor’
impedance
At resonant
frequency:
∞
Inductor’s
impedance
Frequency
周波数
Application of Inductor and Capacitor “Band-pass Filter and Trap Filter”
Impedance of series circuit: Lowest at frequency resonance point
Impedance of parallel circuit: Highest at frequency resonance point
Typical characteristic of
trap filter
Typical characteristic of
band-pass filter
OUT
IN
Series circuit:
low Z at resonant
frequency:
dropping to the
ground
GND
Parallel circuit:
high Z at resonant
frequency:
passing-through
instead of dropping to
the ground
Gain
Gain
GND
OUT
IN
Frequency
周波数
周波数
Frequency
Real Characteristics of Inductor “Self-Resonance Point Characteristic”
Typical impedance characteristic
of existing inductor
~similar to the typical impedance characteristic
of LCR parallel circuit~
Multilayer inductor
Ex) Stray capacitance
existed between internal
and external electrode
インピーダンス
Impedance
Wound chip inductor
周波数
Frequency
Ex) Stray capacitance
existed between winding
wires
Inductor for the low frequency side,
capacitor for the high frequency side and
at resonance point, impedance is limited.
Application Ex. using Self-Resonance Characteristic of Inductor “Trapping Formulation by Low-pass Filter”
OUT
IN
GND
インピーダンス
Impedance
Example of Low-pass filter
It has a sharp peak point at
a resonance frequency.
Inductor B: impedance characteristic
インピーダンス
Impedance
Inductor A: impedance characteristic
周波数
Frequency
Filter characteristic of
pure inductor
Inductor A in use
Same inductance as inductor A,
but its impedance is lower than
that of A’s.
周波数
Frequency
Inductor B in use
Frequency
周波数
Trapping
resulted from
the sharp peak
point
周波数
Frequency
Ｇａｉｎ
Gain
Gain
Trap-less
Transmitting
characteristic
deformed
周波数
Frequency
This self-resonance characteristic is proactively implemented for a filter circuit application,
and therefore this unique characteristic needs to be considered
for both replacement and downsizing applications.
Real Characteristics of Inductor “Lost Elements and Q Characteristic”
ML inductor
Inductor’s Q factor
Wound chip inductor
Impedance of pure inductor:
Inductive reactance
Resistance
elements
(Summation of loss)
R
Print internal electrode
on sheet made of core
material
Wind up wire
around core
Core materials:
Hysterisis loss, Eddy current loss, dielectric material loss
and more …
Internal electrode:
DCR, resistance loss in high frequency zone originated from
skin effect and more…
Pure inductor has no loss at all.
Q＝
XL
Inductive reactance
Resistance elements
Q factor is an approximation value which
expresses how close an inductor is to be
a pure inductor.
The larger the Q factor an inductor has,
the purer the inductor becomes on circuit.
Q Factor and Filter Characteristics of Inductor “Example of How the Difference in Q Factor Influences TrapTrap-Filter Characteristic”
Characteristic”
Example of trap filter
Series resonance of inductor and capacitor
Inductor A: Q factor characteristic
Inductor B: Q factor characteristic
Q
Q
OUT
IN
Low Q factor
GND
周波数
Frequency
Filter characteristic example
of pure inductor
Inductor B in use
Ｇａｉｎ
Inductor A in use
Gain
Gain
周波数
Frequency
周波数
Frequency
周波数
Frequency
Not
enough
trap
周波数
Frequency
In case of resonance circuit with capacitors, generally inductor’s Q factor characteristic
has huge influence on the circuit.
Q-Value and Matching Characteristics “Example of How the Difference in Q-value Influences Matching Characteristic”
Example of matching circuit
Ｑ
Example of matching design
with pure inductor
With the inductor,
impedance is matched at
the center of the chart.
Inductor A: Q factor characteristic
Ｑ
Inductor A: Q factor characteristic
Matching for amplifier and antenna
Low Q factor
Frequency
周波数
Frequency
周波数
Inductor A in use
Inductor B in use
Fit the design
Shifted off the
center of the
chart
Amplifier’s
characteristic:
starting point
In case of matching circuit, generally inductor’s Q factor characteristic
has huge influence on the circuit.
Coffee Break “Q Factor of Inductor and Tan δof Capacitor”
Q factor of inductor
inductor’s loss elements
Tan δof capacitor
capacitor’s loss elements
Impedance of pure capacitor:
Capacitance reactance
Impedance of pure inductor:
inductive reactance
Resistance
elements
Resistance
elements
(summation of loss)
(summation of loss)
R
Q＝
R
XL
Inductive reactance
Resistance elements
Q factor is an approximation value which expresses
how close an inductor is to be a pure inductor.
The larger the Q factor an inductor has,
the purer the inductor becomes on circuit.
Tan δ ＝
Xc
Resistance elements
Capacitance reactance
Tan δ is a value which explains how far
a capacitor is from being a pure capacitor.
The smaller the tan δ a capacitor has,
the purer the capacitor becomes on circuit.
Real Characteristics of Inductor “Example of DC Bias Characteristic”
Example of inductor’s
DC bias characteristic
インピーダンス
Impedance
Example of an inductor
which has a strong
characteristic
against DC bias
Example of an inductor
which has a weak
characteristic
against DC bias
DC Bias
Current
バイアス電流
Impedance gets
lowered as inductance
is dropped by magnetic
saturation.
周波数
Frequency
An inductor which has
a strong characteristic
against DC bias
can maintain high
impedance level
(vice versa).
Generally, an inductor
is selected based
on a margin level for
both required
inductance and
impedance under
operational
circumstances.
インピーダンス
Impedance
インダクタンス
Impedance
In case of magnetic-material core which has
the magnetic saturation characteristic,
inductance is lowered by increasing in
DC bias current.
Example of impedance characteristic
Frequency
周波数
Example of the Influence on Inductor’s DC Bias Characteristic in use of Power Supply Choke
ON/OFF　noise
IC
Load
fluctuation
Inductor:
Blocked by
impedance
Bypass
improved
Bypass characteristic
of capacitor only
インピーダンス
Impedance
Capacitor: Bypass to
the ground
Inductor A: Impedance characteristic
Impedance
increased by
high
frequency
A strong
characteristic
against DC bias
and maintain high
impedance
周波数
Frequency
Inductor A in use
Improved bypass
characteristic at high
frequency range
Inductor B: Impedance characteristic
インピーダンス
Impedance
Example of power supply choke circuit
A weak characteristic
against DC bias and
unable to keep high
impedance
周波数
Frequency
Inductor B in use
Inferior bypass
characteristic
In case of power supply choke application, it should take full advantage of impedance characteristic
in terms of designing of bypass circuit. Since impedance characteristic is degraded by DC bias,
it should be paid attention to see if the required value left under operational circumstances
comparing with self-resonance characteristic.
Example of the Influence on Inductor’s DC Bias Characteristic of Power Supply Switching Circuit Application
Example of step-up power supply circuit
General relationship between
DC bias characteristic and Is
DC Output
Vout
Is
Vs
While Vs turned on, Is flows to IC and then voltage
is raised by inductor. When Vs being off, it is added
onto the input DC and then Output DC is up-converted.
When Vs is being on, Vin = L・dIs/dt, solving for this→
Is = Vin / L・t
Is gradually increases as Vs turned on,
it increases rapidly with small inductance .
It is important to know of the tolerance current
when selecting an inductor for the power supply circuit.
Ｉs 及び
and Vs
Vs：ON
OFF
ON
OFF
ON
As DC bias current
increases, the
inductance starts
decreasing.
DC Bias
バイアス電流
ＩＣを流れる電流：Ｉｓ
Current
(Is) flows into IC
DC Input
Vin
インダクタンス
Impedance
Inductance: L
Switching IC
broken down
Is increases as times goes on.
Is increases even faster with
small inductance.
時間Time
DC bias current
passes at some
point, inductance
drops suddenly.
When DC bias
current passes
the tolerance current,
(for the worst case
scenario) the switching
IC is broken down.
時間
Is
current
Time
Switching interval is shortened by high frequency
power supply IC, and therefore large inductance is
no longer needed for IC.
Addition to this, flat DC bias characteristic isn’t ideal for
all kinds of circuit. It would be better to match a specific
DC bias characteristic with IC and power supply demand.
Coffee Break “The Charging and Discharging Mechanisms of Capacitor”
Charging mechanism
Increasing
electric charge
+Q
Voltage raised
-Q
Electric
current
Capacitor
Battery
Discharging mechanism
Decreasing
electric charge
+Q
Voltage dropped
-Q
Electric
current
Capacitor
A time-varying electric charge induces electric current.
-I = dQ/dt
Capacitance is the constant of proportion derived from
the relationship between the quantity of electric
charge and voltage.
Q = C・V
The relationship among voltage, electric current
and capacitance
-V = 1/c・∫idt or –I = C・dV/dt
The equivalent relationship for inductor
-V = L・di/dt
Apply voltage to a capacitor, electronic charge is built up in
the inside of capacitor. On the other hand, when both sides of
external electrodes are short-circuited, the capacitor discharges
the built-up electronic charge.
The quantity of electronic charge is proportional to voltage.
(In case with inductor, an electronic current creates magnetic
flux. The quantity of magnetic flux is proportional to
electronic current.)
Capacitor’s capacitance is the constant of proportion between the
quantity of electronic charge and voltage. (In case with
inductor, inductance is the constant of proportion from
magnetic flux and electronic current.
A time-varying electric charge or discharge induces electric current.
In case with inductor, a time-varying magnetic flux induces
electric voltage.
- Chapter 3 -
Electro-Magnetic Compatibility
(EMC)
The Different Types of Noise
Contents
Countermeasure components
Radiation noise
It leaks out as an electromagnetic wave. The
sources are signal line and power line. There are
restrictions in countries. (VCCI, FCC, CISPR, EN,
etc.)
Mainly ML Ferrite Chip Beads BK
series, Rectangular Ferrite Chip
Beads (High Current) FB series M
type. Resistors and capacitors may
also be used.
Conduction
noise (noise
It runs through DC power line, i.e. switching noise,
etc. The sources are DC-DC power supply
converter, etc.
Mainly Surface Mount High Current
Inductors NP series, Wound Chip
Inductors LB series and such ferrite
components and capacitors for DCDC, etc.
Ripple voltage
(current)
A fluctuation by voltage drop occurred when IC
operates. It becomes a problem at power line with
high power consumption for CPU, etc.
Mainly capacitors
Electrostatic
A discharge phenomenon, which is caused by
friction charge. It causes element destruction and
malfunctions.
Mainly Chip Varistors and Diodes.
Capacitors and Beads may also be
used.
Surge noise
Instantaneous high voltage and current. It is
occurred by natural phenomenon (eg.
thunderstorm), inserting and removing a cable, etc.
Spark Gaps and Varistors.
Beads and Resistors for low voltage.
terminal voltage)
Standards of Radiation Electric Field
Global Standard: CISPR
Japan: VCC class2
(Consumer Equipment)
U.S.A.: FCC part15
Europe: EN55022
Other countries: Setting regulation based on CISPR
Regulation of the frequency band is between 30MHz to 1000MHz for VCCI.
Others are referred on the next page.
EMI Regulation Example for High Frequency Band (Tightening Regulation for GHz band noise)
1. CISPR 11 Group 2 Class B (1999 industry, chemistry, medical)
For equipment with embedded frequency of 400MHz and above
Regulated frequency: 1-2.4GHz band
Standard: 70dBuV/m and below (3m electric field intensity)
2. CISPR 22 CIS/G/210/CD (2001 IT equipment)
For equipment with embedded frequency of 200MHz and above
Regulated frequency: 1-2.7GHz band
Standard: Average of 50dBuV/m and below,
Max 70dBuV/m and below (3m electric field intensity)
3. FCC Part 15 (IT equipment)　Measurement up to 2GHz is required for an operation
between 108 to 500MHz band.
Measurement up to 5GHz is required for an operation
between 500 to 1000MHz band.　Mechanism of Radiation Noise 1
Spectrum
Digital waveform
Measurement system: Spectrum Analyzer
Measurement system: Oscilloscope
Voltage
(current)
Time axis is transformed to frequency.
Time
Noise
(voltage, current)
Fourier transform
Noise standard restricts
the noise received with
an antenna.
Frequency
Digital wave is formed by various frequencies.
Voltage
(current)
Spectrum Analyzer
O
sc
e
op
c
s
illo
Frequency
Time
Mechanism of Radiation Noise 2
Flux occurs only with direct current.
Current
Flux
Electric
field
Magnetic
field
Electric and magnetic fields
Electric
occur with alternate current.
field
Current
Magnetic
field
Voltage
voltage
0V
0V
Current
current
0A
0A
Radiated from digital wave
Noise
Clock
Noise
Digital signal
Vcc
Leakage of
high frequency
IC
・
・
・
IC
Vcc
Mechanism of Radiation Noise 3
Magnetic
Magnetic
Magnetic
Magnetic
field
field
field
field
Electric
Electric
Electric
Electric
field
field
field
field
Antenna
RF signal source
Spectrum
Analyzer
Radiation electromagnetic field measurement
(open site, anechoic chamber)
Antenna
Direct wave
EUT
Reflected
wave
Noise standard restricts
the received noise value.
Spectrum
Analyzer
Mechanism of Radiation Noise 4
Ringing occurring
Voltage
Voltage
Time
Spectrum changes
with waveform
distortion.
Time
Level changes
Noise
Noise
Frequency
Frequency
Cause: mismatching of transmission line
Standing wave
=traveling wave+reflected wave
Reflected wave
Because harmonics of a digital signal
make a standing wave, the emission
of the signal increases as noise.
Traveling wave
Transmission line pattern
Mismatching of impedance
Fin.
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