nr110eseries an en

NR110E SERIES APPLICATION NOTE
NR110E Series
Application Note Rev.2.0
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
Copy Right: SANKEN ELECTRIC CO., LTD.
Page.1
Rev.2.0
NR110E SERIES APPLICATION NOTE
Rev.2.0
CONTENTS
General Descriptions ----------------------------------------------------------------------- 3
1. Electrical Characteristics ------------------------------------------------------------- 4
1.1 Absolute Maximum Ratings ----------------------------------------------------- 4
1.2 Recommended Operating Conditions --------------------------------------- 4
1.3 Electrical Characteristics -------------------------------------------------------- 5
2. Block Diagram & Pin Functions ----------------------------------------------------- 7
2.1 Functional Block Diagram ------------------------------------------------------- 7
2.2 Pin Asignments & Functions --------------------------------------------------- 7
3. Example Application Circuit---------------------------------------------------------- 8
4. Allowable package power dissipation -------------------------------------------- 9
5. Package Outline ------------------------------------------------------------------------- 10
6. Operational Descriptions ------------------------------------------------------------- 11
6.1 PWM (Pulse Width Modulation) Output Control ------------------------- 11
6.2 Power Supply Stability ----------------------------------------------------------- 11
6.3 Over Current Protection (OCP) ------------------------------------------------ 12
6.4 Thermal Shutdown (TSD) ------------------------------------------------------- 12
6.6 Soft-Start ------------------------------------------------------------------------------ 12
6.7 ON and OFF the Regulator (Enable) ----------------------------------------- 13
7. Design Notes ----------------------------------------------------------------------------- 14
7.1 External Components ------------------------------------------------------------ 14
7.2 Pattern Design ---------------------------------------------------------------------- 20
7.3 Applied Design ---------------------------------------------------------------------- 23
OPERATING PRECAUTIONS ----------------------------------------------------------- 25
Heat dissipation and reliability ----------------------------------------------------- 25
Parallel operation ----------------------------------------------------------------------- 25
Thermal shut down --------------------------------------------------------------------- 25
IMPORTANTS NOTES --------------------------------------------------------------------- 26
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Page.2
NR110E SERIES APPLICATION NOTE
General Descriptions
Rev.2.0
Package
 Exposed SOIC 8
Thermally enhanced 8-Pin package
The NR110E series is buck regulator ICs integrates
High-side power MOSFETs. The feature increasing
efficiency at light loads allows the device to be
used in the energy-saving applications. With the
current mode control, ultra low ESR capacitors such
as ceramic capacitors can be used. The ICs have
protection functions such as Over-Current Protection
(OCP), Under-Voltage Lockout (UVLO) and
Thermal Shutdown (TSD). An adjustable Soft-Start
by an external capacitor prevents the excessive inrush
current at turn-on. The ICs integrate phase
compensation circuit which reduces the number of
external components and simplifies the design of
customer application. The ON/OFF pin (EN Pin)
turns the regulator on or off and helps to achieve low
power consumption requirements. The NR110E
series is available in an 8-pin SOIC package with an
exposed thermal pad on the back side.
Electrical Characteristics
 2A / 4A output current
 Operating input range VIN = 6.5V~31V
 Output adjustable VO= 0.8V~24V
 Fixed frequency
NR119E: 364kHz
NR111E:350kHz
Features & Benefits
 Current mode PWM control
 Up to 94% Efficiency,
Up to 68% Efficiency at IO = 20mA Light Load
 Stable with low ESR ceramic output capacitors
 Built-in protection function
Over Current Protection (OCP)
Thermal Shutdown (TSD)
Under Voltage Lockout (UVLO)
 Built-in phase compensation
 Adjustable Soft-Start with an external capacitor
 Turn ON/OF the regulator function
Applications




LCD TV / Blu-Ray / Set top box
Home appliance
Green Electronic products
Other power supply
Series Lineup
Product No.
fSW
NR111E
350kHz
VIN
6.5V to 31V
VO
(1)
0.8V to 24V
NR119E
364kHz
The minimum input voltage shall be either of 6.5V or VO+3V, whichever is higher.
(2)
The I/O condition is limited by the Minimum on-time (TON(MIN)).
(1)
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Page.3
IO
(2)
4A
2A
NR110E SERIES APPLICATION NOTE
Rev.2.0
1. Electrical Characteristics
1.1 Absolute Maximum Ratings
Table 1 Absolute maximum rating of NR110E series
Parameter
Symbol
Ratings
Units
DC input voltage
VIN
35
V
BS Pin voltage
VBS
44
V
VBS-SW
8
V
SW Pin voltage
VSW
35
V
FB Pin voltage
VFB
5.5
V
EN Pin voltage
VEN
35
V
SS Pin voltage
VSS
5.5
V
BS-SW Pin voltage
Glass-epoxy board mounting
in a 30×30mm.
(copper area in a 25×25mm)
Max TJ =150°C
Power dissipation
(3)
PD
1.76
W
Junction temperature
(4)
TJ
40 to 150
°C
TS
40 to 150
°C
θJP
26
°C /W
Storage temperature
Thermal resistance
(junction- Pin No. 4)
Conditions
Glass-epoxy board mounting
Thermal resistance
θJA
(junction-ambient air)
71
°C /W
in a 30×30mm.
(copper area in a 25×25mm)
(3)
Limited by thermal shutdown.
(4)
The temperature detection of thermal shutdown is about 160°C
1.2 Recommended Operating Conditions
Operating IC in recommended operating conditions is required for normal operating of circuit functions shown in
Table 3 Electrical characteristics of NR110E series.
Table 2 Recommended operating conditions of NR110E series
Parameter
Symbol
(5)
DC input voltage
DC output current
NR111E
(6)
NR119E
(7)
Output voltage
Ambient operating temperature
(7)
Ratings
Units
MIN
MAX
Vo+3
31
0
4.0
0
2.0
Vo
0.8
24
V
Top
40
85
°C
VIN
Io
(5)
V
A
The minimum value of input voltage is taken as the larger one of either 6.5V or VO +3V.
(6)
Recommended circuit refer to Typical Application Circuit (fig.5).
(7)
To be used within the allowable package power dissipation characteristics (fig. 6)
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Page.4
Conditions
NR110E SERIES APPLICATION NOTE
Rev.2.0
1.3 Electrical Characteristics
Electrical characteristics indicate specific limits, which are guaranteed when IC is operated under the
measurement conditions shown in the circuit diagram (fig. 1)
Table 3 Electrical characteristics of NR110E series
Parameter
Symbol
Reference voltage
Output voltage temperature
coefficient
NR111E
Switching
frequency
NR119E
(Ta=25°C)
Ratings
MIN
TYP
MAX
VREF
0.784
0.800
0.816
⊿VREF/⊿T
―
±0.05
―
280
350
420
291
364
437
fSW
Units
Test conditions
V
VIN = 12V,IO = 1.0A
V = 12V, IO = 1.0A
mV/°C IN
40°C to +85°C
kHz
VIN=12V, VO=5.0V,
IO=1A
VIN=8V~31V, VO
=5.0V, IO=1A
VIN=12V, VO=5.0V,
mV
IO=0.1A~2.0A
VIN =12V, VO =5.0V
ISET=OPEN
VIN =12V, VO =5.0V
ISET=SHORT
A
VIN=12V, VO =5.0V
ISET=OPEN
VIN =12V, VO =5.0V
ISET=SHORT
VIN = 12V
mA
VEN=10kΩ pull up to VIN
VIN =12V, IO =0A,
μA
VEN=0V
Line regulation
(8)
VLine
―
50
―
Load regulation
(8)
VLoad
―
50
―
IS1
―
1.5
―
IS2
―
5.5
―
IS1
―
0.9
―
IS2
―
2.8
―
IIN
―
1
―
IIN(off)
0
1
―
Source current
at low level
voltage
Sink current
IEN/SS
6
10
14
μA
VSS=0V, VIN =12V
20
50
μA
VEN= 10V
Threshold voltage
VC/EH
0.7
1.4
2.1
V
VIN =12V
VISET
DMAX
V
VIN =12V
―
90
―
%
―
150
―
―
150
―
NR111E
Overcurrent protection
threshold
NR119E
Supply Current
Shutdown Supply Current
SS Pin
EN Pin
ISET Pin
Open voltage
Max on-duty
Minimum on-time
NR111E
NR119E
Thermal shutdown threshold
temperature
Thermal shutdown
restart hysteresis
of temperature
(8)
IEN
(8)
(8)
TON(MIN)
1.5
mV
nsec
(8)
TSD
151
165
―
°C
(8)
TSD_hys
―
20
―
°C
Guaranteed by design,not tested.
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Page.5
NR110E SERIES APPLICATION NOTE
R3
2
7
EN
Rev.2.0
1
IN
C10
L1
3
BS
SW
R5
8
C1
SS
C2
NR 111 E
IO
R4
IIN
I EN
C4
I Fset
GND
ISET
FB
VO
5
4
VIN
VEN
C5
6
V SS
D1
IISET
V FB
R6
VISET
C1+C2: 10uF×2
C4+C5: 22uF×2
C10: 0.1uF
R3: 22Ω
R4: 18 kΩ, R5: 2.7kΩ (VO=5.0V)
R6: 3.9kΩ
fig.1 Measurement circuit diagram
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Page.6
L1: 10uH
RL
NR110E SERIES APPLICATION NOTE
Rev.2.0
2. Block Diagram & Pin Functions
2.1 Functional Block Diagram
fig.2 Block diagram of NR110E series
2.2 Pin Asignments & Functions
fig.3 Pin Assignments
Table2 Pin assignments & functions of NR110E series
Pin No.
Symbol
1
BS
2
IN
3
SW
4
GND
5
FB
6
ISET
Description
High-side Boost input.
BS supplies the drive for High-side Nch-MOSFET switch.
Connect a capacitor and a resistor between SW to BS.
Power input. IN supplies the power to the IC as well as the regulator switches
Power switching output.
SW supplies power to the output.
Connect the LC filter from SW to the output.
Note that a capacitor is required from SW to BS to supply the power the High-side
switch
Ground
Connect the exposed pad to Pin No.4
Feedback input Pin to compare Reference Voltage. The feedback threshold is 0.8V.
To set the output voltage, FB Pin is required to connect between resistive voltage
divider R4,R5 and R6.
Adjust Pin of OCP starting current
OCP starting current can be adjusted by connecting a resistor to ISET Pin.
In the case of using at Maximum Io, ISET Pin is required to connect to GND.
7
EN
8
SS
Enable input.
Drive EN Pin high to turn on the regulator, low to turn it off.
Soft-Start control input.
To set the soft-start period, connect to a capacitor between GND.
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Page.7
NR110E SERIES APPLICATION NOTE
Rev.2.0
3. Example Application Circuit
Each ground of all components is connected as close as possible to the Pin No.1 at one point.
To help heat dissipation, connect a large copper plane to exposed pad on the back side of the package. The
copper plane is required for GND
C1, C2: 10μF / 35V
C4, C5: 22μF / 16V
C9: 0.1μF
C10: 0.1μF
D2:Option
R1: 510kΩ
L1: 10μH
R3: 22Ω
R4: 18kΩ, R5: 2.7kΩ (Vo=5.0V)
R6: 3.9kΩ
D1: SJPW-T4(Sanken)
fig. 4 Typical Application Circuit of NR110E series
The fig4 is the basic connection without optional parts.Demo-board circuit is the fig30 in the Page 22.
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Page.8
NR110E SERIES APPLICATION NOTE
Rev.2.0
4. Allowable package power dissipation
fig. 5 Allowable package powe disspation of NR110E series
NOTES:
1) Glass-epoxy board mounting in a 30×30mm
2) copper area : 25×25mm
3) The power dissipation is calculated at the junction temperature 125 °C
4) Losses can be calculated by the following equation.
As the efficiency is subject to the input voltage and output current, it shall be obtained from the efficiency curve
and substituted in percent
5) Thermal design for D1 shall be made separately.

 100 
V
PD  VO  I O 
 1  VF  I O 1  O
 x

 VIN




VO: Output voltage
VIN: Input voltage
IO: Output current
ηx: Efficiency(%)
VF: Diode forward voltage
SJPB-L4…0.55V(IO=3A)
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Page.9
NR110E SERIES APPLICATION NOTE
Rev.2.0
5. Package Outline
 Exposed SOIC8 package
An outside size is supplied by either Package type A or Package type B.
Package outline, dimensions
Symbol
Package A
Package B
MIN
TYP
MAX
MIN
TYP
MAX
A1
0
-
0.1524
0
0.10
0.15
A2
1.398
1.448
1.498
1.25
1.40
1.65
b
0.330
-
0.508
0.38
-
0.51
D
4.80
4.902
5.004
4.80
4.90
5.00
D1
3.053
3.18
3.307
3.10
3.30
3.50
E
5.893
-
6.918
5.80
6.00
6.20
E1
3.73
-
3.89
3.80
3.90
4.00
E2
2.033
2.16
2.287
2.20
2.40
2.60
e
-
1.27
-
-
1.27
-
L
0.508
-
0.762
0.45
0.60
0.80
Note:
1 Dimension is in millimeters, dimension in bracket is in inches.
2. Drawing is not to scale.
NR111E
SKYMW
XXXX
Part Number
Lot Number
Y= last digit of the year (0-9)
M= Month (1-9, O, N, or D)
W= Week Code (1-3)
Sanken Control Number
fig.7 Marking of NR110E series
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Page.10
NR110E SERIES APPLICATION NOTE
Rev.2.0
6. Operational Descriptions
6.1 PWM (Pulse Width Modulation) Output Control
The NR110E series consist of three blocks; two feedback loops (voltage control and current control) and one slope
compensation. The PWM is controlled with the current mode control by calculating the voltage feedback control, and
the current feedback control and the slope compensation signals. (fig. 8) For the voltage feedback control, the output
voltage feed back to the PWM control. The error amplifier compares the output voltage divided by resistors with the
reference voltage VREF = 0.8V. For the current feedback control, the inductor current feed back to the PWM control.
The inductor current divided by Sense-MOSFET is detected with the current sense amplifier. To prevent sub-harmonic
oscillations, which is characteristic in current mode control, the slope of current control is compensated.
fig. 8 Basic Structure of Chopper Type Regulator with PWM Control by Current Control
The NR110E series start the switching operation when UVLO is released, or EN or SS Pin voltage exceeds the
threshold. Initially, it operates switching with minimum ON duty or maximum ON duty. The high-side switch (M1) is
the switching MOSFET that supplies output power. At first, the boost capacitor C3 that drives M1 is charged by
internal circuit. When M1 is ON, as the inductor current is increased by applying voltage to SW Pin and the inductor,
the output of inductor current sense amplifier is also increased. Sum of the current sense amplifier output and slope
compensation signal is compared with the error amplifier output. When the summed signal exceeds the error amplifier
(Error Amp.) output voltage, the current comparator output becomes “High” and the RS flip-flop is reset. The
regenerative current flows through D1, when the M1 turns OFF.
In NR110E series, the set signal is generated in each cycle and RS flip-flop is set. In the case that the summed signal
does not exceed the error amplifier (Error Amp.) output voltage, RS flip-flop is reset without fail by the signal from
OFF duty circuit.
6.2 Power Supply Stability
The phase characteristics of chopper type regulator are the synthesis of the internal phase characteristics of regulator IC,
the combination of output capacitor C4 (C5) and load resistance Rout. The internal phase characteristics of regulator
IC are generally determined by the delay time of control block and the phase characteristics of output error amplifier.
The phase delay due to the delay time of control block is very small and not problem in actual use. As the built-in
phase compensation for output error amplifier, in order to ensure stable operation, refer to “7.1.3 Output Capacitor
C4 (C5)” and “7.1.4 Output Voltage Set-up (FB Pin)” for setting output capacitor and the output voltage.
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Page.11
6.3 Over Current Protection (OCP)
The NR110E series integrate the drooping type over-current
protection circuit. The peak current of switching transistor is
detected. When the peak current exceeds rated value, the
over-current protection limits the current by forcibly
shortening the ON time of transistor and decreasing the
output voltage. It prevents the current increment at low
output voltage by decreasing the switching frequency, if the
output voltage drops lower. When the over-current state is
released, the output voltage automatically returns.
Rev.2.0
Output Voltage Vo [V]
NR110E SERIES APPLICATION NOTE
Output Voltage Vo [V]
fig.9 OCP Characteristics of NR110E series
6.4 Thermal Shutdown (TSD)
The thermal shutdown circuit detects the IC junction
temperature. When the junction temperature exceeds the
rated value (around 160°C), it shuts-down the output
transistor and turns the output OFF. If the junction
temperature falls below the thermal shutdown rated value by
around 20°C, the operation returns automatically.
* (Thermal Shutdown Characteristics) Notes
The circuit protects the IC against temporary heat generation.
It does not guarantee the operation including reliabilities
under the continuous heat generation conditions, such as
short circuit for a long time.
Output voltage
Rated
Protection
Temperature
Rated Restart
Temperature
Junction
Temperature
fig.10 TSD Characteristics of NR110E series
6.6 Soft-Start
出力起動時間
[msec]
Time of Soft-Start
ソフトスタート時間 [ms]
By connecting a capacitor between Pin No.8 (SS) and Pin
No.4 (GND), Soft-Start operates when the power is supplied
to the IC. Output Voltage (Vo) is ramped up by the charge
voltage level of Css.
Time of Soft-Start can be calculated from the time constant
of charging Css.
A capacitor Css controls OFF period of PWM and then the
rise time is determined. The rise time t_ss and the delay time
t_delay are calculated in following equations.
In the case of operating IC without using Soft-Start function,
Pin No.4 is required for open.
100
10
1
0.1
0.01
0.0001
0.001
0.01
SSコンデンサCss [uF]
Pin SS capacitance
Css [uF]
tSS = CSS × (VSS2 – VSS1) / (ISS × VSS1)
VSS1 (0.9V) < SS Pin voltage < VSS2 (1.79V)
fig.11 SS Pin capacitance CSS VS Soft-Start
t_delay = CSS × VSS1 / ISS
SS Pin voltage < VSS1(th) = VSS1 (0.9V)
fig.12 Soft-Start operating description
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t_delay
t_ss
t_all
Page.12
0.1
NR110E SERIES APPLICATION NOTE
Rev.2.0
In the case of without or too small Css, IC starts up at the
time constant that output current limited by Is charges output
capacitor C2.
Following equation shows the time constant of start up by the
output capacitor C2 at no load.
t = (CO × VO) / IS
*At the start up with a load, load current is detracted from Is.
fig.13 Discharge time of SS capacitor
Pin SS Open Voltage: 3V
SS Discharge Capability: 500µA
The left graph shows the SS Pin voltage changing
time from 3V to 0V.
6.7 ON and OFF the Regulator (Enable)
EN Pin (Pin No.7) turns the regulator ON or OFF. When
drive EN under 1.4V (VENL), output is turned OFF (fig.14).
1.4V (VENL) can be achieved by connecting a bipolar
transistor in an open collector configuration. When the
external ON/OFF function isn't used, connect only Pull-up
resistor of 510kΩ between IN and EN.
It starts when a VIN voltage is inputted.
2. IN
510kΩ
7.EN
NR111E
fig. 14 ON / OFF Control 1
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Page.13
NR110E SERIES APPLICATION NOTE
Rev.2.0
7. Design Notes
7.1 External Components
All components are required for matching to the condition of use.
7.1.1 Choke Coil L1
The choke coil L1 is one of the most important components in the chopper type switching regulators. In order to
maintain the stabilized regulator operation, the coil should be carefully selected so it must not enter saturation or over
heat excessively at any conditions. The selection points of choke coil are as follows:
a) The coil type is only required for switching regulator.
It is recommended not to use a coil for noise filer since it causes high heat generation due to high power dissipation.
From fig.15 shows the selection range of inductance L to
prevent the sub-harmonic oscillations. As for the upper
limit of inductance L, the value is for reference, because it
may vary depending on input/output conditions and load
current.
The ripple portion of choke coil current ΔIL and the peak
current ILp are calculated from the following equations:
IL 
(VIN  Vo )  Vo
L  VIN  f
IL
ILp 
 Io
2
Inductance L
Selection
Range
Inductance
Inductance
L
L
Selection
Selection
Range
Range
------ (1)
Output Voltage Vo [V]
fig.15 Selection Range of Inductance L in NR110E
------ (2)
The ΔIL and ILp increase when the inductance of the choke
coil L becomes smaller.
If the inductance is too small, the regulator operation may be
unstable because the choke coil current fluctuates largely. It
is necessary to give attention to decreasing of the inductance
due to the magnetic saturation such as in overload and load
shortage.
High Inductance
Inductance L [µH]
b) The sub-harmonic oscillations should be prevented.
Under the peak detection current control, the inductor current may fluctuate at a frequency that is an integer multiple
of switching operation frequency. This phenomenon is the known as sub-harmonic oscillation and this phenomenon
theoretically occurs in the peak detection current control mode. In order to stabilize the operation, the inductor
current compensation is made internally. The inductance corresponding to the output voltage should be selected.
Low Inductance
fig.16 Relationship between inductance and ripple current
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Page.14
NR110E SERIES APPLICATION NOTE
Rev.2.0
c) The coil should be of proper rated current.
The rated current of the choke coil should be higher than the maximum load current used. If the load current exceeds
the rated current of coil, the inductance decreases drastically and eventually enters into the saturation state. In this
status, it is necessary to give attention because the high-frequency impedance decreases and the excess current runs.
d) The magnetic noise should be minimized.
The open magnetic circuit type core like a drum type may generate noise in peripheral circuit due to the magnetic
flux passing outside of coil. Coils of closed magnetic circuit type core, such as toroidal type, EI type and EE type are
preferable.
7.1.2 Input Capacitor C1 (C2)
The input capacitor operates as a bypass capacitor of input circuit. It supplies the short current pulses to the regulator
during switching and compensates the input voltage drop. It should be connected close to the regulator IC. Even if the
rectifying capacitor of AC rectifier circuit is in input circuit, the input capacitor cannot be used as a rectifying capacitor
unless it is connected near IC.
The selection points of C1 (C2) are as follows:
a) The capacitor should be of proper breakdown voltage rating
b) The capacitor should have sufficient allowable ripple current rating
If the input capacitor C1 (C2) is used under the conditions of
excessive breakdown voltage or allowable ripple current, or
without derating, the regulator may become unstable and the
capacitor’s lifetime may be greatly reduced. The selection of
the capacitor C1 (C2) is required for the sufficient margins to
the ripple current. The effective value of ripple current Irms
that flows across the input capacitor is calculated from the
equation (3):
Irms  1.2 
IIN
VIN
IN
Ripple
current
C1 (C2)
Vo
 Io ------ (3)
Vin
fig. 17 C1 (C2) Current path
In the case of VIN = 20V, Io = 3A, Vo = 5V,
Irms  1.2 
5
 3  0.9A
20 IIN
The capacitor is required
VIN for the allowable ripple current
1.VIN of
0.9A or higher.
Ripple
Ip
0
current
Iv
C1
Ton
T
fig.18 C1 (C2) Current Waveform
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Page.15
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.1.3 Output Capacitor C4 (C5)
In the current control mode, the feedback loop which detects the inductor current is added to the voltage control mode.
The stable operation is achieved by adding inductor current to the feedback loop without considering the effect of
secondary delay factor of LC filter. It is possible to reduce the capacitance of LC filter that is needed to make
compensations for the secondary delay, and the stable operation is achieved even by using the low ESR capacitor
(ceramic capacitor).
The output capacitor C4 (C5) comprises the LC low-pass filter with choke coil L1 and works as the rectifying capacitor
of switching output. The current equal to ripple portion ΔIL of choke coil current charges and discharges the output
capacitor. In the same way as the input capacitor, the breakdown voltage and the allowable ripple current should be met
with sufficient margins.
IL
The ripple current effective value of output capacitor is
calculated from the equation (4):
Irms 
IL
2 3
Vout
L1
------ (4)
ESR
When ΔIL = 0.5A,
Irms 
Io
Ripple
current
0.5
≒ 0.14A
2 3
RL
C4 (C5)
Therefore a capacitor with the allowable ripple current of
0.14A or higher is needed.
IL
fig. 19 C4 (C5) Current path
The output ripple voltage of regulator Vrip is determined by Vout
the product of choke current ripple L1
portion ΔIL (= C4 (C5)
discharge and charge current) and output capacitor C4 (C5)
Ripple
Io
equivalent series resistance ESR.
current
Vrip  IL  C4 ESR
------ESR
(5)
RL
It is necessary to select a capacitor with low equivalent series
resistance ESR in order to lower the output ripple voltage. As
C2
for general electrolytic capacitors of same product series, the
ESR shall be lower for products of higher capacitance with
same breakdown voltage, or of higher breakdown voltage
with same capacitance.
When ΔIL = 0.5A, Vrip = 40mV,
C4 ESR  40  0.5  80m
A capacitor with ESR of 80mΩ or lower should be selected.
Since the ESR varies with temperature and increases at low
temperature, it is required to check the ESR at the actual
operating temperatures. It is recommended to contact
capacitor manufacturers for the ESR value since it is peculiar
to every capacitor series.
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Page.16
C2 Current
Waveform
0
∆IL
fig. 20 C4 (C5) Current Waveform
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.1.4 Output Voltage Set-up ( FB Pin )
The FB Pin is the feedback detection Pin that controls the
output voltage. It is recommended to connect close to the
output capacitor C4 (C5). If they are not close, the abnormal
oscillations may be caused by the poor regulation and the
increased switching ripple.
The setting of output voltage is achieved by connecting
between resistive voltage divider R4 (R5) and R6. Setting the
IFB to about 0.2mA is recommended.
(The target of IFB lower limit is 0.2mA, and the upper limit is
not defined. However, it is necessary to consider that the
circuit current shall increase according to the IFB value.)
R4 (R5), R6 and the output voltage are calculated from the
following equations:
IFB = VFB / R6
R4+R5
R6
fig. 21 Detection and setting of output voltage
*VFB = 0.8V ± 2%
R4 + R5 = ( VO  VFB ) / IFB
R6 = VFB / IFB
VO = ( R4 + R5 ) × ( VFB / R6 ) + VFB
R6 is required to connect for the stable operation when set to VO = 0.8V.
Regarding the relation of input / output voltages, it is recommended that setting of the ON width of the SW Pin is more
than 200nsec
The PCB circuit traces of FB Pin, R4 (R5) and R6 are required for not parallel to the flywheel diode. The switching
noise may affect the detection voltage and the abnormal oscillation may be caused. Especially, it is recommended to
design the circuit trace short from FB Pin to R6.
7.1.5 External Bootstrap Diode for Low Input
Although the NR110E series drives with input voltages lower than 6V, it is recommended to connect a diode between
IN Pin and BS Pin in order to enhance the efficiency (fig.22). Alternatively an external voltage source can be
connected through a diode to the BS Pin (fig.23).
NOTES:
1) The external voltage is required to be set from 5V to 6V.
2) In the case that the input voltage VIN is higher than 6V, the Bootstrap Diode must not be connected.
5V
2. IN
1.BS
1.BS
NR111E
NR111E
3.SW
3.SW
fig.22 Bootstrap Diode Connection 1
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fig.23 Bootstrap Diode Connection 2
Page.17
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.1.6 Flywheel Diode D1
A shcottky Barrier Diode as a flywheel diode is required for connection between SW Pin and GND.
The flywheel diode D1 is for releasing the energy stored in the choke coil at switching OFF. If a general rectifying
diode or a fast recovery diode is used, the IC may fail to operate properly becase of applying reverse voltage due to the
recovery and ON voltage. Since the output voltage from the SW Pin (Pin No. 3) is almost equal to the input voltage, it
is required to use the flywheel diode with the reverse breakdown voltage of equal or higher than the input voltage.
It is recommended not to use ferrite beads for flywheel diode.
7.1.7 Output Voltage VO and Output Capacitor C4 (C5)
From Table 6 shows the comparison of output voltage and output capacitor, for maintaining the IC stable operations,
for reference.
ESR of Electrolytic Capacitor is required from 100m Ω to 200mΩ.
Regarding the inductance L, it is recommended to select it according to 7.1.1 Choke Coil L1.
Table 6 NR110E (fSW=350kHz) VO and C4 (C5) Comparison
C4 (C5) (µF)
VO(V)
Electrolytic Capacitor
Ceramic Capacitor
(ESR≒100mΩ)
1.2
22
to
100
4.7
to
330
1.8
22
to
100
4.7
to
470
3.3
10
to
68
4.7
to
330
5
4.7
to
47
4.7
to
220
9
4.7
to
47
4.7
to
220
12
4.7
to
47
4.7
to
220
16
4.7
to
47
4.7
to
220
20
4.7
to
47
4.7
to
220
24
4.7
to
47
4.7
to
220
7.1.6 External Bootstrap Diode for Low
By connecting a resistor to the terminal 6, the over current value is set up. The relations of the peak electric current
RISET-ILpeak
become the following characteristics at a resistance level and an overcurrent.
NR111E Setup Over Current Protection Value
設定値
Over Current Protection[A]
過電流開始ピーク電流 [A]
8.00
7.00
↑Curve(A)
6.00
設定値
5.00
4.00
↑Curve(B)
3.00
2.00
1.00
0.00
10
100
1000
10000
ISET terminal Resistance RISET[kΩ]
過電流開始電流
設定抵抗Rset [kΩ]
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Page.18
100000
NR110E SERIES APPLICATION NOTE
Rev.2.0
NR119E Setup Over Current Protection Value
5.00
過電流開始ピーク電流
Current Protection[A] [A]
Over
4.50
4.00
↑Curve(A)
3.50
3.00
2.50
↑Curve(B)
2.00
1.50
1.00
0.50
0.00
10
100
1000
10000
100000
過電流開始電流 設定抵抗Rset [kΩ]
ISET terminal Resistance RISET[kΩ]
The vertical axis of the graph becomes the OCP start peak current.
The next expression is an expression to exchanging a peak current (ILpeak) to for an output current (IO).
IO=ILpeak-⊿IL×0.5
Only continuous current mode are applied
⊿IL = Vo×(1-Vo/VIN)/(L×fo)
An OCP activation point can be adjusted by the setup value of RISET. However, because OCP-characteristic has the
dispersion, the value of the Ip-detection to start OCP, it becomes the dispersion of between the curve(A) and the
curve(B).
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Page.19
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.2 Pattern Design
7.2.1 High Current Line
High current paths in the circuit are marked as bold lines in the circuit diagram below. These paths are required for
wide and short trace as possible.
fig.24 Circuit Diagram
7.2.2 Input / Output Capacitors
The input capacitor C1 (C2) and the output capacitor C4 (C5) are required to connect to the IC as short as possible. If
the rectifying capacitor for AC rectifier circuit is in the input side, it can be also used as an input capacitor. However, if
it is not close to the IC, the input capacitor is required to be connected in addition to the rectifying capacitor. A similar
care should be taken when designing pattern for other capacitors.
fig. 25 Recommended Pattern example
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Page.20
fig. 26 No good pattern example
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.2.3 PCB Layout Pattern
Each ground of all components is connected as close as possible to the Pin No.4 at one point.
To help heat dissipation, connect a large copper plane to exposed pad on the back side of the package. The
copper plane is required for GND
fig.27 Front Side: Component Side (double sided board)
fig.28 Back Side: GND Side (double sided board)
NOTES:
Size of the PCB is about 40mm×40mm
0.61 (0.024)
1.27 (0.050)
1.60 (0.063)
2.35 (0.092)
3.24 (0.127)
NOTES:
1) Dimension is in millimeters, dimension in bracket is in inches.
2) Drawing is not to scale.
fig.29 Recommended land pattern
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Page.21
5.40 (0.213)
NR110E SERIES APPLICATION NOTE
Rev.2.0
・The circuit diagram of Demo-board for Evaluation
Z1
fig.30 The circuit diagram of Demo-board for Evaluation
C1, C2: 10μF / 35V
C3:0.1μF
C4, C5: 22μF / 16V
C6:Option
C7: 0.1μF
C9: Short
C10: Open
C11: Option
C12: Option
R1:510kΩ
R2: Option
R3:22Ω
R4:18kΩ
R5:2.7kΩ (Vo=5.0V)
R6:3.9kΩ
R7:Open
R8: Option
R9:For adjust
R10: Option
L1: 10μH
D1:SJPW-T4
(Sanken)
D2:Option
Z1:NR111E
/ NR119E
*R9 refer to Page18
to 19,Setup OCP
value
The demonstration boards of the fig 27 and the fig 28 are some kinds of IC common use. This is the circuit board
which contains optional part mounting for the experiment.
As for the part number of the demonstration board "circuit-diagram", a circuit board concerned doesn't partly fit
each other with the above application circuit example and so on for NR110, NR120 and the NR880 series common
use. Approve it in advance. C9, R9 and C10 aren't used in the NR110 series. And, D2, R3, R8,R10, C11 and C12
are options.
*Mount ISET setup resistor R9 on the position of C10.
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Page.22
NR110E SERIES APPLICATION NOTE
Rev.2.0
7.3 Applied Design
7.3.1 Spike Noise Reduction(1)
The addition of the BS serial resistor
The “turn-on switching speed” of the internal
Power-MOSFETcan be slowed down by inserting RBS
(option) of the fig30.It is tendency that Spike noise becomes
small by reducing theswitching-speed. Set up 22-ohm as an
upper limit when you use RBS.
*Attention
1) When the resistance value of RBS is enlarged by mistake
toomuch, the internal power-MOSFET becomes an
under-drive,it may be damaged worst.
2) The “defective starting-up” is caused when the resistance
value of RBS is too big.
*The BS serial resistor RBS is R3 in the Demonstration Board.
NR11xEseries
fig.30 The ddition of BS resistor RBS
7.3.2 Spike Noise Reduction(2)
IN
The addition of the Snubber circuit
In order to reduce the spike noise, it is possible to compensate
the output waveform and the recovery time of diode by
connecting a capacitor and resistor parallel to the flywheel
diode (snubber method). This method however may slightly
reduce the efficiency.
* For observing the spike noise with an oscilloscope, the
probe lead (GND) should be as short as possible and
connected to the root of output capacitor. If the probe GND
lead is too long, the lead may act like an antenna and the
observed spike noise may be much higher and may not show
the real values.
*The snubber circuit parts are C12 and R10.
NR11xEseries
SW
≒10Ω
GND
≒1000pF
fig.31 The addition of snubber circuit
・Attention about the insertion of the bead-core
fig.32
In the area surrounded by the red dotted line within the fig32, don't insert the bead-core such as Ferrite-bead.
As for the pattern-design of printed-circuit-board, it is recommended that the parasitic-inductance of wiring-pattern is
made small for the safety and the stability.
When bead-core was inserted, the inance of the bead-core is added to parasitic-inductance of the wiring-pattern.
By this influence, the surge-voltage occurs often, or , GND of IC becomes unstable, and also, negative voltage occurs
often.
Because of this, faulty operation occurs in the IC. The IC has the possibility of damage in the worst case.
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Page.23
NR110E SERIES APPLICATION NOTE
Rev.2.0
About the Noise-reduction, fundamentally, Cope by "The addition of CR snubber circuit" and "The addition of BS serial
resistor".
7.3.2 Reverse Bias Protection
A diode for reverse bias protection may be required between
input and output in case the output voltage is expected to be
higher than the input Pin voltage (a common case in battery
charger applications).
2. IN
3.SW
NR111E
fig.33 Reverse bias protection diode
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Page.24
NR110E SERIES APPLICATION NOTE
Rev.2.0
OPERATING PRECAUTIONS
Reliability can be affected adversely by improper storage environments and handling methods. Please observe the
following cautions.
Heat dissipation and reliability
Thermal performance of the surface mount package IC depends on the material and area size of PCB and its
copper plane. Design thermal condition with sufficient margin
Parallel operation
The parallel operation to increase the current is not available.
Thermal shut down
The NR111E has a thermal protection circuit.This circuit protects the IC from the heat generation by the over
load.This circuit cannot guarantee the long-term reliability against the continuously over load status.
Cautions for Storage
 Ensure that storage conditions comply with the standard temperature (5 to 35°C) and the standard relative
humidity (around 40 to 75%); avoid storage locations that experience extreme changes in temperature or
humidity.
 Avoid locations where dust or harmful gases are present and avoid direct sunlight.
 Reinspect for rust on leads and solderability of products that have been stored for a long time.
Cautions for Testing and Handling
 When tests are carried out during inspection testing and other standard test periods, protect the products from
power surges from the testing products, shorts between the product pins, and wrong connections. In addition,
avoid tests exceeded ratings
Soldering
When soldering the products, please be sure to minimize the working time, within the following limits.
・Reflow
Preheat ; 180°C / 90±30s
Heat ; 250°C / 10±1s (260°C peak ,2times)
・Soldering iron ; 380±10°C / 3.5±0.5s (1time)
Electrostatic Discharge
 When handling the products, the operator must be grounded. Grounded wrist straps worn should have at least
1MΩ of resistance from the operator to ground to prevent shock hazard, and it should be placed near the
operator.
 Workbenches where the products are handled should be grounded and be provided with conductive table and
floor mats.
 When using measuring equipment such as a curve tracer, the equipment should be grounded.
 When soldering the products, the head of a soldering irons or the solder bath must be grounded in order to
prevent leak voltages generated by them from being applied to the products.
 The products should always be stored and transported in Sanken shipping containers or conductive containers,
or be wrapped in aluminum foil.
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Page.25
NR110E SERIES APPLICATION NOTE
Rev.2.0
IMPORTANTS NOTES
 The contents in this document are subject to changes, for improvement and other purposes, without
notice. Make sure that this is the latest revision of the document before use.
 Application and operation examples described in this document are quoted for the sole purpose of
reference for the use of the products herein and Sanken can assume no responsibility for any
infringement of industrial property rights, intellectual property rights or any other rights of Sanken or
any third party which may result from its use.
 Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of
failure and defect of semiconductor products at a certain rate is inevitable. Users of Sanken products
are requested to take, at their own risk, preventative measures including safety design of the
equipment or systems against any possible injury, death, fires or damages to the society due to device
failure or malfunction.
 Sanken products listed in this document are designed and intended for the use as components in
general purpose electronic equipment or apparatus (home appliances, office equipment,
telecommunication equipment, measuring equipment, etc.).
When considering the use of Sanken products in the applications where higher reliability is required
(transportation equipment and its control systems, traffic signal control systems or equipment,
fire/crime alarm systems, various safety devices, etc.), please contact your nearest Sanken sales
representative to discuss, prior to the use of the products herein.
The use of Sanken products without the written consent of Sanken in the applications where
extremely high reliability is required (aerospace equipment, nuclear power control systems, life
support systems, etc.) is strictly prohibited.
 In the case that you use Sanken semiconductor products or design your products by using Sanken
semiconductor products, the reliability largely depends on the degree of derating to be made to the
rated values. Derating may be interpreted as a case that an operation range is set by derating the load
from each rated value or surge voltage or noise is considered for derating in order to assure or
improve the reliability. In general, derating factors include electric stresses such as electric voltage,
electric current, electric power etc., environmental stresses such as ambient temperature, humidity etc.
and thermal stress caused due to self-heating of semiconductor products. For these stresses,
instantaneous values, maximum values and minimum values must be taken into consideration.
In addition, it should be noted that since power devices or IC’s including power devices have large
self-heating value, the degree of derating of junction temperature affects the reliability significantly.
 When using the products specified herein by either (i) combining other products or materials
therewith or (ii) physically, chemically or otherwise processing or treating the products, please duly
consider all possible risks that may result from all such uses in advance and proceed therewith at your
own responsibility.
 Anti radioactive ray design is not considered for the products listed herein.
 Sanken assumes no responsibility for any troubles, such as dropping products caused during
transportation out of Sanken’s distribution network.
 The contents in this document must not be transcribed or copied without Sanken’s written consent.
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Page.26