R1224N SERIES
PWM/VFM step-down DC/DC Controller
NO.EA-096-181004
1
OUTLINE
The R1224N Series are CMOS-based PWM step-down DC/DC Converter controllers with low supply current.
Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a
phase compensatio n circuit , a soft-start circuit , a prote cti on circuit , a P WM/VF M alt ernative circ uit, a chip enable
circuit, resistors for out put voltage dete ct , and input voltage detect ci rcuit . A low ripple, high efficiency step-down
DC/DC convert er can be easily compo sed of this IC with only several external compone nts, or a power-transistor,
an inductor, a diode and ca pacitors. Output Volt age is fixed or can be adjusted w ith external resisto rs (Adjustable
types are without PWM/ VFM alternative circuit).
With a PWM/VFM alternative circuit, when the load current is small, the operation is automatically switching
into the VFM oscillator from PWM oscillator. Therefore, the efficiency at small load current is improved. Several
types of the R1224 Nx xx, which are without a P WM /VFM alternati ve circuit, are also avail able.
If the term of maximum duty cycle keeps on a certain time, the embedded protection circuit works. The
protection circuit is Reset-type protection circuit, and it works to restart the operation with soft-start and repeat
this operation until maximum dut y cycle condi tion is releas ed. When the ca use of large load current or something
else is removed, the operation is automatically released and returns to normal operation. Further, built-in UVLO
function works when the input voltage is equal or less than UVLO threshold, it makes this IC be standby and
suppresses the consumption current and avoid an unstable o peration.
FEATURES
• Supply Current ................................................................ Typ. 20µA (R1224Nxx2E/F/M/L, R1224N102M)
Typ. 30µA (R1224Nxx2G, R1224N102 G)
Typ. 40µA (R1224Nxx2H, R1224N102H )
• Standby Current .............................................................. Typ. 0µA
• Input Voltage Range ....................................................... 2.3V to 18.5V
• Output Voltage Range ..................................................... 1.2V to 6.0V (0.1V steps; R1224Nxx2x)
1.0V to VIN (R1224N102x)
• Output V oltage Accuracy ................................................. ±2.0%
• Oscillator Frequency ....................................................... Typ. 180kHz (R1224Nxx2L/M, R1224 N102M)
Typ. 300kHz (R1224Nxx2E/G, R1224 N102G)
Typ. 500kHz (R1224Nxx2F/H, R1224N102H)
• Efficiency ......................................................................... Typ. 90%
• Low Temperature-Drift Coefficient of Output Voltage ..... Typ. ±100ppm/°C
• Package .......................................................................... SOT-23-5
• Built-in Soft-start Function ............................................... Typ. 10ms
• Built-in Current Limit Circuit
APPLICATIONS
• Power source for hand-held communication equipment, cameras, video instruments such as VCRs,
camcorders.
• Power source for bat tery-powered equipment.
• Power source for household electrical appli ances.
R1224N
NO.EA-096-181004
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BLOCK DIAGRA M
Fixed Output Voltage Type
OSC
Amp
Vref
Vref
VOUT
CE
VIN
EXT
GND
PWM/VFM
CONTROL
Soft Start
Protection
Chip Enable
UVLO
5
4
2
1
3
Adjustable Output Voltage Type
OSC
Amp
Vref
Vref
V
FB
CE
V
IN
EXT
GND
Soft Start
Protection
Chip Enable
UVLO
5
4
2
1
3
R1224N
NO.EA-096-181004
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SELECTI ON GUIDE
The output voltage, the oscillator frequency, the modulation method and the output voltage adjustment for the
ICs can be selected at the user’s requ est.
Product Name
Package
Quantity per Reel
Pb Free
Halogen Free
R1224Nxx2∗-TR-FE SOT-23-5 3,000 pcs Yes Yes
xx : The output voltage can be designated in the range from 1.2V(12) to 6.0V(60) in 0.1V steps.
(For externally adj ust able output voltag e type, feedback voltage of 1.0V(10).)
∗ : The oscillator frequency, the modulation method and t he output voltage adjustment are option s as
follows.
Code Oscillator frequ ency
PWM/VFM
alternative circui t
Output voltage
adjustment
E
300kHz
Yes
No
F
500kHz
Yes
No
G 300kHz No Yes
H
500kHz
No
Yes
L
180kHz
Yes
No
M
180kHz
No
Yes
PIN CONFIGURATION
• SOT-23-5
1
2
3
4
5
(mark side)
PIN DESCRIPTION
Pin No
Symbol
Pin Description
1
CE
Chip Enable Pin ("H" Active)
2
GND
Ground Pin
3
V
OUT
(V
FB
)
Pin for Monitoring Out put Voltage (Feedback Volta ge)
4
EXT
External Transistor Drive Pin (CMOS Output)
5
V
IN
Power Supply P i n
R1224N
NO.EA-096-181004
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ABSOLUTE MAXIMUM RATINGS GND=0V
Symbol
Item
Rating
Unit
V
IN
V
IN
Supply Voltage
−0.3 to 20
V
V
EXT
EXT Pin Output Voltage
−
0.3 to V
IN+
0.3
V
V
CE
CE Pin Input Voltage
−
0.3 to V
IN+
0.3
V
V
OUT
/V
FB
V
OUT
/V
FB
Pin Input Voltage
−
0.3 to V
IN+
0.3
V
I
EXT
EXT Pin Inductor Drive Out put Cur rent
±
50
mA
P
D
Power Dissipat i on (SOT-23-5)∗
420
mW
Topt
Operating Temperature Range
−40 to 85
°C
T
stg
Storage Temperature Range
−
55 to 125
°
C
∗) For Power Dissipation, please refer to PACKAGE INFORMATION.
ABSOLUTE MAXIMUM RATINGS
Electronic and mechanical stress momentarily exceeded absolute maximum ratings may cause the
permanent damages an d may degr ade the li fe time and saf ety f or both device and system u sing t he device
in the field. he funct i onal operation at or over these absolute maximum ratings is not as sured.
R1224N
NO.EA-096-181004
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ELECTRICAL CHARACTERISTICS
• R1224Nxx2x (x=E/F/G/H/L/M) except R1224N102x Topt=25°C
Symbol
Item
Conditions
Min.
Typ.
Max.
Unit
V
IN
Operating Input Voltage
2.3
18.5
V
VOUT Step-down Output Voltage
V
IN
=V
CE
=V
SET
+1.5V, I
OUT
=−100mA
When VSET≤1.5V, VIN=VCE=3.0V
V
SET
×
0.98
VSET
V
SET
×
1.02
V
∆
V
OUT
/
∆Topt
Step-down Output Voltage
Temperature Coefficient
−40°C≤Topt≤85°C ±100 ppm/°C
fosc Oscillator Frequency VIN=VCE=VSET+1.5V, IOUT=−100mA
L/M Version
E/G Version
F/H Version
144
240
400
180
300
500
216
360
600
kHz
∆
f
osc
/
∆Topt
Oscillator Frequency
Temperature Coefficient
−40°C≤Topt≤85°C ±0.2 %/°C
IDD1 Supply Current 1
V
IN
=V
CE
=V
OUT
=18.5V
E/F/L/M Version
G version
H version
20
30
40
50
60
80
µA
Istandby
Standby Current
V
IN
=18.5V, V
CE
=0V, V
OUT
=0V
0
0.5
µA
IEXTH EXT "H" Output Current
V
IN
=8V, V
EXT
=7.9V, V
OUT
=8V,
VCE=8V
−17 −10 mA
IEXTL EXT "L" Output Current
V
IN
=8V, V
EXT
=0.1V, V
OUT
=0V,
VCE=8V
20 30 mA
I
CEH
CE "H" Input Current
V
IN=
V
CE=
V
OUT=
18.5V
0
0.5
µ
A
I
CEL
CE "L" Input Current
V
IN
=V
OUT
=18.5V, V
CE
=0V
−0.5
0
µA
V
CEH
CE "H" Input Voltage
V
IN=
8V, I
OUT=−
10mA
1.5
V
V
CEL
CE "L" Input Voltage
V
IN=
8V, I
OUT=−
10mA
0.3
V
Maxduty
Oscillator Maximum
Duty Cycle
100 %
VFMdty
VFM Duty Cycle
E/F/L Version
35
%
V
UVLO1
UVLO Voltage
V
IN
=V
CE
=2.5V to 1.5V, V
OUT
=0V
1.8
2.0
2.2
V
VUVLO2 UVLO Release Voltage VIN=VCE=1.5V to 2.5V, VOUT=0V
V
UVLO1
+0.1
2.3 V
tstart Delay Time by Soft-Start function
V
IN
=V
SET
+1.5V, I
OUT
=−10mA
VCE=0V→VSET+1.5V
5 10 20 ms
tprot Delay Time for protection circuit
V
IN
=V
CE
=V
SET
+1.5V
VOUT=VSET+1.5V→0V
5 15 30 ms
RECOMMEN DED OPERATING CONDIT IONS (ELECTRICAL CHARACTERISTICS)
All of electronic equipment should be design ed t hat the mounted semiconductor devices operate within the
recommended operating conditions. The semiconductor devices cannot operate normally over the
recommended operating conditions, even if when they are used over such conditions by momentary
electronic noise o r surge. And the semiconductor devices may rec eive serious d amage when t hey continue
to operate over the recommended operati ng conditions.
R1224N
NO.EA-096-181004
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• R1224N102x (x=G/H/M) Topt=25°C
Symbol
Item
Conditions
Min.
Typ.
Max.
Unit
V
IN
Operating Input Voltage
2.3
18.5
V
V
FB
Feedback Voltage
V
IN=
V
CE=
3.0V, I
OUT=−
100mA
0.98
1.00
1.02
V
∆
V
FB
/
∆
Topt
Feedback Voltage
Temperature Coefficient
−40°C≤Topt≤85°C ±100 ppm/°C
fosc Oscillator Frequency
V
IN
=V
CE
=2.5V, I
OUT
=−100mA
M Version
G Version
H Version
144
240
400
180
300
500
216
360
600
kHz
∆
f
osc
/
∆
Topt
Oscillator Frequency
Temperature Coefficient
−40°C≤Topt≤85°C ±0.2 %/°C
IDD1 Supply Current 1
V
IN
=V
CE
=V
FB
=18.5V
M Version
G Version
H Version
20
30
40
50
60
80
µA
I
standby
Standby Current
V
IN=
18.5V, V
CE=
0V, V
FB=
0V
0
0.5
µ
A
IEXTH EXT "H" Output Current
V
IN
=8V, V
EXT
=7.9V, V
FB
=8V,
VCE=8V
−17 −10 mA
IEXTL EXT "L" Output Current
V
IN
=8V, V
EXT
=0.1V, V
FB
=0V,
V
CE
=8V
20 30 mA
I
CEH
CE "H" Input Current
V
IN=
V
CE=
V
FB=
18.5V
0
0.5
µ
A
I
CEL
CE "L" Input Current
V
IN=
V
FB=
18.5V, V
CE=
0V
−
0.5
0
µ
A
V
CEH
CE "H" Input Voltage
V
IN=
8V, I
OUT=−
10mA
1.5
V
V
CEL
CE "L" Input Voltage
V
IN
=8V, I
OUT
=−10mA
0.3
V
Maxduty
Oscillator Maximum Duty Cycle
100
%
V
UVLO1
UVLO Voltage
V
IN=
V
CE=
2.5V to 1.5V, V
FB=
0V
1.8
2.0
2.2
V
VUVLO2 UVLO Release Voltage VIN=VCE=1.5V to 2.5V, VFB=0V
V
UVLO1
+0.1
2.3 V
tstart Delay Time by Soft-Start function
V
IN
=2.5V, I
OUT
=−10mA
VCE=0V→2.5V
5 10 20 ms
tprot Delay Time for protection circuit
V
IN
=V
CE
=2.5V
V
FB
=2.5V→0V
5 15 30 ms
RECOMMEN DED OPERATING CONDIT IONS (ELECTRICAL CHARACTERISTICS)
All of electroni c equipment shoul d be designed that t he mounted sem i conductor devices o perate within the
recommended operating conditions. The semiconductor devices cannot operate normally over the
recommended operating conditions, even if when they are used over such conditions by momentary
electronic noise o r surge. And the semiconductor devices may rec eive serious d amage when t hey continue
to operate over the recommended operati ng conditions.
R1224N
NO.EA-096-181004
7
TYPICAL APPLICATION AND APPLICATION HINTS
(1) Fixed Output Voltage Type (R1224Nxx2E/F/ G / H/ L /M except xx=10)
CE CONTROL
R1224N
EXT
GND
VOUT
VIN
CE
C3
L
LOAD
C1
R1
C2
PMOS
SD
5
1
2
3
4
PMOS: uPA1914 (Renesas) L : CR105NP-270MC (Sumida, 27µH)
SD1 : CMS06 (TOSHIBA) C3 : 47µF (Tantalum Type)
C1 : 10µF (Ceramic Type) C2 : 0.1µF (Ceramic Type)
R1 : 10Ω
(2) Adjustable Ou tput Type (R1224N102G/H/ M ) Example: Output Voltage=3.2V
CE CONTROL
C3
L
LOAD
C1
R1
C2
PMOS
SD
C4
R3
R4
R2
R1224N
EXT
GND
VFB
VIN
CE
5
1
2
3
4
PMOS: uPA1914 (Renesas) L : CR105NP-270MC (Sumida, 27µH)
SD1 : CMS06 (TOSHIBA) C3 : 47µF (Tantalum Type)
C1 : 10µF (Ceramic Type) C2 : 0.1µF (Ceramic Type) C4: 1000pF (Ceramic T y pe)
R1 : 10Ω, R2=22kΩ, R3=2.7kΩ, R4=33kΩ
R1224N
NO.EA-096-181004
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When you use these ICs, consider the following issues;
⋅As shown in the block diagram, a parasitic diode is formed in each terminal, each of these diodes is not formed
for load current, therefore do not use it in such a way. When you control the CE pin by another power supply, do
not make its “H” level m ore than the voltage l evel of VIN pin.
⋅Set external components as close as possible to the IC and minimize the connection between the components
and the IC. In particular, a capa citor should be connect ed to VIN pin with the minimum connection. Make suf ficient
ground and reinforce supplying. A large switching current could flow through the connection of power supply, an
inductor and the connection of VIN. If the impedance of the connection of power supply is high, the voltage level
of power supply of the IC fluctuates with the switching current. This m ay cause unstable ope ration of the IC.
⋅Protection circuit may work if the maximum duty cycle continue for the time defined in the electrical characteristics.
Once after stoppin g the output volt age, output will res tart with soft-start operation. I f the dif ference betwe en input
voltage and output voltage is small, the protect i on circuit may work.
⋅Use capacitors with a capacity of 22µF or more for VOUT pin, and with good high frequency characteristics such
as tantalum capacitors. We recommend you to use output capacitors with an allowable voltage at least twice as
much as setting output voltage. This is because there may be a case where a spike-shaped high voltage is
generated by an inductor when an external transistor is on and off.
⋅Choose an inductor that has sufficiently small D.C. resistance and large allowable current and is hard to reach
magnetic saturation. And if the value of inductance of an inductor is extremely small, the ILX may exceed the
absolute maximum rat i ng at the maximum loading.
Use an inductor with appropriate inductance.
⋅Use a diode of a S chot t ky t ype with high switching speed, and also pay at tention to its current capacity.
⋅Do not use this IC un der the condition wit h VIN voltage at equal or less than minimum operating voltage.
⋅When the threshold level of an external power MOSFET is rather low and the drive-ability of voltage supplier is
small, if the output pin is short circuit, input voltage may be equal or less than UVLO detector threshold. In this
case, the devise is reset with UVLO function that is different from the reset-protection function caused by
maximum duty cycle.
⋅With the PWM/VFM alternative circuit, when the on duty cycle of switching is 35% or less, the R1224N alters
from PWM mode to VFM mode (Pulse skip mode). The purpose of this circuit is raising the efficiency with a light
load by skipping the frequency and suppressing the consumption current. However, the ratio of output voltage
against input voltage is 35% or less, (ex. VIN>8.6V and VOUT=3.0V) even if the large current may be loaded, the
IC keeps its VFM mode. As a result, freq uency might be decrease d, and oscillat ion wavef orm might be unstable.
These phenomena a re the typical characteristics of the IC with P WM/VFM alternat i ve circuit.
⋅If the input voltage is equal or more than 6V, R1 and C2 in the typical application are necessary as a VIN filter to
prevent unstable operation.
The performanc e of power source circuits using these ICs extremely depends upon t he peripheral circuits.
Pay attention in the selection of the peripheral circuits. In particular, design the peripheral circuits in a way that
the values such as v oltage, current, and power of ea ch compone nt, P CB pattern s and the IC do not excee d their
respected rated val ues.
R1224N
NO.EA-096-181004
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How to Adjust Output Voltage and a bout Phase Compensation
As for Adjustable Output type, feedback pin (VFB) volt age i s c ontrolled to maintai n 1.0V.
Output Voltage, V OUT is as f ol lowing equation:
VOUT: R2+R4=VFB: R2
VOUT=VFB×(R2+R4)/R2
Thus, with changin g the value of R2 and R4, output voltage can be set i n the specified range.
In the DC/DC conve rter, wi t h the load cu rrent and ext ernal com pon ents such a s L and C, phase might be b ehind
180 degree. In this case, the phase margin of the system will be less and stability will be worse. To prevent this,
phase margin should be secured with proceeding the phase. A pole is formed with external components L and
C3.
C3L1/2 ~ Fpole ×π
A zero (signal back to zero) is formed with R4 and C4.
≅Fzero~1/(2π×R4×C4)
For example, if L=27µH, C3=47µF, the cut of f f requency of the pole is approxim ately 4.5kHz.
To make the cut off frequency of the pole as much as 4.5kHz, set R4=33kΩ and C4=1000pF.
If VOUT is set at 2.5V, R2=22kΩ is appropriate.
R3 prevents feedb ack of the noise to VFB pin, about 2.7kΩ is appropriate value.
CE CONTROL
C3
L
LOAD
C1
R1
C2
PMOS
SD
C4
R3
R4
R2
R1224N
EXT
GND
VFB
VIN
CE
5
1
2
3
4
R1224N
NO.EA-096-181004
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OPERATION of step-down DC/DC converter and Output Current
The step-down DC/D C conv erter charg e s energy in the inducto r when Lx transist or is ON, and discha rges the
energy from the inductor when Lx transistor is OFF and controls with less energy loss, so that a lower output
voltage than the input voltage is obtained. The operation will be explained with reference to the following
diagrams:
<Basic Circui ts> <Current through L>
I
OUT
Lx Tr
L
SD
V
IN
i1
V
OUT
CL
i2
GND
T=1/fosc
ton
toff
topen
ILmin
ILmax
IL
Step 1: Lx Tr. turns on and current IL (=i1) flows, and energy is charged into CL. At this moment, IL increases
from ILmin. (=0) to r each ILmax. in proportion t o t he on-time period (ton) of Lx Tr.
Step 2: When Lx Tr. turns off, Schottky diode (SD) turns on in order that L maintains IL at ILmax, and current IL
(=i2) flows.
Step 3: IL decreases gradually and reaches ILmin. after a time period of topen, and SD turns off, provided that
in the continuous mode, nex t cy cle starts before IL becomes to 0 becau se toff time is not enough. In this
case, IL value is from this ILmin (>0).
In the case of PWM control system, the output voltage is maintained by controlling the on-time period (ton), with
the oscillator frequency (fosc) being maintained constant.
Discontinuous Conduction Mode and Continuous Conduction Mode
The maximum value (ILmax) and the minimum value (ILmin) current which flow through the inductor is the
same as those when Lx Tr. is ON and when it is OFF.
The difference between ILmax and ILmin, whic h is represented by ∆I;
∆I=ILmax-ILmin=VOUT×topen/L=(VIN-VOUT)×ton/L ................................... Equation 1
wherein, T=1/fosc=ton+toff
duty (%)=ton/T×100=ton×fosc×100
topen
<
=
toff
In Equation 1, VOUT×topen/L and (VIN-VOUT)×ton/L are respectively shown the change of the current at ON, and
the change of the cur rent at OFF.
When the output current (IOUT) is relatively small, topen<toff as illustrated in the above diagram. In this case, the
energy is charged in the inductor during the time period of ton and is discharged in its entirely during the time
period of toff, therefore ILmin becomes to zero (ILmin=0). When Iout is gradually increased, eventually, topen
becomes to toff (topen=toff), and when IOUT is further increased, ILmin becomes larger than zero (ILmin>0). The
former mode is refe rred to as the discont inuous mode and the latter mode is referred to as continuous mode.
R1224N
NO.EA-096-181004
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In the continuous mode, when Equation 1 i s solv ed for ton and assumed that the solution is tonc,
tonc=T×VOUT/VIN ..................................................................................... Equation 2
When ton<tonc, the m ode is the discontinuous mode, and when ton =tonc, the mode is the continuous mode.
OUTPUT CURRENT AND SELECTIO N O F EXTERN AL CO M PO NENT S
When Lx Tr. is ON:
(Wherein, Ripple Current P-P value is described as IRP, ON resistance of Lx Tr. is described as Rp the direct
current of the inductor is described as RL.)
VIN=VOUT+(Rp+RL)×IOUT+L×IRP/ton ................................................. Equation 3
When Lx Tr. is OFF:
L×IRP/toff=VF+VOUT+RL×IOUT ............................................................ Equation 4
Put Equation 4 to Equation 3 and solve for ON duty, t on/(toff +t on)=DON,
DON=(VOUT+VF+RL×IOUT)/(VIN+VF−Rp×IOUT) ...................................... Equation 5
Ripple Current is as foll ows;
IRP=(VIN−VOUT−Rp×IOUT−RL×IOUT)×DON/f/L ........................................ Equation 6
Wherein, peak current that flows through L, Lx Tr., and SD is as follows;
ILmax=IOUT+IRP/2 ............................................................................ Equation 7
Consider ILmax, condition of input and output and select external components.
The above explanation is directed to the calculat i on in an ideal case in cont i nuous mode.
R1224N
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External Components
1. Inductor
Select an inductor that peak current does not exceed ILmax. If larger current than allowable current flows,
magnetic saturation occurs and make transform efficiency worse.
When the load curre nt is definite, the smaller v alue of L, the larger the ripple current.
Provided that the allowable current is large in that case and DC current is small, therefore, for large output
current, efficiency is better than using an inductor with a large value of L and vice versa.
2. Diode
Use a diode with low VF (Schottky type is recommended.) and high switching speed.
Reverse voltage rati ng should be more than VIN and current rating sho ul d be equal or more than ILm ax.
3. Capacitors
As for CIN, use a capacitor with low ESR (Equivalent Series Resistance) and a capacity of at least 10µF for
stable operation.
COUT can reduce ripple of Output Voltage, therefore 47µF or more value of tantalum type capacitor is
recommended.
4. Lx Transistor
Pch Power MOSFE T is required for this IC.
Its breakdown vol t age between gate and source should be a few V hi gher than Input Voltage.
In the case of Input Voltage is low, to turn on MOSFET completely, to use a MOSFET with low threshold
voltage is effective.
If a large load current is necessary for your application and important, choose a MOSFET with low ON
resistance for good efficiency.
If a small load current is ma inly neces sary for y our application, choose a MOSFE T with low gat e capacity f or
good eff i ciency.
Maximum continuou s drain current of MO S F ET should be larger than peak current, ILmax .
R1224N
NO.EA-096-181004
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TIMING CHART
V
OUT
Set Output Voltage
UVLO Voltage
Input Voltage
Rising Time
UVLO Res et
V
OUT
Set Output Voltage
Protection Ci rcuit Delay Time
V
OUT
Set Out put
Voltage
V
IN
CE
EXT
V
OUT
V
OUT
Set Out put
Voltage
Stable
Operation
Stable
Operation
Stable
Operation
Soft Start
Soft Start
Soft Start
Soft Start
Reset Protection
The timing chart shown above describes the changing process of input voltage rising, stable operating,
operating with large cur rent, stable operating, input voltage f alling, input voltage recovering, and st able operating.
First, until when the input voltage (VIN) reaches UVLO voltage, the circuit inside keeps the condition of pre-
standby.
Second, after VIN becomes beyond the UVLO threshold, soft-start operation starts, when the soft-start operation
finishes, the operat ion becomes stable.
If too large current flows through the circuit because of short or other reasons, EXT signal ignores that during
the delay time of protection circuit. (The current value depends on the circuit.)
After the delay time passes, reset prot ection works, or EXT signal will be “H”, then out put will turn of f, then soft -
start operation s tarts. After the soft-start operation, EXT signal will be “L”, but if the large current is still flowing,
after the delay time of protection circuit passes, reset protection circuit will work again, the operation will be
continuously repeated unless the cau se of large current f l owing i s not removed.
Once the cause of t he large current fl owing is remov e d, wit hin the del ay t ime, the oper ation w ill be back to t he
stable one.
If the timing for release the large current is in the protection process, the operation will be back to the normal
one after the soft-start operation.
If the VIN becomes lower than the set V OUT, that situation is same as large current condition, so protection circuit
may be ready to work, therefore, after th e del ay time of protecti on circuit, EXT will be “H”.
Further, if the VIN is lower than UVLO voltage, the circ ui t inside will be stopped by UV LO function.
After that, if VIN rises, until when the VIN reaches UVLO voltage, the circuit inside keeps the condition of spre-
standby.
Then after VIN becomes beyond the UVLO threshold, soft-start operation starts, when the soft-start operation
finishes, the operat ion becomes stable.
R1224N
NO.EA-096-181004
14
TEST CIRCUITS
Output Voltage, Oscillator Frequency, CE “H” Input Voltage, CE “L” Input Voltage, Soft-start time
R1224N
EXT
GND
V
OUT
V
IN
CE
D1
C1
PMOS
V
Oscilloscope
C2
(V
FB
)
2
3
1
5
4
L1
Supply Current 1 Standby Current
A
R1224N
GND
V
OUT
V
IN
CE
(V
FB
)
2
3
1
5
A
R1224N
GND
VOUT
VIN
CE
(V
FB
)
2
3
1
5
EXT “H” Output Current EXT “L” Output Current
A
R1224N
GND
VOUT
VIN
CE
(V
FB
)
EXT
2
3
1
5
4
A
R1224N
GND
V
OUT
V
IN
CE
(V
FB
)
EXT
2
3
1
5
4
CE “H” Input Current, CE “L” Input Cu rrent Output Delay Time for Protection Circuit
A
R1224N
GND
VOUT
VIN
CE
(VFB)
2
3
1
5
R1224N
GND
V
OUT
V
IN
CE
(V
FB
)
EXT
Oscilloscope
C2
2
3
1
5
4
PMOS : HAT1044M (Hit achi ) L : CD104NP-270MC (S um i da, 27µH)
SD1 : RB491D (Rohm)
C1 : 47µF (Tantalum Type) C2 : 47µF (Tantalum Type)
R1224N
NO.EA-096-181004
15
TYPICAL CHARACTERISTICS
1)Output Voltage vs. Output Current (*Note)
R1224N182E L=10µH R1224N182F L=10µH
R1224N182G L=10µH R1224N182H L=10µH
R1224N182L L=27µH R1224N182M L=27µH
R1224N
NO.EA-096-181004
16
R1224N332E L=10µH R1224N332F L=10µH
R1224N332G L=10µH R1224N332G (VIN=10V)
R1224N332G (VIN=16V) R1224N332H L=10µH
R1224N
NO.EA-096-181004
17
R1224N332L L=27µH R1224N332M L=27µH
R1224N332M (VIN=5V) R1224N332M (VIN=10V)
R1224N332M (VIN=18V) R1224N502E L=10µH
R1224N
NO.EA-096-181004
18
R1224N502F L=10µH R1224N502G L=10µH
R1224N502G (VIN=10V) R1224N502G (VIN=16V)
R1224N502H L=10µH R1224N502L L=27µH
R1224N
NO.EA-096-181004
19
R1224N502M L=27µH
*Note: Typical characteristics 1) are obtained with using
the following components;
PMOS : IRF7406 (IR)
L : CDRH127-100MC (Sumida: 10µH)
SD : RB083L-20 (Rohm)
C1 : 25SC47 (Sanyo/OS-con: 47µF/25V)×2
C2 : 0.1µF (Ceramic Type)
C3 : 10SA220 (Sanyo/OS-con: 220µ F/10V)
R1 : 10Ω
2) Efficiency vs. Output Current (*Note)
R1224N182F (V IN=3.3V) CDRH127-10µH R1224N182F (V IN=5.0V) CDRH127-10µH
R1224N182G (VIN=3.3V) CDRH127-10µH R1224N182G (VIN=5.0V) CDRH127-10µH
R1224N
NO.EA-096-181004
20
R1224N182G (VIN=12V) CDRH127-10µH R1224N182H (VIN=3.3V) CDRH127-10µH
R1224N182H (VIN=5.0V) CDRH127-10µH R1224N182H (VIN=12V) CDRH127-10µH
R1224N182L (VIN=3.3V) CDRH127-27µH R1224N182L (VIN=5.0V) CDRH127-27µH
R1224N
NO.EA-096-181004
21
R1224N182M (VIN=3.3V) CDRH127-27µH R1224N182M (VIN=5.0V) CDRH127-27µH
R1224N182M (VIN=12V) CDRH127-27µH R1224N332E (VIN=7.0V) CDRH127-10µH
R1224N332E (VIN=4.8V) CDRH127-10µH R1224N332F (V IN=7.0V) CDRH127-10µH
R1224N
NO.EA-096-181004
22
R1224N332F (V IN=4.8V) CDRH127-10µH R1224N332G (VIN=12V) CDRH127-10µH
R1224N332G (VIN=4.8V) CDRH127-10µH R1224N332G (VIN=10V)
R1224N332G (VIN=16V) R1224N332G (VIN=15V) CDRH127-10µH
R1224N
NO.EA-096-181004
23
R1224N332H (VIN=12V) CDRH127-10µH R1224N332H (VIN=4.8V) CDRH127-10µH
R1224N332H (VIN=15V) CDRH127-10µH R1224N332L (VIN=7.0V) CDRH127-27µH
R1224N332L (VIN=4.8V) CDRH127-27µH R1224N332M (VIN=12V) CDRH127-27µH
R1224N
NO.EA-096-181004
24
R1224N332M (VIN=4.8V) CDRH127-27µH R1224N332M (VIN=5V)
R1224N332M (VIN=10V) R1224N332M (VIN=18V)
R1224N332M (VIN=15V) CDRH127-27µH R1224N502E (VIN=6.5V) CDRH127-10µH
R1224N
NO.EA-096-181004
25
R1224N502E (VIN=10V) CDRH127-10µH R1224N502F (VIN=6.5V) CDRH127-10µH
R1224N502F (V IN=10V) CDRH127-10µH R1224N502G (VIN=10V)
R1224N502G (VIN=16V) R1224N502G (VIN=6.5V) CDRH127-10µH
R1224N
NO.EA-096-181004
26
R1224N502G (VIN=12V) CDRH127-10µH R1224N502G (VIN=15V) CDRH127-10µH
R1224N502H (V IN=6.5V) CDRH127-10µH R1224N502H (VIN=12V) CDRH127-10µH
R1224N502H (V IN=15V) CDRH127-10µH R1224N502L (VIN=6.5V) CDRH127-27µH
R1224N
NO.EA-096-181004
27
R1224N502L (VIN=10V) CDRH127-27µH R1224N502M (VIN=6.5V) CDRH127-27µH
R1224N502M (VIN=12V) CDRH127-27µH R1224N502M (VIN=15V) CDRH127-27µH
*Note: Typical cha ra ct eristics 2) are obtained with using the f ol lowing components;
C2 : 0.1µF (Ceramic Type)
C3 : 10SA220 (Sany o/OS-con: 220µF/10V )
PMOS : IRF7406 (IR)
L : CDRH127-100MC (Sumida: 10µH)
SD : RB083L-20 (Rohm)
C1 : 25SC47 (Sanyo/OS-con: 47µF/25V)×2 R1 : 10Ω
R1224N
NO.EA-096-181004
28
3) Ripple Voltage vs. Output Current
R1224N182E L=10µH R1224N182F L=10µH
R1224N182G L=10µH R1224N182H L=10µH
R1224N182L L=27µH R1224N182M L=27µH
R1224N
NO.EA-096-181004
29
R1224N332E L=10µH R1224N332F L=10µH
R1224N332G L=10µH R1224N332H L=10µH
R1224N332L L=27µH R1224N332M L=27µH
R1224N
NO.EA-096-181004
30
R1224N502E L=10µH R1224N502F L=10µH
R1224N502G L=10µH R1224N502H L=10µH
R1224N502L L=27µH R1224N502M L=27µH
R1224N
NO.EA-096-181004
31
4) Output Voltage vs. Input Voltage
R1224N182E L=10µH R1224N182F L=10µH
R1224N182G L=10µH R1224N182H L=10µH
R1224N182L L=27µH R1224N182M L=27µH
R1224N
NO.EA-096-181004
32
R1224N332E L=10µH R1224N332F L=10µH
R1224N332G L=10µH R1224N332H L=10µH
R1224N332L L=27µH R1224N332M L=27µH
R1224N
NO.EA-096-181004
33
R1224N502E L=10µH R1224N502F L=10µH
R1224N502G L=10µH R1224N502H L=10µH
R1224N502L L=27µH R1224N502M L=27µH
R1224N
NO.EA-096-181004
34
5) Output Voltage vs. Temperature
R1224N332E R1224N122F
R1224N602L R1224N102G
6) Oscillator Frequency vs. Temperature
R1224N102G R1224N102H
R1224N
NO.EA-096-181004
35
R1224N102M
7) Supply Current vs. Temperature
R1224N332E R1224N602L
R1224N602F R1224N102G
R1224N
NO.EA-096-181004
36
R1224N102H R1224N102M
8) Soft-start time vs. Temperature
R1224N102G
9) Delay Time for Protection vs. Temperature
R1224N332E
R1224N
NO.EA-096-181004
37
10) EXT “H” Output Current vs. Temperature
R1224N332E
11) EXT “L” Output Current vs. Temperature
R1224N332E
12) Load Transient Response
R1224N332G L=10µH VIN=4.8V R1224N332G L=10µH VIN=4.8V
R1224N
NO.EA-096-181004
38
R1224N332G L=10µH VIN=10V R1224N332G L=10µH V IN=10V
R1224N332H L=10µH V IN=4.8V R1224N332H L=10µH VIN=4.8V
R1224N332H L=10µH V IN=10V R1224N332H L=10µH VIN=10V
R1224N
NO.EA-096-181004
39
R1224N332M L=27µH VIN=4.8V R1224N332M L=27µH VIN=4.8V
R1224N332M L=27µH VIN=10V R1224N332M L=27µH VIN=10V
12) UVLO Voltage vs. Temperature
R1224N332E
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