R1224Nxxxx - Ricoh Co., Ltd. - Datasheet.Directory

PWM/VFM step-down DC/DC Converter

R1224N Series

2002. Mar. 4

12345

12345

Rev. 1.10 - 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 compensation circuit, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip enable

circuit, resistors for output voltage detect, and input voltage detect circuit. A low ripple, high efficiency step-down

DC/DC converter can be easily composed of this IC with only several external components, or a power-transistor, an

inductor, a diode and capacitors. Output Voltage is fixed or can be adjusted with external resistors (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 R1224NXXX, which are without a PWM/VFM alternative circuit, are also available.

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 duty cycle condition is released. When the cause 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 operation.

■

■■

■ FEATURES

● Range of Input Voltage • • • • • • • • • • • • •2.3V∼18.5V

● Built-in Soft-start Function and Protection Function (Reset type protection)

● Three options of Oscillator Frequency • • • • • •180kHz, 300kHz, 500kHz

● High Efficiency • • • • • • • • • • • • • • • • • •TYP. 90%

● Output Voltage • • • • • • • • • • • • • Stepwise Setting with a step of 0.1V in the range of 1.2V to 6.0V as

fixed voltage type. Reference Voltage of Adjustable Type is 1.0V

● Standby Current • • • • • • • • • • • • • • • • •TYP. 0.0µA

● High Accuracy Output Voltage • • • • • • • • • •±2.0%

● Low Temperature-Drift Coefficient of Output Voltage • • • • • TYP. ±100ppm/°C

■

■■

■ APPLICATIONS

● Power source for hand-held communication equipment, cameras, video instruments such as VCRs,

camcorders.

● Power source for battery-powered equipment.

● Power source for household electrical appliances.

12345

Rev. 1.10 - 2 -

■

■■

■ BLOCK DIAGRAM

*Fixed Output Voltage Type

OSC

V

IN

EXT

GND

VOUT

Vref

CE

Chip Enable

Soft Start

Protection

PWM/VFM

CONTROL

Vref

Amp

UVLO

*Adjustable Output Voltage Type



OSC

V

IN

EXT

GND

VFB

Vref

CE

Chip Enable



Soft Start

Protection

PWM/VFM



CONTROL



Vref

UVLO

Amp

12345

Rev. 1.10 - 3 -

■

■■

■ SELECTION GUIDE

In the R1224N Series, the output voltage, the oscillator frequency, the optional function, and the taping type

for the ICs can be selected at the user’s request.

The selection can be made with designating the part number as shown below;

R1224NXX2X-TR

↑ ↑ ↑

a b c

Code Contents

a Setting Output Voltage(VOUT):

Stepwise setting with a step of 0.1V in the range of 1.2V to 6.0V is possible.

Adjustable type; a=10 means Reference voltage=1.0V Optional Function is G/H/M.

b Designation of Oscillator Frequency

2 : fixed

c Designation of Optional Function

E : 300kHz, with a PWM/VFM alternative circuit (Under Development)

F : 500kHz, with a PWM/VFM alternative circuit (Under Development)

G : 300kHz, without a PWM/VFM alternative circuit

H : 500kHz, without a PWM/VFM alternative circuit

L : 180kHz, with a PWM/VFM alternative circuit (Under Development)

M : 180kHz, without a PWM/VFM alternative circuit

■

■■

■ PIN CONFIGURATION

● SOT-23-5

13

V

OUT

CE GND (VFB)

(mark side)

54

2

VIN EXT

■ PIN DESCRIPTION

Pin No. Symbol Description

1 CE Chip Enable Pin (Active with “H”)

2 GND Ground Pin

3V

OUT /(VFB) Pin for Monitoring Output Voltage(Feedback Voltage)

4 EXT External Transistor Drive Pin(CMOS Output)

5V

IN Power Supply Pin

12345

Rev. 1.10 - 4 -

■

■■

■ ABSOLUTE MAXIMUM RATINGS

(GND=0V)

Symbol Item Rating Unit

VIN V

IN Supply Voltage 20 V

VEXT EXT Pin Output Voltage -0.3∼VIN+0.3 V

VCE CE Pin Input Voltage -0.3∼VIN+0.3 V

VOUT/(VFB) V

OUT/VFB Pin Input Voltage -0.3∼VIN+0.3 V

IEXT EXT Pin Inductor Drive Output Current ±50 mA

PD Power Dissipation 250 mW

Topt Operating Temperature Range -40∼+85 °C

Tstg Storage Temperature Range -55∼+125 °C

■

■■

■ ELECTRICAL CHARACTERISTICS

●R1224Nxx2X (X=E/F/G/H/L/M) except R1224N102X (Topt=25°C)

Symbol Item Conditions MIN. TYP. MAX. Unit

VIN Operating Input Voltage 2.3 18.5 V

VOUT Step-down Output Voltage VIN=VCE=VSET+1.5V, IOUT=-100mA

When VSET≤1.5V, VIN=VCE=3.0V

VSET×

0.98

VSET VSET×

1.02

V

∆VOUT/

∆T

Step-down Output Voltage

Temperature Coefficient

-40°C ≤ Topt ≤ 85°C±100 ppm

/°C

fosc Oscillator Frequency VIN=VCE=VSET+1.5V, IOUT=-100mA

When VSET≤1.5, VIN=VCE=3.0V

L/M version

E/G version

F/H version

144

240

400

180

300

500

216

360

600

kHz

∆fOSC/

∆T

Oscillator Frequency

Temperature Coefficient

-40°C ≤ Topt ≤ 85°C±0.2 %

/°C

IDD1 Supply Current1 VIN=VCE=VOUT=18.5V

E/F/L/M version

G version

H version

20

30

40

50

60

80

µA

Istb Standby Current VIN=18.5V, VCE=0V, VOUT=0V 0.0 0.5 µA

IEXTH EXT "H" Output Current VIN=8V,VEXT=7.9V,VOUT=8V,VCE=8V -17 -10 mA

IEXTL EXT "L" Output Current VIN=8V,VEXT=0.1V,VOUT=0V,VCE=8V 20 30 mA

ICEH CE "H" Input Current VIN=VCE=VOUT=18.5V 0.0 0.5 µA

ICEL CE "L" Input Current VIN= VOUT=18.5V, VCE=0V -0.5 0.0 µA

VCEH CE "H" Input Voltage VIN=8V,VOUT=0V 1.5 V

VCEL CE "L" Input Voltage VIN=8V,VOUT=0V 0.3 V

Maxdty Oscillator Maximum Duty Cycle 100 %

VFMdty VFM Duty Cycle E/F/L version 35 %

VUVLO1 UVLO Voltage VIN=VCE=2.5V to 1.5V, VOUT=0V 1.8 2.0 2.2 V

VUVLO2 UVLO Release Voltage VIN=VCE=1.5V to 2.5V, VOUT=0V VUVLO1

+0.1

2.3 V

Tstart Delay Time by Soft-Start function VIN=VSET+1.5V, IOUT=-10mA

VCE=0V->VSET+1.5V

51020ms

Tprot Delay Time for protection circuit VIN=VCE=VSET+1.5V

VOUT=VSET+1.5V->0V

51530ms

12345

Rev. 1.10 - 5 -

●R1224N102X (X=G/H/M) (Topt=25°C)

Symbol Item Conditions MIN. TYP. MAX. Unit

VIN Operating Input Voltage 2.3 18.5 V

VFB Feedback Voltage VIN=VCE=3.5V, IFB=-100mA 0.98 1.00 1.02 V

∆VFB/

∆T

Feedback Voltage

Temperature Coefficient

-40°C ≤ Topt ≤ 85°C±100 ppm

/°C

fosc Oscillator Frequency VIN=VCE=3.5V, IFB=-100mA

M version

G version

H version

144

240

400

180

300

500

216

360

600

kHz

∆fOSC/

∆T

Oscillator Frequency

Temperature Coefficient

-40°C ≤ Topt ≤ 85°C±0.2 %

/°C

IDD1 Supply Current1 VIN=VCE=VFB=18.5V

M version

G version

H version

20

30

40

50

60

80

µA

Istb Standby Current VIN=18.5V, VCE=0V, VFB=0V 0.0 0.5 µA

IEXTH EXT "H" Output Current VIN=8V,VEXT=7.9V,VFB=8V,VCE=8V -17 mA

IEXTL EXT "L" Output Current VIN=8V,VEXT=0.1V,VFB=0V,VCE=8V 30 mA

ICEH CE "H" Input Current VIN=VCE=VFB=18.5V 0.0 0.5 µA

ICEL CE "L" Input Current VIN= VFB=18.5V, VCE=0V -0.5 0.0 µA

VCEH CE "H" Input Voltage VIN=8V,VFB=0V 1.5 V

VCEL CE "L" Input Voltage VIN=8V,VFB=0V 0.3 V

Maxdty Oscillator Maximum Duty Cycle 100 %

VUVLO1 UVLO Voltage VIN=VCE=2.5V to 1.5V, VFB=0V 1.8 2.0 2.2 V

VUVLO2 UVLO Release Voltage VIN=VCE=1.5V to 2.5V, VFB=0V VUVLO1

+0.1

2.3 V

Tstart Delay Time by Soft-Start function VIN=2.5V, IFB=-10mA

VCE=0V->2.5V

51020ms

Tprot Delay Time for protection circuit VIN=VCE=2.5V

VFB=2.5V->0V

51530ms

■

■■

■ TYPICAL APPLICATION AND APPLICATION HINTS

(1) Fixed Output Voltage Type (R1224Nxx2E/F/G/H/L/M except xx=10)

C3

C2

L

C1

R1

SD

VOUT

VIN

CE

CE CONTROL

LOAD

EXT

GND

PMOS

PMOS: HAT1044M (Hitachi) L: CR105-270MC (Sumida, 27µH)

SD1: RB063L-30 (Rohm) C3: 47µF (Tantalum Type)

C1: 10

µF (Ceramic Type) C2: 0.1µF (Ceramic Type)

R1: 10

Ω

12345

Rev. 1.10 - 6 -

(2) Adjustable Output Type (R1224N102G/H/M) Example: Output Voltage=3.2V

C3

C2

L

C1

R1

SD

VFB

VIN

CE

CE CONTROL

LOAD

EXT

GND

C4

R2

R4

R3

PMOS

PMOS: HAT1044M (Hitachi) L: CR105-270MC (Sumida, 27µH)

SD1: RB063L-30 (Rohm) C3: 47µF (Tantalum Type)

C1: 10µF (Ceramic Type) C2: 0.1µF (Ceramic Type) C4: 1000pF(Ceramic Type)

R1: 10Ω, R2=22kΩ, R3=2.7kΩ, R4=33kΩ

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 more than the voltage level 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 capacitor should be connected to VOUT pin with the minimum connection. Make sufficient

ground and reinforce supplying. A large switching current could flow through the connection of power supply, an

inductor and the connection of VOUT. 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 may cause unstable operation of the IC.

● Protection circuit may work if the maximum duty cycle continue for the time defined in the electrical characteristics.

Once after stopping the output voltage, output will restart with soft-start operation. If the difference between input

voltage and output voltage is small, the protection 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 rating at the maximum loading.

Use an inductor with appropriate inductance.

● Use a diode of a Schottky type with high switching speed, and also pay attention to its current capacity.

● Do not use this IC under the condition with 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 R1225N 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, frequency might be decreased, and oscillation waveform might be unstable. These phenomena

12345

Rev. 1.10 - 7 -

are the typical characteristics of the IC with PWM/VFM alternative circuit.

✰ The performance of power source circuits using these ICs extremely depends upon the 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 voltage, current, and power of each component, PCB patterns and the IC do not exceed their

respected rated values.

■ How to Adjust Output Voltage and about Phase Compensation

As for Adjustable Output type, feedback pin (VFB) voltage is controlled to maintain 1.0V.

Output Voltage, VOUT is as following equation:

VOUT: R2+R4=VFB: R2

V

OUT=VFB×(R2+R4)/R2

Thus, with changing the value of R2 and R4, output voltage can be set in the specified range.

In the DC/DC converter, with the load current and external components such as L and C, phase might be behind 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.

Fpole ∼1/2π√L×C3

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 off frequency of the pole is approximately 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 feedback of the noise to VFB pin, about 2.7kΩ is appropriate value.

C3

C2

L

C1

R1

SD

VFB

VIN

CE

CE CONTROL

LOAD

EXT

GND

C4

R2

R4

R3

PMOS

12345

Rev. 1.10 - 8 -

■ OPERATION of step-down DC/DC converter and Output Current

The step-down DC/DC converter charges energy in the inductor when Lx transistor is ON, and discharges 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 Circuits> <Current through L>

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 reach ILmax. in proportion to the 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, next cycle starts before IL becomes to 0 because 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, which 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 current 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

referred to as the discontinuous mode and the latter mode is referred to as continuous mode.

In the continuous mode, when Equation 1 is solved for ton and assumed that the solution is tonc,

tonc=T×VOUT/VIN⋅⋅⋅ Equation 2

When ton<tonc, the mode is the discontinuous mode, and when ton=tonc, the mode is the continuous mode.

■ OUTPUT CURRENT AND SELECTION OF EXTERNAL COMPONENTS

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.)

SD

L

CL

VOUT

IOUT

VIN Lx Tr

i1

i2

T=1/fosc

toffton

ILmax

ILmin topen

12345

Rev. 1.10 - 9 -

V

IN=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, ton/(toff+ton)=DON,

D

ON=(VOUT+VF+RL×IOUT)/(VIN+VF-Rp×IOUT)⋅⋅⋅Equation 5

Ripple Current is as follows;

I

RP=(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 calculation in an ideal case in continuous mode.

■ 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 current is definite, the smaller value 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 rating should be more than VIN and current rating should be equal or more than ILmax.

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 MOSFET is required for this IC.

Its breakdown voltage between gate and source should be a few V higher 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 mainly necessary for your application, choose a MOSFET with low gate capacity for good

efficiency.

Maximum continuous drain current of MOSFET should be larger than peak current, ILmax.

12345

Rev. 1.10 - 10 -

■ TEST CIRCUITS

A) Output Voltage, Oscillator Frequency, CE”H” Input Voltage, CE”L” Input Voltage, Soft-start time

EXT

GND

VOUT

(VFB)

VIN

CE

PMOS

L1

+

-

C1 +

-

C2

D1

Oscilloscope

V

B) Supply Current1 C) Standby Current

EXT

GND

VOUT

(VFB)

VIN

CE

A

EXT

GND

VOUT

(VFB)

VIN

CE

A

D) EXT “H” Output Current E) EXT “L” Output Current

EXT

GND

VOUT

(VFB)

VIN

CE

A

EXT

GND

VOUT

(VFB)

VIN

CE

A

F) CE “H” Input Current, CE “L” Input Current G) Output Delay Time for Protection Circuit

EXT

GND

VOUT

(VFB)

VIN

CE A

Oscilloscope

EXT

GND

VOUT

(VFB)

VIN

CE

+

-

C2

PMOS: HAT1044M (Hitachi) L: CD104-270MC (Sumida, 27µH)

SD1: RB491D (Rohm)

C1: 47µF (Tantalum Type) C2: 47µF (Tantalum Type)

12345

Rev. 1.10 - 11 -

■ TYPICAL CHARACTERISTICS

1) Output Voltage vs. Output Current (*Note)

R1224N332G(VIN=10V)

3.30

3.31

3.32

3.33

3.34

3.35

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Output Voltage VOUT(V)

R1224N332G(VIN=16V)

3.30

3.31

3.32

3.33

3.34

3.35

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Output Voltage VOUT(V)

R1224N502G(VIN=10V)

5.00

5.01

5.02

5.03

5.04

5.05

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Output Voltage VOUT(V)

12345

Rev. 1.10 - 12 -

R1224N502G(VIN=16V)

5.00

5.01

5.02

5.03

5.04

5.05

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Output Voltage VOUT(V)

R1224N332M(VIN=5V)

3.30

3.31

3.32

3.33

3.34

3.35

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Output Current IOUT(A)

Output Voltage VOUT(V)

R1224N332M(VIN=10V)

3.30

3.31

3.32

3.33

3.34

3.35

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Output Current IOUT(A)

Output Voltage VOUT(V)

12345

Rev. 1.10 - 13 -

R1224N332M(VIN=18V)

3.30

3.31

3.32

3.33

3.34

3.35

01234

Output Current IOUT(A)

Output Voltage VOUT(V)

2) Efficiency vs. Output Current (*Note)

R1224N332G(VIN=10V)

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Efficiency (%)

R1224N332G(VIN=16V)

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Efficiency (%)

12345

Rev. 1.10 - 14 -

R1224N502G(VIN=10V)

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Efficiency (%)

R1224N502G(VIN=16V)

0

10

20

30

40

50

60

70

80

90

100

0.1 1 10 100 1000 10000

Output Current IOUT(mA)

Efficiency (%)

R1224N332M(VIN=5V)

80

82

84

86

88

90

92

94

96

98

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Output Current IOUT(A)

Efficiency (%)

12345

Rev. 1.10 - 15 -

R1224N332M(VIN=10V)

80

82

84

86

88

90

92

94

96

98

100

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Output Current IOUT(A)

Efficiency (%)

R1224N332M(VIN=18V)

80

82

84

86

88

90

92

94

96

98

100

01234

Output Current IOUT(A)

Efficiency (%)

*Note: Typical characteristics 9), 10) are obtained with using the following components;

PMOS: IRF7406 (IR)

L: CDRH127-100MC (Sumida: 10µ

µµ

µH) C2: 0.1µ

µµ

µF (Ceramic Type)

SD: RB083L-20 (Rohm) C3: 10SA220(Sanyo/OS-con: 220µ

µµ

µF/10V)

C1: 25SC47(Sanyo/OS-con: 47µ

µµ

µF/25V)×

××

×2 R1: 10Ω

ΩΩ

Ω

3) Ripple Voltage vs. Output Current

4) Oscillator Frequency vs. Input Voltage

5) Output Voltage vs. Input Voltage

12345

Rev. 1.10 - 16 -

6) Output Voltage vs. Temperature

R1224N332E

3.27

3.28

3.29

3.30

3.31

3.32

3.33

-40 -20 0 20 40 60 80

Temperature Topt

Output Voltage VOUT(V)

R1224N122F

1.190

1.195

1.200

1.205

1.210

-40-200 20406080

Temperature Topt

Output Voltage VOUT(V)

R1224N602L

5.90

5.95

6.00

6.05

6.10

-40-200 20406080

Temperature Topt

Output Voltage VOUT(V)

(°C)

(°C)

(°C)

12345

Rev. 1.10 - 17 -

R1224N102G

0.990

0.995

1.000

1.005

1.010

-40-200 20406080

Temperature Topt

Output Voltage VOUT(V)

7) Oscillator Frequency vs. Temperature

R1224N102G

240

270

300

330

360

-40-200 20406080

Temperature Topt

Oscillator Frequency fosc (kHz)

R1224N102H

400

450

500

550

600

-40 -20 0 20 40 60 80

Temperature Topt

Oscillator Frequency fosc(kHz)

(°C)

(°C)

(°C)

12345

Rev. 1.10 - 18 -

R1224N102M

144

162

180

198

216

-40 -20 0 20 40 60 80

Temperature Topt

Oscillator Frequency fosc(kHz)

8) Supply Current vs. Temperature

R1224N332E

0

5

10

15

20

25

-40-200 20406080

Temperature Topt

Supply Current1 Iss1(uA)

R1224N602L

0

5

10

15

20

25

-40 -20 0 20 40 60 80

Temperature Topt

Supply Current1 Iss1(uA)

(°C)

(°C)

(°C)

12345

Rev. 1.10 - 19 -

R1224N602F

0

5

10

15

20

25

-40-20 0 20406080

Temperature Topt

Supply Current1 Iss1(uA)

R1224N102G

0

10

20

30

40

-40-200 20406080

Temperature Topt

Supply Current1 Iss1(uA)

R1224N102H

0

10

20

30

40

50

60

-40-20 0 20406080

Temperature Topt

Supply Current1 Iss1(uA)

(°C)

(°C)

(°C)

12345

Rev. 1.10 - 20 -

R1224N102M

0

10

20

30

40

-40 -20 0 20 40 60 80

Temperature Topt

Supply Current1 Iss1(uA)

9) Soft-start time vs. Temperature

R1224N102G

5

10

15

-40-200 20406080

Temperature Topt

Soft-start time Tsoft(ms)

10) Delay Time for Protection vs. Temperature

R1224N332E

10

15

20

25

30

-40-200 20406080

Temperature Topt

Delay Time for Protection Tprot(ms)

(°C)

(°C)

(°C)

12345

Rev. 1.10 - 21 -

11) EXT "H" Output Current vs. Temperature

R1224N332E

-25

-20

-15

-10

-40 -20 0 20 40 60 80

Temperature Topt

EXT "Ｈ

ＨＨ

Ｈ" Output Current IEXTH(mA)

12) EXT"L" Output Current vs. Temperature

R1224N332E

20

30

40

50

-40 -20 0 20 40 60 80

Temperature Topt

EXT ”L” Output Current IEXTL(mA)

13) Load Transient Response

14) Turn-on Waveform

(°C)

(°C)

12345

Rev. 1.10 - 22 -

15) UVLO Voltage vs. Temperature

R1224N332E

1.90

1.95

2.00

2.05

2.10

2.15

2.20

-40-200 20406080

Temperature Topt

UVLO Voltage VUVLO(Ｖ

ＶＶ

Ｖ)