R1215D SERIES
STEP-UP DC/DC CONTOLLER
NO.EA-134-0604
OUTLINE
The R1215D Series are CMOS-based PWM step-up DC/DC converter controllers with low supply current.
Each of the R1215D Series consists of an oscillator, a PWM comparator circuit, a reference voltage unit, an
error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low
ripple, high efficiency step-up DC/DC converter can be composed of this IC with some external components, or
an inductor, a diode, a power MOSFET, resisters, and capacitors.
Maximum duty cycle and the soft start time are easily adjustable with external resistors and capacitors. As for
the protection circuit, after the soft-starting time, if the maximum duty cycle is continued for a certain period, the
R1215D Series latch the external driver with its off state, or the latch-type protection circuit works.
The delay time for latch the state can be set with an external capacitor.
To release the protection circuit, restart with power-on (Voltage supplier is equal or less than UVLO detector
threshold level).
FEATURES
•
•
•
•
•
•
•
•
Input Voltage Range ....................................................... 1.8V to 5.5V
Two Options of Basic Oscillator Frequency .................... Typ.700kHz, 1.4MHz
Built-in Latch-type Protection Function (Output Delay Time can be set with an external capacitor)
Maximum Duty Cycle/Soft-start time ............................. Adjustable with external capacitors
High Reference Voltage Accuracy .................................. ±1.5%
UVLO Threshold level..................................................... Typ.1.6V/1.79V by mask option
Small Temperature Coefficient of Reference Voltage ... Typ.±150ppm/°C
Package .......................................................................... SON-8 ( t = Max. 0.9mm )
APPLICATIONS
• Constant Voltage Power Source for portable equipment.
• Constant Voltage Power Source for LCD and CCD.
1
R1215D
BLOCK DIAGRAM
VIN
Internal VR
VREFOUT
VREFOUT
UVLO
Oscillator
EXT
DTC
PWM Comp
Latch
VREF
VFB
Er.Amp
AMPOUT
GND
DELAY
SELECTION GUIDE
In the R1215D Series, the oscillator frequency and UVLO detector threshold can be selected at the user's
request.
The selection can be made with designating the part number as shown below;
R1215D002x-TR-x ←Part Number
↑
a
Code
a
b
2
↑
b
Contents
Desiguation of Oscillator Frequency and Detector Threshold
A: Oscillator Frequency Typ. 700kHz, UVLO Detector Threshold Typ. 1.79V
B: Oscillator Frequency Typ. 1.4MHz, UVLO Detector Threshold Typ. 1.79V
E: Oscillator Frequency Typ. 700kHz, UVLO Detector Threshold Typ. 1.60V
F: Oscillator Frequency Typ. 1.4MHz, UVLO Detector Threshold Typ. 1.60V
Desiguation of composition of pin plating
-F: Lead free plating
R1215D
PIN CONFIGURATION
SON-8
Top View
8
7
Bottom View
6 5
5
∗
1
2
6
7
8
∗
3 4
∗
4
3
2
1
PIN DESCRIPTION
Pin No
1
2
3
Symbol
EXT
GND
DTC
4
DELAY
5
6
7
8
VFB
VREFOUT
AMPOUT
VIN
Description
External FET Drive Pin (CMOS Output)
Ground Pin
Pin for Setting Maximum Duty Cycle and Soft start time
Pin for External Capacitor
(for Setting Output Delay of Protection)
Feedback Pin for monitoring Output Voltage
Reference Voltage Output Pin
Amplifier Output Pin
Power Supply Pin for the IC
∗ Tab in the
parts have GND level. (They are connected to the reverse side of this IC.)
Do not connect to other wires or land patterns.
ABSOLUTE MAXIMUM RATINGS
(GND=0V)
Symbol
VIN
Item
VIN Pin Voltage
Rating
6.5
Unit
V
VEXT
EXT Pin Output Voltage
−0.3 to VIN+0.3
V
VDLY
DELAY Pin Voltage
−0.3 to VIN+0.3
V
VREFOUT Pin Voltage
−0.3 to VIN+0.3
V
VAMP
AMPOUT Pin Voltage
−0.3 to VIN+0.3
V
VDTC
DTC Pin Voltage
−0.3 to VIN+0.3
V
VFB
VFB Pin Voltage
−0.3 to VIN+0.3
V
IAMP
AMPOUT Pin Current
mA
IROUT
VREFOUT Pin Current
±10
30
IEXT
EXT Pin Inductor Drive Output Current
PD
Power Dissipation
VREFOUT
mA
±80
480
mW
mA
Topt
Operating Temperature Range
−40 to +85
°C
Tstg
Storage Temperature Range
−55 to +125
°C
∗1 For Power Dissipation, please refer to PACKAGE INFORMATION to be described.
3
R1215D
ELECTRICAL CHARACTERISTICS
•
Symbol
Item
Conditions
Min.
Typ.
Unit
5.5
V
Operating Input Voltage
VFB
VFB Voltage Tolerance
VIN=2.5V
VFB Voltage Line Regulation
VIN: from 2.0V to 5.5V
VFB Voltage Temperature
Coefficient
−40°C
IFB
VFB Input Current
VIN=5.5V, VFB=0V or 5.5V
AV
Open Loop Voltage Gain
VIN=2.5V
100
dB
fT
Unity Gain Frequency Band
VIN=2.5V, AV=0
1.0
MHz
Oscillator Frequency
VIN=2.5V, VDLY=VFB=0V
Oscillator Frequency Line
Regulation
VIN: from 2.0V to 5.5V
Oscillator Frequency
Temperature Coefficient
−40°C <
=
∆VFB/∆Topt
fosc
∆fosc/∆VIN
2.0
Max.
VIN
∆VFB/∆VIN
<
=
Topt
<
=
0.985 1.000 1.015
V
3
mV
±150
ppm/
°C
85°C
−0.1
595
0
700
0.1
805
µA
kHz
50
kHz
85°C
±0.3
kHz/
°C
Supply Current 1
VIN=5.5V, VDLY=VFB=0V
600
VREFOUT Voltage
VIN=2.5V,IROUT=1mA
VREFOUT Maximum Output
Current
VIN=2.5V
∆VREFOUT/
∆VIN
VREFOUT Line Regulation
VIN: from 2.0V to 5.5V
5
10
mV
∆VREFOUT/
∆IROUT
VREFOUT Load Regulation
VIN=2.5V,
IROUT: from 0.1mA to 5.0mA
6
20
mV
VREFOUT Short Current Limit
VIN=2.5V, VREFOUT=0V
15
mA
VREFOUT Voltage Temperature
Coefficient
−40°C <
=
±150
ppm/
°C
REXTH
EXT "H" ON Resistance
VIN=2.5V, IEXT=−50mA
2.8
6.0
Ω
REXTL
EXT "L" ON Resistance
VIN=2.5V, IEXT=50mA
1.8
4.0
Ω
tr
EXT Rising Time
VIN=2.5V, CEXT=1000pF
12
ns
tf
EXT Falling Time
VIN=2.5V, CEXT=1000pF
8
ns
IDLY1
DELAY Pin Charge Current
VIN=2.5V, VDLY=VFB=0V
3.0
6.0
8.5
µA
IDLY2
DELAY Pin Discharge Current
VIN=VFB=2.0V, VDLY=0.1V
0.08
0.20
0.36
mA
0.95
1.00
1.05
V
1.79
1.88
V
∆fosc/∆Topt
IDD1
VREFOUT
IOUT
ILIM
∆VREFOUT/
∆Topt
VDLY
4
Topt=25°C
R1215D002A
Topt
<
=
1000
µA
1.280 1.300 1.320
V
10
Topt
<
=
85°C
DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V
mA
VUVLO1
UVLO Detector Threshold
VIN=2.5V to 0V, VDLY=VFB=0V
1.70
VUVLO2
UVLO Released Voltage
VIN=0V to 2.5V, VDLY=VFB=0V
1.78
1.88
1.98
V
VHYS
UVLO Hysteresis Range
0.04
0.09
0.14
V
VDTC0
Duty=0% DTC Pin Voltage
VIN=2.5V
0.28
0.38
0.48
V
VDTC20
Duty=20% DTC Pin Voltage
VIN=2.5V
0.48
V
VDTC80
Duty=80% DTC Pin Voltage
VIN=2.5V
0.92
V
VDTC100
Duty=100% DTC Pin Voltage
VIN=2.5V
0.92
1.02
1.12
V
IAMPH
AMP "H" Output Current
VIN=2.5V, VAMP=1.0V, VFB=0.9V
1.6
3.2
5.8
mA
IAMPL
AMP "L" Output Current
VIN=2.5V, VAMP=1.0V, VFB=1.1V
40
85
130
µA
R1215D
•
Topt=25°C
R1215D002B
Symbol
Item
Conditions
Min.
Typ.
VIN
Operating Input Voltage
VFB Voltage Tolerance
VIN=2.5V
VFB Voltage Line Regulation
VIN: from 2.0V to 5.5V
VFB Voltage Temperature
Coefficient
−40°C
IFB
VFB Input Current
VIN=5.5V, VFB=0V or 5.5V
AV
Open Loop Voltage Gain
VIN=2.5V
100
dB
fT
Unity Gain Frequency Band
VIN=2.5V, AV=0
1.0
MHz
Oscillator Frequency
VIN=2.5V, VDLY=VFB=0V
Oscillator Frequency Line
Regulation
VIN: from 2.0V to 5.5V
100
kHz
Oscillator Frequency
Temperature Coefficient
−40°C <
=
±0.6
kHz/
°C
∆VFB/∆Topt
fosc
∆fosc/∆VIN
∆fosc/∆Topt
<
=
Topt
Topt
<
=
<
=
5.5
Unit
VFB
∆VFB/∆VIN
2.0
Max.
V
0.985 1.000 1.015
V
3
mV
±150
ppm/
°C
85°C
−0.1
0
0.1
µA
1.190 1.400 1.610 MHz
85°C
Supply Current 1
VIN=5.5V, VDLY=VFB=0V
VREFOUT Voltage
VIN=2.5V,IROUT=1mA
VREFOUT Maximum Output
Current
VIN=2.5V
∆VREFOUT/
∆VIN
VREFOUT Line Regulation
VIN: from 2.0V to 5.5V
5
10
mV
∆VREFOUT/
∆IROUT
VREFOUT Load Regulation
VIN=2.5V,
IROUT: from 0.1mA to 5.0mA
6
20
mV
VREFOUT Short Current Limit
VIN=2.5V, VREFOUT=0V
15
mA
VREFOUT Voltage Temperature
Coefficient
−40°C <
=
±150
ppm/
°C
EXT "H" ON Resistance
VIN=2.5V, IEXT=−50mA
2.8
6.0
4.0
IDD1
VREFOUT
IOUT
ILIM
∆VREFOUT/
∆Topt
REXTH
1800
µA
1.280 1.300 1.320
900
V
10
Topt
<
=
85°C
mA
Ω
EXT "L" ON Resistance
VIN=2.5V, IEXT=50mA
1.8
tr
EXT Rising Time
VIN=2.5V, CEXT=1000pF
12
ns
tf
EXT Falling Time
VIN=2.5V, CEXT=1000pF
8
ns
IDLY1
DELAY Pin Charge Current
VIN=2.5V, VDLY=VFB=0V
3.0
6.0
8.5
µA
IDLY2
DELAY Pin Discharge Current
VIN=VFB=2.0V, VDLY=0.1V
0.08
0.20
0.36
mA
VDLY
DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V
0.95
1.00
1.05
V
REXTL
Ω
VUVLO1
UVLO Detector Threshold
VIN=2.5V to 0V, VDLY=VFB=0V
1.70
1.79
1.88
V
VUVLO2
UVLO Released Voltage
VIN=0V to 2.5V, VDLY=VFB=0V
1.78
1.88
1.98
V
0.04
0.09
0.14
V
0.28
0.38
0.48
V
VHYS
UVLO Hysteresis Range
VDTC0
Duty=0% DTC Pin Voltage
VIN=2.5V
VDTC20
Duty=20% DTC Pin Voltage
VIN=2.5V
0.47
V
VDTC80
Duty=80% DTC Pin Voltage
VIN=2.5V
0.93
V
VDTC100
Duty=100% DTC Pin Voltage
VIN=2.5V
0.92
1.02
1.12
V
IAMPH
AMP "H" Output Current
VIN=2.5V, VAMP=1.0V, VFB=0.9V
1.6
3.2
5.8
mA
IAMPL
AMP "L" Output Current
VIN=2.5V, VAMP=1.0V, VFB=1.1V
40
85
130
µA
5
R1215D
•
Symbol
Item
Conditions
Min.
Typ.
Operating Input Voltage
VFB Voltage Tolerance
VIN=2.5V
VFB Voltage Line Regulation
VIN: from 1.8 V to 5.5V
VFB Voltage Temperature
Coefficient
−40°C
IFB
VFB Input Current
VIN=5.5V, VFB=0V or 5.5V
AV
Open Loop Voltage Gain
VIN=2.5V
100
dB
fT
Unity Gain Frequency Band
VIN=2.5V, AV=0
1.0
MHz
Oscillator Frequency
VIN=2.5V, VDLY=VFB=0V
Oscillator Frequency Line
Regulation
VIN: from 1.8V to 5.5V
Oscillator Frequency
Temperature Coefficient
−40°C <
=
fosc
∆fosc/∆VIN
∆fosc/∆Topt
<
=
Topt
Topt
<
=
<
=
5.5
Unit
VIN
∆VFB/∆Topt
1.8
Max.
VFB
∆VFB/∆VIN
V
0.985 1.000 1.015
V
3
mV
±150
ppm/
°C
85°C
−0.1
595
85°C
0
700
0.1
805
µA
kHz
50
kHz
±0.3
kHz/
°C
Supply Current 1
VIN=5.5V, VDLY=VFB=0V
VREFOUT Voltage
VIN=2.5V,IROUT=1mA
VREFOUT Maximum Output
Current
VIN=2.5V
∆VREFOUT/
∆VIN
VREFOUT Line Regulation
VIN: from 1.8V to 5.5V
5
10
mV
∆VREFOUT/
∆IROUT
VREFOUT Load Regulation
VIN=2.5V,
IROUT: from 0.1mA to 5.0mA
6
20
mV
VREFOUT Short Current Limit
VIN=2.5V, VREFOUT=0V
15
mA
VREFOUT Voltage Temperature
Coefficient
−40°C <
=
±150
ppm/
°C
EXT "H" ON Resistance
VIN=2.5V, IEXT=−50mA
2.8
6.0
4.0
IDD1
VREFOUT
IOUT
ILIM
∆VREFOUT/
∆Topt
REXTH
1000
µA
1.280 1.300 1.320
600
V
10
Topt
<
=
85°C
mA
Ω
EXT "L" ON Resistance
VIN=2.5V, IEXT=50mA
1.8
tr
EXT Rising Time
VIN=2.5V, CEXT=1000pF
12
ns
tf
EXT Falling Time
VIN=2.5V, CEXT=1000pF
8
ns
IDLY1
DELAY Pin Charge Current
VIN=2.5V, VDLY=VFB=0V
3.0
6.0
8.5
µA
IDLY2
DELAY Pin Discharge Current
VIN=VFB=1.8V, VDLY=0.1V
0.08
0.18
0.36
mA
VDLY
DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V
0.95
1.00
1.05
V
REXTL
6
Topt=25°C
R1215D002E
Ω
VUVLO1
UVLO Detector Threshold
VIN=2.5V to 0V, VDLY=VFB=0V
1.50
1.60
1.70
V
VUVLO2
UVLO Released Voltage
VIN=0V to 2.5V, VDLY=VFB=0V
1.56
1.67
1.78
V
0.03
0.07
0.11
V
0.28
0.38
0.48
V
VHYS
UVLO Hysteresis Range
VDTC0
Duty=0% DTC Pin Voltage
VIN=2.5V
VDTC20
Duty=20% DTC Pin Voltage
VIN=2.5V
0.48
V
VDTC80
Duty=80% DTC Pin Voltage
VIN=2.5V
0.92
V
VDTC100
Duty=100% DTC Pin Voltage
VIN=2.5V
0.92
1.02
1.12
V
IAMPH
AMP "H" Output Current
VIN=2.5V, VAMP=1.0V, VFB=0.9V
1.6
3.2
5.8
mA
IAMPL
AMP "L" Output Current
VIN=2.5V, VAMP=1.0V, VFB=1.1V
40
85
130
µA
R1215D
•
Topt=25°C
R1215D002F
Symbol
Item
Conditions
Min.
Typ.
VIN
Operating Input Voltage
VFB Voltage Tolerance
VIN=2.5V
VFB Voltage Line Regulation
VIN: from 1.8V to 5.5V
VFB Voltage Temperature
Coefficient
−40°C
IFB
VFB Input Current
VIN=5.5V, VFB=0V or 5.5V
AV
Open Loop Voltage Gain
VIN=2.5V
100
dB
fT
Unity Gain Frequency Band
VIN=2.5V, AV=0
1.0
MHz
Oscillator Frequency
VIN=2.5V, VDLY=VFB=0V
Oscillator Frequency Line
Regulation
VIN: from 1.8V to 5.5V
100
KHz
Oscillator Frequency
Temperature Coefficient
−40°C <
=
±0.6
KHz/
°C
∆VFB/∆Topt
fosc
∆fosc/∆VIN
∆fosc/∆Topt
<
=
Topt
Topt
<
=
<
=
5.5
Unit
VFB
∆VFB/∆VIN
1.8
Max.
V
0.985 1.000 1.015
V
3
mV
±150
ppm/
°C
85°C
−0.1
0
0.1
µA
1.190 1.400 1.610 MHz
85°C
Supply Current 1
VIN=5.5V, VDLY=VFB=0V
VREFOUT Voltage
VIN=2.5V,IROUT=1mA
VREFOUT Maximum Output
Current
VIN=2.5V
∆VREFOUT/
∆VIN
VREFOUT Line Regulation
VIN: from 1.8V to 5.5V
5
10
mV
∆VREFOUT/
∆IROUT
VREFOUT Load Regulation
VIN=2.5V,
IROUT: from 0.1mA to 5.0mA
6
20
mV
VREFOUT Short Current Limit
VIN=2.5V, VREFOUT=0V
15
mA
VREFOUT Voltage Temperature
Coefficient
−40°C <
=
±150
ppm/
°C
EXT "H" ON Resistance
VIN=2.5V, IEXT=−50mA
2.8
6.0
4.0
IDD1
VREFOUT
IOUT
ILIM
∆VREFOUT/
∆Topt
REXTH
1800
µA
1.280 1.300 1.320
900
V
10
Topt
<
=
85°C
mA
Ω
EXT "L" ON Resistance
VIN=2.5V, IEXT=50mA
1.8
tr
EXT Rising Time
VIN=2.5V, CEXT=1000pF
12
ns
tf
EXT Falling Time
VIN=2.5V, CEXT=1000pF
8
ns
IDLY1
DELAY Pin Charge Current
VIN=2.5V, VDLY=VFB=0V
3.0
6.0
8.5
µA
IDLY2
DELAY Pin Discharge Current
VIN=VFB=1.8V, VDLY=0.1V
0.08
0.18
0.36
mA
VDLY
DELAY Pin Detector Threshold VIN=2.5V, VFB=0V, VDLY=0V to 2V
0.95
1.00
1.05
V
REXTL
Ω
VUVLO1
UVLO Detector Threshold
VIN=2.5V to 0V, VDLY=VFB=0V
1.50
1.60
1.70
V
VUVLO2
UVLO Released Voltage
VIN=0V to 2.5V, VDLY=VFB=0V
1.56
1.67
1.78
V
0.03
0.07
0.11
V
0.28
0.38
0.48
V
VHYS
UVLO Hysteresis Range
VDTC0
Duty=0% DTC Pin Voltage
VIN=2.5V
VDTC20
Duty=20% DTC Pin Voltage
VIN=2.5V
0.47
V
VDTC80
Duty=80% DTC Pin Voltage
VIN=2.5V
0.93
V
VDTC100
Duty=100% DTC Pin Voltage
VIN=2.5V
0.92
1.02
1.12
V
IAMPH
AMP "H" Output Current
VIN=2.5V, VAMP=1.0V, VFB=0.9V
1.6
3.2
5.8
mA
IAMPL
AMP "L" Output Current
VIN=2.5V, VAMP=1.0V, VFB=1.1V
40
85
130
µA
7
R1215D
TYPICAL APPLICATIONS AND TECHNICAL NOTES
Inductor
Diode
VOUT
R3
C1
VIN
EXT
DELAY
VFB
NMOS
C4
R1
C3
C2
R2
GND AMPOUT
C5
C6
VREFOUT
R5
Inductor
R4
DTC
R6
C7
LDR655312T-100 (TDK)
NMOS
CPH6415 (Sanyo)
Diode
CRS02 (Toshiba)
C1
1.0µF
R1
160kΩ
C2
1.0µF
R2
20k Ω
C3
15µF
R3
1k Ω
C4
1000pF
R4
4.7k Ω
C5
2200pF
R5
68k Ω
C6
1.0µF
R6
240k Ω
C7
1.0µF
Use a 1µF or more capacitance value of bypass capacitor between VIN pin and GND, C1 as shown in the
typical application above. Connect the capacitor as short as possible to the IC.
• In terms of the capacitor for setting delay time of the latch protection, C2 is shown in typical application above.
Latch delay time depends on this C2 value. Refer to the Latch Protection Operation Timing Chart.
Set the C2 GND as close as possible to the IC GND.
• Connect a 1µF or more value of capacitor between VOUT and GND, C3 as shown in typical application above.
(10µF to 22µF is the capacitance recommendation range.) If the operation of the composed DC/DC converter
may be unstable, use a tantalum type capacitor instead of ceramic type
• Connect a capacitor between VREFOUT and GND, C6 as shown in typical application of the previous page.
The capacitance value of C6 is between 0.1µF and 1.0µF.
8
R1215D
•
Output Voltage Setting Method and Phase Compensation Making Method
• The feedback voltage is controlled into 1.0V. The output voltage can be set with divider resistors for voltage
setting, R1 and R2 as shown in typical application of the previous page. Refer to the next formula.
Output Voltage = VFB× (R1+R2)/R2
Output Voltage is adjustable with setting various resistor values combination.
R1+R2 should be equal or less than 500kΩ
As for the DC/DC converter, depending on the load current and external components such as L and C, phase
may loss around 180°. In such case, phase margin becomes less and may be unstable. To avoid this situation,
make the phase margin more. The pole is made with external components L and C.
Fpole∼1/{2×π× (L × C3 ) }
C4, C5, R3, and R4 shown in the diagram are for making phase compensation. The gain of the system can be
set with using these resistors and capacitors. Each value in the diagram is just an example.
R4 and C5 make zero (the backward phase).
Fzero∼1/(2×π×R4×C5)
Choose the R4 and C5 value so as to make the cutoff frequency of this zero point close to the cutoff frequency of
the pole by external components, L and C.
For example, supposed that L=10µH and COUT (C3) =15µF, the cutoff frequency of the pole is approximately
13kHz. Therefore make the cutoff frequency of the zero point close to 13kHz. Then R4=4.7kΩ and C5=2200pF
are appropriate values.
As for setting the gain, the ratio of the composite resistor (RT: RT=R1×R2/(R1+R2)) to R4 is the key.
If the R4 against the composite resistor, RT, is large, the gain becomes also large. If the gain is large, the
response characteristic is improved, however, too large gain makes the system be unstable.
If the spike noise of VOUT may be large, the spike noise may be picked into VFB pin, and the unstable operation
may result. In this case, a resistor R3, shown in typical application of the previous page. The recommended
resistance value of R3 is in the range from 1kΩ to 5kΩ. Then, noise level will be decreased.
Further, R1 and C4 makes another zero point (the backward phase).
Fzero∼1/(2×π×R1×C4)
Make the cutoff frequency of this zero point be lower than the cutoff frequency of the pole by external
components, or, L and C. Herein, R1=160kΩ and C4=1000pF are appropriate values.
• Select the Power MOSFET, the diode, capacitors and the inductor within ratings (Voltage, Current, Power) of
this IC. Choose the power MOSFET with low threshold voltage depending on the input voltage to be able to
turn on the FET completely. Choose the diode with low VF such as Shottky type with low reverse current IR,
and with fast switching speed. When an external transistor is switching, spike voltage may be generated
caused by an inductor, therefore recommended voltage tolerance of capacitor connected to VOUT is twice as
much as the setting voltage or more.
• The soft-start time and the maximum duty cycle setting method
The soft-start time and the maximum duty cycle can be set with R5, R6, and C7 values connected to the
VREFOUT pin and the DTC pin. (Refer to the timing chart: Soft-start operation.)
9
R1215D
Output Current and Selection of External Components
<Basic Circuit>
i2
Diode
Inductor
IOUT
VIN
VOUT
i1
CL
Lx Tr
GND
<Circuit through L>
Discontinuous Mode
IL
IL
Continuous Mode
ILxmax
ILxmax
ILxmin
ILxmin
tf
t
ton
toff
Iconst
ton
t=1/fosc
1/ton
t
toff
t=1/fosc
1/ton
There are two modes, or discontinuous mode and continuous mode for the PWM step-up switching regulator
depending on the continuous characteristic of inductor current.
During on time of the transistor, when the voltage added on to the inductor is described as VIN, the current is
VIN × t/L. Therefore, the electric power, PON, which is supplied with input side, can be described as in next
formula.
PON =
∫
ton
VIN 2 × t / L dt ...................................................................................................Formula 1
0
With the step-up circuit, electric power is supplied from power source also during off time. In this case, input
current is described as (VOUT − VIN) ×t/L, therefore electric power, POFF is described as in next formula.
POFF =
∫
tf
0
VIN × ( VOUT − VIN) × t / L dt .............................................................................Formula 2
In this formula, Tf means the time of which the energy saved in the inductance is being emitted. Thus average
electric power, or PAV is described as in the next formula.
PAV = 1 /( tON + tOFF ) × {
∫
ton
0
VIN2 × t / L dt +
∫
tf
0
VIN × ( VOUT − VIN) × t / L dt } ............................Formula 3
In PWM control, when tf = toff is true, the inductor current becomes continuos, then the operation of switching
regulator becomes continuous mode.
10
R1215D
In the continuous mode, the deviation of the current is equal between on time and off time.
VIN = tON / L = ( VOUT − VIN) × toff / L ................................................................................ Formula 4
Further, the electric power, PAV is equal to output electric power, VOUT × IOUT, thus,
IOUT = fOSC × VIN 2 × tON 2 /{2 × L × ( VOUT − VIN)} = VIN 2 × tON /( 2 × L × VOUT ) ....................... Formula 5
When IOUT becomes more than formula 5, the current flows through the inductor, then the mode becomes
continuous. The continuous current through the inductor is described as Iconst, then,
IOUT = fOSC × VIN 2 × tON 2 /{2 × L × ( VOUT − VIN)} + VIN × Iconst / VOUT ................................. Formula 6
In this moment, the peak current, ILxmax flowing through the inductor and the driver Tr. is described as
follows:
ILx max = Iconst + VIN × tON / L ...................................................................................... Formula 7
With the formula 4,6, and ILxmax is,
ILx max = VOUT / VIN × IOUT + VIN × tON /(2 × L ) ................................................................. Formula 8
Therefore, peak current is more than IOUT. Considering the value of ILxmax, the condition of input and output,
and external components should be selected.
In the formula 7, peak current ILxmax at discontinuous mode can be calculated. Put Iconst=0 in the formula.
The explanation above is based on the ideal calculation, and the loss caused by LX switch and external
components is not included. The actual maximum output current is between 50% and 80% of the calculation.
Especially, when the ILX is large, or VIN is low, the loss of VIN is generated with the on resistance of the switch. As
for VOUT, Vf (as much as 0.3V) of the diode should be considered.
11
R1215D
TIMING CHART
<Soft-start Operation>
The timing chart below describes the state of each pin from the power-on until the IC entering the stable
operation.
By raising the voltage of the DTC pin slowly, the switching duty cycle is limited, and prevent the drastic voltage
rising (over-shoot) and inrush current.
When the VIN voltage becomes equal or more than the UVLO released voltage (VUVLO+VHYS), VREFOUT operation
starts. Following with the increase of the voltage level of VREFOUT, the internal oscillator begins to operate, then
the DTC voltage is also rising, then, soft-start operation starts. When the DTC voltage crosses the chopping
wave level inside the IC, EXT pin starts switching, then, step-up operation begins. During this term, the output
voltage does not reach the set output voltage. Therefore the output of the amplifier is "H". Besides, the protection
circuit may work and the IC charges the DELAY pin. Because of this, the soft-start time should be set shorter
than the latch protection delay time.
After the initial stage, when the output voltage reaches the set output voltage, the level of AMPOUT becomes
the normal state. In other words, the level is determined with the input voltage, the output voltage, and the output
current. When the level of AMPOUT becomes falling, charging the DELAY pin stops and discharges to the GND.
The soft-start time (the time for the DTC pin voltage becoming to VDTC level) can be estimated with the next
formula.
t ≅1/α×ln(VDTC×α/β+1), herein, α=−1/C7×(1/R5+1/R6), and β=VREFOUT/(C7×R5).
VIN
(VUVLO+VHYS)
VREFOUT
OSC
DTC
AMPOUT
DELAY
Soft-start Time
EXT
VREFOUT
R5
DTC
R6
12
C7
R1215D
<Latch Protection Operation>
The operation of Latch protection circuit is as follows: When AMPOUT becomes "H" and the IC detects
maximum duty cycle, charge to an external capacitor, C2 of DELAY pin starts. The maximum duty cycle
continues and the voltage of DELAY pin reaches delay voltage detector threshold, VDLY, outputs "L" to EXT pin
and turns off the external power MOSFET.
To release the latch protection operation, make the supply voltage down to UVLO detector threshold or lower,
and make it rise up to the normal input voltage.
Once after becoming the maximum duty cycle, if the duty cycle decreases before latch operation works, the
charging the capacitor stops immediately, and the DELAY pin voltage is fixed at GND level with IDLY2.
The delay time of latch protection can be calculated with C2, VDLY, and the delay pin charge current, IDLY1, as in
the next formula.
t=C2 × VDLY/IDLY1
DELAY
Output Short
AMPOUT
VDLY
DTC
Normal
Maxduty Operation
Latched
EXT
IDLY1
DELAY
VDLY
C2
13
R1215D
TEST CIRCUITS
VIN
A
VIN
EXT
EXT
VREFOUT
VREFOUT
AMPOUT
AMPOUT
DTC
DTC
VFB
VFB
DELAY
GND
GND
Fig.1 Consumption Current Test Circuit
VIN
Fig.2 Oscillator Frequency, VFB Voltage,
Duty Cycle, EXT rising time/falling time Test Circuit
VIN
EXT
VREFOUT
AMPOUT
EXT
VREFOUT
A
AMPOUT
DTC
DTC
VFB
VFB
DELAY
GND
DELAY
Fig.3 AMP "L" Output Current/
"H" Output Current Test Circuit
GND
DELAY
A
Fig.4 DELAY Pin Charge Current/
Discharge Current Test Circuit
V
VIN
GND
EXT
EXT
VREFOUT
VREFOUT
AMPOUT
AMPOUT
DTC
DTC
VFB
VFB
DELAY
Fig.5 EXT "H" ON Resistance Test Circuit
14
VIN
GND
V
DELAY
Fig.6 EXT "L" ON Resistance Test Circuit
R1215D
VIN
GND
EXT
VIN
VREFOUT
VREFOUT
AMPOUT
AMPOUT
DTC
DTC
VFB
VFB
GND
DELAY
Fig.7 DELAY Pin Detector Threshold Test Circuit
VIN
EXT
Fig.8 UVLO Detector Threshold/Released
Voltage Test Circuit
VIN
EXT
VREFOUT
AMPOUT
AMPOUT
100kΩ
DTC
VFB
DELAY
VFB
10kΩ
Fig.9 Error AMP Gain/Phase Test Circuit
VIN
DELAY
VREFOUT
DTC
GND
EXT
GND
A
V
DELAY
Fig.10 VREFOUT Voltage Test Current
EXT
VREFOUT
AMPOUT
DTC
VFB
GND
DELAY
A
Fig.11 VFB Leakage Current Test Circuit
15
R1215D
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Output Current (Topt=25°C)
R1215D002E
VOUT=9V,Frequency=700kHz
9.2
1.8V
2.5V
5.5V
9.1
9.0
8.9
8.8
100
200
Output Current IOUT(mA)
1.8V
2.5V
5.5V
9.1
9.0
8.9
8.8
0
VOUT=9V,Frequency=1.4MHz
9.2
Output Voltage VIN(V)
Output Voltage VIN(V)
R1215D002F
300
0
100
200
Output Current IOUT(mA)
300
2) Efficiency vs. Output Current (Topt=25°C)
R1215D002E
VOUT=9V,Frequency=700kHz
80
1.8V
2.5V
5.5V
60
40
0
50
100 150 200 250
Output Current IOUT(mA)
VOUT=9V,Frequency=1.4MHz
100
Effciency η(%)
100
Effciency η(%)
R1215D002F
80
40
300
1.8V
2.5V
5.5V
60
0
50
100 150 200 250
Output Current IOUT(mA)
300
3) Supply Current vs. Temperature
R1215D002A/E
600
550
500
450
400
350
-40 -25
16
VIN=5.5V,Frequency=700kHz
900
Supply Current IDD(µA)
Supply Current IDD(µA)
650
R1215D002B/F
0
25
50
Temperature Topt(°C)
75 85
VIN=5.5V,Frequency=1.4MHz
850
800
750
700
650
600
-40 -25
0
25
50
Temperature Topt(°C)
75 85
R1215D
4) VFB Voltage vs. Temperature
5) VREFOUT Voltage vs. Temperature
R1215D002x
VIN=2.5V
1005
1000
995
990
985
980
-40 -25
0
25
50
Temperature Topt(°C)
VIN=2.5V
1.32
VREFOUT Voltage VREFOUT(V)
1010
VFB Voltage VFB(mV)
R1215D002x
1.31
1.30
1.29
1.28
-40 -25
75 85
0
25
50
Temperature Topt(°C)
75 85
6) Oscillator Frequency vs. Temperature
R1215D002B/F
VIN=2.5V
800
Oscillator Frequency fosc(kHz)
Oscillator Frequency fosc(kHz)
R1215D002A/E
750
700
650
600
-40 -25
0
25
50
Temperature Topt(°C)
75 85
VIN=2.5V
1600
1500
1400
1300
1200
-40 -25
0
25
50
Temperature Topt(°C)
75 85
7) UVLO Detector Threshold / Released Voltage vs. Temperature
R1215D002A/B
R1215D002E/F
1.69
UVLO Detector Threshold/
Released Voltage(V)
UVLO Detector Threshold/
Released Voltage(V)
1.90
1.88
1.86
Released Voltage
1.84
1.82
Detector Threshold
1.80
1.78
-40 -25
0
25
50
Temperature Topt(°C)
75 85
1.67
1.65
Released Voltage
1.63
1.61
Detector Threshold
1.59
1.57
-40 -25
0
25
50
Temperature Topt(°C)
75 85
17
R1215D
8) DELAY Pin Charge Current vs. Temperature
9) DELAY Pin Discharge Current vs. Temperature
R1215D002x
VIN=2.5V
6.5
6.0
5.5
5.0
4.5
-40 -25
0
25
50
Temperature Topt(°C)
75 85
10) DELAY Pin Detector Threshold vs. Temperature
DELAY Pin Discharge Current IDLY2(µA)
DELAY Pin Charge Current IDLY1(µA)
R1215D002x
VIN=1.8V
400
350
300
250
200
150
100
50
0
-40 -25
0
25
50
Temperature Topt(°C)
11) VREFOUT Voltage vs. VREFOUT Current
R1215D002x
VIN=2.5V
1.4
1.01
1.00
0.99
0.98
0.97
0.96
-40 -25
VIN=2.5V
1.6
VREFOUT Voltage(V)
DELAY Pin Detector Threshold VDLY(V)
R1215D002x
1.02
75 85
1.2
1.0
0.8
0.6
0.4
0.2
0
0
25
50
Temperature Topt(°C)
0
75 85
10
20
30
40
VREFOUT Current(mA)
50
12) Maximum Duty Cycle vs. DTC Pin Voltage (Topt=25°C)
R1215D002A/E
VIN=2.5V,Frequency=700kHz
80
60
40
20
0
300 400 500 600 700 800 900 1000 1100
DTC Pin Voltage VDTC(mV)
18
100
Maxduty Cycle(%)
Maxduty Cycle(%)
100
R1215D002B/F
VIN=2.5V,Frequency=1.4MHz
80
60
40
20
0
300 400 500 600 700 800 900 1000 1100
DTC Pin Voltage VDTC(mV)
R1215D
13) Error Amplifier Frequency Characteristics (Topt=25°C)
R1215D002X
VIN=2.5V
Gain(dB) / Phase(deg)
200
Error
Amplifier
150
Phase
100kΩ
100
1kΩ
Gain
50
0
-50
1
10
100
1000
Freguency f(kHz)
10000
14) Load Transient Response (VIN=2.5V,Topt=25°C)
Frequency=700kHz
Frequency=1.4MHz
9.1
240
9.1
240
9.0
200
9.0
200
8.9
160
VOUT
8.8
120
8.7
80
8.6
40
IOUT
0
8.5
8.4
Output Voltage VOUT(V)
9.2
Output Current IOUT(mA)
280
9.2
Output Voltage VOUT(V)
R1215D002B/F
-40
0
4
8
Time t (ms)
8.9
160
VOUT
8.8
280
120
80
8.7
8.6
40
IOUT
0
8.5
8.4
Output Current IOUT(mA)
R1215D002A/E
-40
12
0
4
8
Time t (ms)
12
15) Power On Response (VIN=2.5V,Topt=25°C,ROUT=150Ω)
R1215D002A/E
R1215D002B/F
10
Output Voltage VOUT(V)
Output Voltage VOUT(V)
10
8
6
4
2
0
8
6
4
2
0
0
5
15
Time t (ms)
25
0
5
15
Time t (ms)
25
19
PACKAGE INFORMATION
•
PE-SON-8-0510
SON-8
Unit: mm
PACKAGE DIMENSIONS
2.9±0.2
0.15 +0.1
−0.15
0.13±0.05
0.475TYP
1
0.23±0.1
0.2±0.1
5
0.2±0.1
2.8±0.2
3.0±0.2
8
0.15 +0.1
−0.15
4
Attention : Tab suspension leads in the
parts have VDD or GND level. (They are
connected to the reverse side of this IC.)
Refer to PIN DISCRIPTION.
Do not connect to other wires or land patterns.
0.9MAX.
0.13±0.05
Bottom View
0.1
0.65
0.3±0.1
0.1 M
TAPING SPECIFICATION
4.0±0.1
+0.1
φ1.5 0
2.0±0.05
3.3
4.0±0.1
2.0MAX.
∅1.1±0.1
TR
User Direction of Feed
TAPING REEL DIMENSIONS
(1reel=3000pcs)
2±0.5
0
∅ 180 −1.5
∅ 60 +1
0
21±0.8
∅13±0.2
11.4±1.0
9.0±0.3
8.0±0.3
3.2
3.5±0.05
1.75±0.1
0.2±0.1
PACKAGE INFORMATION
PE-SON-8-0510
POWER DISSIPATION (SON-8)
This specification is at mounted on board. Power Dissipation (PD) depends on conditions of mounting on board.
This specification is based on the measurement at the condition below:
Measurement Conditions
Standard Land Pattern
Environment
Mounting on Board (Wind velocity=0m/s)
Board Material
Glass cloth epoxy plactic (Double sided)
Board Dimensions
40mm × 40mm × 1.6mm
Copper Ratio
Top side : Approx. 50% , Back side : Approx. 50%
Through-hole
φ0.5mm × 44pcs
Measurement Result
(Topt=25°C,Tjmax=125°C)
Standard Land Pattern
Free Air
Power Dissipation
480mW
300mW
Thermal Resistance
θja=(125−25°C)/0.48W=208°C/W
333°C/W
On Board
480
500
400
40
Free Air
300
200
40
Power Dissipation PD(mW)
600
100
0
0
25
50
75 85 100
Ambient Temperature (°C)
125
150
Power Dissipation
Measurement Board Pattern
IC Mount Area (Unit : mm)
RECOMMENDED LAND PATTERN
0.65
0.65
1.15
0.35
(Unit: mm)
MARK INFORMATION
ME-R1215D-0603
R1215D SERIES MARK SPECIFICATION
• SON-8
to
1
1
•
2
3
4
5
6
5
,
4
6
Part Number vs. Product Code
Part Number
Product Code
2
3
4
R1215D002A
G 0
1
1
A
R1215D002B
G 0
2
B
R1215D002E
G 0
3
E
R1215D002F
G 0
4
F
: Product Code (refer to Part Number vs. Product Code)
: Lot Number