R1204x Series
Step-up DC/DC Converter with Shutdown Function
No. EA-284-200901
OUTLINE
The R1204x is a low supply current PWM step-up DC/DC converter. Internally, a single IC consists of an NMOS
FET, an oscillator, a PWM comparator, a voltage reference unit, an error amplifier, a current limit circuit, an
under voltage lockout circuit (UVLO), an over-voltage protection circuit (OVP), a soft-start circuit, a maximum
duty cycle limit circuit, and a thermal shutdown protection circuit. By simply using an inductor, a resistor,
capacitors and a diode as external components, a high-efficiency step-up DC/DC converter can be easily
configured. As protection functions, the IC contains a thermal shutdown protection circuit, a current limit circuit,
an OVP circuit, and an UVLO circuit. A thermal shutdown circuit detects overheating of the ICs and stops the
operation to protect it from damage. A current limit circuit limits the peak current of Lx, and an OVP circuit
detects the over voltage of output, and an UVLO circuit detects the low input voltage.
The R1204x provides the R1204xxxA/D/G/H versions, which are optimized for serial driving of white LEDs with
constant current, and the R1204xxxB/C/E/F versions, which are optimized for constant voltage driving. Among
the R1204xxxB/C/E/F versions, only the R1204xxxC/F versions are equipped with PWM/VFM auto-switching
controls. The LED current can be determined by the value of current setting resistor. The brightness of the
LEDs can be quickly adjusted by applying a PWM signal (200 Hz to 300 kHz) to the CE pin. The R1204x is
available in DFN(PLP)1820-6 and TSOT-23-6 packages.
FEATURES
Input Voltage Range.......................................... 2.3 V to 5.5 V
Supply Current .................................................. Typ. 800 µA
Standby Current ................................................ Max. 5 µA
Feedback Voltage ............................................. 0.2 V ±10 mV (R1204xxxxA/D)
0.4 V ±10 mV (R1204xxxxG/H)
V ±15 mV (R1204xxxxB/C/E/F)
Lx Current Limit Function .................................. Min. 700 mA
Over Voltage Protection .................................... 23 V, 33 V, 42 V
Oscillator Frequency ......................................... Typ. 1.0 MHz (R1204xxxxA/B/C/G)
Typ. 750 kHz (R1204xxxxD/E/F/H)
Maximum Duty Cycle ........................................ Min. 91% (R1204xxxxA/B/C/G)
Min. 92% (R1204xxxxD/E/F/H)
FET ON Resistance .......................................... Typ. 0.8 Ω
UVLO Function
Thermal Protection Function
LED Dimming Control for R1204xxxxA/D ......... by external PWM signal (200 Hz to 300 kHz frequency)
Packages .......................................................... DFN(PLP)1820-6, TSOT-23-6
Recommended Bypass Capacitor .................... 1.0 µF
APPLICATIONS
Constant voltage power source for hand-held equipment
OLED power supply for hand-held equipment
White LED driver for hand-held equipment
1
R1204x
No. EA-284-200901
SELECTION GUIDE
The package type, the OVP detector threshold, the feedback voltage and the PWM//VFM auto-switching
control are user- selectable options as described below.
Selection Guide
Product Name
R1204Kxy2z-TR
Package
Quantity per Reel
Pb Free
Halogen Free
DFN(PLP)1820-6
5,000 pcs
Yes
Yes
TSOT-23-6
3,000 pcs
Yes
Yes
R1204Nxy3z-TR-FE
x: OVP Detector Threshold
1: 23 V
2: 33 V
3: 42 V
y: Current Limit
1: Typ. 900 mA
z: Feedback Voltage, Oscillator Frequency, PWM/VFM Auto-Switching Control
2
z
Feedback Voltage
A
B
C
D
E
F
G
H
Typ. 0.2 V
Typ. 1 V
Typ. 1 V
Typ. 0.2 V
Typ. 1 V
Typ. 1 V
Typ. 0.4 V
Oscillator Frequency
Typ. 1 MHz
Typ. 750 kHz
Typ. 1 MHz
Typ. 750 kHz
PWM/VFM
Auto-Switching Control
No
No
Yes
No
No
Yes
No
R1204x
No. EA-284-200901
BLOCK DIAGRAMS
VFB
VIN
Lx
V OUT
UVLO
Err. Amp.
PWM Comp.
+
+
–
R
–
Q
S
vref
Oscillator
Soft-start
Slope Compensation
Driver
Control
OVP
EN
Thermal
Shutdow n
Shutdow n
delay
∑
CE
Current
sense
PWM
Control
Current
Limit
CE
R1204xxxxA/D/G/H Block Diagram
VFB
VIN
Lx
V OUT
UVLO
Err. Amp.
PWM Comp.
+
+
–
–
R
Q
S
vref
Oscillator
Soft-start
Slope Compensation
Driver
Control
OVP
Thermal
Shutdow n
∑
Current
sense
CE
Current
Limit
CE
GND
R1204xxxxB/E Block Diagram
3
R1204x
No. EA-284-200901
VFB
VIN
UVLO
Err. Amp.
PWM Comp.
+
+
–
–
CE
Lx
VFM Control
R
Q
S
vref
Oscillator
Soft-start
Slope Compensation
Driver
Control
OVP
Thermal
Shutdow n
Current
sense
∑
Current
Limit
CE
GND
R1204xxxxC/F Block Diagram
4
V OUT
R1204x
No. EA-284-200901
PIN DESCRIPTIONS
Top View
6
5
Bottom View
4
4
5
6
6
5
4
(mark side)
1
2
3
3
2
1
1
DFN(PLP)1820-6 Pin Configuration
DFN(PLP)1820-6 Pin Description
Pin No
Symbol
2
3
TSOT-23-6 Pin Configuration
Description
1
V OUT
Output Pin
2
LX
3
GND
4
V IN
Input Pin
5
CE
Chip Enable Pin, Active-high
6
V FB
Feedback Pin
Switching Pin, Open Drain Output
Ground Pin
The exposed tab is substrate level (GND). It is recommended that the exposed tab be connected to the ground plane on
the board or otherwise be left open.
TSOT-23-6 Pin Description
Pin No
Symbol
Description
1
LX
Switching Pin, Open Drain Output
2
GND
3
V FB
Feedback Pin
4
CE
Chip Enable Pin, Active-high
5
V OUT
6
V IN
Ground Pin
Output Pin
Input Pin
5
R1204x
No. EA-284-200901
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings
(GND = 0 V)
Symbol
Parameter
Rating
Unit
V IN
V IN Pin Voltage
−0.3 to 6.5
V
V CE
CE Pin Voltage
−0.3 to 6.5
V
V FB
V FB Pin Voltage
−0.3 to 6.5
V
V OUT
V OUT Pin Voltage
−0.3 to 48
V
V LX
L X Pin Voltage
−0.3 to 48
V
I LX
L X Pin Current
1200
mA
PD
Power
Dissipation(1)
Tj
Junction Temperature Range
−40 to 125
°C
Tstg
Storage Temperature Range
−55 to 125
°C
DFN(PLP)1820-6
JEDEC STD. 51-7
2200
TSOT-23-6
Standard Test
Land Pattern
460
mW
ABSOLUTE MAXIMUM RATINGS
Electronic and mechanical stress momentarily exceeded absolute maximum ratings may cause permanent
damage and may degrade the lifetime and safety for both device and system using the device in the field. The
functional operation at or over these absolute maximum ratings is not assured.
RECOMMENDED OPERATING CONDITIONS
Recommended Operating Conditions
Symbol
Parameter
Rating
Unit
V IN
Input Voltage
2.3 to 5.5
V
Ta
Operating Temperature Range
−40 to 85
°C
RECOMMENDED OPERATING CONDITIONS
All of electronic equipment should be designed that the mounted semiconductor devices operate within the
recommended operating conditions. The semiconductor devices cannot operate normally over the recommended
operating conditions, even if they are used over such ratings by momentary electronic noise or surge. And the
semiconductor devices may receive serious damage when they continue to operate over the recommended operating
conditions.
(1)
6
Refer to POWER DISSIPATION for detailed information.
R1204x
No. EA-284-200901
ELECTRICAL CHARACTERISTICS
R1204xxxxx Electrical Characteristics
Symbol
Parameter
Test Conditions/Comments
IDD
Supply Current
VIN = 5.5 V, VFB = 0 V, LX at no load
Istandby
Standby Current
VIN = 5.5 V, VCE = 0 V
VUVLO1
UVLO Detector Threshold
VIN falling
VUVLO2
UVLO Released Voltage
VIN rising
VCEH
VCEL
CE Input Voltage "H"
CE Input Voltage "L"
VIN = 5.5 V
VIN = 2.3 V
RCE
CE Pull Down
Resistance
VIN = 3.6 V
VFB
VFB Voltage Accuracy
VIN = 3.6 V
IFB
VFB Input Current
VIN = 5.5 V, VFB = 0 V or 5.5 V
Tstart
RON
Soft-start Time
FET ON Resistance
VIN = 3.6 V, R1204xxxxB/C/E/F
VIN = 3.6 V, ILX = 100 mA
ILXLEAK
FET Leakage Current
VLX = 40 V
ILXLIM
FET Current Limit
VIN = 3.6 V
fosc
Oscillator Frequency
Maxduty
VOVP1
Oscillator Maximum
Duty Cycle
OVP Detector Threshold
1.9
OVP Released Voltage
TTSR
Thermal Shutdown
Temperature
Thermal Shutdown
Released Temperature
1.0
5.0
2.0
2.1
0.5
R1204xxxxA/B/D/E/G/H
1200
R1204xxxxC/F
600
R1204xxxxA/D
0.19
0.2
0.21
R1204xxxxG/H
0.39
0.4
0.41
R1204xxxxB/C/E/F
0.985 1.000 1.015
VIN = 3.6 V, R1204xxxxA/B/C/G
VFB = 0 V
R1204xxxxD/E/F/H
VIN = 3.6 V, R1204xxxxA/B/C/G
VFB = 0 V
R1204xxxxD/E/F/H
R1204x1xxx
VIN = 3.6 V,
R1204x2xxx
VOUT rising
R1204x3xxx
VIN = 3.6 V,
R1204x2xxx
VOUT falling
−0.1
V
V
kΩ
V
0.1
µA
ms
Ω
3.0
µA
mA
MHz
kHz
%
%
10
0.8
700
0.9
675
91
92
22.0
31.5
40.2
µA
V
V
1.5
R1204x3xxx
TTSD
Typ.
0.8
VUVLO1
+0.1
R1204x1xxx
VOVP2
Min.
(Ta = 25ºC)
Max. Unit
mA
900
1.0
750
1100
1.1
825
23
33
42
VOVP1
−0.6
VOVP1
−1.2
VOVP1
−2.4
24.0
34.5
43.8
V
V
VIN = 3.6 V
150
°C
VIN = 3.6 V
100
°C
All test items listed under Electrical Characteristics are done under the pulse load condition (Tj ≈ Ta = 25ºC).
7
R1204x
No. EA-284-200901
THEORY OF OPERATION
Operation of Step-Up DC/DC Converter and Output Current
i2
IOUT
VOUT
Diode
L
VIN
i1
Lx Tr
CL
GND
Discontinuous mode
Continuous mode
ILmax
IL
IL
ILmax
ILmin
ILmin
topen
t
toff
ton
T=1/fosc
t
ton
toff
T=1/fosc
There are two operation modes of the step-up PWM control-DC/DC converter. That is the continuous mode
and discontinuous mode by the continuousness inductor.
When the transistor turns ON, the voltage of inductor L becomes equal to VIN voltage. The increase value of
inductor current (i1) will be
∆i1 = V IN × ton / L............................................................................................................................ Formula 1
As the step-up circuit, during the OFF time (when the transistor turns OFF) the voltage is continually supply
from the power supply. The decrease value of inductor current (i2) will be
∆i2 = (V OUT − V IN ) × topen / L ......................................................................................................... Formula 2
8
R1204x
No. EA-284-200901
At the PWM control-method, the inductor current become continuously when topen = toff, the DC/DC converter
operate as the continuous mode.
In the continuous mode, the variation of current of i1 and i2 is same at regular condition.
V IN × ton / L = (V OUT - V IN ) × toff / L ................................................................................................ Formula 3
The duty at continuous mode will be
duty (%) = ton / (ton + toff) = (V OUT - V IN ) / V OUT ............................................................................ Formula 4
The average of inductor current at tf = toff will be
IL (Ave.) = V IN × ton / (2 × L) ........................................................................................................... Formula 5
If the input voltage = output voltage, the I OUT will be
I OUT = V IN 2 × ton / (2 × L × V OUT ) .................................................................................................... Formula 6
If the I OUT value is large than above the calculated value (Formula 6), it will become the continuous mode, at
this status, the peak current (I LMAX ) of inductor will be
I LMAX = I OUT × V OUT / V IN + V IN × ton / (2 × L) .................................................................................. Formula 7
ILMAX = IOUT × VOUT / VIN + VIN × T × (VOUT - VIN) / (2 × L × VOUT) ...................................................... Formula 8
The peak current value is larger than the IOUT value. In case of this, selecting the condition of the input and the
output and the external components by considering of ILMAX value.
The explanation above is based on the ideal calculation, and the loss caused by LX switch and the external
components are not included.
The actual maximum output current will be between 50% and 80% by the above calculations. Especially, when
the IL is large or VIN is low, the loss of VIN is generated with on resistance of the switch. Moreover, it is necessary
to consider Vf of the diode (approximately 0.8 V) about VOUT.
9
R1204x
No. EA-284-200901
PWM/VFM Auto-Switching Control (R1204xxxxC/F)
In low output current, the IC automatically switches to high-efficiency VFM mode. The minimum Onduty
(DON_MIN) of VFM mode is set to approximately 30% and is fixed inside the IC. If the difference between the
voltages of the input and the output is small, or the Onduty in continuous mode (DON_CON) becomes lower than
DON_MIN, the IC will not shift to PWM mode but will stay with VFM mode instead even in high output current, as
a result, the ripple current will be increased. DON_MIN should be 70% or more (VSET > VIN x 3.33).
Soft-Start Function
(R1204xxxxA/D/G/H)
Unless otherwise VOUT is beyond the threshold (Vf x number of LED lights), current will not flow through LEDs,
as a result, VFB voltage will not increase. The IC increases VOUT by controlling the output of error amplifier to
“H” and turning the LX switch on and off for a certain period of time (until the current flow). At the mean time,
the inrush current is controlled by gradually increasing the current limit. If VOUT is over the threshold (the current
flows), the IC controls the soft-start function by gradually increasing the reference voltage of error amplifier.
(R1204xxxxB/C/E/F)
The IC controls the soft-start function by gradually increasing the reference voltage of error amplifier. Soft-start
begins when the output voltage of error amplifier is 0V and ends when it reaches the constant voltage.
Current Limit Function
If the peak current of inductor (ILMAX) exceeds the current limit, current limit function turns the driver off and
turns it on in every switching cycle to continually monitor the driver current.
Under Voltage Lock Out Function (UVLO)
UVLO function stops DC/DC operation and prevents malfunction when the supply voltage falls below the UVLO
detector threshold.
Over Voltage Protection Circuit (OVP)
OVP circuit monitors the VOUT pin voltage and if it reaches the OVP voltage it will stop oscillation. When the
VOUT pin voltage decreases it will restart oscillation, but if the cause of the excess VOUT pin voltage is not
removed the OVP circuit will operate repeatedly so as to restrict the VOUT pin voltage.
Thermal Shutdown Function
If the junction temperature exceeds the thermal shutdown temperature, thermal shutdown function turns the
driver off. If the junction temperature becomes lower than the thermal shutdown released temperature, the
thermal shutdown function resets the IC to restart the operation.
10
R1204x
No. EA-284-200901
APPLICATION INFORMATION
R1204xxxxA/D/G/H Typical Applications
VIN = 2.3V to 5.5V
L1
C1
C2
VIN
C2
VIN
VLED =
VIN -VFB to
VOUT
LX
VLED =
VIN -VFB to
VOVP1MIN-3V
VOUT
CE
VFB
GND
D1
C1
LX
CE
LEDs in Parallel (LED Arrays)
VIN = 2.3V to 5.5V
L1
D1
VOVP1MIN-3V
VFB
GND
R1
R1
Figure 1.
Figure 2.
VInductor = VIN to VOVP1MIN-3V
VInductor = VIN to VOVP1MIN-3V
VIN =
2.3V to 5.5V
LEDs in Parallel (LED Arrays)
L1
L1
C3
VIN =
2.3V to 5.5V
C2
VIN
LX
CE
VOUT
GND
VFB
VLED =
VIN -VFB to
C1
C3
C2
VIN
LX
CE
VOUT
GND
VFB
VLED =
VIN -VFB to
C1
VOVP1MIN-3V
VOVP1MIN-3V
R1
R1
Figure 3.
Figure 4.
R1204xxxxB/C/E/F Typical Applications
VIN = 2.3V to 5.5V
L1
VInductor = VIN to VOVP1MIN-3V
D1
L1
C1
VIN =
2.3V to 5.5V
VIN
LX
C1
CE
VIN
LX
CE
VOUT
VOUT
C3
R2
GND
C4
VFB
R1
Figure 5.
C2
R2
R3
GND
C3
C2
R3
VFB
R1
Figure 6.
11
R1204x
No. EA-284-200901
Selection of Inductor
Peak current of inductor (ILMAX) in normal mode when the efficiency is 80% can be calculated by the following
formula.
ILMAX = 1.25 x IOUT x VOUT / VIN + 0.5 x VIN x (VOUT - VIN) / (L1 x VOUT x fosc)
⋅
⋅
⋅
⋅
When starting up the IC or when adjusting the brightness of LEDs, a large transient current may flow into an
inductor (L1).
ILMAX should be equal or smaller than the current limit of the IC.
When deciding the rated current of inductor, ILMAX should be considered.
It is recommended that L1 with 10 µH to 22 µH be used.
Table 1. Peak Current Values for VIN, VOUT, IOUT, and L1
VIN (V)
VOUT (V)
IOUT (mA)
3
21
20
3
21
20
3
30
20
3
30
20
Table 2. Recommended Inductors
L1 (μH)
Parts No.
10
VLS252010ET-100M
10
VLF302512MT-100M
10
VLF403212MT-100M
22
VLF302512MT-220M
22
VLF403212MT-220M
22
VLF504012MT-220M
Rated Current (mA)
550
620
900
430
540
800
L1 (µH)
10
22
10
22
Size (mm)
2.5 × 2.0 × 1.0
3.0 × 2.5 × 1.2
4.0 × 3.2 × 1.2
3.0 × 2.5 × 1.2
4.0 × 3.2 × 1.2
5.0 × 4.0 × 1.2
ILMAX (mA)
280
225
365
305
Versions
R1204xxxxA/B/C/G
R1204xxxxD/E/F/H
Selection of Capacitor
⋅
Place a 1 µF or more bypass capacitor (C1) as close as possible to the VIN and GND pins
[R1204xxxxA/D/G/H]
⋅
⋅
⋅
Place a 1 µF or more output capacitor (C2) as close as possible to the VOUT and GND pins.
In the case of operating the inductor using a separated power supply from the IC, place a 1 µF or more
bypass capacitor (C3) as close as possible to Vinductor and the GND pin.
Note the VOUT that depends on LED used, and select the rating of VOUT or more.
[R1204xxxxB/C/E/F]
⋅
⋅
Place 1 µF to 10 µF C2 as close as possible to the VOUT and GND pins.
In the case of operating the inductor using a separated power supply from the IC, place a 1 µF or more
bypass capacitor (C4) as close as possible to Vinductor and the GND pin.
12
R1204x
No. EA-284-200901
SBD (Schottky Barrier Diode) Selection
⋅
⋅
Choose a diode that has low VF, low reverse current IR, and low capacitance.
SBD is an ideal type of diode for R1204x since it has low VF, low reverse current IR, and low capacitance.
Table 3. Recommended Components for R1204xxxxA/D/G/H
Symbol
Rated Voltage (V)
Parts No.
D1
60
CRS12
C1
6.3
CM105B105K06
C2012X5R1H105K
C2
50
C3 (Option: Figure 4)
Select by the input voltage
C2012X5R1H225K
(R1204xxxxG/H: ILED > 22 mA)
1 µF or more
Table 4. Recommended Components for R1204xxxxB/C/E/F
Symbol
Rated Voltage (V)
Parts No.
D1
60
CRS12
C1
6.3
CM105B105K06
16
C2012X5R1C475K
25
C2012X5R1E105K
50
C2012X5R1H105K
Select by the input voltage
1 µF or more
C2
C4 (Option: Figure 6)
Table 5. Recommended Component Values for R1204xxxxB/C/E/F
VSET (V)
7 < VSET ≤ 10
10 < VSET ≤ 25
25 < VSET
R1 (kΩ)
10
10
10
R2 (kΩ)
(VSET -1) x R1
(VSET -1) x R1
(VSET -1) x R1
R3 (Ω)
0
0
0
C1 (µF)
1.0
1.0
1.0
C2 (µF)
4.7
1.0 × 2
1.0
C3 (pF)
10
10
10
C4 (µF)
1.0
1.0
1.0
13
R1204x
No. EA-284-200901
Other External Components Settings
Set a capacitor (C3) between the VOUT and VFB pins to improve the response of DC/DC converter by giving
high-frequency voltage feedback. Please note that C3 operation could be different from the theory of operation
depending on component layouts and parasitic capacitances.
Output Voltage Setting (R1204xxxxB/C/E/F)
The relation between the output voltage (VSET) and the resistors (R1, R2) is calculable by the following formula.
VSET = VFB × (R1 + R2) / R1
The sum of R1 and R2 should be 300 kΩ or less. Ensure the VIN and GND lines are sufficiently robust. If their
impedances are too high, noise pickup or unstable operation may result. Set a capacitor (C2) with a suitable
voltage resistance (more than 1.5 times of VSET) between the VIN and GND pins, and as close as possible to
the pins.
LED Current Setting (R1204xxxxA/D/G/H)
The LED current (ILED) when a ”H” signal is applied to the CE pin (Duty = 100%) can be determined by the
value of feedback resistor (R1).
ILED = 0.2 / R1 (R1204xxxxA/D)
ILED = 0.4 / R1 (R1204xxxxG/H)
LED Dimming Control (R1204xxxxA/D/G/H)
The brightness of the LEDs can be adjusted by applying a PWM signal to the CE pin. By inputting “L” voltage
for a certain period of time (Typ. 9 ms (R1204xxxxA/G) / 12 ms (R1204xxxxD/H) or more), the IC goes into
standby mode and turns off LEDs. ILED can be controlled by the duty of a PWM signal for the CE pin.
The relation between the high-duty of the CE pin (Hduty) and ILED is calculatable by the following formula.
ILED = Hduty × VFB / R1
The frequency range of a PWM signal should be set within the range of 200 Hz to 300 kHz. In the case of
using a 20 kHz or less PWM signal for dimming the LEDs, the increasing or decreasing of the inductor current
(IL) may make noise in the audible band. In this case, a high frequency PWM signal should be used.
CE
Hduty
VFB
R1
Figure 7. Dimming Control by CE Pin
14
R1204x
No. EA-284-200901
Low luminance Dimming Accuracy (R1204xxxxG/H)
Low luminance Dimming filtered VFB voltage tolerance depends on the offset voltage of the internal DC/DC
converter. By this offset voltage, some voltage difference may be generated between VREF voltage and VFB
voltage. Low luminance Dimming Accuracy is shown in Table 5.
Table 6. Low luminance Dimming Accuracy for R1204xxxxG/H (R1 = 20 Ω)
The duty of a PWM signal for the CE pin
3.5% (Frequency = 20 kHz to 300 kHz)
(2)
ILED Min.
0.01
mA( 2)
ILED Max.
2.1 mA(2)
Guaranteed by design engineering (Ta = 25ºC).
15
R1204x
No. EA-284-200901
TECHNICAL NOTES
Current Path on PCB
Figure 8 and Figure 9 show flows of current paths of the application circuits when MOSFET is ON and when
MOSFET is OFF, respectively.
⋅
Parasitic elements (impedance, inductance or capacitance) in the paths pointed with red arrows in Figure 8
and Figure 9 influence stability of the system and cause noise outbreak. It is recommended that these
⋅
parasitic elements be minimized.
In addition, except for the paths of LED load, it is recommended that the all wirings of the current paths be
made as short and wide as possible.
Load
Load
Figure 8. MOSFET-ON
Figure 9. MOSFET-OFF
Layout Guide for PCB
⋅
⋅
⋅
⋅
Place C1 as close as possible to the VIN and GND pins. Also, connect the GND pin to the wider GND plane.
Make the LX land pattern as small as possible.
Make the wirings between the LX pin, the inductor and the diode as short as possible. Also, connect C2 as
close as possible to the cathode of the diode.
Place C2 as close as possible to the GND pin.
16
R1204x
No. EA-284-200901
PCB Layout
PKG: DFN(PLP)1820-6 pin
R1204Kxx2A/D/G/H
Topside
Backside
Topside
Backside
R1204Kxx2B/C/E/F
17
R1204x
No. EA-284-200901
PKG: TSOT-23-6 pin
R1204Nxx3A/D/G/H
Topside
Backside
Topside
Backside
R1204Nxx3B/C/E/F
18
R1204x
No. EA-284-200901
TYPICAL CHARACTERISTICS
1) Efficiency vs. Output Current of R1204xxxxA/D/G/H
Used LED: NICHIA, NSSW208A (Vf = 3.0 V (ILED = 20 mA))
1-1) Efficiency vs. Output Current with Different Output Voltages, 10 LEDs in Series (VOUT = 30 V (IOUT = 20 mA))
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
100
Vin= 3.2 V
90
Vin= 4.2 V
Vin= 3.6 V
95
Vin= 3.2 V
Vin= 3.6 V
Vin= 5 V
90
Vin= 4.2 V
Vin= 5 V
Efficiency [%]
Efficiency [%]
95
85
80
75
70
85
80
75
70
65
65
60
60
0
5
10
15
20
25
Output Current [mA]
30
0
35
5
10
15
20
25
Output Current [mA]
30
35
8 LEDs in Series (VOUT = 24 V (IOUT = 20 mA))
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
95
Vin= 3.2 V
Vin= 3.6 V
95
90
Vin= 4.2 V
Vin= 5 V
90
Efficiency [%]
Efficiency [%]
100
85
80
75
85
80
75
70
Vin= 3.2 V
Vin= 3.6 V
65
65
Vin= 4.2 V
Vin= 5 V
60
60
70
0
5
10
15
20
25
30
0
35
5
10
15
20
25
30
35
Output Current [mA]
Output Current [mA]
6 LEDs in Series (VOUT = 18 V (IOUT = 20 mA))
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
85
80
75
70
Vin= 3.2 V
Vin= 3.6 V
65
Vin= 4.2 V
Vin= 5 V
85
80
75
70
Vin= 3.2 V
Vin= 3.6 V
65
Vin= 4.2 V
Vin= 5 V
60
60
0
5
10
15
20
25
Output Current [mA]
30
35
0
5
10
15
20
25
30
35
Output Current [mA]
19
R1204x
No. EA-284-200901
1-2) Efficiency vs. Output Current with Different Inductors (VIN = 3.6 V)
10 LEDs in Series (VOUT = 30 V (IOUT = 20 mA))
R1204xxxxA/G
R1204xxxxD/H
100
100
VLS252010ET-100M
VLF302512MT-100M
VLF403212MT-100M
VLF302512MT-220M
Efficiency [%]
90
85
VLS252010ET-100M
VLF302512MT-100M
VLF302512MT-220M
VLF504012MT-220M
95
Efficiency [%]
95
80
75
70
90
85
80
75
70
65
65
60
60
0
5
10
15
20
25
30
0
35
5
10
15
20
30
35
30
35
25
Output Current [mA]
Output Current [mA]
8 LEDs in Series (VOUT = 24 V (IOUT = 20 mA))
R1204xxxxA/G
R1204xxxxD/H
100
100
VLS252010ET-100M
VLF302512MT-100M
VLF403212MT-100M
VLF302512MT-220M
90
85
95
Efficiency [%]
Efficiency [%]
95
80
75
70
90
85
80
75
VLS252010ET-100M
VLF302512MT-100M
VLF302512MT-220M
VLF504012MT-220M
70
65
65
60
60
0
5
10
15
20
25
30
35
0
5
10
Output Current [mA]
15
20
25
Output Current [mA]
1-3) Efficiency vs. Output Current with Different Numbers of LEDs
R1204xxxxA/G, L=10µH (VLF302512MT-100M)
R1204xxxxD/H, L=22µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
LEDs in 3 Parallels (VIN = 3.6 V)
85
80
75
3LEDs in Series
6LEDs in Series
7LEDs in Series
70
65
60
80
75
70
3LEDs in Series
6LEDs in Series
65
7LEDs in Series
60
0
20
85
5
10
15
20
25
30
Output Current (/1Series)[mA]
35
0
5
10
15
20
25
Output Current (/1Series)[mA]
30
35
R1204x
No. EA-284-200901
LEDs in 3 Parallels (VIN = 5.0 V)
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
85
80
75
3LEDs in Series
70
6LEDs in Series
65
7LEDs in Series
85
80
75
60
70
3LEDs in Series
6LEDs in Series
65
7LEDs in Series
60
0
5
10
15
20
25
30
35
0
5
Output Current (/1Series)[mA]
10
15
20
25
30
35
Output Current (/1Series)[mA]
1-4) Efficiency vs. Output Current with Different Numbers of LEDs
LEDs in 3 Parallels (VIN = 3.6 V, Inductor Voltage = 12.0 V)
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
85
80
7LEDs in Series
8LEDs in Series
9LEDs in Series
10LEDs in Series
75
70
65
85
80
7LEDs in Series
8LEDs in Series
9LEDs in Series
10LEDs in Series
75
70
65
60
60
0
5
10
15
20
25
30
35
0
5
Output Current (/1Series) [mA]
10
15
20
25
30
Output Current (/1Series) [mA]
35
LEDs in 6 Parallels (VIN = 3.6 V, Inductor Voltage = 12.0 V)
R1204xxxxD/H, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxA/G, L = 10 µH (VLF302512MT-100M)
85
80
75
70
7LEDs in Series
65
9LEDs in Series
85
80
75
70
7LEDs in Series
9LEDs in Series
65
60
60
0
5
10
15
20
25
30
Output Current (/1Series) [mA]
35
0
5
10
15
20
25
30
35
Output Current (/1Series) [mA]
21
R1204x
No. EA-284-200901
2) Efficiency vs. Output Current of R1204xxxxB/C/E/F
2-1) Efficiency vs. Output Current with Different Output Voltages
VSET = 31 V
VIN = Inductor Voltages
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
95
Vin= 3.2 V
90
Vin= 3.6 V
85
Vin= 5 V
90
Vin= 3.2 V
Vin= 3.6 V
85
Vin= 5 V
95
Efficiency [%]
Efficiency [%]
100
80
75
70
80
75
70
65
65
60
60
0
10
20
30
40
50
60
70
80
0
90
10
20
Output Current [mA]
30 40 50 60
Output Current [mA]
70
80
90
Different VIN / Inductor Voltages (VIN = 3.6 V)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
85
80
75
V Inductor= 7.2 V
70
V Inductor= 9 V
V Inductor= 12 V
65
85
80
75
V Inductor= 7.2 V
70
V Inductor= 9 V
65
V Inductor= 12 V
60
60
0
50
100
150
Output Current [mA]
0
200
50
100
150
Output Current [mA]
200
VSET = 25 V
VIN = Inductor Voltages
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
100
Efficiency [%]
90
85
80
75
70
90
85
80
75
70
65
65
60
60
0
10
20 30 40
50 60
70 80 90 100 110
Output Current [mA]
22
Vin= 3.2 V
Vin= 3.6 V
Vin= 5 V
95
Efficiency [%]
Vin= 3.2 V
Vin= 3.6 V
Vin= 5 V
95
0
10
20 30 40 50 60 70 80 90 100 110
Output Current [mA]
R1204x
No. EA-284-200901
Different VIN / Inductor Voltages (VIN = 3.6 V)
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
95
95
90
90
Efficiency [%]
Efficiency [%]
100
85
80
75
V Inductor= 7.2 V
70
V Inductor= 9 V
65
V Inductor= 12 V
60
85
80
75
70
V Inductor= 7.2 V
V Inductor= 9 V
65
V Inductor= 12 V
60
0
50
100
150
200
Output Current [mA]
250
0
50
100
150
200
Output Current [mA]
250
VSET = 21 V
VIN = Inductor Voltage
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
95
95
90
90
85
80
75
Vin= 3.2 V
Vin= 3.6 V
Vin= 5 V
70
65
Efficiency [%]
Efficiency [%]
100
85
80
75
Vin= 3.2 V
Vin= 3.6 V
Vin= 5 V
70
65
60
60
0 10 20 30 40 50 60 70 80 90 10 11 12 13
Output Current [mA] 0 0 0 0
0 10 20 30 40 50 60 70 80 90 10 11 12 13
Output Current [mA] 0 0 0 0
Different VIN / Inductor Voltages (VIN = 3.6 V)
R1204xxxxF, L = 22 µH (VLF302512MT-220M)
100
100
95
95
90
90
Efficiency [%]
Efficiency [%]
R1204xxxxC, L = 10 µH (VLF302512MT-100M)
85
80
80
75
V Inductor= 7.2 V
V Inductor= 9 V
70
V Inductor= 9 V
V Inductor= 12 V
65
V Inductor= 12 V
75
V Inductor= 7.2 V
70
65
85
60
60
0
100
200
Output Current [mA]
300
0
100
200
Output Current [mA]
300
23
R1204x
No. EA-284-200901
2-2) Efficiency vs. Output Current with PWM Control and PWM/VFM Auto-Switching Control
(VIN = 3.6 V, VSET = 12 V)
R1204xxxxE/F, L = 22 µH (VLF302512MT-220M)
90
90
80
80
70
70
Efficiency [%]
Efficiency [%]
R1204xxxxB/C, L = 10 µH (VLF302512MT-100M)
60
50
40
R1204xxxxC
30
R1204xxxxB
20
60
50
40
R1204xxxxF
30
R1204xxxxE
20
0.1
1
10
100
0.1
Output Current [mA]
Inductor Voltage = 7.2 V, VSET = 25 V
R1204xxxxB/C, L = 10 µH (VLF302512MT-100M)
90
Efficiency [%]
80
70
60
50
40
R1204xxxxC
30
R1204xxxxB
20
0.1
1
10
100
Output Current [mA]
3) Maxduty vs. ILED (R1204xxxxA/D/G/H, 10 LEDs in Series, VIN = 3.6 V)
ILED-DUTY VIN=3.6V
25
ILED [mA]
20
15
10
Freq=200Hz
5
Freq=10kHz
Freq=300kHz
0
0
24
20
60
40
Duty [%]
80
100
1
10
Output Current [mA]
100
R1204x
No. EA-284-200901
4) VOUT / ILED Ripple of R1204xxxxA/D/G/H When Dimming (10 LEDs in Series, L = 10 µH (VLF302512MT-100M))
CE Freq = 200 Hz
CE Freq = 10 kHz
10LED
CE Freq=10KHz
10LED
CE Freq=200Hz
16
55
Vou t
32
32
Vou t
40
26
10
14
ILED
14
8
-5
8
12
20
ILED (mA)
25
Output Voltage (V)
CE Voltage (V)
ILED
20
ILED (mA)
Output Voltage (V)
CE Voltage (V)
26
8
CE
CE
-20
2
-4
-10
-35
-5
0
Time (ms)
5
2
-4
-500
10
-250
0
250
4
500
Time (µs)
CE Freq = 300 kHz
10LED
CE Freq=300KHz
16
32
Vou t
12
20
ILED (mA)
Output Voltage (V)
CE Voltage (V)
26
ILED
14
8
CE
8
2
-4
4
-1
3
7
11
15
Time (µs)
5) VOUT Ripple (VIN = 3.6 V, VSET = 21 V, IOUT = 0 mA, L = 10 µH (VLF302512MT-100M))
PWM Control (R1204xxxxB)
VFM Control (R1204xxxxC)
Vout
Vout
VLx
VLx
25
R1204x
No. EA-284-200901
6) Load Transient Response
(VIN = 3.6 V, VSET = 25 V, L = 10 µH (VLF302512MT-100M), IOUT = 10 mA ⇔ 30 mA, Tr = Tf = 0.5 µs)
R1204xxxxC
R1204xxxxF
Output Voltage
Output Voltage
1V /div
1V /div
Load Current
Load Current
20mA /div
20mA /div
7) Supply Current vs. Ambient Temperature
8) UVLO vs. Ambient Temprature
1200
2.2
1100
2.1
1000
2.1
UVLO Voltage [V]
Supply Current [uA]
Time Scale : 1ms /div
R1204xxxxF
Time Scale : 1ms /div
R1204xxxxC
900
800
700
600
Released
2.0
Detected
2.0
1.9
1.9
500
400
1.8
-40
-15
10
35
60
85
-40
-15
10
Temprature Ta [°C]
35
60
85
Temperature Ta [°C]
9) VFB Voltage vs. Ambient Temperature
R1204xxxxG/H
0.220
0.440
0.215
0.430
0.210
0.420
VFB Voltage[V]
VFB Voltage[V]
R1204xxxxA/D
0.205
0.200
0.195
0.400
0.390
0.190
0.380
0.185
0.370
0.360
0.180
-40
-15
10
35
Temperature Ta [°C]
26
0.410
60
85
-40
-15
10
35
Temperature Ta [°C]
60
85
R1204x
No. EA-284-200901
R1204xxxxB/C/E/F
1.100
1.075
VFB Voltage[V]
1.050
1.025
1.000
0.975
0.950
0.925
0.900
-40
-15
10
35
60
85
Temperature Ta [°C]
10) Switch ON Resistance vs. Ambient Temperature
11) OVP Voltage vs. Ambient Temperature
R1204x3xxx
43.0
42.0
1.0
41.0
OVP Voltage [V]
Switch ON Resistanse [ohm]
1.2
0.8
0.6
0.4
Released
40.0
39.0
Detected
38.0
37.0
0.2
36.0
35.0
0
-40
-15
10
35
60
85
-40
-15
10
35
60
85
Temperature Ta [°C]
Temperature Ta [°C]
12) LX Limit Current vs. Ambienet Temperature
1200
LX Current Limit [mA]
1100
1000
900
800
Vin=2.8V
Vin=3.6V
700
Vin=5.5V
600
-40
-15
10
35
60
85
Temperature Ta [°C]
27
R1204x
No. EA-284-200901
13) Oscillator Frequency vs. Ambiemnt Temperature
R1204xxxxA/B/C/G
R1204xxxxD/E/F/H
900
1200
Oscillator Frequency [kHz]
Oscillator Frequency [kHz]
1150
1100
1050
1000
950
Vin=3.6V
900
Vin=5.5V
850
850
800
750
700
Vin=3.6V
650
Vin=5.5V
800
600
-40
-15
10
35
Temperature Ta [°C]
28
60
85
-40
-15
10
35
Temperature Ta [°C]
60
85
POWER DISSIPATION
DFN(PLP)1820-6
Ver. B
The power dissipation of the package is dependent on PCB material, layout, and environmental conditions.
The following measurement conditions are based on JEDEC STD. 51-7.
Measurement Conditions
Item
Measurement Conditions
Environment
Mounting on Board (Wind Velocity = 0 m/s)
Board Material
Glass Cloth Epoxy Plastic (Four-Layer Board)
Board Dimensions
76.2 mm × 114.3 mm × 0.8 mm
Copper Ratio
Outer Layer (First Layer): Less than 95% of 50 mm Square
Inner Layers (Second and Third Layers): Approx. 100% of 50 mm Square
Outer Layer (Fourth Layer): Approx. 100% of 50 mm Square
Through-holes
0.2 mm × 34 pcs
Measurement Result
(Ta = 25°C, Tjmax = 125°C)
Item
Measurement Result
Power Dissipation
2200 mW
Thermal Resistance (ja)
ja = 45°C/W
Thermal Characterization Parameter (ψjt)
ψjt = 18°C/W
ja: Junction-to-Ambient Thermal Resistance
ψjt: Junction-to-Top Thermal Characterization Parameter
2500
2200
Power Dissipation (mW)
2000
1500
1000
500
0
0
25
50
75 85
100
125
Ambient Temperature (°C)
Power Dissipation vs. Ambient Temperature
Measurement Board Pattern
i
PACKAGE DIMENSIONS
DFN(PLP)1820-6
Ver. B
DFN(PLP)1820-6 Package Dimensions
*
*∗
The tab on the bottom of the package is substrate level (GND). It is recommended that the tab be connected to the
ground plane on the board, or otherwise be left floating.
i
POWER DISSIPATION
TSOT-23-6
Ver. A
The power dissipation of the package is dependent on PCB material, layout, and environmental conditions.
The following conditions are used in this measurement.
Measurement Conditions
Item
Standard Test Land Pattern
Environment
Mounting on Board (Wind Velocity = 0 m/s)
Board Material
Glass Cloth Epoxy Plastic (Double-Sided Board)
Board Dimensions
40 mm × 40 mm × 1.6 mm
Top Side: Approx. 50%
Copper Ratio
Bottom Side: Approx. 50%
φ 0.5 mm × 44 pcs
Through-holes
Measurement Result
(Ta = 25°C, Tjmax = 125°C)
Standard Test Land Pattern
Item
Power Dissipation
460 mW
Thermal Resistance (θja)
θja = 217°C/W
Thermal Characterization Parameter (ψjt)
ψjt = 40°C/W
θja: Junction-to-Ambient Thermal Resistance
ψjt: Junction-to-Top Thermal Characterization Parameter
600
Power Dissipation PD (mW)
500
460
400
300
200
100
0
0
25
50
75 85
100
125
Ambient Temperature (°C)
Power Dissipation vs. Ambient Temperature
Measurement Board Pattern
i
TSOT-23-6
PACKAGE DIMENSIONS
+0.100
0.125-0.025
2.9±0.2
5
4
1
2
3
S
0.12 M
0∼15°
0 ∼ 0.1
+0.10
0.4-0.05
0.85±0.10
0.95
2.8±0.2
+0.2
1.6-0.1
6
0.4±0.2
Ver. A
0.10 S
TSOT-23-6 Package Dimensions
i
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April 1, 2012.
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https://www.n-redc.co.jp/en/
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https://www.n-redc.co.jp/en/buy/
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