RP504K231D-E2 [RICOH]
Switching Controller, Voltage-mode, 0.9A, 2550kHz Switching Freq-Max, CMOS, PDSO6, 1.20 X 1.60 MM, HALOGEN FREE AND ROHS COMPLIANT, DFN-6;
| 型号： | RP504K231D-E2 |
| 厂家： | 
RICOH ELECTRONICS DEVICES DIVISION |
| 描述： | Switching Controller, Voltage-mode, 0.9A, 2550kHz Switching Freq-Max, CMOS, PDSO6, 1.20 X 1.60 MM, HALOGEN FREE AND ROHS COMPLIANT, DFN-6 开关 光电二极管 |
| 文件： | 总29页 (文件大小：795K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RP504x SERIES
600mA Step-down DC/DC Converter with Synchronous Rectifier
NO.EA-259-130520
OUTLINE
The RP504x Series are low supply current CMOS-based 600mA step-down DC/DC Converters with
synchronous rectifier. Each of these ICs consists of an oscillator, a reference voltage unit, an error amplifier, a
switching control circuit, a mode control circuit(Ver.A, D), a soft-start circuit, a "latch type" protection circuit, an
under voltage lockout (UVLO) circuit, and switching transistors. A low ripple, high efficiency synchronous rectifier
step-down DC/DC converter can be easily composed of this IC with only an inductor and capacitors. Since
packages are SOT-23-5, DFN1616-6B, DFN(PLP)1216-6F, high density mounting on boards is possible.
As protection circuits, the RP504x Series contain a current limit circuit which limits the Lx peak current in each
clock cycle, and a latch type protection circuit which latches the built-in driver to the OFF state if the load current
exceeds the limit value or the output short continues for a specified time (the protection delay time). The latch
protective circuit can be released by once putting the IC into the standby mode with the CE pin and then into the
active mode, or, by turning the power off and back on. Setting the supply voltage lower than the UVLO detector
threshold can also release the latch protective circuit.
In terms of the output voltage, since the feedback resistances are built-in, the voltage is fixed internally. 0.1V
step output can be set by laser-trim and 1.5% or 18mV tolerance depending on the output voltage is
guaranteed. By inputting a signal to a MODE pin, the RP504x Series can be switched between PWM/VFM auto
switching control and Forced PWM control. PWM/VFM auto switching control switches to high-efficiency VFM
mode in low output current. Forced PWM control switches to fixed-frequency Forced PWM mode for reducing
noise in low output current.
)This is an approximate value, because output current depends on conditions and external parts.
FEATURES
Supply Current...................................................... Typ. 25A(at VFM mode, at no load)
Standby Current.................................................... Max. 5A
Input Voltage Range ............................................. 2.3V to 5.5V (VOUT≧1.0V)
Output Voltage Range........................................... 0.8V to 3.3V (With a 0.1V step)
Output Voltage Accuracy....................................... 1.5% (VOUT1.2V), 18mV (VOUT<1.2V)
Temperature-Drift Coefficient of Output Voltage... Typ. 40ppm/C
Oscillator Frequency............................................. Typ. 2.25MHz
Oscillator Maximum Duty Cycle............................ Min. 100%
Built-in Driver ON Resistance ............................... Typ. Pch. 0.34Ω、Nch. 0.43Ω(VIN=3.6V)
UVLO Detector Threshold..................................... Typ. 2.0V
Soft Start Time....................................................... Typ. 0.15ms
LX Current Limit..................................................... Typ. 900mA
Latch type Protection Circuit................................. Typ. 1.5ms
Auto discharge function ........................................ Only for D Version
Two choices of Switching Mode............................ DFN1616-6B and DFN(PLP)1216-6F are available in
adjustable switching control options from PWM/VFM auto switching type or Forced PWM type by using
MODE pin. SOT-23-5 is available in fixed switching control options: PWM/VFM auto switching type for B
version or Forced PWM type for C version.
Packages .............................................................. SOT-23-5, DFN1616-6B, DFN(PLP)1216-6F
1
RP504x
APPLICATIONS
Power source for battery-powered equipment.
Power source for hand-held communication equipment, cameras, VCRs, camcorders.
Power source for HDD, portable equipment.
BLOCK DIAGRAMS
RP504xxxxA
VIN
CURRENT
CHIP
ENABLE
RAMP
COMPENSATION
CE
FEEDBACK
OSCILLATOR
CURRENT
PROTECTION
Lx
VREF
SWITCHING
CONTROL
PWM
VOUT
SOFT
START
UVLO
MODE
GND
RP504xxxxB
VIN
CE
CURRENT
CHIP
ENABLE
RAMP
COMPENSATION
FEEDBACK
OSCILLATOR
CURRENT
PROTECTION
Lx
VREF
SWITCHING
CONTROL
PWM
VOUT
SOFT
START
UVLO
MODE
GND
2
RP504x
RP504xxxxC
VIN
CE
CURRENT
RAMP
COMPENSATION
CHIP
ENABLE
FEEDBACK
OSCILLATOR
CURRENT
PROTECTION
Lx
VREF
SWITCHING
CONTROL
PWM
SOFT
START
VOUT
UVLO
MODE
GND
RP504xxxxD
VIN
CHIP
ENABLE
RAMP
COMPENSATION
CURRENT
FEEDBACK
CE
OSCILLATOR
CURRENT
PROTECTION
LX
VREF
SWITCHING
CONTROL
PWM
VOUT
SOFT
START
UVLO
MODE
GND
3
RP504x
SELECTION GUIDE
In the RP504x Series, output voltage, MODE control, auto discharge function, and package for the ICs are
selectable at the user’s request.
Product Name
RP504Nxx1$-TR-FE
RP504Lxx1$-TR
Package
SOT-23-5
Quantity per Reel
3,000 pcs
Pb Free
Yes
Halogen Free
Yes
Yes
Yes
DFN1616-6B
DFN(PLP)1216-6F
5,000 pcs
Yes
RP504Kxx1$-E2
5,000 pcs
Yes
1
xx : The output voltage can be designated in the range from 0.8V(08) to 3.3V(33) in 0.1V steps .
Designation is possible in the range from 0.8V to 3.3V with a step of 0.1V
(Refer to the marking information)
$ : Designation of mask option
Symbol
Package
Mode Control
Auto discharge function
Yes
DFN1616-6B
DFN(PLP)1216-6F
A
(“H” forced PWM,
“L” PWM/VFM automatic shift)
No
No
B
C
SOT-23-5
SOT-23-5
No
No
(PWM/VFM automatic shift)
No
(forced PWM)
Yes
DFN1616-6B
DFN(PLP)1216-6F
D
(“H” forced PWM,
“L” PWM/VFM automatic shift)
Yes
Auto-discharge function quickly lowers the output voltage to 0V, when the chip enable signal is switched from the active
mode to the standby mode, by releasing the electrical charge accumulated in the external capacitor.
1) 0.05V step is also available as a custom code.
PIN CONFIGURATIONS
SOT-23-5
DFN1616-6B
Top View Bottom View
DFN(PLP)1216-6F
Top View Bottom View
Top View
5
4
6
5
4
4
5
6
6
5
4
4
5
6
(mark side)
1
2
3
3
2
1
1
2
3
3
2
1
1
2
3
4
RP504x
PIN DESCRIPTIONS
RP504Nxx1B, RP504Nxx1C : SOT-23-5
Pin No.
Symbol
VOUT
GND
LX
Description
1
2
3
4
5
Output Pin
Ground Pin
LX Switching Pin
Input Pin
VIN
CE
Chip Enable Pin ("H" Active)
RP504Lxx1A, RP504Lxx1D : DFN1616-6B
Pin No.
Symbol
Description
1
2
3
4
5
6
CE
Chip Enable Pin ("H" Active)
MODE
VIN
Mode Control Pin (“H” forced PWM, “L” PWM/VFM automatic shift)
Input Pin
LX
LX Switching Pin
Ground Pin
Output Pin
GND
VOUT
) Tab is GND level. (They are connected to the reverse side of this IC.)
The tab is better to be connected to the GND, but leaving it open is also acceptable.
RP504Kxx1A, RP504Kxx1D : DFN(PLP)1216-6F
Pin No.
Symbol
Description
1
2
3
4
5
6
VIN
Input Pin
MODE
CE
Mode Control Pin (“H” forced PWM, “L” PWM/VFM automatic shift)
Chip Enable Pin ("H" Active)
Output Pin
VOUT
GND
LX
Ground Pin
LX Switching Pin
5
RP504x
ABSOLUTE MAXIMUM RATINGS
(GND=0V)
Symbol
VIN
Item
Rating
-0.3 to 6.5
-0.3 to VIN + 0.3
-0.3 to 6.5
-0.3 to 6.5
-0.3 to 6.5
900
Unit
VIN Input Voltage
LX Pin Voltage
V
V
VLX
VCE
CE Pin Input Voltage
Mode Control Pin Voltage
VOUT Pin Voltage
V
VMODE
VOUT
ILX
V
V
LX Pin Output Current
mA
Power Dissipation (SOT-23-5)
420
Power Dissipation (DFN1616-6B)
PD
mW
640
Power Dissipation (DFN(PLP)1216-6F)
Operating Temperature Range
Storage Temperature Range
385
Ta
-40 to 85
-55 to 125
C
C
Tstg
) 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 and may degrade the life time 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 (ELECTRICAL CHARACTERISTICS)
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 when they are used over such conditions by momentary
electronic noise or surge. And the semiconductor devices may receive serious damage when they continue
to operate over the recommended operating conditions.
6
RP504x
ELECTRICAL CHARACTERISTICS
RP504xxxxA, RP504xxxxD
(Ta=25C)
Symbol
Item
Conditions
Min.
2.3
Typ.
Max.
5.5
Unit
VOUT ≥1.0
VIN
Operating Input Voltage
V
VOUT <1.0
2.3
4.5
VOUT≥1.2V
0.985
-0.018
1.015
+0.018
VIN=VCE=3.6V
or VSET+1V
VOUT
Output Voltage
V
VOUT<1.2V
Output Voltage Temperature
Coefficient
±40
VOUT/T
-40C Ta 85C
ppm/C
fosc
Oscillator Frequency
Supply Current 1
VIN=VCE=3.6V or VSET+1V
1.95
2.25
400
25
400
0
2.55
800
40
800
5
MHz
IDD1
VIN=VCE=5.5V, VOUT=VSET0.8
A
VMODE=0V
IDD2
Supply Current 2
VIN=VCE=VOUT=5.5V
A
VMODE=5.5V
VIN=5.5V,VCE=0V
VIN=VCE=5.5V
Istandby
ICEH
Standby Current
A
A
A
A
A
A
A
A
A
V
CE "H" Input Voltage
CE "L" Input Voltage
Mode "H" Input Current
Mode "L" Input Current
-1
-1
-1
-1
-1
-1
-1
-5
1.0
0
1
ICEL
VIN=5.5V,VCE=0V
VIN=VMODE=5.5V
0
1
IMODEH
IMODEL
IVOUTH
IVOUTL
ILXLEAKH
ILXLEAKL
VCEH
0
1
VIN=5.5V, VMODE=0V
VIN=VOUT=5.5V,VCE=0V
VIN=5.5V,VCE=VOUT=0V
VIN=VLX=5.5V,VCE=0V
VIN=5.5V,VCE=VLX=0V
VIN=5.5V
0
1
VOUT "H" Input Current
1
0
1
VOUT "L" Input Current
LX Leakage Current "H"
LX Leakage Current "L"
CE "H" Input Voltage
CE "L" Input Voltage
Mode ”H” Input Voltage
Mode ”L” Input Voltage
0
1
0
5
0
1
VCEL
VIN=2.3V
0.4
0.4
V
VMODEH
VMODEL
RLOW
VIN=VCE=5.5V
1.0
V
VIN=VCE=2.3V
V
Nch On Resistance
2
VIN=3.6V,VCE=0V
VIN=3.6V, ILX=−100mA
VIN=3.6V, ILX=−100mA
30
Ω
RONP
On Resistance of Pch Tr.
On Resistance of Nch Tr.
0.34
0.43
Ω
RONN
Ω
Maxduty Oscillator Maximum Duty Cycle
100
%
tstart
ILXlim
Soft-start Time
VIN=VCE=3.6V or VSET+1V
VIN=VCE=3.6V or VSET+1V
VIN=VCE=3.6V or VSET+1V
VIN=VCE
150
900
1.5
2.0
2.1
310
s
mA
ms
V
Lx Current Limit
700
0.5
1.9
2.0
tprot
Protection Delay Time
UVLO Detector Threshold
UVLO Released Voltage
5
VUVLO1
VUVLO2
2.1
2.2
VIN=VCE
V
Test circuit is "OPEN LOOP" and AGND=PGND=0V unless otherwise specified.
1) without auto discharge version only
2) with auto discharge version only
7
RP504x
RP504xxxxB, RP504xxxxC
(Ta=25C)
Symbol
Item
Conditions
Min.
2.3
Typ.
Max.
5.5
Unit
VOUT ≥1.0
VIN
Operating Input Voltage
V
VOUT <1.0
2.3
4.5
VOUT
1.2V
0.985
-0.018
1.015
VIN=VCE=3.6V
or VSET+1V
VOUT
Output Voltage
V
VOUT < 1.2V
+0.018
Output Voltage Temperature
Coefficient
±40
VOUT/T
-40C Ta 85C
ppm/C
fosc
Oscillator Frequency
Supply Current 1
VIN=VCE=3.6V or VSET+1V
1.95
2.25
400
40
500
0
2.55
800
60
840
5
MHz
IDD1
VIN=VCE=5.5V, VOUT=VSET0.8
A
RP504xxxxB
RP504xxxxC
IDD2
Supply Current 2
VIN=VCE=VOUT=5.5V
A
Istandby
ICEH
Standby Current
VIN=5.5V,VCE=0V
VIN=VCE=5.5V
A
A
A
A
A
A
A
V
CE "H" Input Voltage
CE "L" Input Voltage
VOUT "H" Input Current
VOUT "L" Input Current
LX Leakage Current "H"
LX Leakage Current "L"
CE "H" Input Voltage
CE "L" Input Voltage
On Resistance of Pch Tr.
On Resistance of Nch Tr.
-1
-1
0
1
ICEL
VIN=5.5V,VCE=0V
0
1
IVOUTH
IVOUTL
ILXLEAKH
ILXLEAKL
VCEH
VIN=VOUT=5.5V,VCE=0V
VIN=5.5V,VCE=VOUT=0V
VIN=VLX=5.5V,VCE=0V
VIN=5.5V,VCE=VLX=0V
VIN=5.5V
-1
0
1
-1
0
1
-1
0
5
-5
0
1
1.0
VCEL
VIN=2.3V
0.4
V
RONP
RONN
VIN=3.6V, ILX=−100mA
VIN=3.6V, ILX=−100mA
0.34
0.43
Ω
Ω
Maxduty Oscillator Maximum Duty Cycle
100
%
tstart
ILXlim
Soft-start Time
VIN=VCE=3.6V or VSET+1V
VIN=VCE=3.6V or VSET+1V
VIN=VCE=3.6V or VSET+1V
VIN=VCE
150
900
1.5
2.0
2.1
310
s
mA
ms
V
LX Current Limit
700
0.5
1.9
2.0
tprot
Protection Delay Time
UVLO Detector Threshold
UVLO Released Voltage
5
VUVLO1
VUVLO2
2.1
2.2
VIN=VCE
V
Test circuit is "OPEN LOOP" and AGND=PGND=0V unless otherwise specified.
8
RP504x
TYPICAL APPLICATION
RP504N:SOT-23-5 (MODE Pin is not included.)
VOUT
GND
LX
CE
Control
RP504N
Series
Load
VIN
VIN
COUT 4.7F
L 2.2H
CIN 2.2F
RP504L:DFN1616-6B / RP504K:DFN(PLP)1216-6F (MODE Pin is included.)
VOUT
CE
Control
Control
RP504L,K
Series
MODE
GND
Load
VIN
VIN
LX
COUT 4.7F
L 2.2H
CIN 2.2F
) MODE=“H” forced PWM
MODE=“L” PWM/VFM automatic shift
Symbol
Recommendation components
C1608JB0J225K (TDK)
2.2F
C1005JB0J225K (TDK)
JMK105BJ225MV (Taiyo Yuden)
2.2F2
CIN
Ceramic
C1005X5R0J475M (TDK)
JMK105BJ475MV (Taiyo Yuden)
4.7F
4.7F
C1608JB0J475K (TDK)
GRM188B30J475KE18 (Murata)
COUT
Ceramic
Inductor
MIPSZ2520D2R2 (FDK)
MIPS2520D2R2 (FDK)
MLP2520S2R2M (TDK)
VLS252010T-2R2M (TDK)
L
2.2H
9
RP504x
TECHNICAL NOTES
When you use these ICs, consider the following issues:
Set external components such as an inductor, CIN, COUT as close as possible to the IC, in particular, minimize
the wiring to VIN pin and PGND pin. Reinforce the VIN, PGND, and VOUT lines sufficiently. Large switching
current may flow in these lines. If the impedance of VIN and PGND lines is too large, the internal voltage level in
this IC may shift caused by the switching current, and the operation might be unstable. The wiring between
VOUT and load and between L and VOUT should be separated.
The recommended capacitance value for the CIN capacitor connected between the VIN and PGND pins is
2.2µF or more. Also, the recommended capacitance value for the COUT capacitor is 4.7µF ~ 10µF.Please be
aware of the characteristics of bias dependence and temperature fluctuation of ceramic capacitor.
Choose an inductor with inductance range from 2.2H to 4.7H. The phase compensation has been made by
these values with output capacitors. The recommendation characteristics of the inductor are low DC resistance,
large enough permissible current, and strong against the magnetic saturation. Inductance value may shift
depending on an inductor. If the inductance value at an actual load current is low, LX peak current may increase
and may overlap the LX current limit. As a result, over current protection may work.
Over current protection circuit, Latch-type protection circuit may be affected by self-heating and heat radiation
environment.
The performance of power supply circuits using this IC largely depends on the peripheral circuits. Please be
very careful when setting the peripheral parts. When designing the peripheral circuits of each part, PCB
patterns, and this IC, please do not exceed the rated values (Voltage, Current, Power).
10
RP504x
Operation of step-down DC/DC converter and Output Current
The 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 Circuit>
<Current through L>
IL
ILmax
i1
ILmin
topen
VIN
VOUT
i1
i2
L
Pch Tr
Nch Tr
i2
CL
ton
toff
GND
T=1/fosc
Step 1: Pch 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 Pch Tr.
Step 2: When Pch Tr. turns off, Synchronous rectifier Nch Tr. turns on in order that L maintains IL at ILmax, and
current IL (=i2) flows.
Step 3: IL (=i2) decreases gradually and reaches IL=ILmin=0 after a time period of topen, and Nch Tr. 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 increases 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.
The maximum value (ILmax) and the minimum value (ILmin) of the current flowing through the inductor are the
same as those when Pch Tr. turns on and 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 respectively show the change of the current at "ON", and
the change of the current at "OFF".
11
RP504x
Discontinuous mode and Continuous mode
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.
Discontinuous mode
Continuous mode
ILmax
IL
IL
ILmax
ILmin
ILmin
topen
Iconst
t
t
ton
T=1/fosc
toff
ton
toff
T=1/fosc
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.
12
RP504x
Output Current and selection of External components
The relation between the output current and external components is as follows:
(Wherein, Ripple Current p-p value is described as IRP, ON resistance of Pch Tr. and Nch Tr. of LX are
respectively described as RONP and RONN, and the DC resistor of the inductor is described as RL.)
When Pch Tr. of LX is ON:
VIN = VOUT + (RONP + RL) IOUT + L IRP / ton ................................................................. Equation 3
When Pch Tr. of LX is "OFF" (Nch Tr. is "ON"):
L IRP / toff = RONN IOUT + VOUT + RL IOUT ................................................................. Equation 4
Put Equation 4 to Equation 3 and solve for ON duty of Pch transistor, DON = ton / (toff + ton),
DON = (VOUT + RONN IOUT + RL IOUT) / (VIN + RONN IOUT − RONP IOUT)....................... Equation 5
Ripple Current is as follows:
IRP = (VIN − VOUT − RONP IOUT − RL IOUT) DON / fosc / L............................................. Equation 6
wherein, peak current that flows through L, and LX Tr. is as follows:
ILXmax = IOUT + IRP / 2 .................................................................................................... Equation 7
Consider ILXmax, condition of input and output and select external components.
The above explanation is directed to the calculation in an ideal case in continuous mode.
13
RP504x
TIMING CHART
(1) Soft Start Time
In the case of starting this IC with CE
In the case of starting this IC with CE, the operation can be as in the timing chart below.
When the voltage of CE pin (VCE) is beyond the threshold level, the operation of the IC starts. The threshold
voltage of CE pin is in between CE "H" input voltage (VCEH) and CE "L" input voltage (VCEL) described in the
electrical characteristics table. Soft-start circuit operates, and after the certain time, the reference voltage
inside the IC (VREF) is rising gradually up to the constant value.
VCEH
Threshold Level
VCEL
CE Pin
Input Voltage
(VCE)
Soft-start Time
IC Internal Voltage
Reference
Soft-start Circuit
operating
(VREF)
Lx Voltage
(VLX)
PWM mode operating
during the Soft-start Time
Output Voltage
Depending on Power supply,
Load Current, External Components
(VOUT)
Soft-start time is the time interval from soft start circuit starting point to the reference voltage level reaching
point up to this constant level.
Soft start time is not always equal to the turn-on speed of DC/DC converter.
The power supply capacity for this IC, load current, inductance and capacitance values affect the turn-on
speed.
In the case of starting with power supply
In the case of starting with power supply, when the input voltage (VIN) is larger than UVLO released voltage
(VUVLO2), soft start circuit operates, and after that, the same explanation above is applied to the operation.
Soft-start time is the time interval from soft start circuit starting point to the reference voltage level reaching
point up to this constant level.
Set VOUT
VUVLO2
VUVLO1
Input Voltage
(VIN)
Soft-start Time
IC Internal Voltage
Reference
(VREF)
Lx Voltage
(VLX)
PWM mode operating during the Soft-start Time
Set VOUT
Output Voltage
Depending on Power supply,
Load Current, External Components
(VOUT)
Turn-on speed is affected by next conditions;
(a) Input Voltage (VIN) rising speed depending on the power supplier to the IC and input capacitor CIN.
(b) Output Capacitor COUT value and load current value.
14
RP504x
(2) Under Voltage Lockout (UVLO) Circuit
The step-down DC/DC converter stops and ON duty becomes 100%, if input voltage (VIN) becomes less
than the set output voltage (Set VOUT), the output voltage (VOUT) gradually drops according to the input
voltage (VIN). If the input voltage drops more and becomes less than UVLO detector threshold (VUVLO1), the
under voltage lockout circuit (UVLO) operates, the IC internal reference voltage (VREF) stops, switching
transistors turn off and the output voltage drops according to the load and output capacitor COUT value.
To restart the normal operation, the input voltage (VIN) must be more than the UVLO released voltage
(VUVLO2).
The timing chart below describes the operation with varying the input voltage (VIN).
Set VOUT
VUVLO2
VUVLO1
Input Voltage
(VIN)
Soft-start Time
IC Internal Voltage
Reference
(VREF)
Lx Voltage
(VLX)
Output Voltage
Set VOUT
(VOUT)
Depending on Power supply,
Load Current, External Components
Actually, the waveform of VOUT at UVLO working and releasing varies depending on the initial voltage of
COUT and load current situation.
15
RP504x
(3) Over Current Protection Circuit, Latch Type Protection Circuit
Over current protection circuit supervises the inductor peak current (the current flowing through Pch
transistor) in each switching cycle, and if the current exceeds the LX current limit (I
transistor. The LX current limit of RP504x is Typ.900mA.
), turns off Pch
LXlim
Latch type protection circuit latches the built-in driver to the OFF state and stops the operation of DC/DC
converter if the over current status continues or the output voltage continues being the half of the setting
voltage for equal or longer than protection delay time (tprot).
LX current limit (I ) and protection delay time (tprot) could be easily affected by self-heating or ambient
LXlim
environment. If the input voltage (VIN) drops drastically or becomes unstable due to short-circuit, the
protection operation and protection delay time may be affected.
Protection Delay Time (tprot)
Lx Current
Lx Current Limit (ILXlim)
Pch Tr. Current
Lx Voltage
(VLX)
To release the condition of latch type protection, restart this IC by inputting "L" signal to CE pin, or restart
this IC with power-on or make the supply voltage lower than UVLO detector threshold (VUVLO1) level.
The timing chart shown below describes the changing process of input voltage rising, stable operating,
operating with large current, reset with CE pin, stable operating, input voltage falling, input voltage
recovering, and stable operating.
Point(1) : If the large current flows through the circuit or the IC goes into low output voltage condition due to
short-circuit or other reasons, the latch type protection circuit latches the built-in driver to OFF state after the
protection delay time (tprot). Then, VLX becomes "L" and the output voltage turns OFF. In this timing chart
below, the latch protective circuit can be released by once putting the IC into "L" with the CE pin and then
into "H" again.
Point(2) : The latch type protection can be released by UVLO reset by making the input voltage lower than
the UVLO detector threshold(VUVLO1).
(1)
(2)
Set VOUT
UVLORelease Voltage (VUVLO2)
UVLODetect Voltage (VUVLO1)
Input Voltage
(VIN)
UV LO Reset
CE Pin
Input Voltage
(VCE)
Set VOUT
CE Reset
Threshold Level
Protection Delay Time Protection Delay Time
Set VOUT
Set VOUT
Lx Voltage
(VLX )
Latch-type Protection
Latch-type Protection
Output Voltage
(VOUT)
Stable
operation
Stable
operation
Stable
operation
Soft-start Time Soft-start Time
Soft-start Time
16
RP504x
TYPICAL CHARACTERISTICS
1) Output Voltage vs. Output Current
RP504x VOUT=0.8V
RP504x VOUT=0.8V
MODE=“L”PWM/VFM automatic shift
MODE=“H” forced PWM
0.820
0.820
0.815
0.810
0.805
0.800
0.795
0.790
0.785
0.780
VIN=3.6V
0.815
VIN=4.5V
0.810
VIN=3.6V
VIN=4.5V
0.805
0.800
0.795
0.790
0.785
0.780
0.01
0.1
1
10
100
0
100 200
300 400 500 600
Output Current IOUT (mA)
Output Current IOUT (mA)
RP504x VOUT=1.2V
RP504x VOUT=1.2V
MODE=“L”PWM/VFM automatic shift
MODE=“H” forced PWM
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
1.220
VIN=3.6V
VIN=5.0V
VIN=3.6V
VIN=5.0V
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
0.01
0.1
1
10
100
0
100 200
300
400 500
600
Output Current IOUT (mA)
Output Current IOUT (mA)
RP504x VOUT=1.8V
RP504x VOUT=1.8V
MODE=“L”PWM/VFM automatic shift
MODE=“H” forced PWM
1.830
1.820
1.810
1.800
1.790
1.780
1.830
VIN=3.6V
VIN=5.0V
VIN=3.6V
1.820
1.810
1.800
1.790
1.780
VIN=5.0V
0
100 200 300 400 500 600
Output Current IOUT (mA)
0.01
0.1
1
10
100
Output Current IOUT (mA)
17
RP504x
RP504x VOUT=3.3V
MODE=“L”PWM/VFM automatic shift
RP504x VOUT=3.3V
MODE=“H” forced PWM
3.320
3.310
3.300
3.290
3.280
3.270
3.320
VIN=4.3V
VIN=4.3V
VIN=5.0V
3.310
3.300
3.290
3.280
3.270
VIN=5.0V
0
100 200 300 400 500 600
Output Current IOUT (mA)
0.01
0.1
1
10
100
Output Current IOUT (mA)
2) Output Voltage vs. Input Voltage
RP504x VOUT=0.8V
RP504x VOUT=1.2V
MODE=“H” forced PWM
MODE=“H” forced PWM
0.820
0.815
0.810
0.805
0.800
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
IOUT=1mA
0.795
IOUT=1mA
IOUT=50mA
0.790
IOUT=50mA
IOUT=250mA
IOUT=250mA
0.785
0.780
2
2.5
3
3.5
4
4.5
2
2.5
3
3.5
4
4.5
(V)
5
5.5
Input Voltage VIN(V)
Input Voltage VIN
RP504x VOUT=1.8V
RP504x VOUT=3.3V
MODE=“H” forced PWM
MODE=“H” forced PWM
3.35
3.34
3.33
3.32
3.31
3.3
1.83
1.82
1.81
1.8
3.29
3.28
3.27
3.26
3.25
IOUT=1mA
IOUT=1mA
1.79
1.78
1.77
IOUT=50mA
IOUT=250mA
IOUT=50mA
IOUT=250mA
3.5
4
4.5
5
5.5
2
2.5
3
3.5
4
4.5
5
5.5
Input Voltage VIN(V)
Input Voltage VIN(V)
18
RP504x
3) Output Voltage vs. Temperature
1.830
1.820
VIN=3.6V
1.810
1.800
1.790
1.780
1.770
-50
-25
0
25
50
75
100
Temperature Ta(°C)
4) Efficiency vs. Output Current
RP504x VOUT=0.8V
RP504x VOUT=1.2V
IN
MODE
V =5.0V, V
=0V
100
90
80
70
60
50
40
30
20
10
0
100
IN
MODE
V =4.5V, V
=0V
90
IN
MODE
V =3.6V, V
=0V
IN
MODE
V =3.6V, V
=0V
80
70
60
50
40
30
20
10
0
IN
MODE
V =V
=4.5V
IN
V =V
MODE
=5.0V
IN
V =V
MODE
=3.6V
IN
V =V
MODE
=3.6V
0.01
0.1
1
10
OUT
100
(mA)
1000
0.01
0.1
1
10
100
1000
Output Current IOUT (mA)
Output Current I
RP504x VOUT=1.8V
RP504x VOUT=3.3V
IN
MODE
V =5.0V, V
=0V
=0V
IN
MODE
V =5.0V, V
=0V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
IN
MODE
V =4.3V, V
IN
MODE
V =3.6V, V
=0V
IN
V =V
MODE
=4.3V
IN
V =V
MODE
=5.0V
IN MODE
V =V
=3.6V
IN
V =V
MODE
=3.6V
0.01
0.1
1
10
100
1000
0.01
0.1
1
10
100
(mA)
1000
OUT
OUT
Output Current I
Output Current I
(mA)
19
RP504x
5) Supply Current vs. Temperature
RP504x VOUT=1.8V(VIN=5.5V)
6) Supply Current vs. Input Voltage
RP504x VOUT=1.8V
MODE=“L”PWM/VFM automatic shift
MODE=“L”PWM/VFM automatic shift
40
40
35
30
25
20
15
10
Closed Loop
35
Closed Loop
Open Loop
Open Loop
30
25
20
15
10
-50
-25
0
25
50
75
100
2
2.5
3
3.5
4
4.5
5
5.5
Input Voltage VIN (V)
Temperature Ta(°C)
7) Output Ripple Voltage Vripple
RP504x VOUT=0.8V(VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
RP504x VOUT=0.8V(VIN=3.6V)
MODE=“H” forced PWM
OUT
OUT
I
=10mA
I
=10mA
0.04
0.03
0.02
0.01
0.00
-0.01
0.04
0.03
0.02
0.01
0.00
-0.01
Output Voltage
IL
Output Voltage
IL
100
50
0
300
200
100
0
-50
-100
10
-100
0
5
10
15
20
0
1
2
3
4
5
6
7
8
9
Time t (µs)
Time t (µs)
RP504x VOUT=1.2V(VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
RP504x VOUT=1.2V(VIN=3.6V)
MODE=“H” forced PWM
IOUT=10mA
OUT
I
=10mA
0.04
0.03
0.02
0.01
0.00
-0.01
0.04
0.03
0.02
0.01
0.00
-0.01
Output Voltage
IL
Output Voltage
IL
100
50
0
-50
-100
300
200
100
0
-100
0
1
2
3
4
5
6
7
8
9 10
0
5
10
15
20
Time t (µs)
Time t (µs)
20
RP504x
RP504x VOUT=1.8V(VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
OUT
RP504x VOUT=1.8V(VIN=3.6V)
MODE=“H” forced PWM
IOUT=10mA
I
=10mA
0.04
0.03
0.02
0.01
0.00
-0.01
0.04
0.03
0.02
0.01
0.00
-0.01
Output Voltage
IL
Output Voltage
IL
100
50
300
200
100
0
0
-50
-100
-100
0
1
2
3
4
5
6
7
8
9 10
0
5
10
15
20
Time t (µs)
Time t (µs)
RP504x VOUT=3.3V(VIN=5.0V)
RP504x VOUT=3.3V(VIN=5.0V)
MODE=“H” forced PWM
MODE=“L”PWM/VFM automatic shift
OUT
I
=10mA
OUT
I
=10mA
0.04
0.03
0.02
0.01
0.00
-0.01
0.04
0.03
0.02
0.01
0.00
-0.01
Output Voltage
IL
Output Voltage
IL
200
150
100
50
0
-50
-100
300
200
100
0
-100
0
1
2
3
4
5
6
7
8
9 10
0
5
10
15
20
Time t (µs)
Time t (µs)
8) Frequency vs. Temperature
9) Frequency vs. Input Voltage
2.5
2.4
2.3
2.2
2.1
2
2.5
-40°C
VIN=3.6V
2.4
2.3
2.2
2.1
2
25°C
85°C
-50
-25
0
25
50
75
100
2
2.5
3
3.5
4
4.5
5
5.5
Temperature Ta (°C)
Input Voltage VIN (V)
21
RP504x
10) Soft Start Time vs. Temperature
220
210
200
190
180
170
-50
-25
0
25
50
75
100
Temperature Ta(°C)
11) UVLO Detector Threshold / Released Voltage vs. Temperature
UVLO Detector Threshold Voltage UVLO Released Voltage
2.3
2.2
2.1
2.0
1.9
2.3
2.2
2.1
2.0
1.9
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature Ta(°C)
Temperature Ta(°C)
12) CE Input Voltage vs. Temperature
CE“H” Input Voltage(VIN=5.5V)
CE“H” Input Voltage (VIN=2.3V)
1
0.9
0.8
0.7
0.6
0.5
0.4
1
0.9
0.8
0.7
0.6
0.5
0.4
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature Ta(°C)
Temperature Ta(°C)
22
RP504x
13) L Current Limit vs. Temperature
X
1000
950
900
850
800
-50
-25
0
25
50
75
100
Temperature Ta(°C)
14) Nch Tr. ON Resistance vs. Temperature
15) Pch Tr. ON Resistance vs. Temperature
0.60
0.50
0.40
0.30
0.20
0.10
0.60
0.50
0.40
0.30
0.20
0.10
0
0
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature Ta(°C)
Temperature Ta(°C)
16) Load Transient Response
RP504x081x (VIN=3.6V)
RP504x081x (VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
MODE=“L”PWM/VFM automatic shift
400
400
200
0
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.00
0.90
0.80
0.70
0.60
1.00
0.90
0.80
0.70
0.60
Output Voltage
Output Voltage
-10
0
10 20 30 40 50 60 70 80 90
Time t (µs)
-100
0
100 200 300 400 500 600 700 800 900
Time t (µs)
23
RP504x
RP504x081x (VIN=3.6V)
MODE=“H” forced PWM
RP504x081x (VIN=3.6V)
MODE=“H” forced PWM
400
200
0
400
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.00
0.90
0.80
0.70
0.60
1.00
0.90
0.80
0.70
0.60
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x081x (VIN=3.6V)
RP504x081x (VIN=3.6V)
600
400
200
0
600
400
200
0
Output Current
200mA-->500mA
Output Current
500mA-->200mA
1.00
0.90
0.80
0.70
0.60
1.00
0.90
0.80
0.70
0.60
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x121x (VIN=3.6V)
RP504x121x (VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
MODE=“L”PWM/VFM automatic shift
400
400
200
0
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.30
1.25
1.20
1.15
1.10
1.30
1.25
1.20
1.15
1.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-100
0
100 200 300 400 500 600 700 800 900
Time t (µs)
24
RP504x
RP504x121x (VIN=3.6V)
MODE=“H” forced PWM
RP504x121x (VIN=3.6V)
MODE=“H” forced PWM
400
200
0
400
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.30
1.25
1.20
1.15
1.10
1.30
1.25
1.20
1.15
1.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x121x (VIN=3.6V)
RP504x121x (VIN=3.6V)
600
400
200
0
600
400
200
0
Output Current
200mA-->500mA
Output Current
500mA-->200mA
1.30
1.25
1.20
1.15
1.10
1.30
1.25
1.20
1.15
1.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x181x (VIN=3.6V)
RP504x181x (VIN=3.6V)
MODE=“L”PWM/VFM automatic shift
MODE=“L”PWM/VFM automatic shift
400
400
200
0
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.90
1.85
1.80
1.75
1.70
1.90
1.85
1.80
1.75
1.70
Output Voltage
Output Voltage
-100
0
100 200 300 400 500 600 700 800 900
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
25
RP504x
RP504x181x (VIN=3.6V)
MODE=“H” forced PWM
RP504x181x (VIN=3.6V)
MODE=“H” forced PWM
400
200
0
400
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
1.90
1.85
1.80
1.75
1.70
1.65
1.90
1.85
1.80
1.75
1.70
1.65
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x181x (VIN=3.6V)
RP504x181x (VIN=3.6V)
600
400
200
0
600
400
200
0
Output Current
500mA-->200mA
Output Current
200mA-->500mA
1.90
1.85
1.80
1.75
1.70
1.65
1.90
1.85
1.80
1.75
1.70
1.65
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x331x (VIN=5.0V)
RP504x331x (VIN=5.0V)
MODE=“L”PWM/VFM automatic shift
MODE=“L”PWM/VFM automatic shift
400
400
200
0
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
3.50
3.40
3.30
3.20
3.10
3.50
3.40
3.30
3.20
3.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-100
0
100 200 300 400 500 600 700 800 900
Time t (µs)
26
RP504x
RP504x331x (VIN=5.0V)
MODE=“H” forced PWM
RP504x331x (VIN=5.0V)
MODE=“H” forced PWM
400
200
0
400
200
0
Output Current
1mA-->300mA
Output Current
300mA-->1mA
3.50
3.40
3.30
3.20
3.10
3.50
3.40
3.30
3.20
3.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
RP504x331x (VIN=5.0V)
RP504x331x (VIN=5.0V)
600
400
200
0
600
400
200
0
Output Current
200mA-->500mA
Output Current
500mA-->200mA
3.50
3.40
3.30
3.20
3.10
3.50
3.40
3.30
3.20
3.10
Output Voltage
Output Voltage
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
-10 0 10 20 30 40 50 60 70 80 90
Time t (µs)
17) Mode Switching Waveform
RP504x (VIN=1.2V, IOUT=1mA)
MODE=“L” --> MODE=“H”
RP504x (VIN=1.2V, IOUT=1mA)
MODE=“H" --> MODE=“L”
5
5
0
Mode Input Voltage
0
Mode Input Voltage
1.30
1.25
1.30
1.25
1.20
1.15
1.20
Output Voltage
Output Voltage
1.15
-100
0
100
200
300
400
-200
0
200
400
600
800
Time t (µs)
Time t (µs)
27
RP504x
RP504x (VIN=1.8V, IOUT=1mA)
MODE="L" --> MODE="H"
RP504x (VIN=1.8V, IOUT=1mA)
MODE="H" --> MODE="L"
5
0
5
0
Mode Input Voltage
Mode Input Voltage
1.90
1.85
1.80
1.75
1.90
1.85
1.80
1.75
Output Voltage
Output Voltage
-200
0
200
400
600
800
-100
0
100
200
300
400
Time t (µs)
Time t (µs)
28
1.The products and the product specifications described in this document are subject to change or
discontinuation of production without notice for reasons such as improvement. Therefore, before
deciding to use the products, please refer to Ricoh sales representatives for the latest
information thereon.
2.The materials in this document may not be copied or otherwise reproduced in whole or in part
without prior written consent of Ricoh.
3.Please be sure to take any necessary formalities under relevant laws or regulations before
exporting or otherwise taking out of your country the products or the technical information
described herein.
4.The technical information described in this document shows typical characteristics of and
example application circuits for the products. The release of such information is not to be
construed as a warranty of or a grant of license under Ricoh's or any third party's intellectual
property rights or any other rights.
5.The products listed in this document are intended and designed for use as general electronic
components in standard applications (office equipment, telecommunication equipment,
measuring instruments, consumer electronic products, amusement equipment etc.). Those
customers intending to use a product in an application requiring extreme quality and reliability,
for example, in a highly specific application where the failure or misoperation of the product
could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system,
traffic control system, automotive and transportation equipment, combustion equipment, safety
devices, life support system etc.) should first contact us.
6.We are making our continuous effort to improve the quality and reliability of our products, but
semiconductor products are likely to fail with certain probability. In order to prevent any injury to
persons or damages to property resulting from such failure, customers should be careful enough
to incorporate safety measures in their design, such as redundancy feature, firecontainment
feature and fail-safe feature. We do not assume any liability or responsibility for any loss or
damage arising from misuse or inappropriate use of the products.
7.Anti-radiation design is not implemented in the products described in this document.
8.Please contact Ricoh sales representatives should you have any questions or comments
concerning the products or the technical information.
For the conservation of the global environment, Ricoh is advancing the decrease of the negative environmental impact material.
After Apr. 1, 2006, we will ship out the lead free products only. Thus, all products that will be shipped from now on comply with RoHS Directive.
Basically after Apr. 1, 2012, we will ship out the Power Management ICs of the Halogen Free products only. (Ricoh Halogen Free products are
also Antimony Free.)
Halogen Free
RICOH COMPANY, LTD.
Electronic Devices Company
http://www.ricoh.com/LSI/
RICOH COMPANY, LTD.
Electronic Devices Company
● Higashi-Shinagawa Office (International Sales)
3-32-3, Higashi-Shinagawa, Shinagawa-ku, Tokyo 140-8655, Japan
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People's Republic of China
Phone: +86-21-5027-3200 Fax: +86-21-5027-3299
RICOH COMPANY, LTD.
Electronic Devices Company
● Taipei office
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