RP500x SERIES
600mA* Step-down DC/DC Converter with Synchronous Rectifier
NO.EA-155-090120
OUTLINE
The RP500x Series are CMOS-based 600mA* step-down DC/DC Converters with synchronous rectifier.
Each of these ICs consists of an oscillator, a switching control circuit, a reference voltage unit, an error
amplifier, a soft-start circuit, protection circuits, UVLO circuit, switching transistors, and so on. A low ripple, high
efficiency step-down DC/DC converter can be easily composed of this IC with only an inductor and capacitors.
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 24mV tolerance depending on the output voltage is guaranteed.
Mode alternative circuit works automatically for improving the efficiency. Considering fixed noise frequency,
PWM fixed control type is also available.
As protection circuits, the current limit circuit which limits peak current of Lx at each clock cycle, and the latch
type protection circuit which works if the term of the over-current condition keeps on a certain time exist. The
latch-type protection circuit works to latch an internal driver with keeping it disable. To release the condition of
the protection, after disabling this IC with a chip enable circuit, enable it again, or restart this IC with power-on or
make the supply voltage at UVLO detector threshold level or lower than UVLO.
Since packages are WLCSP-6-P2, DFN(PLP)1820-6, SOT-23-6W, high density mounting on boards is
possible.
*)This is an approximate value, because output current depends on conditions and external parts.
FEATURES
•
Supply Current ......................................................Typ. 400μA (at PWM mode)
Typ. 100μA (at VFM mode)
•
Standby Current ....................................................Max. 5μA
•
Input Voltage Range .............................................2.55V to 5.50V
•
Output Voltage ......................................................Stepwise setting with a step of 0.1V in the range of
1.1V to 3.3V is possible.
•
Output Voltage Accuracy.......................................±1.5% (V
OUT
>
1.6V),
±24mV
(V
OUT
<1.6V)
=
•
Temperature-Drift Coefficient of Output Voltage ...Typ.
±100ppm/°C
•
Oscillator Frequency .............................................Typ. 1.2MHz
•
Oscillator Maximum Duty Cycle ............................Min. 100%
•
Built-in Driver ON Resistance ...............................Typ. Pch. 0.3Ω, Nch. 0.38Ω (V
IN
=3.6V)
•
UVLO Detect Voltage............................................Typ. 2.2V
•
Soft Start Time.......................................................Typ. 120μs
•
Lx Current Limit.....................................................Typ. 900mA
•
Latch type Protection Circuit .................................Typ. 1.5ms
•
Two choices of Switching Mode............................Automatic PWM/VFM mode change / PWM fixed
•
Packages ..............................................................WLCSP-6-P2, DFN(PLP)1820-6, SOT-23-6W
APPLICATIONS
•
Power source for battery-powered equipment.
•
Power source for hand-held communication equipment, cameras, VCRs, camcorders.
•
Power source for HDD, portable equipment.
1
RP500x
BLOCK DIAGRAMS
RP500xxx1A/2A
V
IN
Chip
Enable
Ramp
Compensation
Current
Feedback
CE
OSC
Current
Protection
L
X
Vref
PWM
∗
Control
Switching
Control
UVLO
Soft Start
V
OUT
AGND
PGND
∗)
RP500xxx1A: automatic PWM/VFM mode change
RP500xxx3A/4A
V
IN
Chip
Enable
Ramp
Compensation
Current
Feedback
CE
OSC
Current
Protection
L
X
Vref
PWM
∗
Control
Switching
Control
UVLO
Soft Start
V
OUT
AGND
PGND
∗)
RP500xxx3A: automatic PWM/VFM mode change
2
RP500x
SELECTION GUIDE
The output voltage, auto discharge function*, and the taping type for the ICs can be selected at the user’s
request.
The selection can be made with designating the part number as shown below;
RP500xxx xx-xx-x
←Part
Number
↑ ↑ ↑
a b c
Code
a
Designation of Package Type:
Z : WLCSP-6-P2
K : DFN(PLP)1820-6
N : SOT-23-6W
Setting Output Voltage (V
OUT
):
Stepwise setting with a step of 0.1V
∗
1
in the range of 1.1V to 3.3V is possible.
Designation of Mask Option
1A : with PWM/VFM alternative, without auto discharge function
∗
2
at OFF state.
2A : PWM fixed, without auto discharge function
∗
2
at OFF state.
3A : with PWM/VFM alternative, with auto discharge function
∗
2
at OFF state.
4A : PWM fixed, with auto discharge function
∗
2
at OFF state.
Designation of Taping Type:
E2 : WLCSP-6-P2
TR : DFN(PLP)1820-6, SOT-23-6W
Designation of composition of pin plating:
-F : Lead free solder plating (WLCSP-6-P2, SOT-23-6W)
None: Au plating (DFN(PLP)1820-6)
↑ ↑
d e
Contents
b
c
d
e
∗1)
0.05V step is also available as a custom code.
∗2)
When the mode is into standby with CE signal, auto discharge transistor turns on, and it makes the turn-off
speed faster than normal type.
3
RP500x
PIN CONFIGURATIONS
•
WLCSP-6-P2
Mark Side
6
5
4
4
•
DFN(PLP)1612-4
Top View
6
5
4
•
SOT-23-6W
6
5
4
5
6
Bump Side
5
6
Bottom View
4
(mark side)
1
2
3
3
2
1
1
2
3
3
2
1
1
2
3
PIN DESCRIPTIONS
•
WLCSP-6-P2
Pin No.
1
2
3
4
5
6
Symbol
V
OUT
PGND
Lx
V
IN
AGND
CE
Description
Output Pin
Ground Pin
Lx Switching Pin
Input Pin
Ground Pin
Chip Enable Pin
•
DFN(PLP)1820-6
Pin No.
1
2
3
4
5
6
Symbol
CE
AGND
V
IN
Lx
PGND
V
OUT
Description
Chip Enable Pin
("H" Active)
Ground Pin
Input Pin
Lx Switching Pin
Ground Pin
Output Pin
("H" Active)
∗)
Tab in the
parts have GND level.
(They are connected to the back side of this IC.)
Do not connect to other wires or land patterns.
•
SOT-23-6W
Pin No.
1
2
3
4
5
6
Symbol
V
OUT
PGND
Lx
V
IN
AGND
CE
Description
Output Pin
Ground Pin
Lx Switching Pin
Input Pin
Ground Pin
Chip Enable Pin
("H" Active)
4
RP500x
ABSOLUTE MAXIMUM RATINGS
Symbol
V
IN
V
Lx
V
CE
V
OUT
I
Lx
P
D
Topt
Tstg
Input Voltage
Lx pin Voltage
CE Pin Input Voltage
Output Voltage
Lx Pin Output Current
Power Dissipation (WLCSP-6-P2) *
Power Dissipation (DFN(PLP)1820-6) *
Power Dissipation (SOT-23-6W) *
Operating Temperature Range
Storage Temperature Range
Item
Rating
6.5
−0.3
to V
IN
+0.3
−0.3
to V
IN
+0.3
−0.3
to V
IN
+0.3
800
650
880
430
−40
to 85
−55
to 125
°C
°C
mW
Unit
V
V
V
V
mA
*) For Power Dissipation, please refer to PACKAGE INFORMATION to be described.
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.
5
