RP502x SERIES
Step-down DC/DC Converter with Synchronous Rectifier
NO.EA-189-110315
OUTLINE
The RP502x Series are CMOS-based 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 soft-start circuit, protection circuits, an UVLO circuit, and switching transistors. By adopting the
synchronous rectification with built-in switching transistors, high efficient step-down DC/DC converter can be
composed of only an inductor and capacitors.
As protection circuits, the current limit circuit and the latch protection circuit are built into the ICs. The current
limit circuit controls the peak current of L
X
at each clock cycle. Latch protection circuit maintains the built-in driver
in OFF state if the load current exceeds the limit value for a certain period of time. To cancel the latch protection,
disable the ICs with a chip enable circuit and then enable it again or make the power supply voltage lower than
UVLO.
The setting voltage for the RP502x Series is the output voltage fixed type with built-in feedback resistance that
is adjustable in 0.1V step with the accuracy of ± 1.5% or ±24mV. The packages for the ICs are WLCSP-6-P2
and DFN1616-6, which enable the high-density mounting. The switching mode for the ICs is selectable from the
PWM/VFM auto switching type, which achieves the high efficiency at the light load condition or PWM fixed type,
which switches at the fixed frequency.
FEATURES
•
Supply Current ......................................................Typ. 750μA (at normal)
Typ. 180μA (at light road)
•
Input Voltage Range .............................................2.5V to 5.5V(V
OUT
≥1.0V)
2.5V to 4.5V(V
OUT
<1.0V)
•
Absolute Maximum Ratings ..................................6.0V
•
Output Voltage Range...........................................0.8V to 3.3V (0.1V steps)
•
Output Voltage Accuracy.......................................±1.5% (V
OUT
≥1.6V)
±24mV
(V
OUT
<1.6V)
•
Oscillator Frequency .............................................Typ. 3.3MHz
•
Maximum Duty ......................................................Min. 100%
•
Built-in Driver ON Resistance ...............................Typ. Pch. 0.5Ω, Nch. 0.5Ω(V
IN
=3.6V)
•
UVLO Detector Threshold.....................................Typ. 2.2V
•
Soft Start Time.......................................................Typ. 0.12ms
•
Lx Current Limit.....................................................Typ. 900mA(V
OUT
≥1.2V)
Typ. 800mA(V
OUT
<1.2V)
•
Latch type Protection Circuit .................................Typ. 1.5ms
•
Chip Enable Function............................................"H" Active
•
Packages ..............................................................WLCSP-6-P2, DFN1616-6
APPLICATIONS
•
Power source for battery-powered equipments.
•
Power source for hand-held communication equipments, cameras, VCRs, camcorders.
•
Power source for HDDs, portable equipments.
1
RP502x
SELECTION GUIDE
In the RP502 Series, output voltage, switching mode, and auto discharge function for the ICs are selectable at
the user’s request.
Product Name
RP502Zxx∗B-E2-F
RP502Lxx∗B-TR
Package
WLCSP-6-P2
DFN1616-6
Quantity per Reel
5,000 pcs
5,000 pcs
Pb Free
Yes
Yes
∗
1
Halogen Free
Yes
Yes
xx : The output voltage can be designated in the range of 0.8V(08) to 3.3V(33) in 0.1V steps .
(For other voltages, please refer to MARK INFORMATIONS.)
∗
: The switching mode and auto discharge function can be designated as shown below.
Code
1
2
3
4
PWM/VFM auto switching
Yes
No
Yes
No
Auto discharge function
No
No
Yes
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.
4
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