RP509x Series
0.5A/1A PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier
No. EA-362-171208
OUTLINE
The RP509x is a low supply current CMOS-based PWM/VFM step-down DC/DC converter with synchronous
rectifier featuring 0.5 A/1 A output current
(1)
. Internally, a single converter consists of a reference voltage unit,
an error amplifier, a switching control circuit, a mode control circuit, a soft-start circuit, an undervoltage lockout
(UVLO) circuit, a thermal shutdown circuit, and switching transistors. The RP509x is employing synchronous
rectification for improving the efficiency of rectification by replacing diodes with built-in switching transistors.
Using synchronous rectification not only increases circuit performance but also allows a design to reduce parts
count. Output voltage controlling method is selectable between a PWM/VFM auto-switching control type and
a forced PWM control type, which further reduces noise than a normal PWM control under a light load, and
these types can be set by the MODE pin. Output voltage type is selectable between an internally fixed output
voltage type and an externally adjustable output voltage type. Protection circuits in the RP509x is current limit
circuit and thermal shutdown circuit. LX current limit value (Typ.) is selectable between 1.6 A and 1.0 A.
The RP509Z is available in WLCSP-6-P6 which achieves high-density mounting on boards. Using capacitor
of 0402-/1005-size (inch/mm) and inductor of 0603-/1608-size (inch/mm) as external parts help to save space
for devices. The RP509N is available in SOT-23-6.
FEATURES
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•
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Input Voltage Range (Maximum Rating) ···························· 2.3 V to 5.5 V (6.5 V)
Output Voltage Range (Fixed Output Voltage Type) ············· 0.6 V to 3.3 V, settable in 0.1 V steps
(Adjustable Output Voltage Type) ······· 0.6 V to 5.5 V
Output Voltage Accuracy (Fixed Output Voltage Type) ·········· ±1.5% (V
SET(2)
≥
1.2 V), ±18 mV (V
SET
< 1.2 V)
Feedback Voltage Accuracy (Adjustable Output Voltage Type) ···· ±9 mV (V
FB
= 0.6 V)
Output Voltage/Feedback Voltage Temperature Coefficient ···· ±100 ppm/°C
Selectable Oscillator Frequency ······································ Typ. 6.0 MHz
Oscillator Maximum Duty ··············································· Min. 100%
Built-in Driver ON Resistance (V
IN
= 3.6 V) ························· Typ. Pch. 0.175
Ω,
Nch. 0.155
Ω
(RP509Z)
Typ. Pch. 0.195 Ω, Nch. 0.175 Ω
(RP509N)
Standby Current ··························································· Typ. 0 µA
UVLO Detector Threshold ·············································· Typ. 2.0 V
Soft-start Time ····························································· Typ. 0.15 ms
Inductor Current Limit Circuit··········································· Typ. 1.6 A/1.0 A, selectable Current Limit
Package ····································································· WLCSP-6-P6 (1.28 mm x 0.88 mm x 0.69 mm)
SOT-23-6
(1)
(2)
This is an approximate value. The output current is dependent on conditions and external components.
V
SET
= Set Output Voltage
1
RP509x
No. EA-362-171208
APPLICATIONS
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•
Portable Communication Equipment: Mobiles/Smartphones, Digital Cameras and Note-PCs
Li-ion Battery-used Equipment
SELECTION GUIDE
The set output voltage, the output voltage type, the auto-discharge function
(1)
, and the LX current limit for the
ICs are user-selectable options.
Selection Guide
Product Name
RP509ZxxX$-E2-F
RP509NxxX$-TR-FE
Package
WLCSP-6-P6
SOT-23-6
Quantity per Reel
5,000 pcs
3,000 pcs
Pb Free
Yes
Yes
Halogen Free
Yes
Yes
xx: Specify the set output voltage (V
SET
)
Fixed Output Voltage Type: 06 to 33 (0.6 V to 3.3 V, 0.1 V steps)
The voltage in 0.05 V step is shown as follows.
1.05 V: RP509Z101B5
1.15 V: RP509N111x5
Adjustable Output Voltage Type: 00 only
X: Specify the LX Current Limit (I
LXLIM
)
Typ. 1.6 A: 1
Typ. 1.0 A: 2
$: Specify the version
Version Output Voltage Type
A
Fixed
B
C
Adjustable
D
Auto-discharge
No
Yes
No
Yes
Oscillator Frequency
6.0 MHz
V
SET
0.6 V to 3.3 V
0.6 V to 5.5 V
(1)
Auto-discharge function quickly lowers the output voltage to 0 V, 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.
2
RP509x
No. EA-362-171208
PIN DESCRIPTION
Top View
Bottom View
6
5
4
2
1
A
B
C
2
(mark side)
1
C
B
A
1
2
3
WLCSP-6 Pin Configurations
SOT-23-6 Pin Configurations
WLCSP-6 Pin Description
Pin No.
Symbol
A1
B1
C1
A2
B2
C2
MODE
LX
VOUT/VFB
VIN
CE
GND
Description
Mode Control Pin
(High: Forced PWM Control, Low: PWM/VFM Auto-switching Control)
Switching Pin
Output/Feedback Voltage Pin
Input Voltage Pin
Chip Enable Pin, Active-high
Ground Pin
SOT-23-6 Pin Description
Pin No.
Symbol
1
CE
2
GND
3
VIN
4
5
6
MODE
LX
VOUT/VFB
Description
Chip Enable Pin, Active-high
Ground Pin
Input Voltage Pin
Mode Control Pin
(High: Forced PWM Control, Low: PWM/VFM Auto-switching Control)
Switching Pin
Output/Feedback Voltage Pin
5
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