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Description
The AP5727 is a high efficiency boost converter in a
compact SOT25 that provides the bias voltages for OLED
Sub Display and TFT-LCD (Liquid Crystal Display).
A high 1.2MHz switching frequency and internal
compensation minimizes external part count, PCB area and
cost. Integrated soft start reduces inrush current.
The AP5727 has a 1.25V feedback voltage making it
compatible with industry standard boost converters used to
bias LCD panels.
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
Pin Assignments
1
SW
2
GND
3
FB
( Top View )
SOT25
AP5727
IN
V
5
7
4
EN
Features
• 30V High Output Voltage
• Fast 1.2MHz Switching Frequency
NEW PRODUCT
• Current limit and UVLO Protections
• Internal Thermal Shutdown
• Maximum 1µA Shutdown Current
• Integrated Soft-start Function
• SOT25: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish/RoHS Compliant (Note 1)
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html.
Applications
• Small size TFT-LCD Bias power supply.
• OLED bias supply for a clamshell handset sub display
• RF amplifier bias voltages
Typical Application Circuit
L1
V
IN
22uH
C
IN
4.7uF
V
IN
SW
D1
R1
C
OUT
10uF
V
OUT
AP5727
Document number: DS31887 Rev. 2 - 2
AP5727
EN
FB
GND
Figure 1. Typical Application Circuit
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Functional Block Diagram
FB
3
V
1.25V
Regulator On/Off Control Input. A high input at EN turns on the converter, and a low input turns it off. When not
used, connect EN to the input source for automatic startup. The EN pin cannot be left floating.
NEW PRODUCT
Pin Descriptions
Name Description
SW Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI.
GND GND pin
FB Feedback Pin. Reference voltage is 1.25V.
EN
VIN Input Supply Pin. Must be locally decoupled - 4.7μF recommended to reduce input noise.
V
EN
5
IN
4
REF
Shutdown
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
1
2
SW
Q1
GND
Comparator
-
A2
+
R
A1
-
+
C
C
C
R
Q
S
Driver
+
Σ
-
RAMP
Generator
1.2MHz
Oscillator
Figure 2. Block Diagram
AP5727
Document number: DS31887 Rev. 2 - 2
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AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
Absolute Maximum Ratings (T
Symbol Parameter Rating Unit
VIN VIN Pin Voltage -0.3~7 V
VSW SW Voltage -0.3~32 V
VFB Feedback Pin Voltage -0.3~7 V
EN EN -0.3~7 V
T
Maximum Junction Temperature 150 °C
J(MAX)
T
Lead Temperature 300 °C
LEAD
TST Storage Temperature Range -65 to +150 °C
Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be
exceeded under any condition.
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VIN Input Voltage 2.7 5.5 V
TJ Operating Junction Temperature -40 125 °C
NEW PRODUCT
TA Operating Ambient Temperature -40 85 °C
Electrical Characteristics (V
Symbol Parameter Conditions Min. Typ. Max. Unit
System Supply Input
VIN Operating Input Voltage 2.7 - 5.5 V
UVLO Under Voltage Lockout - 2.2 2.4 V
Under Voltage Lockout Hysteretic - 85 - mV
IQ Quiescent Current FB=1.3V, No Switching - 500 - μA
ISD Shutdown Current VEN < 0.4V - 0.1 1 μA
Oscillator
F
Operation Frequency 1 1.2 1.4 MHz
OSC
Dmax Maximum Duty Cycle 86 90 - %
Reference Voltage
VFB Feedback Voltage 1.225 1.25 1.275 V
IFB FB Pin Bias Current 10 45 100 nA
MOSFET
R
On Resistance of MOSFET - 0.95 1.2 Ω
DS(on)
I
Switching Current Limit Normal Operati on - 750 - mA
OCP
Control and Protection
EN Voltage High ON 1.5 - - V
EN Voltage Low OFF - - 0.4 V
IEN EN Pin Pull Low Current - 4 6 μA
Thermal Resistance Junction-to-
θ
JA
Ambient
Thermal Resistance Junction-to-
θ
JC
Case
Notes: 2. Test condition for SOT25: Device mounted on FR-4 substrate, single-layer PC board, 2oz copper, with minimum recommended pad layout
AP5727
Document number: DS31887 Rev. 2 - 2
= 25°C)
A
= 3.6V, TA = 25°C, unless otherwise specified)
IN
SOT25 (Note 2) 162
SOT25 (Note 2) 36
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Typical Performance Characteristics (V
3.3V; V
IN
= 15V I
OUT
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
= 20mA)
OUT
NEW PRODUCT
VIN vs. Shutdown Current
0.1
0.08
0.06
0.04
0.02
Shutdown Current(uA)
0
2.5 3 3.5 4 4.5 5 5.5
1.4
1.3
1.2
1.1
Frequency(MHZ)
V
(V)
IN
VIN vs. Frequency
VIN vs. Quiescent Current
800
700
600
500
400
300
200
Quiescent Current(uA)
100
0
2.533.544.555.5
V
(V)
IN
VIN vs. Max Duty
100
95
90
Max Duty (%)
85
1
2.5 3 3.5 4 4.5 5 5.5
VIN vs. Feedback Voltage
1.27
1.26
1.25
1.24
Feedback Voltage(V)
1.23
1.22
2.533.544.555.5
AP5727
Document number: DS31887 Rev. 2 - 2
80
V
(V)
IN
2.5 3 3.5 4 4.5 5 5.5
V
(V)
IN
I
vs. Feedback Voltage
OUT
1.27
1.26
1.25
1.24
1.23
Feedback Voltage(V)
1.22
(V)
V
IN
0 1020304050
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I
OUT
(mA)
January 2011
© Diodes Incorporated
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Typical Performance Characteristics (V
3.3V; V
IN
= 15V I
OUT
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
= 20mA)
OUT
NEW PRODUCT
Temperature vs. Shutdown Current
2
1.6
1.2
0.8
0.4
Shutdown Current(uA)
0
-50 -25 0 25 50 75 100 125
Temperature (℃)
Temperature vs. Feedback Voltage
1.3
1.28
1.26
1.24
Feedback Voltage(mV)
1.22
1.2
-50 -25 0 25 50 75 100 125
Temperature (℃)
Temperature vs. Frequency
1.7
1.4
1.1
Frequency (MHZ)
0.8
0.5
-50 -25 0 25 50 75 100 125
90
85
80
75
70
65
Efficiency(%)
60
55
50
0 20406080
Temperature (℃)
I
(mA) vs. Efficiency (%)
OUT
I
(mA)
OUT
VIN = 5V
VIN = 4.2V
VIN = 3.6V
VIN = 3.3V
AP5727
Document number: DS31887 Rev. 2 - 2
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Typical Performance Characteristics (Continued)
V
Ripple
OUT
= 3.3V; VOUT = 15V ; IOUT = 5mA
V
IN
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
V
Ripple
OUT
= 3.3V; VOUT = 15V ; IOUT = 50mA
V
IN
SW
V
OUT
NEW PRODUCT
POWER ON
= 3.3V; VOUT = 15V ; IOUT = 50mA
V
IN
VIN = 3.3V; VOUT = 15V ; IOUT = 50mA
POWER OFF
VEN
VOUT
I
L
SW
VOUT
VEN
VOUT
I
L
AP5727
Document number: DS31887 Rev. 2 - 2
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Typical Performance Characteristics (Continued)
Load Transient Response
= 3.3V; VOUT = 15V ; IOUT = 5~50mA
V
IN
VOUT
IOUT
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
NEW PRODUCT
Application Information
Inductor Selection
A 10μH~22μH inductor is recommended for most AP5727 applications. Although small size and high efficienc y are major
concerns, the inductor should have low core loss at 1.2MHz and low DCR.
Capacitor Selection
Ceramic capacitors, due to their small size, are ideal for AP5727 applications. X5R and X7R types are recommended
because they retain their capacitance over wider voltage and temperature ranges than other types such as X5R and X7R.
A 4.7μF input capacitor and a 10μF output capacitor are sufficient for most AP5727 applications.
Diode Selection
Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal choices for AP5727 applications.
The forward voltage drop of a Schottky diode represents the conduction loss in the diod e, while the diode capacitance (C
represents the switching loss. For diode selection, both forward voltage d rop and diode capac itance need to be considere d.
Schottky diodes with higher current ratings usually have lower forward voltage drop and larger diode capacitance, which can
cause significant switching loss at the 1.2MHz switching frequency of the AP5727.
)
T
AP5727
Document number: DS31887 Rev. 2 - 2
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V
Application Circuit
AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
VOUT
Cout
10uF
Table 1. Suggested Inductors
Vendor
Wurth Electronics 22 0.51A SMD 3.8X 3.8 X 1.6 744031220
NEW PRODUCT
GOTREND 22 0.56A SMD 3.8 X 3.8 X 1.05 GLP3810PH220N
TAIYO YUDEN 22 0.51A SMD 4.0 X 4.0 X 1.25 NR4012
Table 2. Suggested Capacitors for C
Vendor Capacitance Type Series
TAIYO YUDEN 4.7uF SMD LMK316 B7 475KL-T
TAIYO YUDEN 10uF SMD LMK316 F 106ZL-T
Table 3. Suggested Diodes
Vendor Rating Type Series
ZETEX 40V/0.5A SOD323 ZLLS400
DIODES 40V/0.5A SOD323 B0540WS
DIODES 40V/0.25A SOD523 SDM20U40
Table 4. Suggested Resistor
endor Type Series
YAGEO SMD FR-SK
R1
11K
Inductors
(uH)
D1
B0540WS
R2
1K
Current Rating
(A)
and C
IN
OUT
1 2
U1
1
SW
2
GND
3
FB
AP5727
Type
L1
22uH
5
Vin
4
EN
Dimensions
(mm)
VIN
Cin
4.7uF
Series
Ordering Information
AP 5727 W
Package
W : SOT25
G - 7
Green
G : Green
Packing
7 : Tape & Reel
Device
AP5727WG-7 W SOT25 3000/Tape & Reel -7
Note: 3. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Package Code
AP5727
Document number: DS31887 Rev. 2 - 2
Packaging
(Note 3)
www.diodes.com
Quantity Part Number Suffix
8 of 10
7” Tape and Reel
January 2011
© Diodes Incorporated
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Marking Information
(1) SOT25
( Top View )
5
XX Y
1 2 3
Part Number Package Identification Code
AP5727 SOT25 H8
Package Outline Dimensions (All Dimensions in mm)
(1) Package Type: SOT25
NEW PRODUCT
W X
7
4
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
: Identification Code
XX
Y
: Year 0~9
W
: Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
: A~Z : Green
X
AP5727
AP5727
Document number: DS31887 Rev. 2 - 2
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AP5727
BIAS POWER SUPPLY FOR OLED
SUB DISPLAY AND TFT-LED
NEW PRODUCT
IMPORTANT NOTICE
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changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
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Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can b e reasonably expected
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Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support dev ices or
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Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
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Copyright © 2010, Diodes Incorporated
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AP5727
Document number: DS31887 Rev. 2 - 2
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