ANACHIP AP1522

AP1522
Step-Up DC/DC Converter
„ Features
„ General Description
- High Efficiency: 84% Typical
- 36V High Output Voltage
- Fast 1MHz Switching Frequency
- Low Profile SOT23-5 Pb-Free Packaging
The AP1522 is a step-up DC/DC converter in a
5-Lead low profile SOT23-5 package. The AP1522
switches at 1MHz that allows the use of tiny
external components. A low 1.25V feedback voltage
minimizes power loss in the current setting resistor
for better efficiency.
„ Applications
- Cellular Phones
- PDAs, Handhelp Computers
- Digital Cameras
- LCD Bias Voltage, Battery Backup
-
„ Pin Descriptions
„ Pin Assignments
Name
Top View
VIN
SHDN
SW
VSS
FB
SHDN
SW VSS
FB
VIN
SOT23-5L
Description
Switch Pin. Connect inductor/diode
here. Minimize trace area at this pin
to reduce EMI.
GND pin
Feedback Pin. Reference voltage is
1.25V.
Shutdown Pin. Tie to 0.6V or higher
to enable device ; 0.5Vor less to
disable device.
Input Supply Pin. Must be locally
bypassed.
„ Ordering Information
AP1522
X X
Package
Packing
W: SOT23-5L
Blank : Tube
A : Taping
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev. 1.0 May. 5, 2005
1/8
AP1522
Step-Up DC/DC Converter
„ Block Diagram
1 SW
Comparator
Driver
A2
+
-
A1
R
S
Q
Q1
RC
+
CC
FB 3
+
VREF
1.25V
Σ
-
VIN 5
RAMP
Generator
2 GND
Shutdown
SHDN 4
1MHz
Oscillator
„ Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
VIN
VIN Pin Voltage
10
V
VSW
SW Voltage
36
V
VFB
Feedback Pin Voltage
10
V
VSHDN
TJ
TLEAD
TOPR
SHDN Pin Voltage
10
Maximum Junction Temperature
125
o
C
300
o
C
-40 to +85
o
C
Power Dissipation
Operating Temperature Range
V
o
TSTG
Storage Temperature Range
-40 to +125
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 conditions.
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
2/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Electrical Characteristics (Ta=25°C, VIN = 5V, VSHDN = 5V, unless otherwise noted.)
Symbol
VIN
VIN
VFB
IFB
Parameter
Minimum Operation Voltage
Maximum Operation Voltage
Feedback Pin Voltage
Feedback Pin Bios Current
Conditions
Operation current
Supply Current
VSHDN = 0V
Min.
2.5
1.225
10
-
Typ.
1.25
45
2
Max.
10
1.275
100
3
Unit
V
V
V
nA
mA
-
0.1
1.0
µA
FSW
Switching frequency
0.75
1.0
1.25
MHz
Duty
ISW
VSAT
PWM Maximum Duty Cycle
Switch Current Limit
Switch VSAT
Switch Leakage Current
SHDN Pin Voltage High
SHDN Pin Voltage Low
SHDN Pin Bios Current
85
280
0.6
-
90
320
350
0.1
10
360
5
0.5
-
%
mA
mV
µA
V
V
µA
VSHDN
VSHDN
ISHDN
ISW = 250mA
VSW = 5V
Enable
Disable
„ Typical Application Circuit
L1
10uH
D1
Vout=10V
C2
4.7uF
Vin=3.3V
C1
4.7uF
Option
R1
70K
Vin
SW
Vss
R2
10K
FB
SHDN
ON OFF
R1
)
R2
1K < R2 < 50K
VOUT=VFB (1+
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
3/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Typical Application Circuit (Continued)
Step up DC-DC Regulator
L
22uH
VIN
2.5V~3.3V
VIN
CIN
4.7uF
VOUT
4.8V
D
57K
SW
AP1522
4.7pF
FB
SHDN
COUT
4.7uF
20K
GND
1-Cell Li-lon to 3.3V SEPIC Converter
L1
10uH
VIN
2.5V to 4.2V
C3
1uF
5
1
VIN
SW
C1
4.7uF
AP1522
4
D1
3.3V
50mA
L2 33K
10uH
4.7pF
C2
10uF
3
FB
SHDN
20K
GND
2
4-Cell to 5V SEPIC Converter
L1
10uH
VIN
3V to 6V
C1
4.7uF
C3
1uF
5
1
VIN
SW
AP1522
4
FB
D1
5V
40mA
L2
10uH
30K 4.7pF
C2
10uF
3
SHDN
10K
GND
2
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
4/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Typical Application Circuit (Continued)
+20V Dual Output Converter with Output Disconnect
D3
C4
1uF
D2
C5
1uF D1
L1
10uH
VIN
2.5V to 5V
C1
4.7uF
5
1
VIN
SW
AP1522
4
-20V
4mA
C3
1uF
FB
D4
20V
4mA
150K 4.7pF
C2
10uF
3
SHDN
10K
GND
2
„ Applications Information
Open-Circuit Protection
In the cases of output open circuit, when the R1 are
disconnected from the circuit, the feedback voltage
will be zero. The AP1522 will then switch at a high
duty cycle resulting in a high output voltage, which
may cause the SW pin voltage to exceed its
maximum 36V rating. A zener diode can be used
at the output to limit the voltage on the SW pin
(Figure 1). The zener voltage should be larger
than the maximum forward voltage of the VOUT.
The current rating of the zener should be larger
than 0.1mA.
Inductor Selection
A 10µH inductor is recommended for most AP1522
applications.
Although small size and high
efficiency are major concerns, the inductor should
have low core losses at 1MHz and low DCR
(copper wire resistance).
Capacitor Selection
The small size of ceramic capacitors makes them
ideal for AP1522 applications. X5R and X7R types
are recommended because they retain their
capacitance over wider voltage and temperature
ranges than other types such as Y5V or Z5U. A
4.7µF input capacitor and a 4.7µF output capacitor
are sufficient for most AP1522 applications.
L
22uH
V IN
Diode Selection
Schottky diodes, with their low forward voltage drop
and fast reverse recovery, are the ideal choices for
AP1522 applications. The forward voltage drop of
a Schottky diode represents the conduction losses
in the diode, while the diode capacitance (CT or CD)
represents the switching losses.
For diode
selection, both forward voltage drop and diode
capacitance need to be considered.
Schottky
diodes with higher current ratings usually have
lower forward voltage drop and larger diode
capacitance, which can cause significant switching
losses at the 1MHz switching frequency of the
AP1522. A Schottky diode rated at 100mA to
200mA is sufficient for most AP1522 applications.
D
COUT
2uF
R1
200K
4.7pF
C IN
1uF
VIN
SW
AP1522
SHDN
GND
FB
R2
1K
R3
14K
Figure 1. With Open-Circuit Protection
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
5/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Typical Performance Characteristics
Feedback Voltage v.s. Temperature
Vin=5V; Vout=15V
1.26
1000
900
800
700
600
500
400
300
200
100
0
Feedback Voltage (V)
Frequency (KHz)
Frequency v.s. Temperature
Vin=5V; Vout=15V
1.25
1.24
1.23
1.22
-40
10
60
110
-40
o
60
110
Temperature ( C)
Supply Current v.s. Temperature
Vin=5V; Vout=15V; Iout=0A
Supply Current v.s. Supply Voltage
Vout=15V; Iout=0A
3
3
2.5
2.5
Supply Current (mA)
Supply Current (mA)
10
o
Temperature ( C)
2
1.5
1
0.5
2
1.5
1
0.5
0
0
-40
10
o
60
Temperature ( C)
0
110
5
10
15
Supply Voltage (V)
Efficiency v.s. Output Current
Vin=5V; Vout=15V
Efficiency v.s. Output Current
Vin=3.3V; Vout=15V
90
85
Efficiency (%)
Efficiency (%)
85
80
75
70
75
65
55
0
20
40
Output Current (mA)
0
60
20
40
60
Output Current (mA)
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
6/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Typical Performance Characteristics (Continued)
Frequency v.s. Supply Voltage
Vout=15V
1200
Frequency (KHz)
1000
800
600
400
200
0
0
2
4
6
8
Supply Voltage (V)
10
12
„ Marking Information
4
7
5
XX Y M
Identification code
(See Appendix)
1
2
3
Appendix
Part
Number
AP1522
Month: A~L
Package
SOT23-5
Identification
Code
FA
Year: 0-9
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
7/8
May. 5, 2005
AP1522
Step-Up DC/DC Converter
„ Package Information
Package Type: SOT23-5L
D
e1
θ1(4x)
4
5
E1
A
E
0.10 C
5x
A2
Seating Plane
A1
1
2
θ 2(4x)
3
b
e
With
Plating
b1
C
C1
Gauge Plane
0.25 mm
θ
Base
Metal
L
b
Symbol
L1
Dimensions In Millimeters
Dimensions In Inches
Min.
Nom.
Max.
Min.
Nom.
Max.
A
1.05
1.20
1.35
0.041
0.047
0.053
A1
0.05
0.10
0.15
0.002
0.004
0.006
A2
1.00
1.10
1.20
0.039
0.043
0.047
b
0.25
-
0.55
0.010
-
0.022
b1
0.25
0.40
0.45
0.010
0.016
0.018
c
0.08
-
0.20
0.003
-
0.008
c1
0.08
0.11
0.15
0.003
0.004
0.006
D
2.70
2.85
3.00
0.106
0.112
0.118
E
2.60
2.80
3.00
0.102
0.110
0.118
E1
1.50
1.60
1.70
0.059
0.063
0.067
L
0.35
0.45
0.55
0.014
0.018
0.022
L1
0.60 Ref.
0.024 Ref.
e
0.95 Bsc.
0.037 Bsc.
e1
θ
0o
1.90 Bsc.
5o
10o
0o
0.075 Bsc.
5o
10o
θ1
3o
5o
7o
3o
5o
7o
θ2
6o
8o
10o
6o
8o
10o
Anachip Corp.
www.anachip.com.tw
Rev. 1.0
8/8
May. 5, 2005