AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 1 of 7 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Lead-free
• Input voltage range: 2.2V~5.5V (VOUT type)
• Oscillator frequency: 600KHz (Typ.)
• Internal reference: 1.0V (Typ.)
• High efficiency: 93% (Typ.)
• Stand-by capability: ISTB=2µA. (Typ.)
• Soft-start time set-up externally type possible
• Current limit and thermal shutdown protection
• Lead Free Package: SOT25
• SOT25: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
The AP1604A series are multi-functional step-down DC/DC
converters with built-in speed, low ON resistance drivers. It is
capable to deliver more than 800mA output current with external
coil, diode and capacitor.
Output voltage is set-up by the external resistors. (±2.5%
accuracy). The 600KHz AP1604A that can work out with small
value external components comes out more compact board.
The device switches to and works under PFM mode with light
loads. It keeps at high efficiency for both light loads and large
output current.
AP1604A can be soft-start with a proper capacitor connected
between CE/SS pin and ground. The stand-by current is less
than 2uA when CE/SS pin is at “LOW” status. The device is
forced to switch off as the voltage at that pin is lower than the
stipulated voltage.
Applications
• Electronic Information Organizers
• Palmtops
• Cellular and portable phones
• Portable Audio Systems
• Various Multi-function Power Supplies
Ordering Information
AP1604A W X - 7
Packing
Package Lead Free
W : SOT25 7 : Tape & Reel
L : Lead Free
G : Green
Device Package
Code Packaging
(Note 2) 7” Tape and Reel
Quantity Part Number Suffix
AP1604AWL-7 W SOT25
3000/Tape & Reel -7
AP1604AWG-7 W SOT25
3000/Tape & Reel -7
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS e xempt ion s app lied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
2. 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.
Features General Description
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 2 of 7 FEBRUARY 2009
www.diodes.com © Diodes In corp orated
Pin Assignment
1 32
5 4
CE/SS
VOUT VCC
GND
SOT25
FB
(Top View)
AP1604A
Pin Description
Block Diagram
Phase
Compensation
Vref with
CE
+
-
PWM/PFM
Controller
+
-
Ramp Wave
Generator,
OSC
VOUT
CE/SS GND
VCC
PWM
Comparator
FB
Current Limit
Soft
Start
ERR
AMP
SVCC
Pin Name Description
VOUT Output Voltage
GND Ground
VCC Input Supply
CE/SS Chip Enable / Soft Start
FB Feedback pin
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 3 of 7 FEBRUARY 2009
www.diodes.com © Diodes In corp orated
Absolute Maximum Ratings (TA=25°C)
Symbol Parameter Ratings Units
VCC/SVCC V
IN Pin Voltage -0.3 ~ 6.5 V
VOUT V
OUT Pin Voltage -0 .3 ~ VIN+0.3 V
VFB FB Pin Voltage -0.3 ~ VIN+0.3 V
VCE/SS CE/SS Pin Voltage -0.3 ~ VIN+0.3 V
PD Continuous Total Power Dissipation Internal limited
TOP Operating Ambient Temperature -25 ~ +80 °C
TST Storage Temperature Range -40 ~ +125 °C
Electrical Characteristics
VIN = 5V, VOUT＝2V, Load = 300mA, TA = 25°C
Sym. Parameter Conditions Min Typ. Max Units
VFB FB 0.975 1.0 1.025 V
VIN Input Voltage 2.2 - 5.5 V
Line Regulation VIN = 2.2 ~ 5.5V, Load = 10mA - - 0.12 %
Load Regulation IOUT = 10 ~ 800mA - - 1.2 %
VUVLO UVLO Voltage（min.
operating voltage） VCC, voltage required to maintain H at
VOUT - - 2 V
ICC Operating Current CE/SS = VIN,No Load - 100 150 μA
ICCQ Supply Current No external components,
CE/SS = VIN,VFB = 1.2V - 90 120 μA
ISTB Stand-by Current No external components,
CE/SS = 0V,VFB = 0V - 2 - μA
ICL Current Limit peak current
VIN = 5V, VOUT = 2V 800 1000 1200 mA
Fosc Oscillator Frequency Load = 300mA, VIN = 5V, VOUT = 2V 500 600 700 kHz
MAXDTY Maximum Duty Ratio 85 90 - %
PFMD TY PFM Duty Ratio No load 15 25 35 %
VCEH CE/SS ”High” Voltage Apply 1.4V (min.) to CE/SS, determine
VOUT ”High” 1.4 - - V
VCEL CE/SS ”Low” Voltage Same as VCEH, determine VOUT/”Low” - - 0.6 V
EFFI Efficiency VCC = 5V, VOUT = 3.3V, Load = 300mA - 93 - %
Rdson Rdson Condition IOUT = 300mA, VIN = 5V, VOUT = 2V - 350 450 mΩ
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 4 of 7 FEBRUARY 2009
www.diodes.com © Diodes In corp orated
Typical Performance Characteristics
V
cc vs. Operating Current
V
cc vs. Quiescent Current
0
20
40
60
80
100
120
140
160
180
200
2.5 3 3.5 4 4.5 5 5.5
Vcc
(
V
)
Operating Current (uA)
0
20
40
60
80
100
120
140
160
180
200
2.533.544.555.5
Vcc (V)
Quiescent Current (uA)
V
cc vs. Stand-by Current
V
cc vs. Frequency
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
2.5 3 3.5 4 4.5 5 5.5
Vcc (V)
Stand-by Cur r ent (uA)
500
520
540
560
580
600
620
640
660
680
700
2.533.544.555.5
Vcc (V)
Frequency (KHz)
V
cc vs. Current Limit
V
cc vs. RDS(ON)
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
33.544.555.5
Vcc
(
V
)
Current Lim it (A )
Current Limit
Vout=2V
0
100
200
300
400
500
600
2.5 3 3.5 4 4.5 5 5.5
RDS(ON) (mΩ)
Vcc (V)
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 5 of 7 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics (Continued)
Line Regulation Load Regulation
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
2.533.544.555.5
Vcc (V)
V / VOUT (%)
-3
-2
-1
0
1
2
3
0 100 200 300 400 500 600 700 800
Load (mA)
V / VOUT (%)
Typical Application Circuit
0.1uF
V
IN
FB
V
CC
GND
10uH
AP1604A
V
OUT
CE/SS
68uF
2.2V ~ 5.5V
B240A R2
R1 0.1uF 68uF
V
OUT
10nF
100nF
~
1MΩ
Vout = 1
(1 + R1
R2 )
R1 = 100K ~ 200K
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 6 of 7 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
Marking Information
(1) SOT25
1 2 3
5
7
4
XX YW X
XX : Identification code
W : Week : A~Z : 1~26 week;
X : a~z : Lead Free
( Top View )
Y : Year 0~9
a~z : 27~52 week; z represents
52 and 53 week
A~Z : Green
Part Number Package Identification Code
AP1604AW SOT25 ER
Package Information (All Dimensions in mm)
(1) Package Type: SOT25
AP1604A
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1604A Rev. 2 7 of 7 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
IMPORTANT NOTICE
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notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither
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President of Diodes Incorporated.