AP1635
PWM/PFM DUAL MODE STEP-DOWN DC/DC
CONVERTER
AP1635 Rev. 4 4 of 8 FEBRUARY 2009
www.diodes.com © Diodes Incorporated
Electrical Characteristics
V
IN
=5V, V
OUT
＝2V, Load=300mA, TA=25°C
Symbol Parameter Conditions Min Typ. Max Units
V
FB
FB 0.975 1.0 1.025 V
V
IN
Input Voltage 2.2 - 5 V
Line Regulation V
IN
=2.2~5V, Load=10mA - - 0.12 %
Load Regulation I
OUT
=10~1200mA - - 1.2 %
V
UVLO
UVLO Voltage（min.
operating voltage）
V
CC
, voltage required to maintain H at V
OUT
- - 2 V
I
CC
Operating Current CE/SS=V
IN
, No Load - 100 150 μA
I
CCQ
Supply Current
No external components,
CE/SS=V
IN
, V
FB
=1.2V
- 90 120 μA
I
STB
Stand-by Current
No external components,
CE/SS=0V, V
FB
=0V
- 6 - μA
I
CL
Current Limit
Peak current
V
IN
=5V, V
OUT
=2V
1200 1400 1600 mA
Fosc Oscillator Frequency Load=300mA, V
IN
=5V, V
OUT
=2V 500 700 - kHz
MAXDTY Maximum Duty Ratio 85 90 - %
PFMDTY PFM Duty Ratio No load 15 25 35 %
V
CEH
CE/SS ”High” Voltage
Apply 1.4V (min.) to CE/SS, determine
V
OUT
“Hi
h”
1.4 - - V
V
CEL
CE/SS ”Low” Voltage Same as V
CEH
, determine V
OUT
/“Low” - - 0.6 V
EFFI Efficiency V
CC
=5V, V
OUT
=3.3V, Load=300mA - 93 - %
Rdson Rdson Condition I
OUT
=300mA, V
IN
=5V, V
OUT
=2V - 350 450 mΩ
