Owner manual

AP1539
18V 4A 300KHz BUCK CONVERTER
AP1539 Rev. 4 5 of 13 OCTOBER 2009
DS31477 www.diodes.com © Diodes Incorporated
Electrical Characteristics
(V
IN = 12V, T
A
= 25°C, unless otherwise specified)
Symbol Parameter Conditions Min Typ. Max Unit
V
FB
Feedback Voltage I
OUT
= 0.1A 0.784 0.8 0.816 V
I
FB
Feedback Bias Current I
OUT
= 0.1A - 0.1 0.5 µA
I
SHDN
Current Consumption During
Power Off
V
EN
= 0V - 10 - µA
∆V
OUT
/ V
IN
Line Regulation V
IN
= 5V~18V - 1 2 %
∆V
OUT
/ V
OUT
Load Regulation I
OUT
= 0.1 to 4A - 0.2 0.5 %
f
OSC
Oscillation Frequency Measure waveform at SW pin 240 300 400 KHz
f
OSC1
Frequency of Current Limit or
Short Circuit Protection
Measure waveform at SW pin - 50 - KHz
V
IH
EN Pin Input Voltage
Evaluate oscillation at SW pin 2.0 - -
V
V
IL
Evaluate oscillation stop at SW pin - - 0.8
I
SH
EN Pin Input Leakage Current
EN Pin High - 20 - µA
I
SL
EN Pin Low - -10 - µA
I
OCSET
OCSET Pin Bias Current -- 75 90 105 µA
R
DS(ON)
Internal MOSFET R
DS(ON)
V
IN
= 5V, V
FB
= 0V - 90 -
mΩ
V
IN
= 12V, V
FB
= 0V - 50 -
EFFI Efficiency
V
IN
= 12V, V
OUT
= 5V
I
OUT
=4
A
- 92 - %
T
SHDN
Thermal shutdown threshold - 150 - °C
T
HYS
Thermal shutdown hysteresis - 55 - °C
θ
JC
Thermal Resistance
Junction-to-Case
SOP-8L-DEP (Note 5) - 26 -
o
C/W
Notes: 5. Test condition for SOP-8L-DEP: Devices mounted on 2oz copper, minimum recommended pad layout on top & bottom layer with thermal vias,
double sided FR-4 PCB.