Data Sheet
340kHz, 3A Synchronous DC-DC Buck Converter AP3503F
Oct. 2012 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
5
Electrical Characteristics
T
A
=25ºC, V
IN
=V
EN
=12V, V
OUT
=3.3V, unless otherwise specified.
Parameter Symbol Conditions Min Typ Max Unit
SUPPLY VOLTAGE (IN PIN)
Input Voltage V
IN
4.5 18 V
Quiescent Current I
Q
V
FB
=1V,V
EN
=3V 1.2 1.4 mA
Shutdown Supply Current I
SHDN
V
EN
=0V 0.1 10
μA
UNDER VOLTAGE LOCKOUT
Input UVLO Threshold V
UVLO
V
IN
Rising 3.65 4.00 4.25 V
Input UVLO Hysteresis V
HYS
200 mV
ENABLE (EN PIN)
EN Shutdown Threshold Voltage 1.1 1.5 2 V
EN Shutdown Threshold Voltage Hysteresis
(Note 2)
350 mV
EN Lockout Threshold Voltage 2.2 2.5 2.7 V
EN Lockout Hysteresis 210 mV
VOLTAGE REFERENCE (FB PIN)
Feedback Voltage V
FB
0.907 0.925 0.943 V
Feedback Over Voltage Threshold V
FBOV
1.1 V
Feedback Bias Current I
FB
V
FB
=1V -0.1 0.1
μA
MOSFET
High-side Switch On-resistance(Note 3) R
DSONH
I
SW
=0.2A/0.7A
100
mΩ
Low-side Switch On-resistance(Note 3) R
DSONL
I
SW
=-0.2A/-0.7A
100
mΩ
CURRENT LIMIT
High-side Switch Leakage Current I
LEAKH
V
IN
=18V,V
EN
=V
SW
=0V 0.1 10
μA
High-side Switch Current Limit I
LIMH
4.3 5.6 A
Low-side Switch Current Limit I
LIML
From drain to Source 1.4 A
SWITCHING REGULATOR
Oscillator Frequency f
OSC1
280 340 400 kHz
Short Circuit Oscillator Frequency f
OSC2
90 kHz
Max. Duty Cycle D
MAX
V
FB
=0.85V 90 %
Min. Duty Cycle D
MIN
V
FB
=1V 0 %
ERROR AMPLIFIER
Error Amplifier Voltage Gain (Note 2) A
EA
400 V/V
Error Amplifier Transconductance G
EA
800
A/V
COMP to Current Sense Transconductance G
CS
5.2 A/V
THERMAL SHUTDOWN
Thermal Shutdown (Note 2) T
OTSD
160 ºC
Thermal Shutdown Hysteresis (Note 2) T
HYS
20 ºC
SOFT START (SS PIN)
Soft-start Time (Note 2) t
SS
C
SS
=0.1μF
15 ms
Soft-start Current V
SS
=0V 6
μA
Note 2: Not tested, guaranteed by design.
Note 3: R
DSON
=
SW2SW1
SW2SW1
I-I
V-V
.
