Datasheet

Maxim Integrated │ 3
MAX17503 4.5V-60V, 2.5A, High-Efciency,
Synchronous Step-Down DC-DC Converter
With Internal Compensation
www.maximintegrated.com
Electrical Characteristics (continued)
(V
IN
= V
EN/UVLO
=24V,R
RT
= 40.2kI(500kHz),C
VCC
=2.2μF,V
PGND
= V
SGND
= V
MODE
= V
SYNC
= 0V, LX = SS = RESET = open,
V
BST
to V
LX
= 5V, V
FB
= 1V, T
A
= T
J
= -40ºC to +125ºC, unless otherwise noted. Typical values are at T
A
= +25ºC. All voltages are
referencedtoSGND,unlessotherwisenoted.)(Note2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER MOSFET AND BST DRIVER
High-SidenMOSOn-Resistance R
DS-ONH
I
LX
= 0.3A 165 325
mI
Low-SidenMOSOn-Resistance R
DS-ONL
I
LX
= 0.3A 80 150
mI
LX Leakage Current I
LX_LKG
V
LX
= V
IN
- 1V, V
LX
= V
PGND
+ 1V, T
A
= +25ºC -2 +2 µA
SOFT-START (SS)
Charging Current I
SS
V
SS
= 0.5V 4.7 5 5.3 µA
FEEDBACK (FB)
FBRegulationVoltage V
FB_REG
-40ºC ≤T
A
≤+125ºC 0.89 0.9 0.91 V
FB Input Bias Current I
FB
0 < V
FB
< 1V, T
A
= +25ºC -50 +50 nA
MODE
MODE Threshold
V
M-DCM
MODE = V
CC
(DCM mode)
V
CC
-
1.6
V
V
M-PFM
MODE = open (PFM mode) V
CC
/ 2
V
M-PWM
MODE=GND(PWMmode) 1.4
PFM/HIBERNATE MODE
FB Threshold for Entering
HibernateMode
V
FB_HBR
V
FB
rising 100.8 102.3 103.5 %
FBThresholdforExitingHibernate
Mode
V
FB_HBF
V
FB
falling 100 101.1 102.3 %
CURRENT LIMIT
Peak Current-Limit Threshold I
PEAK-LIMIT
3.2 3.7 4.3 A
RunawayCurrent-LimitThreshold I
RUNAWAY-LIMIT
3.7 4.3 5 A
Valley Current-Limit Threshold I
SINK-LIMIT
MODE = open/V
CC
-0.16 0 +0.16
A
MODE=GND -1.8
PFM Current-Limit Threshold I
PFM
MODE = open 0.6 0.75 0.9 A
RT AND SYNC
Switching Frequency f
SW
R
RT
= 210kΩ 90 100 110
kHz
R
RT
= 102kΩ 180 200 220
R
RT
= 40.2kΩ 475 500 525
R
RT
= 8.06kΩ 1950 2200 2450
R
RT
= open 460 500 540
SYNCFrequencyCaptureRange f
SW
setbyR
RT
1.1 x
f
SW
1.4 x
f
SW
kHz