3A, Low-Voltage, Step-Down Regulator with
Synchronous Rectification and Internal Switches
MAX1623
ABSOLUTE MAXIMUM RATINGS
IN to PGND .....................................................................0V to 6V
V
CC
to GND ................................................................-0.3V to 6V
PGND to GND.....................................................................±0.5V
IN to V
CC
.............................................................................±0.5V
LX to PGND.................................................................-0.5V to 6V
SHDN
to GND .............................................................-0.3V to 6V
REF, FBSEL, COMP, FB, TOFF to GND .....-0.3V to (V
CC
+ 0.3V)
REF Short to GND ......................................................Continuous
Continuous Power Dissipation (T
A
= +70°C) (with part mounted
on 1 sq. inch of one ounce copper)
20-Pin SSOP (derate 22mW/°C above +70°C) ................1.3W
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= +5V, FBSEL unconnected, R
TOFF
= 110kΩ,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
=
+25°C.)
PARAMETER
Input Voltage Range
FBSEL = unconnected
Output Voltage
Output Adjustment Range
Reference Output Voltage
Reference Load Regulation
Current-Limit Threshold
PMOS Switch On-Resistance
NMOS Switch On-Resistance
Maximum Switching Frequency
Idle Mode Threshold (Note 2)
No-Load Supply Current
Shutdown Supply Current
LX Leakage Current
Thermal Shutdown Threshold
Undervoltage Lockout Threshold
FB Input Bias Current
Error-Amplifier Gain Bandwidth
Off-Time Adjustment Range
Off-Time Default Period
AC Output Load Regulation
SHDN
Input Current
SHDN
Input Low Voltage
SHDN
Input High Voltage
2
FBSEL = GND
FBSEL = REF
SHDN
= GND or V
CC
-1
V
CC
falling, 100mV hysteresis
FBSEL = GND, adjustable output mode, V
FB
= 1.2V
(Note 1)
4.1
-25
500
0.5
0.85
1.00
1
2
0.03
1
0.8
4
1.15
Does not include switching losses
SHDN
= GND
V
IN
= 5.5V, V
LX
= 5.5V or 0
145
4.2
4.3
25
V
IN
= 4.5V
V
IN
= 4.5V
I
LOAD
≥
1.5A (Note 1)
1
1.25
400
0.5
V
IN
= 4.5V to 5.5V,
I
LOAD
= 0 to 3A
FBSEL = V
CC
FBSEL = GND or REF
CONDITIONS
MIN
4.5
3.296
2.49
1.089
V
REF
1.089
3.65
55
60
1.100
3.330
2.525
1.100
TYP
MAX
5.5
3.366
2.550
1.110
3.80
1.110
1
4.65
100
100
350
1.5
525
10
±20
V
V
mV
A
mΩ
mΩ
kHz
A
µA
µA
µA
°C
V
nA
kHz
µs
µs
%
µA
V
V
V
UNITS
V
FBSEL = GND or REF (Note 1)
I
REF
= 0
I
REF
= -1µA to 10µA
2
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
