Datasheet

MAX8556/MAX8557
4A Ultra-Low-Input-Voltage
LDO Regulators
_______________________________________________________________________________________ 3
Note 2: Specifications to T
A
= -40°C are guaranteed by design and not production tested.
Note 3: Minimum supply voltage for output accuracy must be at least 1.425V.
ELECTRICAL CHARACTERISTICS (continued)
(V
EN
= V
IN
= 1.8V, V
OUT
= 1.5V, I
OUT
= 2mA, T
A
= -40°C to +85°C, typical values are at T
A
= +25°C, unless otherwise noted.) (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
POK Output Current, High V
POK
= 3.6V V
FB
= 0.5 0.001 1 µA
POK Delay Time From FB rising to POK high 25 50 100 µs
EN
EN rising 1.25
Enable Input Threshold V
IN
= 1.425V to 3.6V
EN falling 0.4
V
Enable Input Bias Current V
EN
= 0V or 3.6V -1 +1 µA
THERMAL SHUTDOWN
T
J
rising +160
Thermal-Shutdown Threshold Output on and off
T
J
falling +115
°C
POR
FB Power-On Reset Fault Threshold FB falling, V
IN
= 1.425V to 3.6V, 10mV hysteresis 440 450 460 mV
POR Output Voltage, Low V
FB
= 0.4V, I
POR
= 2mA 25 200 mV
POR Output Current, High V
POR
= 3.6V, V
FB
= 0.5V 0.001 1 µA
POR Rising Delay Time FB rising to POR high impedance 100 140 200 ms
SOFT-START
Soft-Start Time 100 µs
Typical Operating Characteristics
(V
EN
= V
IN
= +1.8V, V
OUT
= +1.5V, I
OUT
= 4A, C
OUT
= 20µF, C
IN
= 20µF, and T
A
= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX8556 toc01
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
3.02.41.8
1.35
1.40
1.45
1.50
1.55
1.30
1.2 3.6
T
A
= -25
°
C
T
A
= -40
°
C
T
A
= -85
°
C
I
LOAD
= 2A
OUTPUT VOLTAGE vs. LOAD CURRENT
MAX8556 toc02
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
321
1.4980
1.4985
1.4990
1.4995
1.5000
1.5005
1.5010
1.5015
1.5020
1.5025
1.4975
04
T
A
= -40
°
C
T
A
= +85
°
C
T
A
= +25
°
C
GND CURRENT vs. INPUT VOLTAGE
MAX8556 toc03
INPUT VOLTAGE (V)
GND CURRENT (µA)
2.41.2
100
200
300
400
500
600
700
800
900
1000
0
0 3.6
I
LOAD
= 4A
I
LOAD
= 2A
I
LOAD
= 0A