Datasheet

MAX1973/MAX1974
Smallest 1A, 1.4MHz Step-Down Regulators
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
CTL_
= 3.3V, FB = OUT, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS
MIN
TYP
MAX
UNITS
SS Source Current -25 -20 -15 µA
SS Sink Current 10 20 35 µA
SS to GND Resistance in
Shutdown
540
100
Ω
FBSEL
Low Input Threshold 0.3 V
High Input Threshold
V
IN
-
0.3
V
Input Bias Current FBSEL = GND or IN, V
IN
= 5.5V -20 10
+20
µA
COMP
Transconductance from FB to
COMP
40 60 80 µS
COMP to GND Resistance in
Shutdown
540
100
Ω
Clamp Voltage Low 0.6 0.9 1.2 V
Clamp Voltage High
1.35 1.75 2.15
V
LX
On-Resistance High V
IN
= 3.3V
0.23 0.46
Ω
On-Resistance Low V
IN
= 3.3V
0.16 0.32
Ω
Current-Sense Transresistance
0.275 0.335 0.425
V/A
Positive Current-Limit Threshold
1.1 1.6
1.75
A
Negative Current-Limit Threshold
-1.2 -0.8 -0.4
A
V
LX
= V
IN
= 5.5V 20
LX Shutdown Leakage Current
LX = GND, V
IN
= 5.5V -20
µA
Switching Frequency 1.2 1.4 1.6
MHz
CTL1, CTL2 (MAX1973), ON (MAX1974)
Logic-Low Input Threshold 0.6 V
Logic-High Input Threshold 1.6 V
Logic Input Current -1 +1 µA
POK (MAX1974 only)
Output Low Voltage POK sinking 1mA 10
100
mV
Rising 90
92.5
95
Output Valid Threshold for POK
Percentage of nominal
regulation voltage
Falling 88 90 92
%