MAX1970/MAX1971/MAX1972
Dual, 180° Out-of-Phase, 1.4MHz, 750mA Step-
Down Regulator with POR and RSI/PFO
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
CC
= V
EN
= 5V, R
POR
= 100kΩ to IN, R
PFO
= 100kΩ to IN, V
RSI
= 0, C
REF
= 0.1µF, FBSEL1 = unconnected, FBSEL2 =
unconnected, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
PFO (MAX1970 and MAX1972 Only)
V
CC
rising 4.04 4.12
PFO Trip Threshold IN = V
CC
V
CC
falling 3.86 3.94
V
PFO Output Current, High PFO = IN -1 1 µA
PFO Output Voltage, Low I
PFO
= 1mA, V
IN
= 4.3V 0.01 0.05 V
EN AND RSI (MAX1971 Only)
V
IL
0.4 0.95
Logic Input Thresholds IN = 2.6V to 5.5V
V
IH
1.0 1.6
V
RSI Input Resistance Internal pullup resistor to IN 5 10 20 kΩ
V
IL
-1 1
EN Logic Input Current
Logic input at 0 or
5.5V, V
IN
= 5.5V
V
IH
-1 1
µA
ELECTRICAL CHARACTERISTICS
(V
IN
= V
CC
= V
EN
= 5V, V
FB1
= V
FB2
= 1.15V, R
POR
= 100kΩ to IN, R
PFO
= 100kΩ to IN, RSI = 0, C
VCC
= 0.1µF, C
REF
= 0.1µF,
FBSEL1 = unconnected, FBSEL2 = unconnected, T
A
= -40°C to +85°C.) (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
IN AND V
CC
IN Voltage Range 2.6 5.5 V
MAX1971 10
IN Supply Current
Switching with no load
V
IN
= 3.3V
MAX1970/MAX1972 20
mA
MAX1970/MAX1972 20
IN Shutdown Current V
IN
= 5.5V, V
EN
= 0
MAX1971 100
µA
V
CC
rising 2.55
V
CC
Undervoltage
Lockout Threshold
V
CC
falling 2.20
V
REF
REF Voltage I
REF
= 0, V
IN
= 2.6V to 5.5V 1.185 1.212 V
REF Shutdown Resistance REF to GND, V
EN
=0 25 Ω
REF Soft-Start Current V
REF
= 1V 20 30 µA
FB1 AND FB2
FB_ Regulation Voltage
FBSEL_ = unconnected, OUT1 = FB1, OUT2 = FB2,
V
COMP_
= 1.20V to 1.80V, V
IN
= 2.6V to 5.5V
1.185 1.212 V
OUT_ Voltage Range FBSEL_ = unconnected 1.2 V
IN
V
V
IN
= 2.6V to 5.5V V
COMP1
= 1.2V, FBSEL1= GND 1.778 1.818
OUT1 Regulation Voltage
V
IN
= 4.5V to 5.5V V
COMP1
= 1.2V, FBSEL1 = V
CC
3.259 3.333
V
V
COMP2
= 1.2V, FBSEL2 = GND 1.481 1.515
OUT2 Regulation Voltage V
IN
= 2.6V to 5.5V
V
COMP2
= 1.2V, FBSEL2 = V
CC
2.469 2.525
V
Maximum Output Current Guaranteed by design (Note 1) 750 mA
