MAX8855/MAX8855A
Dual, 5A, 2MHz Step-Down Regulators
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
IN_
= V
VDD
= V
VDL
= 3.3V, V
FB_
= 0.5V, V
SS_
= V
REFIN
= 600mV, PGND_ = GND, R
FSYNC
= 10kΩ, L = 0.47μH, C
BST_
= 0.1μF,
C
SS_
= 0.022μF, PWRGD_ not connected; 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
EN1, EN2
EN_ Logic-Low 0.7 V
EN_ Logic-High 1.7 V
T
A
= +25°C-1 +1
EN_ Input Current
V
EN_
= 0 or 3.6V,
V
VDD
= 3.6V
T
A
= +85°C 0.01
μA
SS1, SS2
SS_ Charging Current V
SS_
= 300mV 5 8 11 μA
REFIN, SS2
Discharge Resistance In shutdown or a fault condition 335 Ω
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
(Independent Channels)
+165 °C
Thermal-Shutdown Hysteresis 20 °C
Note 2: All devices 100% production tested at T
A
= +25°C. Limits over temperature are guaranteed by design.
Note 3: V
VDD
must equal V
VDL
and be equal to or greater than V
IN
_.
EFFICIENCY
vs. LOAD CURRENT WITH 3.3V INPUT
MAX8855/MAX8855A toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
1000
10
20
30
40
50
60
70
80
90
100
0
100 10,000
V
OUT_
= 2.5V
V
OUT_
= 1.2V
V
OUT_
= 1.8V
EFFICIENCY
vs. LOAD CURRENT WITH 2.5V INPUT
MAX8855/MAX8855A toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
1000
10
20
30
40
50
60
70
80
90
100
0
100 10,000
V
OUT_
= 1.2V
V
OUT_
= 1.8V
SWITCHING FREQUENCY vs. R
FSYNC
MAX8855/MAX8855A toc03
R
FSYNC
(kΩ)
SWITCHING FREQUENCY (kHz)
12
600
800
1000
1200
1400
1600
1800
2000
2200
2400
400
369 151821
Typical Operating Characteristics
(V
IN1
= V
IN2
= 3.3V, MAX8855/MAX8855A, circuit of Figure 6, T
A
= +25°C, unless otherwise noted.)
