Datasheet
MAX1920/MAX1921
Low-Voltage, 400mA Step-Down
DC-DC Converters in SOT23
_______________________________________________________________________________________ 3
100
0
0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 3.3V)
20
MAX1920 toc01
LOAD CURRENT ( mA)
EFFICIENCY (%)
40
60
80
70
50
30
10
90
V
IN
= 3.6V
V
IN
= 4.2V
V
IN
= 5V
100
0
0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 2.5V)
20
MAX1920 toc02
LOAD CURRENT ( mA)
EFFICIENCY (%)
40
60
80
70
50
30
10
90
V
IN
= 2.7V
V
IN
= 3.3V
V
IN
= 5V
100
0
0.1 1 10 100 1000
EFFICIENCY vs. LOAD CURRENT
(V
OUT
= 1.5V)
20
MAX1920 toc03
LOAD CURRENT ( mA)
EFFICIENCY (%)
40
60
80
70
50
30
10
90
V
IN
= 2.5V
V
IN
= 3.3V
V
IN
= 5V
3.201
3.234
3.267
3.300
3.333
3.366
3.399
0 10050 150 200 250 300 350 400
OUTPUT VOLTAGE ACCURACY vs. LOAD
(V
OUT
= 3.3V)
MAX1920 toc04
LOAD (mA)
OUTPUT VOLTAGE
V
IN
= 3.6V
V
IN
= 5V
V
IN
= 4.2V
2.425
2.450
2.475
2.500
2.525
2.550
2.575
0 10050 150 200 250 300 350 400
OUTPUT VOLTAGE ACCURACY vs. LOAD
(V
OUT
= 2.5V)
MAX1920 toc05
LOAD (mA)
OUTPUT VOLTAGE
V
IN
= 3V
V
IN
= 5V
1.455
1.470
1.485
1.500
1.515
1.530
1.545
0 10050 150 200 250 300 350 400
OUTPUT VOLTAGE ACCURACY vs. LOAD
(V
OUT
= 1.5V)
MAX1920 toc06
LOAD (mA)
OUTPUT VOLTAGE
V
IN
= 5V
V
IN
= 3.3V
V
IN
= 2.5V
Typical Operating Characteristics
(C
IN
= 2.2µF ceramic, Circuit of Figure 1, components of Table 1, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 3.6V, SHDN = IN, T
A
= 0°C to +85°C. Typical parameters are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Low-Side Current Limit
I
LIMN
350 550
800 mA
High-Side On-Resistance
R
ONHS
I
LX
= -40mA, V
IN
= 3V
0.6 1.1 Ω
Rectifier On-Resistance
R
ONSR
I
LX
= 40mA, V
IN
= 3V
0.5 0.9 Ω
Rectifier Off-Current Threshold
I
LXOFF
60 mA
LX Leakage Current
I
LXLEAK
IN = SHDN = 5.5V, LX = 0 to IN
0.1 5.0 µA
LX Reverse Leakage Current
I
LXLKR
IN unconnected, V
LX
= 5.5V, SHDN = GND
0.1 5.0 µA
Minimum On-Time
t
ON(MIN)
0.28
0.4 0.5 µs
Minimum Off-Time
t
OFF(MIN)
0.28
0.4 0.5 µs
Note 1: All devices are 100% production tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed
by design.