Datasheet

MAX1920/MAX1921
Low-Voltage, 400mA Step-Down
DC-DC Converters in SOT23
4 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(C
IN
= 2.2µF ceramic, Circuit of Figure 1, components of Table 1, unless otherwise noted.)
10,000
1
0.1 1 100 1000
SWITCHING FREQUENCY vs. LOAD
(V
OUT
= 1.8V)
10
100
1000
MAX1920 toc07
LOAD (mA)
SWITCHING FREQUENCY (kHz)
10
V
IN
= 3.3
10,000
1
0.1 1 100 1000
SWITCHING FREQUENCY vs. LOAD
(V
OUT
= 1.5V)
10
100
1000
MAX1920 toc08
LOAD (mA)
SWITCHING FREQUENCY (kHz)
10
V
IN
= 3.3
NO LOAD SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1920 toc09
SUPPLY VOLTAGE (V)
NO-LOAD SUPPLY CURRENT (µA)
5..04.54.03.53.02.52.0
10
100
1000
10,000
1
1.5 5.5
V
OUT
= 3.3V
V
OUT
= 2.5V
V
OUT
= 1.5V
LIGHT-LOAD SWITCHING WAVEFORM
MAX1920 toc10
V
OUT
AC-COUPLED
5mV/div
V
LX
2V/div
1µs/div
V
IN
= 3.3V, V
OUT
= 1.5V,
I
LOAD
= 40mA
MEDIUM-LOAD SWITCHING WAVEFORM
MAX1920 toc11
V
OUT
AC-COUPLED
5mV/div
V
LX
2V/div
1µs/div
V
IN
= 3.3V, V
OUT
= 1.5V,
I
LOAD
= 250mA
SOFT-START AND SHUTDOWN RESPONSE
MAX1920 toc12
V
OUT
1V/div
I
IN
100mA/div
V
SHDN
5V/div
200µs/div
V
IN
= 3.3V, V
OUT
= 1.5V,
R
LOAD
= 6Ω
MEDIUM-LOAD
LINE-TRANSIENT RESPONSE
MAX1920 toc13
V
IN
AC-COUPLED
200mV/div
V
OUT
AC-COUPLED
5mV/div
4µs/div
V
IN
= 3.8V to 4.2V,
V
OUT
= 1.5V, I
LOAD
= 250mA
LIGHT-LOAD
LINE-TRANSIENT RESPONSE
MAX1920 toc14
V
IN
AC-COUPLED
200mV/div
V
OUT
AC-COUPLED
5mV/div
4µs/div
V
IN
= 3.8V to 4.2V,
V
OUT
= 1.5V, I
LOAD
= 20mA
LOAD-TRANSIENT RESPONSE
MAX1920 toc15
V
OUT
AC-COUPLED
100mV/div
I
LOAD
200mA/div
I
L
200mA/div
40µs/div
V
IN
= 3.3V, V
OUT
= 1.5V,
I
LOAD
= 20mA TO 320mA