Datasheet

LTC3822-1
5
38221f
Maximum Current Sense Voltage
vs I
TH
Pin Voltage
Oscillator Frequency
vs Input Voltage
Shutdown Quiescent Current
vs Input Voltage
Quiescent Current in Normal
Operation vs Input Voltage
I
TH
VOLTAGE (V)
0.5
–20
CURRENT LIMIT (%)
0
20
40
60
100
1 1.5
38221 G03
2
80
Burst Mode OPERATION
(I
TH
RISING)
Burst Mode OPERATION
(I
TH
FALLING)
FORCED CONTINUOUS
MODE
PULSE SKIPPING
MODE
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C unless otherwise noted.
INPUT VOLTAGE (V)
2.5
–5
–4
–3
NORMALIZED FREQUENCY SHIFT (%)
–2
–1
0
2
4.0
38221 G11
4
1
3
5
3.0 3.5 4.5
INPUT VOLTAGE (V)
2.5
0
2
SHUTDOWN CURRENT (µA)
4
6
8
12
4.5
38221 G12
16
10
14
18
3.53.0 4.0
INPUT VOLTAGE (V)
2.5
QUIESCENT CURRENT (µA)
360
4.5
3822 G13
380
370
390
340
330
350
3.53.0 4.0
V
RUN
1V/DIV
V
OUT
1V/DIV
FIGURE 10 CIRCUIT
V
IN
= 3.3V
V
OUT
= 1.8V
R
LOAD
= 1.5Ω
200µs/DIV
38221 G14
V
RUN
1V/DIV
V
OUT
1V/DIV
V
TRACK/SS
1V/DIV
FIGURE 10 CIRCUIT
V
IN
= 3.3V
V
OUT
= 1.8V
R
LOAD
= 1.5Ω
C
SS
= 0.01µF
4ms/DIV
38221 G15
Start-Up with Internal Soft-Start
Start-Up with External Soft-Start
Capacitor
Soft-Start with Tracking Continuous Mode Operation
V
OUT
1V/DIV
V
TRACK/SS
500mV/DIV
FIGURE 10 CIRCUIT
V
IN
= 3.3V
V
OUT
= 1.8V
R
LOAD
= 1.5Ω
4ms/DIV
38221 G16
V
OUT
20mV/DIV
AC COUPLED
I
L
2A/DIV
V
SW
2V/DIV
FIGURE 10 CIRCUIT
V
IN
= 3.3V
V
OUT
= 1.8V, 100mA
2µs/DIV
38221 G17