LTC3822-1_15 Datasheet, PDF (5/24 Pages) Linear Technology – No RSENSE, Low Input Voltage, Synchronous Step-Down DC/DC Controller

LTC3822-1
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise noted.
Oscillator Frequency
vs Input Voltage
5
4
3
2
1
0
–1
–2
–3
–4
–5
2.5
3.0
3.5
4.0
INPUT VOLTAGE (V)
4.5
38221 G11
Quiescent Current in Normal
Operation vs Input Voltage
390
380
370
360
350
340
330
2.5
3.0
3.5
4.0
INPUT VOLTAGE (V)
4.5
3822 G13
Maximum Current Sense Voltage
vs I_TH Pin Voltage
100
Burst Mode OPERATION
(I_TH RISING)
80
Burst Mode OPERATION
(I_TH FALLING)
FORCED CONTINUOUS
60
MODE
PULSE SKIPPING
40
MODE
20
0
–20
0.5
1
1.5
I_TH VOLTAGE (V)
2
38221 G03
Start-Up with Internal Soft-Start
Shutdown Quiescent Current
vs Input Voltage
18
16
14
12
10
8
6
4
2
0
2.5
3.0
3.5
4.0
4.5
INPUT VOLTAGE (V)
38221 G12
Start-Up with External Soft-Start
Capacitor
V_RUN
1V/DIV
V_OUT
1V/DIV
V_RUN
1V/DIV
V_TRACK/SS
1V/DIV
V_OUT
1V/DIV
200µs/DIV
FIGURE 10 CIRCUIT
V_IN = 3.3V
V_OUT = 1.8V
R_LOAD = 1.5Ω
38221 G14
4ms/DIV
FIGURE 10 CIRCUIT
V_IN = 3.3V
V_OUT = 1.8V
R_LOAD = 1.5Ω
C_SS = 0.01µF
38221 G15
Soft-Start with Tracking
Continuous Mode Operation
V_TRACK/SS
500mV/DIV
V_OUT
1V/DIV
4ms/DIV
FIGURE 10 CIRCUIT
V_IN = 3.3V
V_OUT = 1.8V
R_LOAD = 1.5Ω
38221 G16
V_SW
2V/DIV
V_OUT
20mV/DIV
AC COUPLED
I_L
2A/DIV
2µs/DIV
FIGURE 10 CIRCUIT
V_IN = 3.3V
V_OUT = 1.8V, 100mA
38221 G17
38221f
5