LTC3836_15 Datasheet, PDF (4/30 Pages) Linear Technology – Dual 2-Phase, No RSENSETM Low VIN Synchronous Controller

LTC3836
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise noted.
Efficiency vs Load Current
100
Load Step
(Forced Continuous Mode)
90
80
70
PULSE-SKIPPING
MODE
V_OUT
AC COUPLED
100mV/DIV
60
FORCED
INDUCTOR
50
CONTINUOUS
CURRENT
MODE
5A/DIV
40
30
SYNC/FCB = V_IN
SYNC/FCB = 0V
20
1
10
100
1000 10000
LOAD CURRENT (mA)
V_IN = 3.3V
V_OUT = 1.5V
CIRCUIT OF FIGURE 15
3836 G01
V_IN = 3.6V
100μs/DIV
V_OUT = 1.8V
CONTINUOUS MODE: 400mA TO 4A
CIRCUIT OF FIGURE 15
Load Step
(Pulse-Skipping Mode)
V_OUT
AC COUPLED
100mV/DIV
INDUCTOR
CURRENT
5A/DIV
3836 G02
V_IN = 3.6V
100μs/DIV
3836 G03
V_OUT = 1.8V
PULSE-SKIPPING MODE: 400MA TO 4A
CIRCUIT OF FIGURE 15
Light Load
(Pulse-Skipping Mode)
V_SW
2V/DIV
V_OUT
20mV/DIV
AC COUPLED
INDUCTOR
CURRENT
5A/DIV
V_IN = 3.6V
2μs/DIV
V_OUT = 1.8V
I_LOAD = 300mA
CIRCUIT OF FIGURE 15
Light Load
(Forced Continuous Mode)
Tracking Start-Up with Internal
Soft-Start (C_RUN/SS = 0μF)
V_SW
2V/DIV
V_OUT
20mV/DIV
AC COUPLED
3836 G04
INDUCTOR
CURRENT
5A/DIV
V_IN = 3.6V
2μs/DIV
V_OUT = 1.8V
I_LOAD = 300mA
CIRCUIT OF FIGURE 15
500mV/DIV
3836 G05
V_IN = 3.6V
250μs/DIV
R_LOAD1 = R_LOAD2 = 1Ω
CIRCUIT OF FIGURE 15
V_OUT1
1.8V
V_OUT2
1.2V
3836 G06
Tracking Start-Up with External
Soft-Start (C_RUN/SS = 0.01μF)
Sequential Start-Up
V_OUT1
1.8V
500mV/DIV
V_OUT2
1.2V
500mV/DIV
V_OUT1
1.8V
V_OUT2
1.2V
V_IN = 3.6V
2.50ms/DIV
R_LOAD1 = R_LOAD2 = 1Ω
CIRCUIT OF FIGURE 15
3836 G07
V_IN = 3.3V
4ms/DIV
R_LOAD1 = R_LOAD2 = 1Ω
V_OUT1: INTERNAL SOFT-START
V_OUT2: C_TRACK/SS = 0.047μF
CIRCUIT OF FIGURE 15
3836 G10
4
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
3836 G08
3836fb