Datasheet

LTC3676/LTC3676-1
8
3636fa
For more information www.linear.com/LTC3676
TYPICAL PERFORMANCE CHARACTERISTICS
Oscillator Frequency Change
vs V
IN
Step-Down Switching Regulators 1
and 2 Efficiency vs I
OUT
Step-Down Switching Regulators 1
and 2 Efficiency vs I
OUT
Step-Down Switching Regulators 3
and 4 Efficiency vs I
OUT
Buck R
DS(ON)
vs Temperature Buck R
DS(ON)
vs V
IN
LOAD CURRENT (mA)
1
0
EFFICIENY (%)
20
30
40
50
60
70
10
100
3676 G08
80
90
100
BURST
10
1000
PULSE
SKIPPING
FORCED
CONTINUOUS
V
IN
= 3.3V
V
OUT
= 1.2V
LOAD CURRENT (mA)
1
0
EFFICIENY (%)
20
30
40
50
60
70
10
100
3676 G09
80
90
100
BURST
10
1000
PULSE
SKIPPING
FORCED
CONTINUOUS
V
IN
= 5V
V
OUT
= 1.2V
LOAD CURRENT (mA)
1
0
EFFICIENY (%)
20
30
40
50
60
V
OUT
= 2.5V
70
10
100
3676 G10
80
90
100
10
1000
V
IN
= 3.3V
PULSE-SKIPPING MODE
V
OUT
= 1.2V
Step-Down Switching Regulator
Load Step
Step-Down Switching Regulator
Current Limit vs Temperature
LTC3676-1 VDDQIN, VTTR and
V
TT
Start-Up
PGOOD
5V/DIV
VTTR
1V/DIV
VTT (BUCK1)
1V/DIV
VDDQIN =
BUCK3
1V/DIV
400µs/DIV
3676 G14
100mV/DIV
500mA/DIV
10µs/DIVC
OUT
= 44µF
3676 G15
V
OUT
= 1.2V
I
LOAD
= 0.5A TO 1.5A
V
IN
(V)
2.5
PERCENT CHANGE (%)
0
3676 G07
–0.4
–0.8
3.5 4.5
3.0
4.0 5.0
0.4
0.8
–0.2
–0.6
0.2
0.6
5.5
TEMPERATURE (°C)
–50
R
DS(ON)
(mΩ)
100
150
150
3676 G11
50
0
0
50
100
250
200
BUCK 1, 2 PMOS
BUCK 1, 2 NMOS
BUCK 3, 4 NMOS
BUCK 3, 4 PMOS
V
IN
(V)
2.5
0
R
DS(ON)
(mΩ)
20
60
80
100
200
140
3.5
4.5
3676 G12
40
160
180
120
5.5
BUCK 3, 4 PMOS
BUCK 1, 2 PMOS
BUCK 1, 2 NMOS
BUCK 3, 4 NMOS
TEMPERATURE (°C)
–50
1.5
CURRENT (µA)
2.0
2.5
3.0
3.5
4.0
4.5
0 50 100 150
3676 G13
BUCK 3, 4
BUCK 1, 2