LTC3520 Datasheet, PDF (6/24 Pages) Linear Technology – Synchronous 1A Buck-Boost and 600mA Buck Converters

LTC3520
TYPICAL PERFORMANCE CHARACTERISTICS
Buck Burst Mode Threshold
V_OUT = 1.8V
45
L = 4.7µH
40
35
30
25
R_BURST = 249k
20
R_BURST
= 274k
15
10
R_BURST = 301k
5
0
2.2 2.7 3.2 3.7 4.2 4.7 5.2
V_IN (V)
3520 G09
Buck R_DS(ON)
400
350
PMOS
300
250
200
NMOS
150
100
50
0
– 45 – 25
–5 15 35 55
TEMPERATURE (°C)
75
3520 G11
Buck Burst Mode Threshold
V_OUT = 1.2V
45
L = 3.3µH
40
35
30
25
R_BURST = 249k
20
15
R_BURST = 301k
10
5
0
2.2 2.7 3.2 3.7 4.2 4.7 5.2
V_IN (V)
3520 G09b
Switching Frequency
2.0
1.5
1.0
0.5
0
– 0.5
–1.0
– 1.5
–2.0
– 45 – 25
–5 15 35 55
TEMPERATURE (°C)
75
3520 G12
Buck-Boost R_DS(ON)
250
PMOS
(SWITCHES A AND D)
200
150
NMOS
(SWITCHES B AND C)
100
50
0
– 45 – 25
–5 15 35 55
TEMPERATURE (°C)
75
3520 G10
Buck-Boost Feedback Voltage
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
– 40 – 20 0
20 40 60 80
TEMPERATURE (°C)
3520 G13
6
Buck Feedback Voltage
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
– 40 – 20
0 20 40 60
TEMPERATURE (°C)
80
3520 G14
No Load Input Current
100
90
80
70
60
50
40
30
20 _{BUCK AND BUCK-BOOST}
10 ^{CONVERTERS ENABLED,}
Burst Mode OPERATION
0
2.2 2.7 3.2 3.7 4.2
V_IN (V)
4.7 5.2
3520 G15
3520f