ltc1649cs-trpbf Linear Technology Corporation, ltc1649cs-trpbf Datasheet - Page 3

• Manufacturer Part Number: ltc1649cs-trpbf
• Description: 3.3v Input High Power Step-down Switching Regulator Contoller
• Manufacturer: Linear Technology Corporation

ELECTRICAL CHARACTERISTICS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a part may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: Maximum Duty Cycle limitations will limit the output voltage
obtainable at very low supply voltages.
TYPICAL PERFOR A CE CHARACTERISTICS
14.0
13.5
13.0
12.5
12.0
11.5
11.0
10.5
850
800
750
700
650
600
550
500
450
400
350
– 40
– 40
I
Error Amplifier Transconductance
vs Temperature
MAX
V
CC
–20
– 20
= 5V
Pin Current vs Temperature
0
0
TEMPERATURE ( C)
TEMPERATURE ( C)
20
20
40
40
g
V
60
m
CC
60
=
W
= 5V
I
COMP
80
80
V
FB
1649 G04
1649 G01
U
100
100
– 0.2
– 0.4
– 0.6
– 0.8
–1.0
240
230
220
210
200
190
180
170
0.4
0.2
– 40
0
Oscillator Frequency
vs Temperature
Load Regulation
0
V
T
V
V
FIGURE 1
CC
–20
A
OUT
CC
1
= 25 C
= 5V
= 5V
= 3.3V
2
0
TEMPERATURE ( C)
LOAD CURRENT (A)
3
20
4
5
Note 4: Supply current at P
needed to charge and discharge the external MOSFET gates. This current
will vary with the operating voltage and the external MOSFETs used.
Note 5: Under normal operating conditions, the charge pump will skip
cycles to maintain regulation and the apparent frequency will be lower than
700kHz.
Note 6: The I
(not current limited) operation, the I
Note 7: Driver rise and fall times are measured from 10% to 90%.
40
6
60
7
8
80
LIM
1649 G02
1649 G06
9
amplifier can sink but not source current. Under normal
100
10
VCC1
100
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
95
90
85
80
70
75
0
– 40
and P
Output Voltage vs Load Current
with Current Limit
0
Maximum Duty Cycle
vs Temperature
LIM
T
V
FIGURE 1
V
V
V
A
CC
COMP
FB
CC
– 20
VCC2
= 25 C
output current will be zero.
= 1.265V
= 5V
= 5V
2
R
IMAX
= V
is dominated by the current
0
TEMPERATURE ( C)
CC
LOAD CURRENT (A)
= 16k
4
20
LTC1649
6
40
R
IMAX
8
60
= 33k
10
80
1649 G03
1649 G07
3
100
12