LTC1435
ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
IN
= 15V, V
RUN/SS
= 5V unless otherwise noted.
Note 2:
The LTC1435 is tested in a feedback loop which servos V
OSENSE
to the balance point for the error amplifier (V
ITH
= 1.19V).
Note 3:
Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
Note 4:
Oscillator frequency is tested by measuring the C
OSC
charge and
discharge currents and applying the formula:
8.4(10
8
)
1 + 1
–1
f
OSC
(kHz) = C
OSC
(pF) + 11 I
CHG
I
DIS
The
q
denotes specifications which apply over the full operating
temperature range.
LTC1435CG/LTC1435CS: 0°C
≤
T
A
≤
70°C
LTC1435IG/LTC1435IS: – 40°C
≤
T
A
≤
85°C
Note 1:
T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula:
LTC1435CG/LTC1435IG: T
J
= T
A
+ (P
D
)(130°C/W)
LTC1435CS/LTC1435IS: T
J
= T
A
+ (P
D
)(110°C/W)
(
)(
)
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Input Voltage
V
OUT
= 3.3V
100
V
OUT
= 3.3V
95
I
LOAD
= 1A
EFFICIENCY (%)
EFFICIENCY (%)
90
85
I
LOAD
= 100mA
80
75
70
90
I
LOAD
= 100mA
85
80
75
70
0
5
10
15
20
INPUT VOLTAGE (V)
25
30
1435 G01
EFFICIENCY (%)
V
IN
– V
OUT
Dropout Voltage
vs Load Current
0.5
0
R
SENSE
= 0.033Ω
V
OUT
DROP OF 5%
0.4
V
IN
– V
OUT
(V)
– 0.75
–1.00
V
ITH
(V)
0.3
∆V
OUT
(%)
0.2
0.1
0
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
3.0
1435 G04
U W
Efficiency vs Input Voltage
V
OUT
= 5V
100
V
OUT
= 5V
95
I
LOAD
= 1A
100
95
90
85
80
75
70
65
60
55
Efficiency vs Load Current
V
IN
= 10V
V
OUT
= 5V
R
SENSE
= 0.033Ω
Burst Mode
OPERATION
CONTINUOUS
MODE
0
5
10
15
20
INPUT VOLTAGE (V)
25
30
1435 G02
50
0.001
1
0.01
0.1
LOAD CURRENT (A)
10
1435 G03
Load Regulation
3.0
R
SENSE
= 0.033Ω
– 0.25
– 0.50
V
ITH
Pin Voltage vs Output Current
2.5
2.0
1.5
Burst Mode
OPERATION
1.0
0.5
0
CONTINUOUS
MODE
–1.25
–1.50
0
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
3.0
1435 G05
0
10 20 30 40 50 60 70 80 90 100
OUTPUT CURRENT (%)
1435 G06
3
LINER [ LINEAR TECHNOLOGY ]
