LTC3803-3
3
38033fd
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
junction temperature range, otherwise specifi cations are at T
A
= 25°C. V
CC
= 8V, unless otherwise noted. (Notes 2, 3)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CLAMP25mA
V
CC
Shunt Regulator Voltage I
CC
= 25mA, V
ITH/RUN
= 0V
LTC3803E-3, LTC3803I-3
LTC3803H-3
LTC3803MP-3
l
l
l
8.4
8.4
8.1
9.5
9.5
9.5
10.5
10.7
10.7
V
V
V
V
MARGIN
V
CLAMP1mA
– V
TURNON
Margin LTC3803E-3, LTC3803I-3,
LTC3803H-3
LTC3803MP-3
l
l
0.05
0.03
0.6
0.6
V
V
I
CC
Input DC Supply Current
Normal Operation
Start-Up
(Note 4)
V
ITH/RUN
= 1.3V
V
CC
= V
TURNON
– 100mV
240
40
350
90
μA
μA
V
ITHSHDN
Shutdown Threshold (at I
TH
/RUN) V
CC
> V
TURNON
, V
ITH/RUN
Falling
LTC3803E-3
LTC3803I-3, LTC3803H-3
LTC3803MP-3
l
l
l
0.15
0.10
0.09
0.28
0.28
0.28
0.45
0.45
0.45
V
V
V
I
ITHSTART
Start-Up Current Source V
ITH/RUN
= 0V 0.2 0.3 0.4 μA
V
FB
Regulated Feedback Voltage (Note 5)
0°C ≤ T
J
≤ 85°C
LTC3803E-3: –40°C ≤ T
J
≤ 85°C
LTC3803I-3: –40°C ≤ T
J
≤ 125°C
LTC3803H-3: –40°C ≤ T
J
≤ 150°C
LTC3803MP-3: –55°C ≤ T
J
≤ 150°C
l
l
l
l
0.788
0.780
0.780
0.780
0.780
0.800
0.800
0.800
0.800
0.800
0.812
0.812
0.820
0.820
0.820
V
V
V
V
V
V
IMAX
Peak Current Sense Voltage R
SL
= 0 (Note 6)
LTC3803E-3
LTC3803I-3, LTC3803H-3
LTC3803MP-3
l
l
l
90
85
85
100
100
100
115
115
120
mV
mV
mV
g
m
Error Amplifi er Transconductance I
TH/RUN
Pin Load = ±5μA (Note 5) 200 333 500 μA/V
ΔV
O(LINE)
Output Voltage Line Regulation (Note 5) 0.05 mV/V
I
FB
V
FB
Input Current (Note 5) 10 50 nA
f
OSC
Oscillator Frequency V
ITH/RUN
= 1.3V 270 300 330 kHz
DC
ON(MIN)
Minimum Switch On Duty Cycle V
ITH/RUN
= 1.3V, V
FB
= 0.8V 8 9.6 %
DC
ON(MAX)
Maximum Switch On Duty Cycle V
ITH/RUN
= 1.3V, V
FB
= 0.8V 70 80 90 %
t
RISE
Gate Drive Rise Time C
LOAD
= 3000pF 40 ns
t
FALL
Gate Drive Fall Time C
LOAD
= 3000pF (Note 7) 40 ns
I
SLMAX
Peak Slope Compensation Output Current (Note 7) 5 μA
t
SFST
Soft-Start Time 1.4 ms
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3803-3 is tested under pulsed load conditions such
that T
J
≈ T
A
. The LTC3803E-3 is guaranteed to meet specifi cations
from 0°C to 85°C junction temperature. Specifi cations over the –40°C
to 125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3803I-3 is guaranteed over the –40°C to 125°C operating junction
temperature range, the LTC3803H-3 is guaranteed over the –40°C to
150°C operating junction temperature range and the LTC3803MP-3 is
tested and guaranteed over the full –55°C to 150°C operating junction
temperature range. High junction temperatures degrade operating
lifetimes; operating lifetime is derated for junction temperatures greater
than 125°C. Note that the maximum ambient temperature consistent with
these specifi cations is determined by specifi c operating conditions in
conjunction with board layout, the rated package thermal impedance and
other environmental factors.
Note 3: Junction temperature T
J
is calculated from the ambient
temperature T
A
and power dissipation P
D
according to the following
formula:
T
J
= T
A
+ (P
D
• 230°C/W).
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 5: The LTC3803-3 is tested in a feedback loop that servos V
FB
to the
output of the error amplifi er while maintaining I
TH
/RUN at the midpoint of
the current limit range.
Note 6: Peak current sense voltage is reduced dependent on duty cycle
and an optional external resistor in series with the SENSE pin (R
SL
). For
details, refer to the programmable slope compensation feature in the
Applications Information section.
Note 7: Guaranteed by design.
