LTC3803
4
3803fc
TYPICAL PERFORMANCE CHARACTERISTICS
Oscillator Frequency
vs Temperature
Oscillator Frequency
vs Supply Voltage
Oscillator Frequency
vs V
CC
Shunt Regulator Current
–60 60 90
0–30 30 150120
TEMPERATURE (°C)
OSCILLATOR FREQUENCY (kHz)
3803 G04
V
CC
= 8V
240
230
220
210
200
190
180
V
CC
SUPPLY VOLTAGE (V)
6
190
OSCILLATOR FREQUENCY (kHz)
194
198
202
6.5
7
7.5 8
3803 G05
8.5
206
210
192
196
200
204
208
9
T
A
= 25°C
I
CC
(mA)
0
190
OSCILLATOR FREQUENCY (kHz)
194
198
202
5
10
15 20
3803 G06
206
210
192
196
200
204
208
25
T
A
= 25°C
Reference Voltage vs Temperature
Reference Voltage
vs Supply Voltage
Reference Voltage
vs V
CC
Shunt Regulator Current
TEMPERATURE (°C)
–60
V
FB
VOLTAGE (mV)
90
3803 G01
0–30 30 60 150120
V
CC
= 8V
780
785
790
795
800
805
810
815
820
V
CC
SUPPLY VOLTAGE (V)
6
799.0
V
FB
VOLTAGE (mV)
799.2
799.6
799.8
800.0
801.0
800.4
7
8
8.5
3803 F02
799.4
800.6
800.8
800.2
6.5
7.5
9
9.5
T
A
= 25°C
V
CC
≤ V
CLAMP1mA
I
CC
(mA)
0
V
FB
VOLTAGE (mV)
799
800
801
15
25
3803 G03
798
797
796
510 20
802
803
804
T
A
= 25°C
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 is tested under pulsed load conditions such that T
J
≈ T
A
.
The LTC3803E 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 is guaranteed to
meet performance specifi cations over the –40°C to 125°C operating junction
temperature range, the LTC3803H is guaranteed to meet performance
specifi cations over the –40°C to 150°C operating junction temperature range
and the LTC3803MP 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: 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 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.
ELECTRICAL CHARACTERISTICS
