LTC1871 Linear Technology, LTC1871 Datasheet - Page 3

• Manufacturer Part Number: LTC1871
• Description: Wide Input Range/ No RSENSE Current Mode Boost/ Flyback and SEPIC Controller
• Manufacturer: Linear Technology

The
V
SYMBOL
Oscillator
f
D
f
t
t
V
V
R
V
Low Dropout Regulator
V
V
V
I
GATE Driver
t
t
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: The LTC1871E is guaranteed to meet performance specifications
from 0 C to 70 C. Specifications over the – 40 C to 85 C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: T
dissipation P
ELECTRICAL CHARACTERISTICS
OSC
SYNC/
SYNC(MIN)
SYNC(MAX)
INTVCC
r
f
IN
IL(MODE)
IH(MODE)
FREQ
INTVCC
LDO(LOAD)
DROPOUT
MAX
MODE/SYNC
V
V
INTVCC
INTVCC
V
V
T
= V
IN1
IN2
J
f
= T
OSC
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T
INTVCC
J
A
is calculated from the ambient temperature T
+ (P
D
PARAMETER
Oscillator Frequency
Oscillator Frequency Range
Maximum Duty Cycle
Recommended Maximum Synchronized
Frequency Ratio
MODE/SYNC Minimum Input Pulse Width
MODE/SYNC Maximum Input Pulse Width
Low Level MODE/SYNC Input Voltage
High Level MODE/SYNC Input Voltage
MODE/SYNC Input Pull-Down Resistance
Nominal FREQ Pin Voltage
INTV
INTV
INTV
INTV
INTV
Bootstrap Mode INTV
Current in Shutdown
GATE Driver Output Rise Time
GATE Driver Output Fall Time
according to the following formula:
= 5V, V
D
• 120 C/W)
CC
CC
CC
CC
CC
Regulator Output Voltage
Regulator Line Regulation
Regulator Line Regulation
Load Regulation
Regulator Dropout Voltage
RUN
= 1.5V, R
CC
Supply
FREQ
= 80k, V
MODE/SYNC
A
and power
CONDITIONS
R
f
V
V
V
7.5V V
15V V
0 I
V
RUN = 0V, SENSE = 5V
C
C
= 0V, unless otherwise specified.
OSC
SYNC
SYNC
IN
IN
L
L
FREQ
= 3300pF (Note 7)
= 3300pF (Note 7)
= 7.5V
= 5V, INTV
INTVCC
= 300kHz (Note 6)
= 80k
= 0V to 5V
= 0V to 5V
IN
IN
30V
15V
20mA, V
Note 4: The dynamic input supply current is higher due to power MOSFET
gate charging (Q
Note 5: The LTC1871 is tested in a feedback loop that servos V
reference voltage with the I
(the no load to full load operating voltage range for the I
1.23V).
Note 6: In a synchronized application, the internal slope compensation
gain is increased by 25%. Synchronizing to a significantly higher ratio will
reduce the effective amount of slope compensation, which could result in
subharmonic oscillation for duty cycles greater than 50%.
Note 7: Rise and fall times are measured at 10% and 90% levels.
CC
Load = 20mA
IN
= 7.5V
G
• f
OSC
). See Applications Information.
TH
pin forced to a voltage between 0V and 1.4V
MIN
250
1.2
5.0
87
– 2
50
0.8/f
1.25
0.62
– 0.2
TYP
300
280
5.2
92
25
50
70
10
17
8
8
OSC
LTC1871
A
TH
= 25 C.
1000
MAX
1.30
350
200
100
100
pin is 0.3V to
0.3
5.4
97
25
20
FB
to the
UNITS
3
kHz
kHz
mV
mV
mV
k
ns
ns
ns
ns
%
%
V
V
V
V
A