LT1082
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 15V, VC = 0.5V, VFB = VREF, output pin open, unless otherwise
specified.
SYMBOL
PARAMETER
CONDITIONS
3V ≤ V ≤ V
MIN
TYP
MAX
UNITS
I
Supply Current
, V = 0.6V
4.5
0.9
7.0
mA
Q
IN
MAX
C
Control Pin Threshold
Duty Cycle = 0
0.7
0.5
1.1
1.25
V
V
●
Normal/Flyback Threshold
on Feedback Pin
0.58
0.67
60
0.8
V
f
Switching Frequency
50
45
70
75
kHz
kHz
●
●
800µA ≥ I ≥ 450µA
12
115
1.5
kHz
V
FB
BV
Output Switch Breakdown Voltage
3V ≤ V ≤ V
, I = 1.5mA
MAX SW
100
IN
Control Voltage to Switch
Current Transconductance
A/V
V
Flyback Reference Voltage
I
= 60µA
FB
17
16
18.6
20.5
21.5
V
V
FB
●
Change in Flyback Reference Voltage
60µA ≤ I ≤ 200µA
3.5
4.6
0.01
300
6.5
0.03
500
V
%/V
FB
Flyback Reference Voltage Line Regulation
I
= 60µA, 3V ≤ V ≤ V
FB IN MAX
Flyback Amplifier Transconductance (g )
∆I = ±10µA
C
150
µmho
m
Flyback Amplifier Source
and Sink Current
V = 0.6V Source
●
●
15
30
32
50
70
90
µA
µA
C
I
= 60µA Sink
FB
V
Output Switch “On” Resistance (Note 2)
I
= 0.7A (LT1082C), I = 0.5A (LT1082M)
●
0.8
1.2
Ω
SAT
LIM
SW
SW
I
Switch Current Limit
(LT1082C)
Duty Cycle = 20%
Duty Cycle ≤ 50%
Duty Cycle = 80% (Note 3)
●
●
●
1.07
1.0
0.8
2.6
2.6
2.4
A
A
A
Switch Current Limit
(LT1082I)
Duty Cycle = 20%
Duty Cycle ≤ 50%
Duty Cycle = 80% (Note 3)
●
●
●
0.85
0.8
0.65
2.8
2.8
2.6
A
A
A
Switch Current Limit
(LT1082M)
Duty Cycle = 20%
Duty Cycle ≤ 50%
Duty Cycle = 80% (Note 3)
●
●
●
0.75
0.7
0.6
3.0
3.0
2.8
A
A
A
∆I
Supply Current Increase
During Switch-On Time
35
45
mA/A
IN
∆I
SW
DC
Maximum Switch Duty Cycle
Flyback Sense Delay Time
85
92
1.5
97
%
µs
MAX
Shutdown Mode Supply Current
3V ≤ V ≤ V
, V = 0.05V
C
120
150
350
µA
IN
MAX
MAX
Shutdown Mode
Threshold Voltage
3V ≤ V ≤ V
70
50
250
300
mV
mV
IN
●
Note 3: For duty cycles (DC) between 50% and 80%, minimum
guaranteed switch current decreases linearly.
Note 1: Absolute Maximum Ratings are those values beyond which the
life of a device may be impaired.
Note 2: Measured with V in hi clamp, V = 0.8V.
C
FB
sn1082 1082fas
3
Linear Systems [ Linear Systems ]
