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Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
Output Switch Voltage
Output Switch Current (Note 2)
Power Dissipation
Storage Temperature Range
Lead Temperature
(Soldering, 10 sec.)
Maximum Junction Temperature
45V
65V
6.0A
Internally Limited
65C to +150C
260C
150C
Minimum ESD Rating
(C = 100 pF, R = 1.5 k
)
2 kV
Operating Ratings
Supply Voltage
Output Switch Voltage
Output Switch Current
Junction Temperature Range
LM1577
LM2577
3.5V
≤
V
IN
≤
40V
0V
≤
V
SWITCH
≤
60V
I
SWITCH
≤
3.0A
55C
≤
T
J
≤
+150C
40C
≤
T
J
≤
+125C
Electrical Characteristics—LM1577-12, LM2577-12
Specifications with standard type face are for T
= 25C, and those in
bold type face
apply over full
Operating Temperature
Range
. Unless otherwise specified, V
IN
= 5V, and I
SWITCH
= 0.
LM1577-12
Limit
(Notes 3, 4)
LM2577-12
Limit
(Note 5)
Units
(Limits)
Symbol
Parameter
Conditions
Typical
SYSTEM PARAMETERS
Circuit of Figure 1 (Note 6)
V
OUT
Output Voltage
V
IN
= 5V to 10V
I
LOAD
= 100 mA to 800 mA
(Note 3)
V
IN
= 3.5V to 10V
I
LOAD
= 300 mA
V
IN
= 5V
I
LOAD
= 100 mA to 800 mA
V
IN
= 5V, I
LOAD
= 800 mA
12.0
V
11.60/
11.40
12.40/
12.60
11.60/
11.40
12.40/
12.60
V(min)
V(max)
mV
Line Regulation
20
50/
100
50/
100
mV(max)
Load Regulation
20
mV
50/
100
50/
100
mV(max)
η
DEVICE PARAMETERS
I
S
Efficiency
80
%
Input Supply Current
V
FEEDBACK
= 14V (Switch Off)
7.5
mA
10.0/
14.0
10.0/
14.0
mA(max)
mA
mA(max)
V
V(min)
V(max)
kHz
kHz(min)
kHz(max)
V
V(min)
V(max)
mV
I
SWITCH
= 2.0A
V
COMP
= 2.0V (Max Duty Cycle)
I
SWITCH
= 100 mA
25
50/
85
50/
85
V
UV
Input Supply
Undervoltage Lockout
2.90
2.70/
2.65
3.10/
3.15
2.70/
2.65
3.10/
3.15
f
O
Oscillator Frequency
Measured at Switch Pin
I
SWITCH
= 100 mA
52
48/
42
56/
62
48/
42
56/
62
V
REF
Output Reference
Voltage
Measured at Feedback Pin
V
IN
= 3.5V to 40V
V
COMP
= 1.0V
V
IN
= 3.5V to 40V
12
11.76/
11.64
12.24/
12.36
11.76/
11.64
12.24/
12.36
Output Reference
7
Voltage Line Regulator
R
FB
Feedback Pin Input
Resistance
Error Amp
Transconductance
9.7
k
G
M
I
COMP
= 30 μA to +30 μA
V
COMP
= 1.0V
370
μmho
μmho(min)
μmho(max)
V/V
V/V(min)
225/
145
515/
615
225/
145
515/
615
A
VOL
Error Amp
Voltage Gain
V
COMP
= 1.1V to 1.9V
R
COMP
= 1.0 M
(Note 7)
80
50/
25
50/
25
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