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