LM1577, LM2577
SNOS658D –JUNE 1999–REVISED APRIL 2013
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Electrical Characteristics—LM1577-12, LM2577-12 (continued)
Specifications with standard type face are for TJ = 25°C, and those in bold type face apply over full Operating Temperature
Range. Unless otherwise specified, VIN = 5V, and ISWITCH = 0.
Symbol
Parameter
Conditions
Typical
LM1577-12
Limit(1)(2)
LM2577-12
Limit(3)
Units
(Limits)
VUV
Input Supply
ISWITCH = 100 mA
2.90
V
V(min)
V(max)
kHz
Undervoltage Lockout
Oscillator Frequency
2.70/2.65
3.10/3.15
2.70/2.65
3.10/3.15
fO
Measured at Switch Pin
ISWITCH = 100 mA
52
48/42
56/62
48/42
56/62
kHz(min)
kHz(max)
V
VREF
Output Reference
Voltage
Measured at Feedback Pin
VIN = 3.5V to 40V
VCOMP = 1.0V
12
7
11.76/11.64
12.24/12.36
11.76/11.64
12.24/12.36
V(min)
V(max)
mV
Output Reference
VIN = 3.5V to 40V
Voltage Line Regulator
RFB
GM
Feedback Pin Input
Resistance
9.7
kΩ
Error Amp
Transconductance
ICOMP = −30 μA to +30 μA
VCOMP = 1.0V
370
μmho
μmho(min)
μmho(max)
V/V
225/145
515/615
225/145
515/615
AVOL
Error Amp
Voltage Gain
VCOMP = 1.1V to 1.9V
80
2.4
RCOMP = 1.0 MΩ(5)
50/25
2.2/2.0
50/25
2.2/2.0
V/V(min)
V
Error Amplifier
Output Swing
Upper Limit
VFEEDBACK = 10.0V
V(min)
V
Lower Limit
0.3
VFEEDBACK = 15.0V
0.40/0.55
0.40/0.55
V(max)
μA
Error Amplifier
Output Current
VFEEDBACK = 10.0V to 15.0V
VCOMP = 1.0V
±200
±130/±90
±130/±90
μA(min)
μA(max)
μA
±300/±400
±300/±400
ISS
Soft Start Current
VFEEDBACK = 10.0V
VCOMP = 0V
5.0
2.5/1.5
7.5/9.5
2.5/1.5
7.5/9.5
μA(min)
μA(max)
%
D
Maximum Duty Cycle
VCOMP = 1.5V
95
ISWITCH = 100 mA
93/90
93/90
%(min)
A/V
Switch
Transconductance
12.5
IL
Switch Leakage
Current
VSWITCH = 65V
VFEEDBACK = 15V (Switch Off)
10
0.5
4.5
μA
μA(max)
V
300/600
0.7/0.9
300/600
0.7/0.9
VSAT
Switch Saturation
Voltage
ISWITCH = 2.0A
VCOMP = 2.0V (Max Duty Cycle)
V(max)
A
NPN Switch
Current Limit
3.7/3.0
5.3/6.0
3.7/3.0
5.3/6.0
A(min)
A(max)
(5) A 1.0 MΩ resistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. In
actual applications, this pin's load resistance should be ≥10 MΩ, resulting in AVOL that is typically twice the ensured minimum limit.
4
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