Features: Requires few external components
NPN output switches 3.0A, can stand off 65V
Wide input voltage range: 3.5V to 40V
Current-mode operation for improved transient response, line regulation, and current limit
52 kHz internal oscillator
Soft-start function reduces in-rush current during start-up
Output switch protected by current limit, under-voltage
lockout, and thermal shutdownApplicationSimple boost regulator
Flyback and forward regulators
Multiple-output regulatorPinout
SpecificationsSupply Voltage 45V
Output Switch Voltage65V
Output Switch Current (Note 2) 6.0A
Power Dissipation Internally Limited
Storage Temperature Range −65˚C to +150˚C
Lead Temperature
(Soldering, 10 sec.) 260˚C
Maximum Junction Temperature150˚C
Minimum ESD Rating
(C = 100 pF, R = 1.5 kΩ)2kV
| Output Range |
1.23V min |
| Switch Current |
3 Amp |
| Input Min Voltage |
3.5 Volt |
| Input Max Voltage |
40 Volt |
| Feedback Voltage |
1.23 Volt |
| Frequency Max |
52 kHz |
| Efficiency (peak) |
80 % |
| Sync Pin |
No |
| Adj Switch Frequency |
No |
| Frequency Min |
52 kHz |
| On/Off Pin |
No |
| Error Flag |
No |
| SoftStart |
Yes |
| Special Features |
SIMPLE SWITCHER regulator |
| Topology |
Boost, Flyback |
| Step-Up |
Yes |
| Inverting |
No |
| Flyback |
Yes |
| RegType |
Switching Regulator |
| Adjustable Output |
Yes |
| Output Power |
Undefined Watt |
| Temperature Min |
-55 deg C |
| Temperature Max |
150 deg C |
| Regulator Family |
SIMPLE SWITCHER |
| AEC Q-100 Automotive Grade |
0 |
| View Using Catalog |
DescriptionThe LM1577/LM2577 are monolithic integrated circuits that provide all of the power and control functions for step-up (boost), flyback, and forward converter switching regulators. The LM1577 is available in three different output voltage versions: 12V, 15V, and adjustable.
Requiring a minimum number of external components, these regulators are cost effective, and simple to use. Listed in this data sheet are a family of standard inductors and flyback transformers designed to work with these switching regulators.
Included on the chip is a 3.0A NPN switch and its associated protection circuitry, consisting of current and thermal limiting, and undervoltage lockout. Other features include a 52 kHz fixed-frequency oscillator that requires no external components, a soft start mode to reduce in-rush current during start-up, and current mode control for improved rejection of input voltage and output load transients.
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LM1577 Data Sheet
