Features: `3.3V,5V,12V,and adjustable output versions
`Adjustable version output voltage range,1.2V to 37V (57V for HV version) ±4% max overl ine and load conditions
`Guaranteed 0.5A output current
`Available in 8-pin surface mount and DIP-8 package
`Input voltage range up to 60V
`150 kHzf ixed frequency internal oscillator
`Shutdown /Soft-start
`Out of regulation error flag
`Error output delay
`BiasSupplyPin (VBS) for internal circuitry improves efficiency at high input voltages
`Lowpowerstandbymode,IQ typically 85A
`High Efficiency
`Uses readily available standard inductors
`Thermal shutdown and current limit protection
Application·Simple high-efficiency step-down (buck) regulator
·Efficient pre-regulator for linear regulators
·On-card switching regulators
·Positive to Negative converterSpecifications
| Output Current |
500 mA |
| Input Min Voltage |
4.5, 7, 4.75, 15 Volt |
| Input Max Voltage |
60 Volt |
| Output Min |
3.3, 1.23, 12, 5 Volt |
| Output Max |
57, 3.3, 12, 5 Volt |
| Frequency Min |
150 kHz |
| Frequency Max |
150 kHz |
| Efficiency (peak) |
88, 80, 82 % |
| On/Off Pin |
Yes |
| Error Flag |
Yes |
| SoftStart |
Yes |
| Sync Pin |
No |
| Inverting |
Yes |
| Flyback |
No |
| RegType |
Switching Regulator |
| Temperature Min |
-40 deg C |
| Temperature Max |
125 deg C |
| Adjustable Output |
Yes, No |
| Adj Switch Frequency |
No |
| PWM Mode |
Voltage |
| Topology |
Buck |
| Special Features |
SIMPLE SWITCHER regulator, error output delay |
| Step-Down |
Yes |
| Multiple Output Capability |
No |
| Output Power |
Undefined Watt |
| Output Voltage |
3.3, Undefined, 5, 15 Volt |
| Output Range |
15V, 5V, 3.3V, 1.23V to 57V |
| Switching Frequency |
150 kHz |
| Regulator Family |
SIMPLE SWITCHER |
| AEC Q-100 Automotive Grade |
Undefined |
| Synchronous Rectification |
No |
| View Using Catalog |
`MaximumSupplyVoltage(VIN)
LM2597....................45V
LM2597HV...................60V
`SD/SS Pin InputVoltage(Note2)........6V
`Delay Pin Voltage (Note2)...........1.5V
`Flag Pin Voltage................-0.3V 45V
`BiasSupply Voltage(VBS) ...........-0.3 V 30V
`Feedback Pin Voltage.............-0.3 V +25V
`Output Voltage to Ground
(SteadyState).................-1V
`Power Dissipation................Internallylimited
`Storage Temperature Range ..........-65 to+150DescriptionThe LM2597/LM2597HV series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck)switching regulator,capable o fdriving a 0.5A load with excellent line and load regulation.These evices are available in fixed output voltages of3.3V,5V, 12V,and an adjustable output version,and arepackaged in an 8-lead DIP and an8-lead surface mount package.
This series of switching regulators is similar to the LM2594 series,with additional supervisory and performance features added.
Requiring a minimum number of external components,these regulators are simple to use and include internal frequency ? compensation ,improved line and load specifications, fixed-frequency oscillator,Shutdown /Soft-start,error flag delay and error flag output.
The LM2597/LM2597HV series operates at a switching fre- quency of 150 kHz thus allowing smaller sized filtercompo- nents than what wo uld be needed with lower frequency switching regulators.Because of its high efficiency,the cop- pe rtraces on the printed circuit board arenormally theonly heat sinking needed.
A standard series of inductors(both through hole and sur- face mount types)are available from several different manu- facturers optimized for use with the LM2597/LM2597HVse- ries.This feature greatly simplifies the design of switch-mode power supplies.
Other features include a guaranteed ±4% tolerance on out-put voltage under all conditions of inpu tvoltage and output load conditions,and ±15%on the oscillator frequency.Ex- ternal shutdown is included,featuring typically 85 A standby current.Self protection features include a two stage current limit for the output switch and an over temperature shutdown for complete protection under fault conditions.
The LM2597HV is for use in applications requiring and input voltage up to 60V.
LM2597HV Data Sheet
