| |
LM78S40 -
Universal Switching Regulator Subsystem
|
|
|---|
Features
| • | Step-up, step-down or inverting switching regulators |
| • | Output adjustable from 1.25V to 40V |
| • | Peak currents to 1.5A without external transistors |
| • | Operation from 2.5V to 40V input |
| • | Low standby current drain |
| • | 80 dB line and load regulation |
| • | High gain, high current, independent op amp |
| • | Pulse width modulation with no double pulsing |
General Description
The LM78S40 is a monolithic regulator subsystem consisting of all the active building blocks necessary for switching regulator systems. More...
| |
| Parameters | Values |
|---|
| Output Current |
1500 mA |
| Input Min Voltage |
2.5 Volt |
| Input Max Voltage |
40 Volt |
| Output Min |
1.245 Volt |
| Output Max |
Undefined Volt |
| Frequency Min |
0.1 kHz |
| Frequency Max |
100 kHz |
| On/Off Pin |
No |
| Error Flag |
No |
| SoftStart |
No |
| Sync Pin |
No |
| Inverting |
Yes |
| Flyback |
Yes |
| RegType |
Switching Regulator |
| Temperature Min |
-55 deg C |
| Temperature Max |
125 deg C |
| Adjustable Output |
Yes |
| Adj Switch Frequency |
Yes |
| PWM Mode |
Voltage |
| Topology |
Buck, Boost, Flyback, Inverting |
| Special Features |
Integrated 1.5A diode, uncommitted op amp |
| Step-Down |
Yes |
| Multiple Output Capability |
Yes |
| Output Voltage |
Undefined Volt |
| Output Range |
1.245V min |
| Switching Frequency |
100 kHz |
| Feedback Voltage |
1.245 Volt |
| Regulator Family |
Undefined |
| Synchronous Rectification |
No |
Connection Diagram
*click for larger image
| |
Datasheet
Package Availability, Models, Samples & Pricing
| Obsolete Part | Alternate Part or
Supplier | Source | Last Time Buy Date |
LM78S40C MDA
| NONE
| NATIONAL SEMICONDUCTOR
| 03 Dec 2008
|
LM78S40J/883
| NONE
| NATIONAL SEMICONDUCTOR
| 01 Dec 2009
|
General Description
The LM78S40 is a monolithic regulator subsystem consisting of all the active building blocks necessary for switching regulator systems. The device consists of a temperature compensated voltage reference, a duty-cycle controllable oscillator with an active current limit circuit, an error amplifier, high current, high voltage output switch, a power diode and an uncommitted operational amplifier. The device can drive external NPN or PNP transistors when currents in excess of 1.5A or voltages in excess of 40V are required. The device can be used for step-down, step-up or inverting switching regulators as well as for series pass regulators. It features wide supply voltage range, low standby power dissipation, high efficiency and low drift. It is useful for any stand-alone, low part count switching system and works extremely well in battery operated systems.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM78S40CN | SLM | 0 | 44046 | 0 | 0 | 3532500 | 1 | 1002356520
|
|
LM78S40J/883 | SLM | 0 | 44046 | 0 | 0 | 3532500 | 1 | 1002356520
|
|
LM78S40N | SLM | 0 | 44046 | 0 | 0 | 3532500 | 1 | 1002356520
|
Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR.
The Long Term Failure Rates were calculated
at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress
temperature of 150°C to an application temperature of 55°C.
For more information on Reliability Metrics, please click here.
Application Notes
| Title | Size in Kbytes |
Date |
 |
| AN-711: Application Note 711 LM78S40 Switching Voltage Regulator Applications |
490
Kbytes |
3-Oct-02 |
Download |
[Information as of 7-Nov-2009]
|
|
RoHS Compliance Information