Datasheet
Package Availability, Models, Samples & Pricing
| Obsolete Part | Alternate Part or
Supplier | Source | Last Time Buy Date |
LM1949M
| NONE
| NONE
| 10 Mar 1998
|
General Description
The LM1949 linear integrated circuit serves as an excellent control of fuel injector drive circuitry in modern automotive
systems. The IC is designed to control an external power NPN Darlington transistor that drives the high current injector solenoid.
The current required to open a solenoid is several times greater than the current necessary to merely hold it open; therefore,
the LM1949, by directly sensing the actual solenoid current, initially saturates the driver until the “peak” injector current
is four times that of the idle or “holding” current (
–
). This guarantees opening of the injector. The current is then automatically reduced to the sufficient holding level for
the duration of the input pulse. In this way, the total power consumed by the system is dramatically reduced. Also, a higher
degree of correlation of fuel to the input voltage pulse (or duty cycle) is achieved, since opening and closing delays of
the solenoid will be reduced.
Normally powered from a 5V ± 10% supply, the IC is typically operable over the entire temperature range (−55°C to +125°C ambient)
with supplies as low as 3 volts. This is particularly useful under “cold crank” conditions when the battery voltage may drop
low enough to deregulate the 5-volt power supply.
The LM1949 is available in the plastic miniDIP, (contact factory for other package options).
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM1949N | SLM | 0 | 42786 | 0 | 0 | 3352500 | 2 | 951281028
|
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.
More Application Notes
| Title | Size in Kbytes |
Date |
 |
| AN-222: Application Note 222 Super Matched Bipolar Transistor Pair Sets New Standards for Drift and Noise |
399 Kbytes |
1-Oct-02 |
Download |
[Information as of 3-Jul-2009]
|
RoHS Compliance Information
