Electrical Characteristics (Continued)
=
These specifications apply for 2V ≤ VIN ≤ 40V (2.2V ≤ VIN ≤ 40V for TJ ≤ −25˚C), timing capacitor CT 3900 pF, and 25% ≤
=
duty cycle ≤ 75%, unless otherwise specified. Values in standard typeface are for TJ 25˚C; values in boldface type apply for
operation over the specified operating junction temperature range.
LM1578A
Limit
LM2578A/
LM3578A
Symbol
Parameter
Conditions
Typical
Units
(Note 5)
(Note 6)
(Note 11)
Limit
(Note 7)
CURRENT LIMIT
VCL
Sense Voltage
Shutdown Level
Referred to VIN or Ground
(Note 10)
110
mV
95
80
mV (min)
mV (max)
%/˚C
140
160
∆VCL/∆T
Sense Voltage
0.3
Temperature Drift
Sense Bias Current
ICL
Referred to VIN
4.0
0.4
µA
µA
Referred to ground
DEVICE POWER CONSUMPTION
IS Supply Current
=
Output OFF, VE 0V
2.0
14
mA
3.0/3.3
3.5/4.0
mA (max)
mA
=
Output ON, IC 750 mA pulsed,
=
VE 0V
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its rated operating conditions.
Note 2: For T ≥ 100˚C, the Emitter pin voltage should not be driven more than 0.6V below ground (see Application Information).
J
Note 3: At elevated temperatures, devices must be derated based on package thermal resistance. The device in the TO-99 package must be derated at 150˚C/W,
junction to ambient, or 45˚C/W, junction to case. The device in the 8-pin DIP must be derated at 95˚C/W, junction to ambient. The device in the surface-mount package
must be derated at 150˚C/W, junction-to-ambient.
Note 4: Human body model, 1.5 kΩ in series with 100 pF.
=
Note 5: Typical values are for T
25˚C and represent the most likely parametric norm.
J
Note 6: All limits guaranteed and 100% production tested at room temperature (standard type face) and at temperature extremes (bold type face). All limits are used
to calculate Average Outgoing Quality Level (AOQL).
Note 7: All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). Room temperature limits are 100% production
tested. Limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate AOQL.
Note 8: Input terminals are protected from accidental shorts to ground but if external voltages higher than the reference voltage are applied, excessive current will
flow and should be limited to less than 5 mA.
Note 9:
I and I are the external sink currents at the inputs (refer to Test Circuit).
1 2
Note 10: Connection of a 10 kΩ resistor from pin 1 to pin 4 will drive the duty cycle to its maximum, typically 90%. Applying the minimum Current Limit Sense Voltage
to pin 7 will not reduce the duty cycle to less than 50%. Applying the maximum Current Limit Sense Voltage to pin 7 is certain to reduce the duty cycle below 50%.
Increasing this voltage by 15 mV may be required to reduce the duty cycle to 0%, when the Collector output swing is 40V or greater (see Ground-Referred Current
Limit Sense Voltage typical curve).
Note 11: A military RETS specification is available on request. At the time of printing, the LM1578A RETS spec complied with the boldface limits in this column. The
LM1578AH may also be procured as a Standard Military Drawing.
3
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