LM1578A

Features:

Inverting and non-inverting feedback inputs
1.0V reference at inputs
 Operates from supply voltages of 2V to 40V
 Output current up to 750 mA, saturation less than 0.9V
 Current limit and thermal shut down
 Duty cycle up to 90%


Application

Switching regulators in buck, boost, inverting, and single-ended transformer configurations
 Motor speed control
Lamp flasher

Specifications

Total Supply Voltage                                                                         50V
Collector Output to Ground                                              −0.3V to +50V
Emitter Output to Ground (Note 2)                                      −1V to +50V
Power Dissipation (Note 3)                                           Internally limited
Output Current                                                                            750 mA
Storage Temperature                                                −65°C to +150°C
Lead Temperature
   (soldering, 10 seconds)                                                             260°C
Maximum Junction Temperature                                                   150°C
ESD Tolerance (Note 4)                                                                    2 kV
Ambient Temperature Range
    LM1578A                                                          −55°C T_A +125°C
    LM2578A                                                            −40°C T_A +85°C
    LM3578A                                                                0°C T_A +70°C
Junction Temperature Range
    LM1578A                                                           −55°C T_J +150°C
    LM2578A                                                           −40°C T_J +125°C
    LM3578A                                                                0°C T_J+125°C

Description

The LM1578A is a switching regulator which can easily be set up for such DC-to-DC voltage conversion circuits as the buck, boost, and inverting configurations. The LM1578A features a unique comparator input stage which not only has separate pins for both the inverting and non-inverting inputs, but also provides an internal 1.0V reference to each input, thereby simplifying circuit design and p.c. board layout. The output can switch up to 750 mA and has output pins for its collector and emitter to promote design flexibility. An external current limit terminal may be referenced to either the ground or the Vin terminal, depending upon the application. In addition,
the LM1578A has an on board oscillator, which sets the switching frequency with a single external capacitor from <1 Hz to 100 kHz (typical).

The LM1578A is an improved version of the LM1578, offering higher maximum ratings for the total supply voltage and output transistor emitter and collector voltages.