LM2596

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3

PIN FUNCTION DESCRIPTION

Pin

Symbol

Description (Refer to Figure 1)

1

Vin

This pin is the positive input supply for the LM2596 step−down switching regulator. In order to minimize voltage transi-

ents and to supply the switching currents needed by the regulator, a suitable input bypass capacitor must be present

(Cin in Figure 1).

2

Output

This is the emitter of the internal switch. The saturation voltage Vsat of this output switch is typically 1.5 V. It should be

kept in mind that the PCB area connected to this pin should be kept to a minimum in order to minimize coupling to

sensitive circuitry.

3

GND

Circuit ground pin. See the information about the printed circuit board layout.

4

Feedback This pin is the direct input of the error amplifier and the resistor network R2, R1 is connected externally to allow pro-

gramming of the output voltage.

5

ON/OFF

It allows the switching regulator circuit to be shut down using logic level signals, thus dropping the total input supply

current to approximately 80 mA. The threshold voltage is typically 1.6 V. Applying a voltage above this value (up to

+Vin) shuts the regulator off. If the voltage applied to this pin is lower than 1.6 V or if this pin is left open, the regulator

will be in the “on” condition.

OPERATING RATINGS (Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee

specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.)

Rating

Symbol

Value

Unit

Operating Junction Temperature Range

TJ

−40 to +125

°C

Supply Voltage

Vin

4.5 to 40

V