Not to scale

Thermal

Pad

1

VIN

2

Output

3

Flag

4

Ground

5

Delay

6

Feedback

7

SD/SS

Not to scale

3

LM2593HV

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SNVS082E – DECEMBER 2001 – REVISED MAY 2016

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5 Pin Configuration and Functions

NDZ Package

7-Pin TO-220

Top View

KTW Package

7-Pin TO-263

Top View

(1)

G = Ground, I = Input, O = Output

(2)

If any of these pins are not used, the respective pin can be left open.

Pin Functions

PIN

DESCRIPTION

NO.

NAME

1

I

This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must

be present at this pin to minimize voltage transients and to supply the switching currents needed by

the regulator.

2

Output

O

approximately

3

Flag

O

Error flag: Open-collector output that goes active low (

≤1 V) when the output of the switching

regulator is out of regulation (less than 95% of its nominal value). In this state it can sink maximum 3

mA. When not low, it can be pulled high to signal that the output of the regulator is in regulation

(power good). During power-up, it can be programmed to go high after a certain delay as set by the

Delay pin (Pin 5). The maximum rating of this pin must not be exceeded, so if the rail to which it will

be pulled up to is higher than 45 V, a resistive divider must be used instead of a single pullup resistor,

as indicated in Test Circuits.

4

Ground

—

Circuit ground.

5

Delay

O

This sets a programmable power-up delay from the moment that the output reaches regulation, to the

high signal output (power good) on Pin 3. A capacitor on this pin starts charging up by means on an

internal (3

μA) current source when the regulated output rises to within 5% of its nominal value. Pin 3

goes high (with an external pullup) when the voltage on the capacitor on Pin 5 exceeds 1.3 V. The

voltage on this pin is clamped internally to about 1.7 V. If the regulated output drops out of regulation

(less than 95% of its nominal value), the capacitor on Pin 5 is rapidly discharged internally and Pin 3

6

Feedback

I

Senses the regulated output voltage to complete the feedback loop. This pin is directly connected to

the Output for the fixed voltage versions, but is set to 1.23 V by means of a resistive divider from the

output for the adjustable version. If a feedforward capacitor is used (adjustable version), then a

negative voltage spike is generated on this pin whenever the output is shorted. This happens

because the feedforward capacitor cannot discharge fast enough, and because one end of it is

dragged to Ground, the other end goes momentarily negative. To prevent the energy rating of this pin

from being exceeded, a small-signal Schottky diode to Ground is recommended for DC input voltages

above 40 V whenever a feedforward capacitor is present (see Test Circuits). Feedforward capacitor

values larger than 0.1

μF are not recommended for the same reason, whatever be the DC input