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dc1948af

DEMO MANUAL DC1948A

Description

LT3090

–36V, 600mA Negative Linear Regulator

with Programmable Current Limit

Demonstration circuit 1948A is a 600mA low dropout

negativelinearregulatorfeaturingtheLT®3090.Thisdevice

isdesignedforapplicationsrequiringnegativeoutputvolt-

age, high current with no heat sink, output adjustability to

zero and low dropout voltage.

The LT3090 features fast transient response, high PSRR

and low output noise. The LT3090 supplies 600mA at a

typicaldropoutvoltageof300mV.Operatingquiescentcur-

rent is nominally 1mA and drops to << 1μA in shutdown.

A single resistor adjusts the LT3090’s precision program-

mable current limit. The LT3090’s positive or negative

current monitor either sources a current (0.5mA/A) or

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

performance summary

sinks a current (1mA/A) proportional to output current.

Built-in protection includes reverse output protection,

internal current limit with foldback and thermal shutdown

with hysteresis.

The LT3090 is offered in a 10 pin DFN package and a

16-lead MSOP package.

The LT3090 data sheet gives a complete description of

thedevice,operationandapplicationinformation.Thedata

sheet should be read in conjunction with this quick start

guide for working on or modifying the demo circuit 1948A.

Design files for this circuit board are available at

http://www.linear.com/demo/DC1948A

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Supply Range

–36

–1.5

V

Output Voltage

Shunt at 1, 2 for JP1

–1.286

–1.25

–1.213

V

Shunt at 3, 4 for JP1

–2.575

–2.5

–2.425

V

Shunt at 5, 6 for JP1

–5.15

–5

–4.85

V

Shunt at 7, 8 for JP1

–12.36

–12

–11.64

V

Shunt at 9, 10 for JP1

–15.45

–15

–14.55

V

Shunt at 11, 12 for JP1 and R10 Stuffed as 357kΩ

–18.54

–18

–17.46

V

Output Current

R1 = 10k, (Note 1)

600

mA

for details.