Linear Technology DC1948A Demo Manual

Description
Demonstration circuit 1948A is a 600mA low dropout
negative linear regulator featuring the
is designed for applications requiring negative output volt-
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
typical dropout voltage of 300mV. Operating quiescent cur-
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
performance summary
SYMBOL PARAMETER
V Input Supply Range
IN
V Output Voltage
OUT
I Output Current
OUT
Note 1. This is for the typical condition when V
for details.
Arrow.com.
Downloaded from
–36V, 600mA Negative Linear Regulator
with Programmable Current Limit
sinks a current (1mA/A) proportional to output current.
LT 3090. This device 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
the device, operation and application information. The data
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
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.
Specifications are at T
CONDITIONS
V = 1.2V, I = 1mA
OUT OUT1
Shunt at 1, 2 for JP1
Shunt at 3, 4 for JP1
Shunt at 5, 6 for JP1
Shunt at 7, 8 for JP1
Shunt at 9, 10 for JP1
Shunt at 11, 12 for JP1 and R10 Stuffed as 357kΩ
R1 = 10k, (Note 1)
– V < 5V. Current limit varies with different values of V
IN OUT
DEMO MANUAL DC1948A
= 25°C
A
MIN
–36
–1.286
–2.575
–5.15
–12.36
–15.45
–18.54
600
– V . Refer to the LT3090 data sheet
IN OUT
LT3090
TYP MAX UNITS
–1.5 V
–1.25 –1.213 V
–2.5 –2.425 V
–5 –4.85 V
–12 –11.64 V
–15 –14.55 V
–18 –17.46 V
mA
dc1948af
1