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dc1855af
DEMO MANUAL DC1855A
Description
LT3030
Dual 750mA/250mA
Low Dropout, Low Noise,
Micropower Linear Regulator
Demonstration circuit 1855A is a dual, micropower, low
noise and low dropout voltage linear regulator featuring
the
LT3030
. The input voltages are independent for each
channel of DC1855A and can range from 2.2V to 20V.
Each channel has a jumper that sets the output voltage to
either 1.5V, 1.8V, 2.5V, 3.3V, 5V or a voltage that is user
programmed by the installation of a resistor. For channel 1
and channel 2, the maximum output currents are 750mA
and 250mA and the ceramic output capacitors are 22µF
and 10µF respectively. The internal reference of each
channel is bypassed with a 10nF capacitor for reduced
output noise. Each channel has a jumper for shutdown
and a terminal for PWRGD that is pulled up to the input
supply. A resistor divider can be easily added that allows
precise lockout at low input voltages.
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
The LT3030 is well suited to applications that require
sequencing between dual regulator channels, particu-
larly microprocessor systems and instrumentation that
require low noise. Systems with batteries will benefit
from the low dropout of the LT3030 and its micropower
operation. DC1855A features the LT3030 in a 28-lead
4mm
×
5mm QFN package. The LT3030 data sheet must
be read in conjunction with this demo manual to properly
use or modify demo circuit DC1855A.
Design files for this circuit board are available at
http://www.linear.com/demo
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Minimum Input Voltage, V
IN
V
OUT
= 1.8V
2.2
V
Maximum Input Voltage, V
IN
20
V
Output Voltage, V
OUT
VOUT SELECT = 1.5V
VOUT SELECT = 1.8V
VOUT SELECT = 2.5V
VOUT SELECT = 3.3V
VOUT SELECT = 5V
1.48
1.77
2.45
3.21
4.86
1.53
1.83
2.56
3.37
5.12
V
V
V
V
V
Maximum Channel 1 Output Current, I
OUT1
V
IN1
= 3.3V, V
OUT1
=1.8V
750
mA
Maximum Channel 2 Output Current, I
OUT2
V
IN2
= 3.3V, V
OUT2
=1.8V
250
mA
Specifications are at T
A
= 25°C
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