DC1515A - Demo Board

DEMONSTRATION CIRCUIT 1515
QUICK START GUIDE
LT3050
100mA, LOW NOISE LINEAR REGULATOR
WITH PRECISION CURRENT LIMIT AND DIAGNOSTIC FUNCTIONS
DESCRIPTION
Demonstration circuit 1515 is an adjustable 100mA
®
linear regulator featuring LT 3050. LT3050 is a micropower, low noise and low dropout voltage linear regulator. The device supplies 100mA of output current
with a dropout voltage of 340mV. A 10nF bypass capacitor reduces output noise to 30µVRMS in a 10Hz to
100kHz bandwidth and soft-starts the reference. The
LT3050’s 45V input voltage rating combined with its
precision current limit and diagnostic functions make
the IC an ideal choice for robust, high reliability applications. The internal current limit should be considered when input-to-output differential is high. See the
datasheet for details.
if the LT3050 is in current limit, operating below its
minimum output current (open-circuit) or is in thermal shutdown. LT3050 optimizes the stability and
transient response with low ESR ceramic cap, requiring a minimum of 2.2µF.
LT3050 current limit can be programmed by a single
resistor, accurate to ±5% over a wide input voltage
and temperature range. A single resistor programs
the LT3050’s minimum output current monitor, useful
for detecting open-circuit conditions. The current
th
monitor function sources a current equal to 1/100 of
output current. See the datasheet “Operation” section
for detailed calculation. A logic FAULT pin asserts low
Design files for this circuit board are available. Call
the LTC factory.
Table 1.
The LT3050 is available in the thermally-enhanced 12Lead 3mm×2mm DFN and MSOP packages.
The LT3050 datasheet gives a complete description of
the part, operation and application information. The
datasheet must be read in conjunction with this quick
start guide for demo circuit 1515.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Performance Summary (TA = 25oC)
PARAMETER
CONDITION
VALUE
Minimum Input Voltage
VOUT=5V, IOUT = 100mA
5.4V
Maximum Input Voltage
VOUT=5V, IOUT = 90mA
45V
Output Voltage VOUT
Header in JP6
4.99V ±2.8%
Maximum Output Current
VIN=12V, VOUT=5V, RIMAX=1.15k
100mA
Minimum Output Current
VIN=12V, VOUT=5V, RIMAX=11.3k
10mA
To µP ADC Voltage
VIN=12V, VOUT=5V, RIMON=3.01k, IOUT=100mA
2.98V
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DEMONSTRATION CIRCUIT 1515
QUICK START GUIDE
QUICK START PROCEDURE
Demonstration circuit 1515 is easy to set up to
evaluate the performance of the LT3050. Refer to
Figure 1 for proper measurement equipment setup
and follow the procedure below:
NOTE: Make
sure that the input voltage does not ex-
ceed 45V.
protect against some, but not all, input transients
due to hot-plugging with a power supply. See Application Note 88 for more details.
NOTE: Connect
the power supply (with power off),
load, and meters as shown in Figure 1.
jumper JP8 shunt is required to
be placed in the OFF or ON position for proper operation.
After all connections are made, turn on input
power and verify that the output voltage according to the output voltage selection jumper (JP1JP7).
NOTE: Place
NOTE: If
1.
NOTE: The shutdown
the output voltage selection jumper
JP1-JP7 at the desired position.
not hot-plug the input voltage terminal
VIN. The absolute maximum voltage on VIN is 50V
and hot-plugging a power supply through wire
leads to the demonstration circuit can cause the
voltage on the extremely low-ESR ceramic input
capacitor to ring to twice its DC value. In order to
protect the IC, a higher ESR Aluminum Electrolytic
capacitor is placed at the input terminals. This may
the output voltage is too low, temporarily
disconnect the load to make sure that the load is
not set too high.
NOTE: Do
2.
Once the proper output voltages are established,
adjust the load within the operating range and
observe the output voltage regulation, efficiency
and other parameters.
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DEMONSTRATION CIRCUIT 1515
QUICK START GUIDE
Figure 1. Proper Measurement Equipment Setup
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DEMONSTRATION CIRCUIT 1515
QUICK START GUIDE
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