DC1865A - Demo Manual

DEMO MANUAL DC1865A
LT3055
500mA, Linear Regulator with
Precision Current Limit and Diagnostics
Description
Demonstration circuit 1865A is an adjustable 500mA linear
regulator featuring LT®3055. LT3055 is a micropower, low
noise and low dropout voltage linear regulator. The device
supplies 500mA of output current with a dropout voltage
of 350mV. A 10nF bypass capacitor reduces output noise
to 25µVRMS in a 10Hz to 100kHz bandwidth and soft-starts
the reference. The LT3055’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.
tion in the data sheet for a detailed calculation. Logic fault
pins assert low if the LT3055 is in current limit (FAULT2),
operating below its minimum output current (FAULT1)
or is in thermal limit (both FAULT1 and FAULT2). The die
temperature is indicated by the TEMP pin.
LT3055 current limit can be programmed by a single
resistor, accurate to ±10% over a wide input voltage
and temperature range. Another resistor programs the
LT3055’s minimum output current monitor, useful for
detecting open-circuit conditions. The internal current limit
should be considered when the input-to-output differential
is high. The current monitor function sources a current
equal to 1/500th of output current. See the Operation sec-
The LT3055 data sheet gives a complete description of
the device, operation and application information. The
data sheet must be read in conjunction with this quick
start guide for DC1865.
Performance Summary
LT3055 optimizes stability and transient response with a
low ESR ceramic capacitor, requiring a minimum of 3.3µF.
The LT3055 is available in the thermally-enhanced 16-lead
4mm × 3mm DFN and MSOP packages.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1865A
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 TA = 25°C
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage (Max)
VOUT = 5V, IOUT = 500mA
5.6V
Maximum Input Voltage
VOUT = 5V
45V
Output Voltage VOUT
Header in JP1
Header in JP2
Header in JP3
Header in JP4
Header in JP5
Header in JP6
Maximum Output Current (Typ)
VIN = 12V, VOUT = 5V, R10 = 604Ω
500mA
Minimum Output Current (Typ)
VIN = 12V, VOUT = 5V, R9 = 121kΩ
10mA
IMON Voltage (to µP ADC) (Typ)
VIN = 12V, VOUT = 5V, R8 = 1k, IOUT = 500mA
Temp voltage (Typ)
VIN = 12V, VOUT = 5V
1.20V ±3%
1.50V ±3%
1.80V ±3%
2.50V ±3%
3.32V ±3%
4.99V ±3%
1V
0.25V
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DEMO MANUAL DC1865A
Quick Start Procedure
DC1865A is easy to set up to evaluate the performance
of the LT3055. Refer to Figure 1 for proper measurement
equipment setup and follow the procedure below:
NOTE: Make sure that the input voltage does not exceed 45V.
NOTE: The shutdown jumper JP8 shunt is required to be
placed in the OFF or ON position for proper operation.
NOTE: Place the output voltage selection jumper JP1-JP7
at the desired position.
NOTE: Do 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
protect against some, but not all, input transients due to
hot-plugging with a power supply. See Application Note
88 for more details.
1.After all connections are made, turn on input power and
verify that the output voltage according to the output
voltage selection jumper (JP1-JP7). If the output voltage
is different from the above values, use the USER option
and install R7. Select R7 according to the following
equation:
R7 = (VOUT/0.6 – 1) • 60.4k
NOTE: If the output voltage is too low, temporarily
disconnect the load to make sure that the load is not
set too high.
2.Once the proper output voltage is established, adjust
the load within the operating range and observe the
output voltage regulation, FAULT1, FAULT2, PWRGD
and other parameters.
NOTE: Connect the power supply (with power off), load,
and meters as shown in Figure 1.
2
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DEMO MANUAL DC1865A
Quick Start Procedure
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
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3
DEMO MANUAL DC1865A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
2
C1, C8
Cap., X7R, 0.01µF, 16V, 10% 0603
AVX, 0603YC103KAT2A
2
2
C2, C3
Cap., X5R, 0.1µF, 16V, 20% 0402
AVX, 0402YD104MAT2A
3
1
C4
Cap., X7R, 22nF, 16V, 10% 0402
AVX, 0402YC223KAT2A
4
2
C5, C6
Cap., X7R, 10µF, 50V, 10% 1210
TAIYO YUDEN, UMK325AB7106KM-T
5
1
C9
Cap., X7R, 100pF, 16V, 10% 0402
AVX, 0402YC101KAT2A
6
2
R1, R12
Res., Chip, 60.4k, 0.06W, 1% 0402
VISHAY, CRCW040260K4FKED
7
1
R2
Res., Chip, 90.9k, 0.06W, 1% 0402
VISHAY, CRCW040290K9FKED
8
1
R3
Res., Chip, 121k, 0.06W, 1% 0402
VISHAY, CRCW0402121KFKED
9
1
R4
Res., Chip, 191k, 0.06W, 1% 0402
VISHAY, CRCW0402191KFKED
10
1
R5
Res., Chip, 274k, 0.06W, 1% 0402
VISHAY, CRCW0402274KFKED
11
1
R6
Res., Chip, 442k, 0.06W, 1% 0402
VISHAY, CRCW0402442KFKED
12
1
R8
Res., Chip, 1.00k, 0.1W, 1% 0603
VISHAY, CRCW06031K00FKEA
13
1
R9
Res., Chip, 121k, 0.1W, 1% 0603
VISHAY, CRCW0603121KFKEA
14
1
R10
Res., Chip, 604Ω, 0.1W, 1% 0603
VISHAY, CRCW0603604RFKEA
15
3
R11, R13, R14
Res., Chip, 499k, 0.1W, 1% 0603
VISHAY, CRCW0603499KFKEA
16
1
U1
I.C., Volt. Reg., DFN-16 (4×3)
LINEAR TECH., LT3055EDE#PBF
SUN SELECT, 50CE22BSS
Additional Demo Board Circuit Components
1
1
CIN
Cap., Alum., 22µF, 50V, 6.3mm × 5.4mm
2
0
C7 (OPT)
Cap., D Case
3
0
R7 (OPT)
Res., 0603
Hardware-For Demo Board Only
1
9
E1-E9
Turret, Testpoint 0.094"
MILL-MAX 2501-2-00-80-00-00-07-0
2
7
JP1-JP7
Headers, 2 Pins 2mm Ctrs.
SAMTEC, TMM-102-02-L-S
3
1
JP8
Headers, Single Row 3 Pins 2mm Ctrs.
SAMTEC, TMM-103-02-L-S
4
2
XJP6, XJP8
Shunt, 2mm Ctrs.
SAMTEC, 2SN-BK-G
4
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GND
VIN
2.2V - 45V
FAULT1
FAULT2
PWRGD
E2
E1
JP8
SHDN
OFF
ON
E5
E9
E8
3
2
1
+
CIN
22uF
50V
R11
499K
1%
0603
R14
499K
1%
0603
1210
1
2
3
6
5
4
C5
10uF
50V
C3
0.1uF
9
11
IN
IN
SHDN
PWRGD
FAULT2
FAULT1
IMIN
REF/BYP
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE 0402.
ALL CAPACITORS ARE 0402.
R13
499K
1%
0603
R9
121k
1%
0603
C1
0.01uF
0603
17
GND
U1
LT3055EDE
OUT
OUT
ADJ
GND
GND
IMAX
TEMP
IMON
C8
0.01uF
16 0603
15
14
12
13
10
7
8
1210
C6
10uF
50V
C4
22nF
R1
60.4K
1%
JP1
1.2V
R12
60.4K
1%
R10
604
1%
0603
R2
90.9K
1%
JP2
1.5V
R3
121K
1%
JP3
1.8V
C9
0.1nF
C2
0.1uF
R4
191K
1%
JP4
2.5V
R8
1.00K
1% 0603
R5
274K
1%
3.3V
JP5
R6
442K
1%
JP6
5V
C7
OPT
"D" Case
R7
OPT
0603
+
E4
E3
USER SELECT
JP7
E7
E6
GND
VOUT
500mA
TEMP
IMON
DEMO MANUAL DC1865A
Schematic Diagram
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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DEMO MANUAL DC1865A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
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ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
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arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
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Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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Linear Technology Corporation
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●
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