DC2033A - Demo Manual

DEMO MANUAL DC2033A
LT6110
Cable/Wire
Drop Compensator
Description
The DC2033A demo board features the LT®6110 cable/
wire drop compensator IC. The LT6110 is a precision
high side current sense that monitors load current via a
sense resistor and converts the sense voltage to a sinking or sourcing current. Using the LT6110 sourcing or
sinking current to control a regulator’s output voltage can
compensate for the voltage loss due to a cable/wire drop.
The LT6110 includes an internal sense resistor or can be
used with an external sense resistor.
The DC2033A is jumper-configurable for the LT6110 to
use the internal sense resistor, an external 25mΩ sense
resistor, or a 5.4mΩ PCB trace sense resistor. The DC2033A
default configuration is for the LT6110 to use the internal
sense resistor.
Design files for this circuit board are available at
http://www.linear.com/demo
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.
Typical Wire Drop Compensation Connections
ILOAD
RWIRE
(Ω)
ILOAD
VLOAD
RIN
CLOAD
V+
+IN
VIN
RS
–IN
VREG
LOAD
RFA
REGULATOR
IIOUT
LT6110
IOUT
+ –
RFB
FB
RG
V–
IMON
DC2033 F01
Figure 1. One Cable/Wire Compensation (One Wire to a Load Sharing the Regulator’s Ground)
ILOAD
RWIRE
(Ω)
ILOAD
RIN
+IN
VIN
V+
+
RS
–IN
CLOAD
VREG
RFA
REGULATOR
IIOUT
IOUT
LT6110
RWIRE
(Ω)
+ –
LOAD
–
VLOAD
RFB
FB
RG
IMON
V–
DC2033 F02
Figure 2. Two Cable/Wire Compensation (One Wire to a Load and One Ground Return Wire)
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DEMO MANUAL DC2033A
Performance Summary
Specifications are at TA = 25°C
PARAMETER
MIN
Supply Range (V+ to V–)
TYP
2
MAX
UNITS
50
V
100
300
µV
IOUT Current Error (Does Not Include VOS or RIN Errors) I+IN = 10µA
I+IN = 100µA
I+IN = 1mA
0.6
0.4
1.5
1.6
1
2.5
%
%
%
IMON Current Error (3 • I+IN)
I+IN = 100µA
1.5
3
%
Amplifier Input Offset Voltage, VOS
IOUT Voltage Range
0.4
IOUT Current Error Change for IOUT Voltage 0.4V to 3.5V
IMON Current Error Change for IMON Voltage 0V to 3.1V
IOUT Signal Bandwidth I+IN = 100µA
Supply Current
V+
V
0.2
%/V
0.2
%/V
180
16
kHz
30
µA
Quick Start Setup
The Quick Start Setup of Figure 3, shows the basic connections required for getting familiar with a DC2033A.
An ammeter is used to measure the load current to a 5Ω
load or an active load. To confirm the operation of the
LT6110, connect a wire jumper from VOUT1 to regulator.
This jumper connects the power supply 5V to the ROUT
100Ω pull-up resistor. The voltmeter across ROUT is for
monitoring the IIOUT current. A DC2033A is assembled with
a 402Ω RIN1 resistor to provide quick testing convenience.
The RIN1 resistor and the VSENSE voltage set the LT6110
output current (IIOUT). To begin, adjust the power supply
for 1A load current. With 1A load current flowing through
the internal 20mΩ RSENSE resistor and 100µV VOS, the
IIOUT current is 50µA, (1A • 20mΩ + 100µV)/402Ω. The
voltmeter should read 5mV (50µA • 100Ω) ± the RSENSE,
VOS, RIN1, ROUT and IIOUT errors. Figure 4 shows the Quick
Setup schematic and IIOUT equations.
Figure 3. Quick Start Setup
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DEMO MANUAL DC2033A
Quick Start Setup
REGULATOR
E1
5V POWER
SUPPLY
ILOAD
1A
ILOAD
1A
RJ3
0Ω
C2
0.1µF
GND
E3
RJ1
0Ω
RJ2
0Ω
5Ω LOAD
E4
GND
R1
1k
RIN1
402Ω
+IN V+
E1 TO E5
WIRE JUMPER
E2
RS
–IN
RSENSE
IIOUT
ROUT
100Ω
E5
VOUT1
IIOUT =
VOUT1 − VOUT2
ROUT
IIOUT =
ILOAD • RSENSE + VOS
RIN1
RJ10
0Ω
E6
VOUT2
LT6110
IOUT
IMON
+ –
V–
DC2033 F04
E7
IMON
RMON
100Ω
3× IIOUT
EB
ROUT = 100
RIN1 = 402
TYPICAL VOS = 100µV
RSENSE = 20mΩ, ±15%
Figure 4. DC2033A Quick Setup Circuit and Equations
Setting Up the DC2033A for Wire Compensation
Testing
The DC2033A default circuit uses the LT6110 internal
20mΩ sense resistor (RSENSE) and is configured with
0Ω RJ1, RJ2 and RJ3 are installed with 0Ω jumpers.
The RJ1 and RJ2 are standard 0Ω jumpers and connect the LT6110 amplifier across the internal RSENSE.
The RJ1 and RJ2 resistance is not a concern as the
current flowing through them is very small (the resistance variation of standard 0Ω resistors is 20mΩ to
100mΩ). However, a standard 0Ω jumper must not be
used in the path of the load current because the jumper's
I • R drop adds an error term to a wire drop compensation
design (for example the I • R drop of a 50mΩ jumper for
2A is 100mV). The RJ3 jumper is ultra-0Ω, with less than
1mΩ and rated for 30A at 70°C. The RJ3 jumper can be
removed and re-installed as RJ6 or RJ9, to configure the
DC2033A with an LT6110 and an external RSENSE (for an
alternative to an ultra-0Ω jumper install two 0.25 inch
length of 18AWG solid copper wires in parallel for up to
20A ILOAD).
The RIN1 resistor and the VSENSE voltage set the LT6110
output current (IIOUT) for regulator output voltage control.
The IIOUT current connects to the regulator feedback resistors and boosts the regulator's output voltage (VREG). The
VREG voltage increases directly with the load current and
cancels the wire's I • R drop (VDROP) to the remote load.
A DC2033A has 0805 size pads for installing a switching
regulator's feedback resistors (RFA, RFB and RG). A low
quiescent current switching regulator has 10µA or less
current flowing through the feedback divider and requires
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3
DEMO MANUAL DC2033A
Quick Start Setup
three feedback resistors for an LT6110 connection, as
in Figure 1. In addition, a DC2033A includes pads for a
feedback loop compensation capacitor, C4.
VREG is the no-load current regulator output voltage.
Quick Design Equations:
V
RIN1 = SENSE VSENSE = ILOAD•RSENSE
IIOUT
A Quick Design Guide.
Variable Definitions:
V
RFA = DROP VDROP = ILOAD•(RSENSE +R WIRE )
IIOUT
ILOAD is the maximum load current and IIOUT is the LT6110
output current, (design target is 100µA).
RSENSE is the LT6110 internal or external current sense
resistor and RWIRE is the copper wire resistance.
(RWIRE includes the resistance of the load current carrying PCB traces and wire connectors minus the RSENSE
resistance).
VFB is the regulator's feedback reference voltage.
IQ is the no-load quiescent current flowing through the
resistor feedback divider, (IQ = VFB/RG), (refer to the
regulator’s demo manual).
–V
V
RFB = REG FB RG =
IQ
VFB
IQ
Quick Design Check:
VREG = (RFA +RFB +RG )•IQ
NOTE: For DC2033A REGULATOR input voltages higher
than 36V, remove the RJ10 jumper sorting the 27V Zener,
D1. Refer to the LT6110 data sheet for additional application circuits and information.
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DEMO MANUAL DC2033A
ApplicationS
DC2033A Application Options
The DC2033A with a Regulator Demo Board
The DC2033A is designed to be used with a regulator
board and copper wire. On board jumper pads and turrets
configure an LT6110 circuit using 0Ω jumpers and provide
for wired connections to a regulator board. Figures 6, 7
and 8 show typical DC2033 application circuit options.
A DC2033A board can be configured and connected to a
regulator demo board for a complete cable/wire drop compensation system evaluation. Typically a regulator demo
board includes a feedback resistor divider that sets the
output voltage VREG. Remove the feedback resistors from
the regulator board and connect the regulator’s feedback pin
(FB or VREF) to the DC2033A VFB (E9). In addition, connect
the VOUT and GND of the regulator board to the REGULATOR
(E1) and to the GND (E3) of the DC2033A respectively.
Figure 5 shows Linear Technology’s buck regulator demo
board, DC1458A, connected to a DC2033A, using an
external sense resistor, REXT. The DC1458A demo board
includes the LT3972, 5V at 3.5A buck regulator. Figure 6
shows the complete cable/wire compensation schematic.
Table 2. DC2033A Current Sense Resistor, RSENSE and Jumper
Options
RSENSE
JUMPERS
JUMPERS
RESISTANCE (25°C) STANDARD 0Ω ULTRA-0Ω
Internal
20mΩ at ILOAD = 1A,
(16.5mΩ to 22.5mΩ
LT6110
RSENSE
22mΩ at ILOAD = 3A,
(18.5mΩ to 24.5mΩ
External
REXT
External
RPCB
ILOADMAX
RJ1, RJ2
RJ3
3A at 125°C
25mΩ at ILOAD = 1A,
±1%
RJ4, RJ5
RJ6
6A at 70°C
5A at 90°C
5.4mΩ at ILOAD = 1A,
±15%
RJ7, RJ8
RJ9
20A at 25°C
10A at 90°C
5.7mΩ at ILOAD = 10A,
±15%
NOTE: The LT3972 R2 and R3 feedback resistors are removed from the DC1458A board and are on the DC2033A
board (RFA, RFB and RG). The no-load LT3972 voltage is
Figure 5. DC1458A and DC2033A Connections
dc2033af
5
6
E4
EXTSS
E2
GND
E8
GND
E1
VIN
RUN
SHDN
EXTSS
+
JP1
1
2
3
4
C2
22µF
D1
MBRA340T3
LT3972
BUCK REGULATOR
DC1458A
C7
0.22µF
SYNC ON
JP2
C8
100pF
SYNC
BURST MODE
GND
PGOOD
VIN
RUN/SS
FB
SW
RT
VC
LT3972EMSE
BOOST
BD
1
2
3
C6
1000pF
R5
15k
R1
63.4k
R3
R2
R4
100k
C4
47µF
E9
SYNC
E3
GND
E7
PGOOD
C5
0.1µF E6
GND
R2 AND R3 ARE
REMOVED.
E5
VOUT
5V AT 3.5A
E9
VFB
C4
47pF
E3
GND
E1
REGULATOR
RJ4
0Ω
IIOUT
RJ10
0Ω
E6
VOUT2
ROUT
100Ω
E5
RG
100k VOUT1
RFB
523k
RFA
9.53k
E7
IMON
RMON
100Ω
V–
+ –
3× IIOUT
LT6110
RSENSE
RS
REXT ILOAD
25mΩ 3.5A
+IN V+
C2
0.1µF
ILOAD
3.5A
IMON
IOUT
RFA, RFB and RG
RIN
VALUES ARE FOR
866Ω
COMPENSATION OF
10ft, 24AWG WIRE
AND 5V AT 3.5A LOAD.
LT6110
WIRE DROP COMPENSATOR
DC2033A
DC1458 TO DC2033
CONNECTIONS.
EB
–IN
R1
1k
RJ5
0Ω
RJ6
0Ω
DC2033 F06
E4
GND
E2
LOAD
Figure 6. An LT3972 5V at 3.5A Buck Regulator with LT6110 Circuit Compensating for the Drop of a 10ft, 24AWG Cable/Wire
R6
100k
C3
4.7µF
C1
0.47µF
L1
6.8µH
LOAD
47µF
VLOAD
5V
3.5A
RWIRE
24AWG
10ft
0.25Ω
DEMO MANUAL DC2033A
ApplicationS
dc2033af
DEMO MANUAL DC2033A
ApplicationS
5V and the feedback voltage, VFB is 0.79V. The values of
the feedback resistors are selected using the Quick Design
Guide with an IQ = 8µA. The specified quiescent current is
8µA. Resistors RFA, RFB and RG are 9.53k, 523k and 100k
respectively. VREG = (9.53k + 523k + 100k) • 8µA = 5V
(±1% and ±1.27% resistor and VFB tolerance respectively).
RJ7 and RJ8. Figure 7 shows the DC2033A schematic with
LT6110 and PCB RSENSE.
The copper thickness of a DC2033A PCB trace is two
ounces. A typical resistance for a 2oz square trace is
0.25mΩ at 25°C. The RPCB serpentine trace length is six
0.15 × 0.6 inch rectangular traces connected by 0.015 ×
0.15 inch traces. The current path area of each rectangular trace is equivalent to three and one-half squares. The
RPCB resistance is 5.4mΩ at 25°C, ±15%. RWIRE is the
total resistance from the regulator output to the remote
load (minus the RSENSE resistance).
The DC2033A PCB Trace RSENSE
A DC2033A has a serpentine PCB trace that can be used as
an LT6110 external sense resistor for high load currents
(5A to 20A). Remove RJ3 ultra-0Ω jumper and install as
RJ9. Remove standard 0Ω jumpers RJ1 and RJ2 and install
DC2033A
E1
REGULATOR
VIN
ILOAD
VREG
RJ9
0Ω
ILOAD
RJ8
0Ω
RJ7
0Ω
E3
GND
REGULATOR
*RPCB
5.4mΩ
±15%
C2
0.1µF
FB
+IN V+
RS
E9
VFB
RFB
RG
E5
VOUT1
RJ10
0Ω
E6
VOUT2
CLOAD
VLOAD
LOAD
*RPCB
IIOUT
ROUT
100Ω
(WIRE RESISTANCES)
–IN
RSENSE
RFA
E4
GND
RWIRE
R1
1k
RIN1
C4
E2
LOAD
LT6110
IOUT
IMON
+ –
V–
DC2033 F07
E7
IMON
RMON
100Ω
3× IIOUT
EB
Figure 7. DC2033 Configured for RPCB (PCB Trace Sense Resistor)
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DEMO MANUAL DC2033A
ApplicationS
The RJ9 jumper in the load current path must be ultra-0Ω,
1mΩ or less (the jumper's I • R drop adds an error term
to a wire drop compensation design). The RJ3 jumper is
ultra-0Ω, less than 1mΩ and can be removed and installed
as RJ9 (for an alternative to an ultra-0Ω jumper install two
0.25 inch length of 18AWG solid copper wires in parallel
for an RJ9 jumper).
Using the DC2033A with an LT6110 DFN Package
The bottom layer of a DC2033A is designed for an LT6110
DFN IC. To use a DC2033A for evaluating with an LT6110
DFN IC with an internal RSENSE requires the following:
Remove U1 (LT6110 SOT IC) and jumper RJ3 from the top
of the board. Install a U2 (LT6110 DFN), RJ11 and RJ12
on the bottom of DC2033A. Figure 8 shows the schematic
of a DC2033A with an LT6110 DFN package.
The DC2033A PCB layout is optimized for an LT6110
SOT23 package. A DC2033A with a LT6110 DFN (U2)
and an internal RSENSE, adds a 2% RSENSE error due to a
PCB via from the top to the bottom PCB layer. In addition
to using a DC2033A with a LT6110 DFN and an internal
RSENSE, the DC2033A can be configured for an LT6110
DFN with an external REXT or RPCB current sense resistor
(refer to the jumper table on the DC2033A schematic).
The load current path RJ6, RJ9, RJ11 and RJ12 jumpers
must be ultra-0Ω, less than 1mΩ, (for an alternative to
an ultra-0Ω jumper install two 0.25 inch length of 18AWG
solid copper wires in parallel for an RJ6, RJ9, RJ11 or
RJ12 jumper).
dc2033af
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DEMO MANUAL DC2033A
ApplicationS
DC2033A
E1
REGULATOR
VIN
E1
REGULATOR
RJ11
0Ω
VREG
REGULATOR
ILOAD
RJ12
0Ω
ILOAD
C2
0.1µF
E3
GND
E3
GND
RJ1
0Ω
RJ2
0Ω
RIN1
R1
1k
FB
+IN V+
RS
E2
LOAD
E4
GND
RWIRE
0Ω
CLOAD
VLOAD
LOAD
–IN
RSENSE
IIOUT
C4
E9
VFB
RFA
ROUT
100Ω
RJ10
0Ω
LT6110
IOUT
+ –
RFB
RG
E5
VOUT1
E6
VOUT2
IMON
V–
DC2033 F08
E7
IMON
RMON
100Ω
3× IIOUT
EB
Figure 8. DC2033 Configure with an LT6110 DFN Package and Internal RSENSE
dc2033af
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DEMO MANUAL DC2033A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
1
MANUFACTURER/PART NUMBER
0
C1, C4
CAP, X7R, 50V, 10%, 0603 OPT
2
1
C2
CAP, X7R, 0.1µF, 50V, 10%, 0603
3
0
C3
CAP, X7R, 50V,1206 OPT
4
1
D1
DIODE, ZENER 27V 200MW SOD-323
DIODES/ZETEX, BZT52C27S-7-F
5
4
E5, E6, E7, E9
TESTPOINT, TURRET, 0.063"
MILL-MAX, 2308-2-00-80-00-00-07-0
6
5
E1 TO E4, E8
TESTPOINT, TURRET, 0.093"
MILL-MAX, 2501-2-00-80-00-00-07-0
VISHAY, WSL2512R0250FEA18
TDK C1608X7R1H104K
7
1
REXT
CURRENT SENSE RESISTOR 0.025Ω 1% 2512
8
0
RIN2, RG, RFA, RFB
RES, CHIP, 1%, 1/8W, 0805 OPT
9
1
RIN1
RES, CHIP, 1%, 1/8W, 402Ω, 0805
VISHAY, CRCW0805402RFKEA
10
3
RJ1, RJ2, RJ10
RES, 0Ω JUMPER, 0805
VISHAY, CRCW08050000Z0EA
11
0
RJ4, RJ5, RJ7, RJ8
RES, 0Ω JUMPER, 0805 OPT
12
1
RJ3
RES, ULTRA-0Ω JUMPER, 2512
NACOMA/TEPRO RN5326
13
0
RJ6, RJ9, RJ11, RJ12
RES, ULTRA-0Ω JUMPER, 2512 OPT
USE TWO 0.25in,18AWG SOLID COPPER WIRES IN
PARALLEL
14
2
ROUT, RMON
RES, CHIP, 1%, 1/8W, 100Ω, 0805
VISHAY, CRCW0805100RFKEA
15
0
RPCB
RES PCB TRACE, 5.4mΩ, ±15%
(PCB TRACE RESISTOR)
16
1
R1
RES, CHIP, 1%, 1/8W, 1k, 0805
VISHAY, CRCW08051K00FKEA
17
1
U1
IC, WIRE DROP COMPENSATOR, TSOT-23-8
LINEAR TECHNOLOGY, LT6110ITS8#PBF
18
0
U2
IC, WIRE DROP COMPENSATOR, 8 LEAD DFN, OPT
19
4
MH1, MH2, MH3, MH4
STANDOFF, SNAP ON
KEYSTONE, 8831
dc2033af
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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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B
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












 









3
3











 
































5




2














1
 

 



 








TECHNOLOGY



1



 




2
A
B
C
D
DEMO MANUAL DC2033A
Schematic Diagram
dc2033af
11
DEMO MANUAL DC2033A
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
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
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,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
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
dc2033af
12 Linear Technology Corporation
LT 0413 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2013
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