Linear Technology DC1659A User manual

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DEMO MANUAL DC1659A
DESCRIPTION
LT6109-1/LT6109-2
High Side Current Sense
Amplifiers with Reference
and Comparators
Demonstration circuit 1659A features the LT
®
6109, a high
side current sense amplifier with two comparators and a
400mV reference.
The demo board circuit amplifies the voltage across an
on-board current sense resistor, to provide a precision
unipolar voltage output that is proportional to the sensed
current. The board has two on-board comparators with
latching outputs and an integrated 400mV reference that
sets the threshold for the comparators. There are two ver-
sions of this demonstration circuit, A and B, depending on
which version of the LT6109 is installed. The DC1659A-A
(LT6109-1) has an inverting and a noninverting compara-
tor input available, while the DC1659A-B (LT6109-2) has
L, LT, LTC, LTM, TimerBlox, 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
OPERATING PRINCIPLES
two inverting inputs available. Both current sense gain
and current fault limits are set by on board resistors and
are the same for both boards. The gain is set at 100V/V
and the comparators are set to trip at current thresholds
of 50mA and 300mA.
The key performance specifications are listed in the table
below.
Design files for this circuit board are available at
http://www.linear.com/demo
(TA= 25°C)
TheLT6109 operates by amplifying the voltage drop across
a sense resistor that is in series with the load. The sense
inputs of the amplifier differentially measure the sense
resistor voltage drop to control an internal variable current
source that allows translation of the input voltage level to
a level referenced to the GND. The circuit gain is set by
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Range 2.7 60 V
VIOUT Measured Output Signal ILOAD = 100mA 1 V
IIOUT Measured Output Current VIOUT = 1V 100 μA
ILOAD Output Load Current Range Thermal Limit of RSENSE 4A
IQIN Quiescent Current VIN = 12V 800 μA
VTHR1 Comparator1 Threshold VIOUT = 3.0V 300 mA
VTHR2 Comparator2 Threshold VIOUT = 0.5V 50 mA
the ratio of the output resistor to the input resistor. The
comparator thresholds are set by the internal reference
and the current trip points are set by dividing the output
resistance into a network of three resistors. The DC1659
is shipped with a 100mΩ sense resistor, a gain of 100 and
current fault thresholds of 50mA and 300mA.
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DEMO MANUAL DC1659A
BLOCK DIAGRAMS
LT6109-1 (DC1659A-A) LT6109-2 (DC1659A-B)
100Ω
OUTA
–
+
–
+
9
10
18
INC2 7
INC1
V+
V–
610912 F01
6
V+
V–
V–
V–
V–
V+
3k
V+
3k
SENSEHI
LT6109-1
SENSELO
200nA
RESET
UNDERCURRENT FLAG
OVERCURRENT FLAG
2EN/RST
3OUTC2
4OUTC1
34V 6V
ENABLE AND
RESET TIMING
–
+
V–
V+
5
400mV
REFERENCE
100Ω
OUTA
–
+
–
+
9
10
18
INC2 7
INC1
V+
V–
610912 F02
6
V+
V–
V–
V–
V–
V+
3k
V+
3k
SENSEHI
LT6109-2
SENSELO
200nA
RESET
OVERCURRENT FLAG
OVERCURRENT FLAG
2EN/RST
3OUTC2
4OUTC1
34V 6V
ENABLE AND
RESET TIMING
–
+
V–
V+
5
400mV
REFERENCE
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DEMO MANUAL DC1659A
QUICK START PROCEDURE
Figure 1. Test Setup
The DC1659A provides a simple way to evaluate the
performance of the LT6109. Refer to Figure1 for proper
measurement equipment setup and follow the procedure
below:
1. With the power off, connect the power supply positive
to IN and the common to GND. With default board
settings the supply can range from 3.3V to 60V. If the
supply does not have an accurate current readout, a
DMM may be connected in series with the supply as
shown in Figure1.
2. Connect a DMM or oscilloscope to the IOUT with the
common connection connected to ground.
3. Connect a load to the demo boards OUT terminal (posi-
tive) and ground. The load may be a power resistor,
active load instrument or a circuit of interest.
4. Turn on the power supply. The comparators start in an
unknown state and must be reset. This can be done
by pressing the reset button. With the load shown in
Figure 1 the comparator outputs should be:
PART COUT1 COUT2
DC1659A-A LT6109-1 High High
DC1659A-B LT6109-2 High Low
5. Measure the output voltage and confirm it corresponds
to the load current. VIOUT = 10 • ILOAD for the factory
installed resistors.
6. If able, sweep load current from 0mA to 300mA to verify
the operation of the comparators. The LED will turn on
when the comparator output has latched low. Use the
reset circuitry to reset comparator output.
0.10A
20.0V
1.0V
Load
200Ω
Reset
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DEMO MANUAL DC1659A
OPERATION
Current Sense Gain
The gain of the LT6109 current sense amplifier is set
by the ratio of ROUT and RIN resistors. In the demo
circuit this means that the gain is set by the ratio of
(R1 + R2 + R3)/R10. The gain error is primarily controlled
by the precision of the resistors used. The factory resis-
tors are a 1% tolerance which will dominate the gain
error. To reduce system gain error, the resistors can be
replaced with 0.1% resistors.
LED Indicators
The LEDs indicate the state of the comparator outputs.
When the LED is on, the comparator is latched low. When
the LED is off, the comparator output is high. When the
comparatoroutputislatchedlow,theLT6109 must be reset
to refresh the comparator output and to turn off the LEDs.
Jumper Summary
Reset(JP1): The Reset jumper has two settings for manual
or auto mode. In manual mode, the user must press the
reset button to reset the latching comparators. In auto
mode, the comparators will be continuously reset every
10 seconds. The factory default setting is manual mode.
Optional Settings
1. For supply voltages below 3.3V, remove R20 and install
R21 (0Ω jumper). When R21 is installed, the supply
voltage must stay between 2.7V to 6V to prevent dam-
aging the TimerBlox
®
circuitry that is used to reset the
comparator outputs.
2. To power the LT6109 from a supply separate from the
load, remove R22 and connect the power supply to V+
turret.
3. There are a number of optional components that (not
installed) allow the DC1659 to be tailored to a specific
application:
A) To free comparator input INC1, remove R2 and R3
and install R19.
B) To free comparator input INC2, remove R1 and R2
and install R18.
C) To add filtering to the amplifier output, install C6.
4. R9 can be set to the same value as R10 to reduce error
caused by input bias current. Typically for values of
R10 (less than 1k) and R9 can be omitted as the error
is negligible.
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DEMO MANUAL DC1659A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 1 C1 Capacitor, 1μF 20% 1206 100V X7R TDK/C3216X7R2A105M
2 1 C2 Capacitor, 0.47μF 20% 0603 16V X5R AVX/0603YD474MAT2A
3 2 C4, C5 Capacitor, 0.1μF 20% 0402 10V X5R Taiyo Yuden/LMK105BJ104MV-F
4 1 C6 Capacitor, 0.1μF 20% 0603 X5R Optional
5 1 C7 Capacitor, 0.1μF 10% 0603 100V X7R Murata/GRM188R72A104KA35D
6 3 E1, E2, E8 Turret Terminal Mill Max 2501-2-00-80-00-00-07-0
7 7 E3-E7, E9, E10 Turret Terminal Mill Max 2308-2-00-80-00-00-07-0
8 1 JP1 Header, 3-Pin, 2mm SAMTEC TMM-103-02-L-S
9 1 JP1 Shunt SAMTEC 2SN-BK-G
10 2 LED1, LED2 Red1206 LED Panasonic/LN1251C
11 1 R1 Resistor, 2k 1% 0603 1/16W AAC/CR16-2001FM
12 1 R2 Resistor, 6.65k 1% 0603 1/16W Vishay/CRCW06036K65FKEA
13 1 R3 Resistor, 1.33k 1% 0603 1/16W AAC/CR16-1331FM
14 3 R4, R5, R14 Resistor, 10k 5% 0402 1/16W AAC/CR05-103JM
15 1 R6 Resistor, 118k 1% 0402 1/16W AAC/CR05-1243FM
16 2 R7, R8 Resistor, 1k 5% 0603 1/16W Vishay/CRCW04021K00JNED
17 1 R10 Resistor, 100Ω 1% 0603 1/16W Vishay/CRCW0603100RFKEA
18 1 R11, R22 Resistor, 0Ω 0402 1/16W Vishay/CRCW04020000Z0ED
19 1 R12 Resistor, 13.7k 1% 0402 1/16W AAC/CR05-1372FM
20 1 R13 Resistor, 249k 1% 0402 1/16W AAC/CR05-2493FM
21 1 R15 Resistor, 0.1Ω 1% 2512 2W IRC/LR2512LF-01-R100-F
22 1 R16, R23 Resistor, 1M 1% 0402 1/16W AAC/CR05-1004FM
23 1 R17 Resistor, 392k 1% 0402 1/16W AAC/CR05-3923FM
24 3 R18, R19, R21 Optional
25 2 R20, R9 Resistor, 0Ω 0603 1/16W AAC/CJ06-000M
26 1 SW1 Switch, Pushbutton Panasonic/EVQPPDA25
28 1 U2 IC, LT3010EMS8E#PBF Linear Technology Corp.
29 1 U3 IC, LT6993CS6-1#PBF Linear Technology Corp.
30 1 U4 IC, LT6991CS6#PBF Linear Technology Corp.
DC1659A-A
1 1 U1 IC, LT6109IMS-1 Linear Technology Corp. LT6109IMS-2
DC1659A-B
1 1 U1 IC, LT6109IMS-2 Linear Technology Corp. LT6109IMS-2
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DEMO MANUAL DC1659A
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1659A
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1659A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
LT 0611 • PRINTED IN USA
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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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