DC1699A - Demo Manual

DEMO MANUAL DC1699A
LT6108-1/LT6108-2
High Side Current Sense Amplifier
with Reference and a Comparator
DESCRIPTION
Demonstration circuit 1699A features the LT®6108, a
high side current sense amplifier with a comparator and
a 400mV reference.
The demo board circuit amplifies the voltage across an
onboard current sense resistor, to provide a precision
unipolar voltage output that is proportional to the sensed
current. The board has one onboard comparator and an
integrated 400mV reference that sets the threshold for the
comparator. There are two versions of this demonstration
circuit, A and B, indicating which version of the LT6108
is installed. The DC1699A-A (LT6108-1) has a latching
PERFORMANCE SUMMARY
SYMBOL
PARAMETER
VIN
Input Supply Range
comparator, while the DC1699A-B (LT6108-2) has a non
latching comparator. Both current sense gain and current fault limits are set by onboard resistors and are the
same for both boards. The gain is set at 25V/V and the
comparator is set to trip at a current threshold of 500mA.
The key performance specifications are listed in the table
below.
Design files for this circuit board are available at
http://www.linear.com/demo
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.
(TA = 25°C)
CONDITIONS
MIN
TYP
MAX
2.7
VIOUT
Measured Output Signal
ILOAD = 100mA
IOUT
Output Load Current Range
Thermal Limit of RSENSE
UNITS
60
V
250
mV
4
A
IQA
VIN Quiescent Current DC1699A-A
VIN = 12V
800
μA
IQB
VIN Quiescent Current DC1699A-B
VIN = 12V
650
μA
VTHR
Comparator Threshold
VIOUT = 1.25V
500
mA
OPERATING PRINCIPLES
The LT6108 operates by amplifying the voltage drop across
a sense resistor that is in series with the load. The voltage
drop at the amplifier inputs is translated, via the internal
variable current source, to a ground referenced signal at
the amplifier output. The circuit gain is set by the ratio of
the output resistor to the input resistor (see Figure 1). 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 DC1699A
is shipped with a 100mΩ sense resistor, a gain of 25 and
current fault threshold of 500mA.
V+
7
V+
LT6108
VBATT
RIN
8 SENSEHI
–
1 SENSELO
+
RSENSE
ISENSE
OUTA 6
4
VOUT
ROUT
V–
dc1699a F01
Figure 1. Amplifier Operation
dc1699af
1
DEMO MANUAL DC1699A
BLOCK DIAGRAMS
7
V+
LT6108-1
100Ω
8
SENSEHI
3k
SENSELO
3k
34V
–
+
1
OUTA
V–
6
V–
V+
V–
6V
200nA
2
EN/RST
ENABLE AND
RESET TIMING
RESET
V+
INC
–
3
5
OVERCURRENT FLAG
OUTC
+
V–
V+
400mV
REFERENCE
V–
4
dc1699a BD1
LT6108-1
7
V+
LT6108-2
100Ω
8
SENSEHI
3k
SENSELO
3k
34V
–
+
1
OUTA
V–
V–
6V
6
V–
V+
100nA
2
EN
V+
INC
–
3
5
OVERCURRENT FLAG
OUTC
+
V–
400mV
REFERENCE
V+
V–
4
dc1699a BD2
LT6108-2
dc1699af
2
DEMO MANUAL DC1699A
QUICK START PROCEDURE
The DC1699A provides a simple way to evaluate the
performance of the LT6108. Refer to Figure 2 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 2.
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 (positive) and ground. The load may be a power resistor,
active load instrument or a circuit of interest.
4. Turn on the power supply. If using the DC1699A-A ,
the comparator starts in an unknown state and must
be reset. This can be done by pressing the reset button. With the load shown in Figure 2 the comparator
outputs should be high.
5. Measure the output voltage and confirm it corresponds
to the load current. VIOUT = 2.5 • ILOAD for the factory
installed resistors.
6. If possible, sweep the load current from 0mA to 500mA
to verify the operation of the comparator. The LED will
turn on when the comparator output has gone low. If
using the DC1699A-A, use the reset circuitry to reset
the comparator output.
20.0V
RESET BUTTON
0.10A
250mV
LOAD
ϮϬϬɏ
250mV
Figure 2.
dc1699af
3
DEMO MANUAL DC1699A
OPERATION
Current Sense Gain
Optional Settings
The gain of the LT6108 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 )/R7.
The gain error is primarily controlled by the precision of
the resistors used. The installed resistors are 1% tolerance
which will dominate the gain error. To reduce system gain
error, the resistors can be replaced with 0.1% resistors.
1. For supply voltages below 3.3V, remove R15 and install
R16 (0Ω jumper). When R16 is installed, the supply
voltage must stay between 2.7V to 6V to prevent damaging the TimerBlox® circuitry that is used to reset the
comparator output.
LED Indicator
The LED indicates the state of the comparator output.
When the LED is on, the comparator’s output is low. When
the LED is off, the comparators output is high. When the
comparator output is latched low, the LT6108-1 must be
reset to unlatch the comparator output and turn off the LED.
Jumper Summary
2. To power the LT6108 from a supply separate from the
load, remove R17 and connect the power supply to V+
turret. The input cannot go more than 33V below V+.
3. There are a number of optional components (not
installed) that allow the DC1699 to be tailored to a
specific application:
To disconnect comparator input CIN from IOUT, remove R1 and R2 and install R14.
To add filtering to the amplifier output, install C6.
Reset (JP1): The Reset jumper has two settings for manual
or auto mode. In manual mode, the user must press the
reset button to trigger the LTC6993 to send the 5μs pulse
that resets the latching comparators. In auto mode, the
LTC6991 will continuously reset the comparators every
10 seconds. The factory default setting is manual mode.
dc1699af
4
DEMO MANUAL DC1699A
PARTS LIST
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
DC1699A Genreral BOM
1
1
C1
Capacitor, 1μF 20% 1206 100V X7R
AVX 12061C105MAT2A
2
1
C2
Capacitor, 0.47μF 20% 0603 16V X5R
AVX 0603YD474MAT2A
3
1
C5
Capacitor, 0.1μF 10% 0402 16V X5R
AVX 0402YD104KAT2A
4
1
C7
Capacitor, 0.1μF 10% 0603 100V X7R
Murata/GRM188R72A104KA35D
5
3
E1, E2, E6
TURRET TERMINAL
Mill Max 2501-2-00-80-00-00-07-0
6
5
E3-E5, E9, E10
TURRET TERMINAL
Mill Max 2308-2-00-80-00-00-07-0
7
1
LED2
RED1206 LED
Panasonic/LN1251C
8
1
R1
Resistor, 1.69k 1% 0603 1/16W
VISHAY/CRCW06031K69FKEA
9
1
R2
Resistor, 806 1% 0603 1/16W
VISHAY/CRCW0603806RFKLEA
10
2
R3, R10
Resistor, 10k 5% 0402 1/16W
VISHAY/CRCW040210K0JNED
11
1
R5
Resistor, 1k 5% 0603 1/16W
VISHAY/CRCW06031K00JNEA
12
2
R6, R7
Resistor, 100 1% 0603 1/16W
VISHAY/CRCW0603100RFKEA
13
1
R8
Resistor, 13.7k 1% 0402 1/16W
VISHAY/CRCW040213K7FKED
14
1
R11
Resistor, 0.1Ω 1% 2512 2W
IRC/LR2512LF-01-R100-F
15
0
R14
OPTIONAL
16
2
R15, R17
Resistor, 0Ω 0603 1/16W
VISHAY/CRCW06030000Z0EA
17
1
U2
IC, LT3010EMS8E#PBF
Linear Technology Corp.LT3010EMS8E#PBF
1
1
DC1699A
GENERAL BOM DC1699A
2
1
C4
Capacitor, 0.1μF 20% 0402 10V X5R
3
1
JP1
HEADER, 3-PIN
SAMTEC TSW-103-07-L-S
4
1
JP1
SHUNT
SAMTEC SNT-100-BK-G
5
1
R4
Resistor, 124k 1% 0402 1/16W
VISHAY/CRCW0402124KFKED
6
1
R9
Resistor, 249k 1% 0402 1/16W
VISHAY/CRCW0402249KFKED
7
2
R12, R18
Resistor, 1M 1% 0402 1/16W
VISHAY/CRCW04021M00FKED
8
1
R13
Resistor, 392k 1% 0402 1/16W
VISHAY/CRCW0402392KFKED
DC1699A-A
TDK/C1005X5R1A104M
9
1
SW1
Switch, push button
Panasonic/EVQPPDA25
10
1
U1
IC, LT6108IMS-1
Linear Technology Corp. LT6108IMS-1
11
1
U3
IC, LTC6993CS6-1#PBF
Linear Technology Corp. LTC6993CS6-1#PBF
12
1
U4
IC, LTC6991CS6#PBF
Linear Technology Corp. LTC6991CS6#PBF
1
1
DC1699A
GENERAL BOM DC1699A
2
1
U1
IC, LT6108IMS-2
DC1699A-B
Linear Technology Corp. LT6108IMS-2
dc1699af
5
E6
E5
E8
1. ALL RESISTORS ARE IN OHMS, 0603
2. ALL CAPACTORS ARE IN MICRO FARADS, 0603
3. INSTALL SHUNTS AT J1 PIN 1+2
3
COUT
EN/RST
V+
THIS CIRCUIT IS PROPRIETARY TO
LINEAR TECHNOLOGY AND SUPPLIED FOR
USE WITH LINEAR TECHNOLOGY PARTS.
CUYLER L.
APP ENG.
SCALE = NONE
CL
APPROVALS
5
6
1
C6
OPT
R6
100
*
R2
806
R1
1.69k
E4
E3
LTC CONFIDENTIAL FORCUSTOMER USE ONLY
WWW.LINEAR.COM
1630 McCarthy Blvd.
Milpitas, CA 95035
PH: (408) 432-1900
R14
OPT
LT6108IMS8-2
LT6108IMS8-1
-A
-B
U1
OUT
CIN
IOUT
4A MAX
E2
DATE
07/01/2010
APPR
CUYLER L.
ASSY
DESCRIPTION
PRODUCTION
N/A
DATE:
SIZE
07/2010
IC NO.
LT6108IMS8-1/-2
DEMO CIRCUIT 1699A
SH 1 of 2
1
REV
PRECISION CURRENT SENSE WITH COMPARATOR AND REFERENCE
TITLE: SCHEMATIC
CIN
IOUT
SENSE -
PCB DES.
SENSE +
GND
0.1 Ohm
2512
R11
U1
LT6108IMS8*
CUSTOMER NOTICE
R3
10k
0402
7
8
RESET 2
R7
100
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT
TO DESIGN A CIRCUIT THAT MEETS CUSTOMERSUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS
THE CUSTOMER'S RESPONSIBILITY TO VERIFY
PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND
PRINTED CIRCUIT LAYOUT MAY SIGNIFICANTLY
AFFECT CIRCUIT PERFORMANCE OR RELIABILITY.
CONTACT LINEAR TECHNOLOGY APPLICATIONS
ENGINEERING FOR ASSISTANCE.
LED2
1206 LED
R5
1k
0402
C7
0.1uF
R17
0 OHM
NOTES: UNLESS OTHERWISE SPECIFIED
GND
COUT
V+
E1
3V
1
2
IN
3.3V-60V
3V
6
4
ECO REV
1
DEMO MANUAL DC1699A
SCHEMATIC DIAGRAM
dc1699af
C1
1uF
1206
8
5
SHDN
IN
4
V-
SENSE
OUT
2
1
2
1
1
2
JP1
RESET
3
C2
0.47uF
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.
THIS CIRCUIT IS PROPRIETARY TO
LINEAR TECHNOLOGY AND SUPPLIED FOR
USE WITH LINEAR TECHNOLOGY PARTS.
V+
3
2
1
SET
GND
RST
U4
DIV
V+
OUT
SCALE = NONE
APP ENG. CUYLER L.
CL
3
2
1
DIV
V+
OUT
4
5
6
C4
0.1u
0402
R13
392k
0402
R12
1Meg
0402
3V
EN/RST
LTC CONFIDENTIAL FORCUSTOMER USE ONLY
WWW.LINEAR.COM
E7
1630 McCarthy Blvd.
Milpitas, CA 95035
PH: (408) 432-1900
RESET
RESET
N/A
DATE:
SIZE
IC NO.
LT6108IMS8-1/-2
DEMO CIRCUIT 1699A
07/2010
SH 2 of 2
1
REV
PRECISION CURRENT SENSE WITH COMPARATOR AND REFERENCE
TITLE: SCHEMATIC
LT6993CS6-1
SET
GND
TRIG
U3
4
5
6
**COMPONENTS ARE OPTIONAL ON
DC1699A-B ASSEMBLY
R4
LT6991CS6
124k
0402
APPROVALS
R9
249k
0402
PCB DES.
OPT
2.7V-5V
R16
AUTO
CUSTOMER NOTICE
MAN
SW1
RESET
C5
0.1uF
0402
0
3V
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT
TO DESIGN A CIRCUIT THAT MEETS CUSTOMERSUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS
THE CUSTOMER'S RESPONSIBILITY TO VERIFY
PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND
PRINTED CIRCUIT LAYOUT MAY SIGNIFICANTLY
AFFECT CIRCUIT PERFORMANCE OR RELIABILITY.
CONTACT LINEAR TECHNOLOGY APPLICATIONS
ENGINEERING FOR ASSISTANCE.
R18
1M
0402
R10
10k
0402
R8
13.7k
0402
3.3V-60V
R15
3V
U2
LT3010EMS8
DEMO MANUAL DC1699A
SCHEMATIC DIAGRAM
dc1699af
7
V+
DEMO MANUAL DC1699A
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
dc1699af
8
Linear Technology Corporation
LT 0911 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
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