DEMO MANUAL DC1785A
LTC2991
I
2
C Temperature, Voltage
and Current Monitor
DESCRIPTION
Demonstration circuit 1785A features the LTC
®
2991, a high
performance temperature, voltage and current monitor
that uses an I
2
C interface for communication. It offers
sub-millivolt voltage resolution, 1% current measurement
and 1°C temperature accuracy.
DC1785A is a member of Linear Technology‘s QuikEval™
family of demonstration boards. It is designed to allow easy
evaluation of the LTC2991 and may be connected directly
to the target application’s analog signals while using the
DC590 USB Serial Controller board and supplied software
to measure performance. The exposed ground planes allow
proper grounding to prototype circuitry. After evaluating
with Linear Technology’s software, the digital signals can
be connected to the end application’s processor/controller
for development of the serial interface.
Design files for this circuit board are available at
http://www.linear.com/demo
L,
LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks
and QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
INPUTS
RIBBON CABLE TO DC590
CONTROLLER
Figure 1. Proper Measurement Equipment Set-Up
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DEMO MANUAL DC1785A
QUICK START PROCEDURE
Connect the DC1785A to a DC590 USB Serial Controller
using the supplied 14-conductor ribbon cable. Connect the
DC590 to host PC with a standard USB A/B cable. Run the
evaluation software supplied with DC590 or downloaded
from http://www.linear.com/software. The correct program
will be loaded automatically. Click the COLLECT button to
start reading the input voltage. Details on software features
are documented in the control panel’s help menu.
SOFTWARE SET-UP
The DC1785A software is designed to give the user ac-
cess to all LTC2991 functionality and features. There are
several options that may be accessed both through right
and left clicks.
Input Settings
By default, all eight inputs are set as single-ended. This may
be modified by either left clicking the input type picture to
cycle through the options or right clicking the picture to
bring up a list of options and left clicking to select.
The legend for each input type icon is included below.
Single-Ended (default)
Differential
Diode Temperature
Input sampling can also be turned on and off by left click-
ing the label of the corresponding input. When an input
is off, the values box below the label will be shaded and
the value will stop updating.
Graph Settings
By default, the QuikEval software will graph V1. To begin
graphing a different input, left click the values box of the
input to be graphed.
To pan the graph, hold down the right mouse button while
hovering over the graph and move the mouse in the direc-
tion of desired motion. The graph will cease to auto-scroll
after a pan has be initiated, to reactivate the auto-scroll
double left click anywhere on the graph.
Figure 2. Software Screenshot
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DEMO MANUAL DC1785A
QUICK START PROCEDURE
To zoom the graph, left click and drag. To undo any zoom
and re-initiate auto-scroll, double left click anywhere on
the graph.
Tools
There are two tools included in the software package;
both are accessible under the tools menu in the software.
Statistics: The statistics window lists some basic informa-
tion about the gathered values. It gives, mean, standard
deviation, min, max and crest factor. The statistics can be
reset with the reset button.
PWM: The PWM window allows the user to configure the
PWM functionality of the LTC2991. The DC1785A includes
a red LED next to the PWM turret which reflects the duty
cycle of the PWM pin. The pin needs to be enabled in this
window in order for proper functionality to be achieved.
This window also allows the user to set the PWM threshold.
Please see the LTC2991 datasheet for an explanation of
the PWM pin functionality.
HARDWARE SET-UP
Connection to DC590 Serial Controller
J1 is the power and digital interface connector. Connect
to DC590 serial controller with supplied 14-conductor
ribbon cable.
Jumper Settings
V1, V2, V7, V8 – (Default VOLT, VOLT, VOLT, VOLT). These
jumpers can be toggled between VOLT and TEMP VOLT
.
connects the corresponding input on the LTC2991 with the
corresponding turret for an external input. TEMP connects
the corresponding input to MMBT (V1 and V2). Please
note that the jumpers should be moved in pairs, V1 and
V2 should both be connected either to VOLT or TEMP and
V7 and V8 should also be both connected to either VOLT
or TEMP Once set the proper selection should also be
.
made inside the QuikEval software in the mode selection
box, to reflect any changes made.
V
CC
– (Default DC590) EXTV
CC
allows the user to provide
the V
CC
voltage (2.9V to 5V) to the LTC2991 at turret
EXTV
CC
while DC590(5V) powers the LTC2991 with 5V
from the DC590. State of V
CC
can be seen through red
LED D1.
ADR0, ADR1, ADR2 – (Default LOW, LOW, LOW) These
jumpers are used to select the I
2
C address for the LTC2991.
When used with QuikEval, the correct address should also
be selected from within the software.
Analog Connections
Analog signal connections are made via the row of turret
posts along the edge of the board. Also, when connecting
the board to an existing circuit the exposed ground planes
along the edges of the board may be used to form a solid
connection between grounds.
GND – (8 turrets) These turrets are connected directly to
the internal ground planes.
EXTV
CC
– This turret allows the user to provide V
CC
to the
LTC2991. Select V
CC
jumper accordingly.
V1, V2, V3, V4, V5, V6, V7, V8 – These turrets are used to
provide input voltage to the monitor when the correspond-
ing jumpers are set to the VOLT position.
Digital Connections
PWM – PWM output pin configurable through the QuikEval
software. State of the PWM pin is reflected quantitatively
through the PWM LED at D2.
SDA, SCL – I
2
C signals brought out to turrets. If DC1785A is
to be run without a DC590 connected or with an alternative
microprocessor, I
2
C signals can be driven at these points.
If DC590 is not used R4 and R5 (Backside of board) can
be populated with appropriate I
2
C pull-up values.
GPO – General purpose output pin can be toggled through
QuikEval software.
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DEMO MANUAL DC1785A
PARTS LIST
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
QTY
0
2
1
1
19
2
8
1
1
1
1
3
0
2
2
2
1
1
8
REFERENCE
C1, C2, C3, C4 (OPT)
C5, C6
D1
D2
E1-E13, E16-E21
E14, E15
JP1-JP8
J1
Q1
Q2
Q3
R1, R2, R3
R4, R5 (OPT)
R6, R7
R8, R9 Bal to #1765A
TP1, TP2
U1
U2
XJP1-XJP8
PART DESCRIPTION
Capicitor, 0603
Capicitor, 0.1μF 25V, X7R, 10%, 0603
,
LED, Red, J-Type, SMD, Tape/Reel, 1208
LED, Green, J-Type, SMD, Tape/Reel, 1208
Turret, Testpoint, 0.065
Turret, Testpoint, 0.095
Header, 3-Pin, 0.079, Single Row
Connector, Header 14POS 2mm Vert Gold
Transistor, PNP –40V, –200MA, SOT23-3
,
Transistor, NPN, 40V, 350MW, SMD, SOT23-3
MOSFET, N-Channel, 60V, 115mA, SOT23-3
Resistor, Chip 4.99k, 0.06W, 1%, 0603
Resistor, 0603
Resistor, Chip, 330Ω, 0.06W, 5%, 0603
Resistor, Chip, 1k, 0.06W, 5%, 0603
Testpoint, Test pad
IC, Temperature, Voltage, Current Monitor MSOP(16)-MS
IC, EEPROM, 2kbit, 400Khz, TSSOP-8
Shunt, .079" Center
MANUFACTURER/PART NUMBER
OPT
TDK, C1608X7R1E104K (Bal to #1787A)
Panasonic, LN1251CTR
Panasonic, LN1351CTR
Mill-Max, 2308-2-00-80-00-00-07-0
Mill-Max, 2501-2-00-80-00-00-07-0
Samtec, TMM-103-02-L-S
Molex, 87831-1420
Diodes/Zetex, FMMT3906TA
Diodes Inc., MMBT3904-7-F
Diodes/Zetex, 2N7002TA
Yageo, RC0603FR-074K99L
OPT
Yageo, RC0603JR-07330RL
Yageo, RC0603JR-071KL
Component Corp., TP-107-02-1
Linear Technology, LTC2991CMS#PBF
Microchip, 24LC025-I/ST
Samtec, 2SN-BK-G
Required Circuit Components
dc1785af
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5
4
3
2
1
REVISION HISTORY
ECO
DESCRIPTION
REV
APPROVED
DATE
SCL
SCL
TP2
TP1
D
D
SDA
SDA
E14
GND
E15
EXTVCC
2.9V - 5.5V
V1
R6
D1
VCC
1
2
3
JP8
2
POWER
EXTVCC
DC590B(5V)
SCHEMATIC DIAGRAM
TEMP
1
1
330
2
VOLT
3
Q1
MMBT3906
C5
0.1uF
VCC
RED
VCC
JP1
E1
U1
LTC2991CMS
VCC
12
PWM
R4
(OPT)
R5
(OPT)
VCC
V+
1
2
6
J1
V1
16
1
V1
V2
V3
V4
V5
V6
V7
V8
GND
9
R1
R2
4.99K 4.99K
1%
1%
V2
VCC
PWM
VUNREG
5V
CS
C
C
TEMP
1
C1
(OPT)
2
2
3
SCL
SDA
10
C2
(OPT)
VOLT
3
11
SCL
SDA
4
7
5
10
JP2
SCK/SCL
SDA/MOSI
MISO
EEVCC
9
11
C6
E2
4
5
V2
DC590B
I2C INTERFACE
EESDA
EESCL
12
14
0.1uF
U2
24LC025-I/ST
E3
C3
(OPT)
V3
6
ADR0
ADR1
ADR2
15
R3
4.99K
1%
13
14
E4
V4
7
C4
(OPT)
E5
V5
EEGND
NC
GND
8
7
6
5
1
VCC
WP
SCL
SDA
A0
A1
A2
VSS
2
3
4
GND
8
GND
8
E6
V6
TEMP
1
2
VOLT
3
WP
JP3
B
E7
Q2
MMBT3904
VSS
R9
1K
E16
13
3
V7
B
V7
GPO
V8
TEMP
1
2
VCC
R7
330
2
VOLT
3
D2
1
JP4
E8
ADR2
VCC
1
VCC
1
2
V8
ADR1
VCC
ADR0
GRN
PWM
HIGH
LOW
JP5
HIGH
3
JP6
1
2
HIGH
LOW
3
JP7
R8
Q3
2N7002
PWM
1K
E19
PWM
E9
2
3
GND
E10
LOW
E20
GND
E21
GND
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.
NOTE: UNLESS OTHERWISE SPECIFIED.
1. ALL RESISTORS ARE IN OHMS,
ALL CAPACITORS ARE IN MICROFARADS,
2. INSTALL SHUNTS AS SHOWN.
C:\PADS PROJECTS\1785A\SCH\1785A_REV2.DSN
GND
E11
GND
E12
GND
E13
GND
A
A
TECHNOLOGY
LEO C
LTC2991CMS
DEMO CIRCUIT 1785A
3
2
1
5
4
DEMO MANUAL DC1785A
dc1785af
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