1
DEMO MANUAL DC2620A-A
Rev.B
DESCRIPTION
LTC7106
A 7-Bit Current DAC with
Digital PMBus Interface
Demonstration circuit 2620A-A uses the LTC
®
7106, a
precision, bidirectional, 7-Bit current DAC with PMBus
interface and can be used to adjust the output voltage of
any conventional VFB referenced regulator. The LTC7106
can work with the vast majority of power management
controllers, regulators or modules to enable digital control
of the output voltage.
The DC2620A-A requires input voltage range from 2.5V
to 5.5V, which can be powered either by external supply
or directly from the DC1613A dongle. The LTC7106 pro-
vides three ranges of IDAC output current: Nominal Range
(–64µA to 63µA), Range High (–256µA to 252µA) and
Range Low (–16µA to 15.75µA). Only the nominal range
is optimized with the highest accuracy. It is recommended
that users design the resistor divider using the nominal
range of the IDAC setting.
All registered trademarks and trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
To explore the power system management features of the
parts, download the GUI software LTpowerPlay
®
onto your
PC and use ADI’s I2C/SMBus/PMBus Dongle DC1613A
to connect to the board. LTpowerPlay allows the user to
reconfigure the part on-the-fly, view IDAC current value
and fault status.
GUI Download
The software can be downloaded from:
LTpowerPlay
For more details and instructions of LTpowerPlay, please
refer to LTpowerPlay for LTC7106 Quick Start Guide.
Design files for this circuit board are available.
Specifications are at TA = 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VDD IC Bias Voltage 2.5 5.5 V
VIDAC IDAC Operation Voltage 0.4 2.0 V
IDAC Output Current Range Nominal, LSB = 1µA –64 63 µA
Range High, LSB = 4µA –256 252 µA
Range Low, LSB = 0.25µA –16 15.75 µA
ACC IDAC Accuracy Nominal Range –1.5 0.8 %
2
DEMO MANUAL DC2620A-A
Rev. B
QUICK START PROCEDURE
Demonstration circuit 2620A-A makes it easy to use
theLTC7106 to adjust any conventional VFB referenced
regulator and evaluate its performances. Refer to Figure1
for the system setup and boards connection.
Connecting a PC and a Regulator to DC2620A-A
You can use a PC to reconfigure the power management
features of the LTC7106 such as: program IDAC cur-
rent, margin IDAC high/low, read back IDAC value and
check fault status. The DC1613A dongle may be plugged
in regardless of whether VIN is present. Dongle can be
hotplugged.
DC2620A-A can adjust the output voltage of any VFB ref-
erenced regulator. Use a twisted wire pair to connect the
IDAC and GND pins of DC2620A-A to VFB and GND pins
of the regulator board.
Figure1. Demo Setup with PC
Follow the procedure below:
1. Make sure JP3 is in OFF position to disable the LTC7106
before turning on the regulator.
2. Turn on the regulator and check for the output voltage
as expected.
3. Once the proper output voltage is established on the
regulator, put JP3 to the ON position to enable the
LTC7106.
4. Open the LTpowerPlay software and adjust the IDAC
current value of the LTC7106 through it. Monitor the
regulator’s output voltage as IDAC is changing. See
LTpowerPlay Quick Start session for details
DC2620A-A F01
Demo Board
DC2620A-A
USB to
I2C/PMBus Dongle
DC1613A
2.5V to 5.5V
Power Supply
(OPTIONAL)
USB CABLE
12-PIN
CONNECTOR
VIN
IDAC
GND
VFB Referenced
Regulator
VFB
GND
3
DEMO MANUAL DC2620A-A
Rev.B
QUICK START PROCEDURE
Figure2 shows an application diagram using the LTC7106
with a typical DC/DC voltage regulator. By connecting
IDAC to the feedback node of the voltage regulator, IDAC
can change the output voltage of the regulator with the
equation:
VOUT =VREF 1+RFB1
R
FB2
⎡
⎣
⎢
⎢
⎢
⎤
⎦
⎥
⎥
⎥
– IDAC • RFB1
where VREF is the reference voltage of the voltage regula-
tor. RFB1 and RFB2 are the resistor divider for the voltage
regulator. IDAC is the programmed bidirectional current
of the LTC7106.
Figure2. An Application Diagram Using the LTC7106 with a Typical DC/DC Voltage Regulator
In order to achieve the best IDAC current accuracy of the
LTC7106, it’s recommended to carefully design the volt-
age divider so that the LTC7106 uses its nominal range.
A design tool has been developed to help customers
optimize their design. It’s built into the toolbox of the
LTpowerCAD
®
software tool and can be downloaded from:
LTpowerCAD
C1
1µF
10k
R1
10k
R2
RFB1
RFB2
C2
330µF
R4
10k
LTC7106
V
DD
GND
IDAC
SDA
SCL
ALERT
GPO
ASEL0
ASEL1
VDD
2.5V
TO 5.5V
SDA
ALERT
SCL
V
DD
V
IN
DC/DC
SW
V
FB
V
OUT
RUN
EN
(0.4V to 2V)
V
IN
VREF
10k
R3
PMBus INTERFACE
–64μA TO 0μA
0μA TO 63μA
DC2620A-A F02
4
DEMO MANUAL DC2620A-A
Rev. B
Figure3. LTpowerPlay Main Interface for LTC7106
LTpowerPlay is a powerful Windows-based develop-
ment environment that supports Analog Devices power
system management ICs, including the LTC3880,
LTC3883, LTC3882, LTC3815, LTC2974 and LTC2978.
The software supports a variety of different tasks. You
can useLTpowerPlay to evaluate Analog Devices ICs
by connecting to a demo board system. LTpowerPlay
utilizes the DC1613A USB-to-SMBus controller to com-
municate with one of many potential targets, including
LTpowerPlay SOFTWARE GUI
the LTC7106’s DC2620A-A demo system, or a customer
board. The software also provides an automatic update
feature to keep the software current with the latest set
of device drivers and documentation. The LTpowerPlay
software can be downloaded from:
LTpowerPlay
To access technical support documents for ADI
DigitalPower Products visit Help. View online help on
the LTpowerPlay menu.
5
DEMO MANUAL DC2620A-A
Rev.B
The following procedure describes how to use LTpowerPlay
to monitor and change the settings of LTC7106.
1. Download and install the LTPowerPlay GUI:
LTpowerPlay
2. Launch the LTpowerPlay GUI.
a. The GUI should automatically identify the
DC2620A-A. The system tree on the left-hand side
should look like this:
LTpowerPlay QUICK START PROCEDURE
b. A blue message box shows for a few seconds in the
lower left-hand corner, confirming that the LTC7106
is communicating:
c. In the Toolbar, click the “R” icon (RAM to
PC) to read the RAM from the LTC7106. This reads
the configuration from the RAM of LTC7106 and
loads it into the GUI. When first powering on, you
should read IDAC current at zero (high impedance
IDAC) due to the LTC7106’s internal power-on reset
circuitry until a valid write takes place. The IDAC
current value can be plotted in real time, shown
in the following screenshot (at zero when first
poweringon):
6
DEMO MANUAL DC2620A-A
Rev. B
d. If you want to change the IDAC current to 10μA
for example, in the Config tab, type “10” in the
MFR_IOUT_COMMAND_LTC7106:
LTpowerPlay QUICK START PROCEDURE
Then, click the “W” icon (PC to RAM) to
write these register values to the LTC7106.
If the write is successful, you will see the following
message:
In the Telemetry Plot, you will see IDAC current value
change to the commanding value:
e. If you want to change the IDAC current to a negative
value (meaning sinking current), you need to change
the MFR_IOUT_MAX_LTC7106 to a negative value
first (see data sheet for more details).
7
DEMO MANUAL DC2620A-A
Rev.B
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 C1 CAP., 1.0μF, X5R, 10V, 10%, 0603 AVX, 0603ZD105KAT2A
2 1 C2 CAP., 100pF, X7R, 25V, 5%, 0603 AVX, 06033C101JAT2A
3 4 R1, R5, R6, R9 RES., 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA
4 3 R2, R3, R7 RES., 10k, 1%, 1/10W, 0603 KOA SPEER, RK73H1JTTD1002F
5 3 R10, R11, R12 RES., 100Ω, 1%, 1/10W, 0603 NIC, NRC06F1000TRF
6 1 U1 IC, DAC 7-BIT CURRENT DAC ANALOG DEVICES, LTC7106EDDB
Additional Demo Board Circuit Components
1 0 C3 CAP., OPTION, 0603 OPTION
2 0 R4 RES., OPTION, 0603 OPTION
3 0 JP4 CONN., OPTION OPTION
4 0 J2 CONN., OPTION OPTION
Hardware
1 8 E1, E2, E3, E4, E5, E6, E7, E8 TEST POINT, TURRET, 0.094", MTG. HOLE MILL-MAX, 2501-2-00-80-00-00-07-0
2 1 J1 CONN., HDR, SHROUDED, 2mm × 6mm, 2mm, THT, VERT FCI, 98414-G06-12ULF
3 2 JP1, JP2 CONN., HDR, MALE, 1mm × 4mm, 2mm, THT, STR WURTH ELEKTRONIK, 62000411121
4 1 JP3 CONN., HDR., MALE, 1mm × 3mm, 2mm, THT, STR SULLINS CONNECTOR SOLUTIONS,
NRPN031PAEN-RC
5 1 LB1 LABEL SPEC, DEMO BOARD SERIAL NUMBER BRADY, THT-96-717-10
6 4 MP1, MP2, MP3, MP4 STANDOFF, NYLON, SNAP-ON, 0.250" KEYSTONE, 8831
7 1 PCB1 PCB, DC2620A ANALOG DEVICES, 600-DC2620A
8 4 XJP1, XJP2, XJP3, XJP4 CONN., SHUNT, FEMALE, 2 POS, 2mm WURTH ELEKTRONIK, 60800213421
8
DEMO MANUAL DC2620A-A
Rev. B
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS AND CAPACITORS ARE 0603
REVISION HISTORY
ECO REV DESCRIPTION APPROVEDDATE
K H
02/18/204 PROD
VERSION IC (U1) R4 R5 R6
-A
-B
LTC7106EDDB
LTC7106EDDB-1
OPT 0
698
0
[2] J1
OPT
STUFF
R3
10K
OPT
J2
OPT
STUFF
[2]
OPT OPT
TO LINDUINO DC2026C
GND*
FLOAT
JP1
FLOAT
GND*
JP2
OFF
OPT
JP4
* ADDRESS IS SET BY USER.
[2] [2]
VDD VDD VDD VDD VDD VDD
VDD
VDD
VDD
VDD
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE: N/A
SKU NO. SCHEMATIC NO. AND REVISION:
PCA BOM:
PCA ASS'Y:
11
M I
K H
7-BIT CURRENT DAC WITH DIGITAL POWER SYSTEM MANAGEMENT
710-DC2620A_REV04
LTC7106EDDB-1(-B)
LTC7106EDDB(-A)
Tuesday, February 18, 2020
705-DC2620A_REV02
700-DC2620A_REV02
DC2620A
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE: N/A
SKU NO. SCHEMATIC NO. AND REVISION:
PCA BOM:
PCA ASS'Y:
11
M I
K H
7-BIT CURRENT DAC WITH DIGITAL POWER SYSTEM MANAGEMENT
710-DC2620A_REV04
LTC7106EDDB-1(-B)
LTC7106EDDB(-A)
Tuesday, February 18, 2020
705-DC2620A_REV02
700-DC2620A_REV02
DC2620A
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE: N/A
SKU NO. SCHEMATIC NO. AND REVISION:
PCA BOM:
PCA ASS'Y:
11
M I
K H
7-BIT CURRENT DAC WITH DIGITAL POWER SYSTEM MANAGEMENT
710-DC2620A_REV04
LTC7106EDDB-1(-B)
LTC7106EDDB(-A)
Tuesday, February 18, 2020
705-DC2620A_REV02
700-DC2620A_REV02
DC2620A
R6
[2] JP2
ASEL0
VDD
FLOAT
GND
1
3
2
4
R1
0
R7 10k
1%
J1 [2]
TO DC1613A
AUXP 1
SDA 2
GND 3
SCL 4
LGKPWR 5
ALERTB 6
GPIO_1 7
OUTEN_0 8
OUTEN_1 9
GND 10
AUXSCL 11
AUXSDA 12
U1
[2]
SDA/SDI
1
SCL/SCLK
2
VDD 3
ALERTB/GPO_INV
4
GND
5
IDAC 6
EN 7
GPO 8
SDO/ASELO 9
CSB/ASEL1 10
C1 1.0uF
C3
OPT
E1
SCL
E4
AUX
E2
ALERTB
E3
SDA
R4
[2]
E8
GPO
JP3
ON
OFF
EN
1
3
2
J2 [2]
V+ 1
3.3V or 5V 2
GND 3
SCK/SCL 4
MISO 5
CS 6
MOSI/SDA 7
GND 8
EESDA 9
EEVCC 10
EESCL 11
EEGND 12
GND 13
GPIO_1 14
R12 100
C2
100pF
R10 100
R3
[2]
E7
VDD JP4
ON
OFF
GPOINV
1
3
2
R9 0
R5 [2]
JP1
ASEL1
VDD
FLOAT
GND
1
3
2
4
R11 100
E5
IDAC
R2
10k
1%
E6
GND
SDA
SCL
AUX
ALERTB
CSB
SDOSDO
SDA
SCL
CSB
AUX
9
DEMO MANUAL DC2620A-A
Rev.B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications
subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
10
DEMO MANUAL DC2620A-A
Rev. B
ANALOG DEVICES, INC. 2017-2020
03/20
www.analog.com
ESD Caution
ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection
circuitry, damage may occur on devices subjected to high energy ESD. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
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