Linear Technology DC1811A Quick setup guide

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DEMO MANUAL DC1811A
DESCRIPTION
LTM4676
Dual Step-Down µModule
Regulator with PMBus Digital
Power System Management
Demonstration circuit 1811A is a dual-output, high ef-
ficiency, high density, µModule
®
regulator with 4.5V to
26.5V input range. Each output can supply 13A maximum
load current. The demo board has a LT M
®
4676 µModule
regulator, which is a dual 13A or single 26A step-down
regulator with PMBus power system management. Please
see LTM4676 data sheet for more detailed information
The DC1811A powers up to default settings and produces
power based on configuration resistors without the need
for any serial bus communication. This allows easy evalu-
ation of the DC/DC converter. To fully explore the extensive
power system management features of the part, download
the GUI software LTpowerPlay™ onto your PC and use
LT C ’s I2C/SMBus/PMBus dongle DC1613A to connect to
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
LTpowerPlay is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
BOARD PHOTO
Figure 1. Dual-Output LTM4676/DC1811A Demo Circuit
the board. LTpowerPlay allows the user to reconfigure the
part on the fly and store the configuration in EEPROM, view
telemetry of voltage, current, temperature and fault status
GUI Download
The software can be downloaded from:
http://www.linear.com/ltpowerplay
For more details and instructions of LTpowerPlay, please
refer to LTpowerPlay GUI for LTM4676 Quick Start Guide.
Design files for this circuit board are available at
http://www.linear.com/demo

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DEMO MANUAL DC1811A
QUICK START PROCEDURE
PERFORMANCE SUMMARY
(TA= 25°C)
PARAMETER CONDITION VALUE
Input Voltage Range 4.5V to 26.5V
Output Voltage, VOUT0 VIN = 4.5V to 26.5V, IOUT0 = 0A to 13A 0.5V to 4V, Default: 1V
Maximum Output Current, IOUT0 VIN = 4.5V to 26.5V, VOUT = 0.5V to 4V 13A
Output Voltage, VOUT1 VIN = 4.5V to 26.5V, IOUT1 = 0A to 13A 0.5V to 5.4V, Default: 1.8V
Maximum Output Current, IOUT1 VIN = 4.5V to 26.5V, VOUT = 0.5V to 5.4V 13A
Typical Efficiency VIN = 12V, VOUT = 1.8V, IOUT = 13A 86.3%
Default Switching Frequency 500kHz
Demonstration circuit 1811A is easy to set up to evaluate
the performance of the LTM4676. Refer to Figure 2 for
the proper measurement equipment setup and follow the
procedure below.
1. With power off, connect the input power supply to VIN
(4.5V to 26.5V) and GND (input return).
2. Connect the 1.0V output load between VOUT0 and GND
(Initial load: no load).
3. Connect the 1.8V output load between VOUT1 and GND
(Initial load: no load).
4. Connect the DVMs to the input and outputs. Set default
jumper position: JP1: ON; JP2: ON.
5. Turn on the input power supply and check for the proper
output voltages. VOUT0 should be 1.0V±1 %, and VOUT1
should be 1.8 ±1%.
6. Once the proper output voltages are established, ad-
just the loads within the operating range and observe
the output voltage regulation, ripple voltage and other
parameters.
7. Connect the dongle and control the output voltages
from the GUI. See “LTpowerPlay GUI for the LTM4676
Quick Start Guide” for details.
Note: When measuring the output or input voltage rip-
ple, do not use the long ground lead on the oscilloscope
probe. See Figure 3 for the proper scope probe technique.
Short, stiff leads need to be soldered to the (+) and (–)
terminals of an output capacitor. The probe’s ground ring
needs to touch the (–) lead and the probe tip needs to
touch the (+) lead.
Connecting a PC to DC1811A
You can use a PC to reconfigure the power management
features of the LTM4676 such as: nominal VOUT, margin
setpoints,OV/UVlimits,temperaturefaultlimits,sequenc-
ing parameters, the fault log, fault responses, GPIOs and
other functionality. The DC1613A dongle may be plugged
when VIN is present.
Table 1. LTM4676 Demo Cards for Up to 130A Point-of-Load Regulation
MAXIMUM OUTPUT CURRENT NUMBER OF OUTPUT VOLTAGES
NUMBER OF LTM4676 µMODULE
REGULATORS ON THE BOARD DEMO BOARD NUMBER
13A, 13A 2 1 DC1811A
26A 1 1 DC2087A
50A 1 2 DC1989A-A
75A 1 3 DC1989A-B
100A 1 4 DC1989A-C
100A 1 1 (+ 3x LTM4620A) DC2106A-A
130A 1 1 (+ 3x LTM4630) DC2106A-B

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DEMO MANUAL DC1811A
QUICK START PROCEDURE
Figure 2. Proper Measurement Equipment Setup
+ –
VOUT GND
COUT
Figure 3. Measuring Output Voltage Ripple

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DEMO MANUAL DC1811A
QUICK START PROCEDURE
Figure 4. Demo Setup with PC
LOAD CURRENT (A)
0
65
EFFICIENCY (%)
70
80
85
90
6 7 8 109 11 12
100
DC1811A F05
75
12345 13
95
VOUT = 1V
VOUT = 1.2V
VOUT = 1.5V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VIN = 5V, fSW = 500kHz, CCM
Figure 5. Efficiency vs Load Current at VIN = 5V Figure 6. Efficiency vs Load Current at VIN = 12V
LOAD CURRENT (A)
0
65
60
EFFICIENCY (%)
70
80
85
90
6 7 8 109 11 12
DC1811A F06
75
12345 13
95
VOUT = 1V
VOUT = 1.2V
VOUT = 1.5V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 5V
VIN = 12V
fSW = 500kHz
CCM

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DEMO MANUAL DC1811A
QUICK START PROCEDURE
VOUT0
(20MHz BW)
50mV/DIV
9.75A TO 13A
LOAD STEP
Figure 7. Output Voltage VOUT0 vs Load Current
(VOUT0 RANGE = 0)
Figure 8. Output Voltage VOUT1 vs Load Current
(VOUT1 Range = 1)
VOUT1
(20MHz BW)
50mV/DIV
9.75A TO 13A
LOAD STEP
VOUT0
(20MHz BW)
10mV/DIV
Figure 9. Output Voltage Ripple at VIN = 12V,
VOUT0 = 1V, IOUT0 = 13A
Figure 10. Output Voltage Ripple at VIN = 12V,
VOUT1 = 1.8V, IOUT1 = 13A
VOUT1
(20MHz BW)
10mV/DIV
Figure 11. Thermal performance at VIN = 12V, VOUT0 = 1.0V, IOUT0 = 13A, VOUT1 = 1.8V, IOUT1 = 13A, TA = 24°C, 200LFM Airflow

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DEMO MANUAL DC1811A
LTpowerPlay SOFTWARE GUI
LTpowerPlay is a powerful Windows-based development
environment that supports Linear Technology power sys-
tem management ICs, including the LTM4676, LTC3880,
LTC3883, LTC2974 and LTC2978. The software supports
a variety of different tasks. You can use LTpowerPlay to
evaluate Linear Technology ICs by connecting to a demo
board system. LTpowerPlay can also be used in an offline
mode (with no hardware present) in order to build a mul-
tichip configuration file that can be saved and reloaded at a
latertime.LTpowerPlayprovidesunprecedented diagnostic
and debug features. It becomes a valuable diagnostic tool
during board bring-up to program or tweak the power
management scheme in a system, or to diagnose power
issues when bringing up rails. LTpowerPlay utilizes the
DC1613A USB-to-SMBus controller to communicate with
one of many potential targets, including the LTM4676, the
LTC3880 and the LTC3883’s demo system, or a customer
board. The software also provides an automatic update
feature to keep the soft-ware current with the latest set
of device drivers and documentation. The LTpowerPlay
software can be downloaded from:
http://www.linear.com/ltpowerplay
To access technical support documents for LT C Digital
Power Products visit Help. View online help on the
LTpowerPlay menu.
Figure 12. LTpowerPlay Main Interface

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DEMO MANUAL DC1811A
LTpowerPlay QUICK START GUIDE
Thefollowing procedure describeshow to use LTpowerPlay
to monitor and change the settings of LTM4676.
1. Download and install the LTPowerPlay GUI:
http://www.linear.com/ltpowerplay
2. Launch the LTpowerPlay GUI.
a. The GUI should automatically identify the DC1811A.
The system tree on the left hand side should look
like this:
b. A green message box shows for a few seconds in
the lower left hand corner, confirming that LTM4676
is communicating:
c. In the Toolbar, click the “R” (RAM to PC) icon to
read the RAM from the LTM4676. This reads the
configuration from the RAM of LTM4676 and loads
it into the GUI.
d. If you want to change the output voltage to a differ-
ent value, like 1.5V. In the Config tab, type in 1.5 in
the VOUT_COMMAND box, like this:
Then, click the “W” (PC to RAM) icon to write these
register values to the LTM4676. After finishing this
step, you will see the output voltage will change to
1.5V.

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DEMO MANUAL DC1811A
LTpowerPlay QUICK START GUIDE
Ifthe writeissuccessful, youwill see thefollowing message:e. You can save the changes into the NVM. In the tool
bar, click “RAM to NVM” button, as following
f. Save the demo board configuration to a (*.proj)
file. Click the Save icon and save the file. Name it
whatever you want.

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DEMO MANUAL DC1811A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 CAP., 150µF, 35V, ALUMINUM ELECTR. SUN ELECT., 35CE150AX
2 4 CIN2, CIN3, CIN4, CIN5 CAP., X5R, 10µF, 35V, 10%,1210 MURATA, GRM32ER6YA106KA12
3 6 COUT1-COUT3, COUT6-COUT8 CAP., X5R, 100µF, 6.3V, 20% 1210 AVX, 12106D107MAT2A
4 2 COUT4, COUT5 CAP., 330µF, 6.3V, POSCAP, D3L SANYO, 6TPF330M9L
5 2 C1, C14 CAP., X7R, 2200pF, 25V, 10%, 0603 AVX, 06033C222KAT2A
6 1 C20 CAP., X5R, 100nF, 16V, 10%,0603 AVX, 0603YD104KAT
7 1 C23 CAP., X7R, 1µF, 25V,10%, 0805 AVX, 08053C105KAT2A
8 3 C21, C22, C24 CAP., X5R, 1µF, 25V,10%, 0603 AVX, 06033D105KAT2A
9 2 JP1, JP2 HEADER 3-PIN 0.079 SINGLE ROW SAMTEC, TMM103-02-L-S
10 3 J2-J4 CONN, BNC, 5 PINS CONNEX, 112404
11 1 J1 CONN HEADER 12 POS 2MM STR DL PCB FCI 98414-G06-12ULF
12 6 J5-J10 BANANA SMALL KEYSTONE, 575-4
13 1 Q1 N-CHANNEL 30-V MOSFET VISHAY, SUD50N03-09P
14 7 R3, R5, R7, R9, R25, R31, R32 RES., CHIP, 0Ω, 1%, 0603 NIC, NRC06Z0000TRF
15 13 R10-R16, R18, R19, R24, R46, R47, R52 RES., CHIP, 10k, 1%, 0603 NIC, NRC06F1002TRF
16 1 R30 RES., CHIP, 6.34k, 1%, 0603 VISHAY, CRCW06036K34FKEA
17 3 R2, R44, R45 RES., CHIP, 4.99k, 1%, 0603 NIC, NRC06F4991TRF
18 1 R22 RES., CHIP, 4.22k, 1%, 0603 VISHAY, CRCW06034K22FKEA
19 1 R48 RES., CHIP, 0Ω, 0.5W, 2010 NIC, NRC50ZOTRF
20 1 R53 RES., CHIP, 0.01Ω, 1/2W, 1%, 2010 VISHAY, WSL2010R0100FEA
21 1 U1 IC, LTM4676EY#PBF LINEAR TECH. LTM4676EY#PBF
22 1 U2 IC, 24LC025T-E/OT SOT-23 6-LEAD MICROCHIP, 24LC025T-E/OT
Additional Demo Board Circuit Components
1 0 C2, C15-C17 (OPT) CAP., 0603
2 0 R8, R26-R29, R33-R39, R41 (OPT) RES., 0603
3 0 R4, R6, R20, R23, R49 (OPT) RES., CHIP OPTIONAL
4 0 R50, R51 (OPT) RES., CHIP, 30, 1%, 2010
Hardware-For Demo Board Only
1 24 E1-E24 TESTPOINT, TURRET, 0.062" MILL-MAX, 2308-2-00-80-00-00-07-0
2 2 XJP1, XJP2 SHUNT SAMTEC, 2SN-BK-G
3 4 (STAND-OFF) STAND-OFF, NYLON 0.50" tall KEYSTONE, 8833(SNAP ON)
4 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 1811A

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DEMO MANUAL DC1811A
SCHEMATIC DIAGRAM