Texas Instruments LM3000 User manual

User’s Guide
LM3000 Buck Controller Evaluation Module User's Guide
Table of Contents
1 Introduction.............................................................................................................................................................................2
2 Powering and Loading Considerations................................................................................................................................ 3
2.1 Quick Setup Procedure...................................................................................................................................................... 3
3 Board Configuration...............................................................................................................................................................4
3.1 External Clock Synchronization......................................................................................................................................... 4
3.2 CLKOUT.............................................................................................................................................................................4
3.3 Tracking..............................................................................................................................................................................4
3.4 Output Voltage Ripple........................................................................................................................................................ 5
4 Typical Performance Waveforms.......................................................................................................................................... 6
5 Evaluation Board Schematic................................................................................................................................................. 7
6 Bill of Materials....................................................................................................................................................................... 8
7 PCB Layout............................................................................................................................................................................10
8 Revision History................................................................................................................................................................... 13
List of Figures
Figure 2-1. Basic Test Setup for LM3000EVAL Board................................................................................................................. 3
Figure 3-1. Synchronization at 3.3-V Output............................................................................................................................... 4
Figure 3-2. Tracking with an External Ramp for 3.3-V Output..................................................................................................... 5
Figure 3-3. Output Voltage Ripple Measurement Setup.............................................................................................................. 5
Figure 4-1. Efficiency of 3.3-V Output at 500 kHz........................................................................................................................6
Figure 4-2. Efficiency of 1.2-V Output at 500 kHz........................................................................................................................6
Figure 4-3. Output Ripple Voltage for 3.3-V Output at 8-A Load................................................................................................. 6
Figure 4-4. Output Ripple Voltage for 1.2-V Output at 15-A Load............................................................................................... 6
Figure 4-5. Output Load Transient from 0 A to 6 A for 3.3-V Output........................................................................................... 6
Figure 4-6. Output Load Transient from 0 A to 10 A for 1.2-V Output......................................................................................... 6
Figure 5-1. Evaluation Board Full Schematic.............................................................................................................................. 7
Figure 7-1. Top Overlay as Viewed from Top.............................................................................................................................10
Figure 7-2. Top Layer as Viewed from Top................................................................................................................................ 10
Figure 7-3. Bottom Overlay as Viewed from Top....................................................................................................................... 11
Figure 7-4. Bottom Layer as Viewed from Top...........................................................................................................................11
Figure 7-5. Internal Layer 1 as Viewed from Top.......................................................................................................................12
Figure 7-6. Internal Layer 2 as Viewed from Top.......................................................................................................................12
List of Tables
Table 6-1. Bill of Materials............................................................................................................................................................8
Trademarks
All trademarks are the property of their respective owners.
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LM3000 Buck Controller Evaluation Module User's Guide 1
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1 Introduction
The LM3000 evaluation board is designed to provide the design engineer with a fully functional power converter-
based solution using the LM3000 dual output emulated current mode controller. This evaluation board provides
two output voltages of 3.3 V and 1.2 V. The 3.3-V output is designed to handle a maximum current of 8 A,
whereas the 1.2-V output has a maximum current capability of 15 A. The switching frequency for the converter
is set at 500 kHz. The gate signals for each output voltage will be 180 degree out of phase from each other. The
printed circuit board consists of four layers of FR4 material with 2-ounce copper on top and bottom layer and
1-ounce copper for internal layers. This user's guide contains the evaluation board schematic, bill of materials
(BOM), and a quick setup procedure. Refer to the LM3000 Dual Synchronous Emulated Current-Mode Controller
data sheet for complete circuit design information.
The performance of the evaluation board is as follows:
Input Range 6 V to 18 V
Output voltage 1 (VO1) 3.3 V
Output current 1 0 A to 8 A
Output voltage 2 (VO2) 1.2 V
Output current 2 0 A to 15 A
Switching frequency 500 kHz
Load regulation 1%
Board size 2.68 × 3.146 × 0.068 inches
Introduction www.ti.com
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2 Powering and Loading Considerations
Read this entire page prior to attempting to power the evaluation board.
2.1 Quick Setup Procedure
1. Set the input power supply current limit to 10 A. Turn off the input power supply. Connect the input power
supply to the VIN terminal. Make sure to connect power supply ground to each GND1 and GND2 terminals
in order to provide a short path for input current to return to the power supply.
2. Connect the load with an 8-A capability on VO1 and 15-A capability on VO2. Connect the positive terminal to
VO1 and VO2 and negative terminal to GND1 and GND2.
3. Connect a secondary power supply to EN1 and EN2 terminals. Set the power supply voltage to 5 V. The
ground return for this power supply should be connected to GND terminal. Since the evaluation board is
configured such that VOUT2 tracks VOUT1, VOUT2 cannot be turned on without turning on VOUT1. Different
configuration can be required in order to turn on VOUT2 independently. This will be discussed later in
Section 3.3.
4. Set VIN to 12 V with no load being applied. Turn on the input power supply followed by the secondary power
supply in order to power up the enable pins. The output voltage should be in regulation with a value of 3.3 V
on VO1 and 1.2 V on VO2.
5. Slowly increase the load in each output into its maximum output current while monitoring the output voltages
in each channel. The output voltages should also be in regulation at each respective maximum output
current.
6. Slowly vary the input voltages from 6 V and 18.5 V. Both output voltages should remain in regulation with a
nominal value of 3.3 V on VO1 and 1.2 V on VO2.
Figure 2-1. Basic Test Setup for LM3000EVAL Board
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LM3000 Buck Controller Evaluation Module User's Guide 3
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3 Board Configuration
3.1 External Clock Synchronization
A SYNC terminal has been provided in this evaluation board in order to synchronize the converter to an
external clock or other fixed frequency signal from 200 kHz to 1.5 MHz. Refer to the LM3000 Dual Synchronous
Emulated Current-Mode Controller data sheet for complete information.
Figure 3-1. Synchronization at 3.3-V Output
3.2 CLKOUT
A CLKOUT terminal provides an external clock signal 90 degrees out of phase with the main clock. This clock
signal can be used to synchronize a second LM3000.
3.3 Tracking
The LM3000 evaluation board is configured such that VOUT2 tracks VOUT1, while VOUT1 voltage increases
with a rate determined by the value of C17, the soft-start capacitor for VOUT1 (Condition 1). This configuration
will not allow VOUT2 to be turned on independently without turning on VOUT1. In order to track VOUT1, the
TRK2 pin should be connected to a divider junction between R14 and R15 through R26.
When both outputs are used to track an external source (Condition 2), then R25, R26, and R28 should be left
open and a 10-Ω resistor should be added into R24 and R27.
If no tracking feature is required, both TRK1 and TRK2 should then be tied to VDD in order to soft start each
output voltage based on a soft-start capacitor value (Condition 3). This can be done by keeping R24, R26, and
R27 open while adding a 10-Ω resistor onto R25 and R28.
Please note that the slew rate of track signal should be lower than the soft-start slew rate, which is set by
soft-start capacitor value.
The following are the summary of different tracking configuration on the LM3000EVAL board:
Condition R24 R25 R26 R27 R28
1 Open 10 Ω 10 Ω Open Open
2 10 Ω Open Open 10 Ω Open
3 Open 10 Ω Open Open 10 Ω
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Figure 3-2. Tracking with an External Ramp for 3.3-V Output
3.4 Output Voltage Ripple
Output voltage ripple measurement should be taken directly across the output capacitor C21 or C22. Care has to
be taken to minimize the loop area between the scope probe tip and the ground lead in order to minimize noise
in the measurement. This can be achieved by removing the spring tip of the probe and ground lead and then
wire a bare wire around the scope probe shaft. The bare wire should be in contact with the probe shaft because
this is the “new” ground lead for the probe. The measurement can be taken by connecting the bare wire onto the
ground side of the capacitor and the probe tip onto the other side of the capacitor. Figure 3-3 shows a diagram of
this measurement technique.
Figure 3-3. Output Voltage Ripple Measurement Setup
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4 Typical Performance Waveforms
Figure 4-1. Efficiency of 3.3-V Output at 500 kHz Figure 4-2. Efficiency of 1.2-V Output at 500 kHz
Figure 4-3. Output Ripple Voltage for 3.3-V Output
at 8-A Load
Figure 4-4. Output Ripple Voltage for 1.2-V Output
at 15-A Load
Figure 4-5. Output Load Transient from 0 A to 6 A
for 3.3-V Output
Figure 4-6. Output Load Transient from 0 A to 10 A
for 1.2-V Output
Typical Performance Waveforms www.ti.com
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5 Evaluation Board Schematic
Figure 5-1. Evaluation Board Full Schematic
www.ti.com Evaluation Board Schematic
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LM3000 Buck Controller Evaluation Module User's Guide 7
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6 Bill of Materials
Table 6-1. Bill of Materials
ID Part Number Type Size Parameters Qty Vendor
C1, C2,
C3, C4 GRM31CR6E106KA12L Capacitor, Ceramic 1206 10 µF, 25 V, X5R, 10% 4 Murata
C5 7343-43 Not Used 0
C6,C7,
C8 EEF-UE0G221R Capacitor, Polymer 7343-43 220 µF, 4 V, 12 mΩ 3 Panasonic
C9, C10,
C11, C14 GRM188R61E105KA12D Capacitor, Ceramic 0603 1 µF, 25 V, X5R, 10% 4 Murata
C12, C13,
C30, C31 GRM188R71E104KA01D Capacitor, Ceramic 0603 0.1 µF, 25 V, X7R, 10% 4 Murata
C15 VJ0603Y821KXXA Capacitor, Ceramic 0603 820 pF, 25 V, X7R, 10% 1 Vishay
C16 VJ0603Y272KXXA Capacitor, Ceramic 0603 2.7 nF, 25 V, X7R, 10% 1 Vishay
C17 06035C273KAT2A Capacitor, Ceramic 0603 0.027 µF, 50 V, X7R, 10% 1 AVX
C18 VJ0603Y183KXXA Capacitor, Ceramic 0603 18 nF, 25 V, X7R, 10% 1 Vishay
C19 VJ0603A121JXAA Capacitor, Ceramic 0603 120 pF, 50 V, COG, 5% 1 Vishay
C20, C21 GRM31CR60J226KE19L Capacitor, Ceramic 1206 22 µF, 6.3 V, X5R, 10% 2 Murata
C22 VJ0603A120KXAA Capacitor, Ceramic 0603 12 pF, 50 V, COG, 5% 1 Vishay
C23 06031A270KAT2A Capacitor, Ceramic 0603 27 pF, 100 V, COG, 10% 1 AVX
C24 06035C122KAT2A Capacitor, Electrolytic 0603 1200 pF, 50 V, X7R, 10% 1 AVX
C25,C26 GRM188R71C104KA01D Capacitor, Ceramic 0603 0.1 µF, 16 V, X7R, 10% 2 Murata
C27 06035A121JAT2A Capacitor, Ceramic 0603 120 pF, 50 V, COG, 5% 1 AVX
C28, C29 EEEFK1H151P Capacitor, Aluminum 10x10.2 mm 150 µF, 50 V, 670 mA 2 Panasonic
C32, C33 06031A180KAT2A Capacitor, Ceramic 0603 18 pF, 100 V, COG, 10% 2 AVX
D1, D2 CMSH3-40M Diode, Schottky SMA 3 A, 40 V 2 Central
Semiconductor
D3 CMPD1001A Diode, Switching SOT-23 250 mA, 90 V 1 Central
Semiconductor
Dz1, Dz2 CMHZ4690 Diode, Zener SOD-123 5.6 V, 500 mW 2 Central
Semiconductor
L1 7443551280 Inductor 2.8 µH, 20 A, 3.8 mΩ 1 Wurth
Elektronik
L2 744318120 Inductor 1.2 µH, 22 A, 1.79 mΩ 1 Wurth
Elektronik
Q1, Q3 HAT2168H N-CH MOSFET LF-PAK 30 A, 30 V, 6 mΩ 2 Renesas
Technology
Q2, Q4 RJK0330DPB N-CH MOSFET LF-PAK 45A, 30V, 2.1 mΩ 2 Renesas
Technology
R1 CRCW060313k3FKEA Resistor 0603 13.3 kΩ, 1% 1 Vishay
R2 CRCW06032k94FKEA Resistor 0603 2.94 kΩ, 1% 1 Vishay
R3, R4 CRCW060322k6FKEA Resistor 0603 22.6 kΩ, 1% 2 Vishay
R5 CRCW06033R01FNEA Resistor 0603 3.01 Ω, 1% 1 Vishay
R6 CRCW06032k67FKEA Resistor 0603 2.67 kΩ, 1% 1 Vishay
R7 CRCW06034k64FKEA Resistor 0603 4.64 kΩ, 1% 1 Vishay
R8 CRCW06034M99FKEA Resistor 0603 4.99 MΩ, 1% 1 Vishay
R9 CRCW060315k4FKEA Resistor 0603 15.4 kΩ, 1% 1 Vishay
R10 CRCW060314k3FKEA Resistor 0603 14.3 kΩ, 1% 1 Vishay
R11, R12 CRCW0603100kFKEA Resistor 0603 100 kΩ, 1% 2 Vishay
R13 CRCW060342k2FKEA Resistor 0603 42.2 kΩ, 1% 1 Vishay
R14 CRCW060335k7FKEA Resistor 0603 35.7 kΩ, 1% 1 Vishay
Bill of Materials www.ti.com
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Table 6-1. Bill of Materials (continued)
ID Part Number Type Size Parameters Qty Vendor
R15 CRCW060310k0FKEA Resistor 0603 10 kΩ, 1% 1 Vishay
R16, R17 CRCW06030000Z0EA Resistor 0603 0 Ω 2 Vishay
R18 CRCW060375k0FKEA Resistor 0603 75 kΩ , 1% 1 Vishay
R19, R21 CRCW06031k33FKEA Resistor 0603 1.33 kΩ, 1% 2 Vishay
R20 CRCW0603102kFKEA Resistor 0603 102 kΩ, 1% 1 Vishay
R22, R23 CRCW040210R0FKED Resistor 0402 10 Ω, 1% 2 Vishay
R24, R27,
R28, R29,
R30
Resistor 0603 Not Used
R25, R26 CRC060310R0FKEA Resistor 0603 10 Ω, 1% 2 Vishay
U1 LM3000 Controller 32 Lead
WQFN 1Texas Instruments
VIN, VO1,
VO2,
GND1,
GND2
1514-2 Turret Terminal 0.090"
diameter 5 Keystone
CLKOUT,
PGOOD2,
TRK2,
EN2,
GND
1573-2 Turret Terminal 0.072"
diameter 5 Keystone
GND,
EN1,
TRK1,
PGOOD1,
SYNC
1573-2 Turret Terminal 0.072"
diameter 5 Keystone
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LM3000 Buck Controller Evaluation Module User's Guide 9
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7 PCB Layout
Figure 7-1. Top Overlay as Viewed from Top
Figure 7-2. Top Layer as Viewed from Top
PCB Layout www.ti.com
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