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Mailing Address:
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Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated
Page 3
EVM IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation kit being sold by TI is intended for use for ENGINEERING
DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to
be fit for commercial use. As such, the goods being provided may not be complete in terms
of required design-, marketing-, and/or manufacturing-related protective considerations,
including product safety measures typically found in the end product incorporating the
goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may not meet the technical
requirements of the directive.
Should this evaluation kit not meet the specifications indicated in the EVM User’s Guide,
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 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.
The user assumes all responsibility and liability for proper and safe handling of the goods.
Further, the user indemnifies TI from all claims arising from the handling or use of the
goods. Please be aware that the products received may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.). 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.
EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER
PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
TI currently deals with a variety of customers for products, and therefore our arrangement
with the user is not exclusive.
TI assumes no liability for applications assistance, customer product design,software performance, or infringement of patents or services described herein.
Please read the EVM User’s Guide and, specifically, the EVM W arnings and Restrictions
notice in the EVM User’s Guide prior to handling the product. This notice contains
important safety information about temperatures and voltages. For further safety
concerns, please contact the TI application engineer.
Persons handling the product must have electronics training and observe good laboratory
practice standards.
No license is granted under any patent right or other intellectual property right of TI
covering or relating to any machine, process, or combination in which such TI products
or services might be or are used.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated
Page 4
EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the specified input and output ranges described in
the EVM User’s Guide.
Exceeding the specified input range may cause unexpected operation and/or irreversible
damage to the EVM. If there are questions concerning the input range, please contact a TI
field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or
possible permanent damage to the EVM. Please consult the EVM User’s Guide prior to
connecting any load to the EVM output. If there is uncertainty as to the load specification,
please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than
60°C. The EVM is designed to operate properly with certain components above 60°C as long
as the input and output ranges are maintained. These components include but are not limited
to linear regulators, switching transistors, pass transistors, and current sense resistors. These
types of devices can be identified using the EVM schematic located in the EVM User’s Guide.
When placing measurement probes near these devices during operation, please be aware
that these devices may be very warm to the touch.
Mailing Address:
Texas Instruments
Post Office Box 655303
Dallas, Texas 75265
Copyright 2001, Texas Instruments Incorporated
Page 5
About This Manual
Trademarks
Preface
Read This First
This users guide describes the characteristics, operation, and use of the
TPS54614 1.8-V SWIFT regulator evaluation module (EVM). The users
guide includes a schematic diagram and bill of materials.
How to Use This Manual
This document contains the following chapters:
- Chapter 1—Inroduction
- Chapter 2—Setup and Test Results
- Chapter 3—Board Layout
- Chapter 4—Schematic and Bill of Materials
FCC Warning
This equipment is intended for use in a laboratory test environment only. It
generates, uses, and can radiate radio frequency energy and has not been
tested for compliance with the limits of computing devices pursuant to subpart
J of part 15 of FCC rules, which are designed to provide reasonable protection
against radio frequency interference. Operation of this equipment in other
environments may cause interference with radio communications, in which
case the user at his own expense will be required to take whatever measures
may be required to correct this interference.
This chapter contains background information for the TPS54614 and support
documentation for the TPS54614 EVM evaluation module. The TPS54614
EVM performance specifications are given, as well as modification
instructions if different preset output voltages are desired.
The TPS54614 evaluation module uses the TPS54614 synchronous buck
regulator to provide a 1.8-V output. This voltage is maintained over an input
range of 3.0 V to 6.0 V, and over a load range of 0 A to 6 A. The TPS54614
EVM circuitry contains only seven electrical components covering an area less
than one square inch.
The TPS54614 has two key features that reduce the number of additional
components compared to traditional synchronous buck controllers. The first
feature is that the MOSFET s are incorporated inside the TPS54614 package.
This eliminates the need for external MOSFETs and their associated drivers.
The second feature is that the compensation components that stabilize the
feedback loop are also incorporated inside the TPS54614 package.
Because the internal compensation of the TPS54614 is fixed, loop stability is
assured by the proper selection of an output inductor and output capacitor. For
guidelines on selecting an output inductor and output capacitor for a specific
application, refer to Texas Instruments application report SLVA105
– Designing With Internally Compensated SWIFTt Regulators.
1.2Performance Specification Summary
A summary of the TPS54614EVM performance specifications is provided by
Table 1–1. All specifications are given for an ambient temperature of 25°C,
unless otherwise noted.
Table 1–1.Performance Specification Summary
SpecificationTest ConditionsMinTypMaxUnits
Input voltage rangeIO = 6 A356V
Output voltage set point1.8V
Output current range0> 6A
Line regulationIO = 6 A–5+5mV
Load regulationVIN = 5 V–9+9mV
The EVM can be modified for different preset output voltages by using other
devices in the TPS5461x family . For output voltages less than 2.5 V, only U1
needs to be changed. For output voltages 2.5 V and higher, the output
capacitor (C1) also needs to be changed. T able 1–2 lists the devices required
for U1 and C1 for different output voltage options.
Table 1–2.Modification Table
Modifications
Output Voltage
(V)
0.9TPS54611Sanyo – 2R5TPB680M
1.2TPS54612Sanyo – 2R5TPB680M
1.5TPS54613Sanyo – 2R5TPB680M
1.8TPS54614Sanyo – 2R5TPB680M
2.5TPS54615Sanyo – 4TPB470M
3.3TPS54616Sanyo – 4TPB470M
SWIFT Device
(U1)
Output Capacitor
(C1)
Introduction
1-3
Page 12
1-4
Page 13
Chapter 2
Setup and Test Results
This chapter describes how to properly connect, set up, and use the
TPS54614 EVM. This chapter also presents the test results for the TPS54614,
and covers efficiency, output voltage regulation, load transients, loop
response, output ripple, and start-up.
The TPS54614 has the following four input/output connections: input, input
return, output, and output return. A diagram showing the connection points is
shown in Figure 2–1. Connect a power supply capable of supplying 5 A to J1
through a pair of 20 AWG wires. Connect the load to J2 through a pair of 16
AWG wires. Wire lengths should be minimized on both the input and output
connections.
The TPS54614 efficiency peaks at around 1.5 A of load current. At a full 6-A
load the efficiency drops to around 83% with a 5-V input source. The efficiency
shown in Figure 2–2 is typical for an ambient temperature of 25°C. The
efficiency is lower at higher ambient temperatures, due to temperature
variation in the drain-to-source resistance of the MOSFETs. The total board
losses are shown in Figure 2–3. The plots of Figure 2–4 and Figure 2–5 are
extended out to current levels where the TPS54614 junction temperature
reaches 125°C at 25°C ambient. When operating the TPS54614 past the 6-A
maximum current rating, care should be taken to ensure that the maximum
junction temperature does not exceed 125°C.
Figure 2–2.Measured Efficiency
95
90
Efficiency
TA = 25°C
85
80
75
Efficency – %
70
65
60
012345678910
Figure 2–3.Measured Board Losses
6
TA = 25°C
5
4
3
VI = 5 V
VI = 3.3 V
IL– Load Current – A
VI = 3.3 V
VI = 5 V
Losses – W
2
1
0
012345678910
IL– Load Current – A
Setup and Test Results
2-3
Page 16
Thermal Performance
2.3Thermal Performance
The plot in Figure 2–4 shows the junction temperature versus the load current
at 25°C ambient temperature. The case temperature is plotted in Figure 2–5.
The low junction-to-case thermal resistance of the PWP package, along with
a good board layout, helps to keep the junction temperature low at high output
currents. With a 3.3-V input source and a 6-A load, the junction temperature
is approximately 65°C, while the case temperature is approximately 59°C.
Figure 2–4.Measured Junction Temperature at 25°C Ambient
125
TA = 25°C
C
°
100
VI = 3.3 V
75
VI = 5 V
50
– Junction Temperature –
J
T
25
0
0123456789
IL– Load Current – A
Figure 2–5.Measured Case Temperature at 25°C Ambient
100
TA = 25°C
80
°
60
40
Case Temperature – C
20
0
012345678910
IL– Load Current – A
VI = 3.3 V
10
VI = 5 V
2-4
Page 17
2.4Output Voltage Regulation
The output voltage load regulation at 25°C is shown in Figure 2–6. The output
voltage varies less than 0.3% over the entire input voltage range of 3.3 V to
5.0 V, and load range of 0 A to 6 A.
Figure 2–6.Measured Load Regulation
1.003
1.002
1.001
Output Voltage Regulation
TA = 25°C
Output Voltage
0.999
(Normalized to 3-A Load)
0.998
0.997
1
0123456
IL– Load Current – A
VI = 5 V
VI = 3.3 V
Setup and Test Results
2-5
Page 18
Output Voltage Regulation
2.5Load Transients
The TPS54614 EVM response to load transients is shown in Figure 2–7 and
Figure 2–8. The load transient in Figure 2–7 transitions from 1.5 A to 4.5 A in
16 µs, while the load transient in Figure 2–8 transitions from 4.5 A to 1.5 A in
12 µs. The transient response can be improved at the cost of adding additional
capacitance to the output.
The loop gain and phase for a 5.0-V input and a 6.0-A load are shown in
Figure 2–9 and Figure 2–10. The loop crossover frequency is approximately
50 kHz, and the phase margin is approximately 46°.
Figure 2–9.Measured Loop Gain
50
40
30
20
10
Loop Gain – dB
0
–10
Output Voltage Regulation
–20
10100100010000100000
Figure 2–10. Measured Loop Phase
180
135
90
Loop Phase – Degrees
45
0
10100100010000100000
f – Frequency – Hz
f – Frequency – Hz
Setup and Test Results
2-7
Page 20
Output Voltage Regulation
2.7Output Voltage Ripple
The output ripple voltage is plotted in Figure 2–11 for a 3.3-V input, and in
Figure 2–12 for a 5.0-V input. The TPS54614 has a typical output voltage
ripple of less than 15 mV
Figure 2–11. Measured Output Voltage Ripple With 3.3-V Input
VI = 3.3 V
IO = 6 A
1 µs/div
pp
.
IO
10 mV/div
Figure 2–12. Measured Output Voltage Ripple With 5.0-V Input
VI = 5 V
IO = 6 A
1 µs/div
VO (AC)
10 mV/div
2-8
Page 21
2.8Input Voltage Ripple
The input voltage ripple for a 6-A load is shown in Figure 2–13 for a 3.3-V input
and in Figure 2–14 for a 5.0-V input. With a 5.0-V input, the ripple is
approximately 260 mVpp. The input voltage ripple can be made lower by
adding capacitance to the input.
Figure 2–13. Measured Input Voltage Ripple With 3.3-V Input
VI = 3.3 V
IO = 6 A
400 ns/div
VI (AC)
100 mV/div
Output Voltage Regulation
Figure 2–14. Measured Input Voltage Ripple With 5.0-V Input
VI = 5 V
IO = 6 A
400 ns/div
VI (AC)
100 mV/div
Setup and Test Results
2-9
Page 22
Output Voltage Regulation
2.9Start-Up
The start-up voltage waveform of the TPS54614 EVM is shown in
Figure 2–15. The TPS54614 output begins to rise when the input rises above
the 3.0-V startup level. The output voltage then ramps linearly to 1.8 V in 3.6
ms. The start-up time is independent of input voltage and load. The slow start
time can be made slower by using an external slow start capacitor (C6).
Figure 2–15. Measured Start-Up Waveforms
VI = 3.3 V
IO = 0 A
2 ms/div
V
I
1 V/div
V
O
1 V/div
2-10
Page 23
Chapter 3
Board Layout
This chapter provides the TPS54614 EVM board layout illustrations.
The board layout for the TPS54614 EVM, shown in Figure 3–1 through Figure
3–4, resembles a layer stack-up encountered in a typical application. The top
and bottom layers are 1.5 oz. copper, while the two internal layers are 0.5 oz.
copper. The circuit components are confined to a small area of the circuit
board. The two internal layers are identical and are used as quiet ground
planes. The power ground plane is routed on the top layer, and is tied to the
quiet (analog) ground planes at the output sense point (test point TP3). A wide
power ground plane is used to keep the input ground current from injecting
noise between the analog and power grounds. A total of 14 vias are used to
tie the thermal land area under the TPS54614 to the internal ground planes
and to the thermal plane on the back side of the board. The thermal plane on
the back side occupies only the area directly underneath the regulator
components, but should be made as large as possible in an actual application.