Texas Instruments TPS5430 User manual

User’s Guide
TPS5430 and TPS5431 Step-Down Converter Evaluation
Module User's Guide
Table of Contents
1 Introduction.............................................................................................................................................................................2
1.1 Background........................................................................................................................................................................ 2
1.2 Performance Specification Summary.................................................................................................................................2
1.3 Modifications...................................................................................................................................................................... 3
2 Test Setup and Results.......................................................................................................................................................... 3
2.1 Input/Output Connections.................................................................................................................................................. 3
2.2 Efficiency............................................................................................................................................................................4
2.3 Output Voltage Load Regulation........................................................................................................................................ 5
2.4 Output voltage Line Regulation..........................................................................................................................................6
2.5 Load Transients..................................................................................................................................................................7
2.6 Loop Characteristics.......................................................................................................................................................... 8
2.7 Output Voltage Ripple........................................................................................................................................................ 9
2.8 Input Voltage Ripple......................................................................................................................................................... 10
2.9 Powering Up.....................................................................................................................................................................11
3 Board Layout.........................................................................................................................................................................12
3.1 Layout.............................................................................................................................................................................. 12
4 Schematic and Bill of Materials...........................................................................................................................................14
4.1 Schematic........................................................................................................................................................................ 14
4.2 Bill of Materials.................................................................................................................................................................16
5 Revision History................................................................................................................................................................... 16
List of Figures
Figure 2-1. TPS5430 Efficiency................................................................................................................................................... 4
Figure 2-2. TPS5431 Efficiency................................................................................................................................................... 5
Figure 2-3. TPS5430 Load Regulation........................................................................................................................................ 5
Figure 2-4. TPS5431 Load Regulation........................................................................................................................................ 6
Figure 2-5. TPS5430 Line Regulation......................................................................................................................................... 6
Figure 2-6. TPS5431 Line Regulation......................................................................................................................................... 7
Figure 2-7. PS5430 Transient Response.....................................................................................................................................7
Figure 2-8. TPS5431 Transient Response.................................................................................................................................. 8
Figure 2-9. TPS5430 Loop Response......................................................................................................................................... 8
Figure 2-10. PS5431 Loop Response......................................................................................................................................... 9
Figure 2-11. TPS5430 Output Ripple...........................................................................................................................................9
Figure 2-12. PS5431 Output Ripple...........................................................................................................................................10
Figure 2-13. TPS5430 Input Ripple........................................................................................................................................... 10
Figure 2-14. TPS5431 Input Ripple............................................................................................................................................11
Figure 2-15. TPS5430 and TPS5431 Start-Up.......................................................................................................................... 11
Figure 3-1. Top-Side Layout...................................................................................................................................................... 12
Figure 3-2. Bottom-Side Layout (Looking From Top Side)........................................................................................................ 13
Figure 3-3. Top-Side Assembly..................................................................................................................................................13
Figure 4-1. TPS5430EVM-173 Schematic.................................................................................................................................15
List of Tables
Table 1-1. Input Voltage and Output Current Summary...............................................................................................................2
Table 1-2. TPS5430EVM-173 and TPS5431EVM-173 Performance Specification Summary.....................................................2
Table 1-3. Output Voltages Available...........................................................................................................................................3
Table 2-1. EVM Connectors and Test Points............................................................................................................................... 4
Table 4-1. TPS5430EVM-173 Bill of Materials...........................................................................................................................16
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Trademarks
PowerPAD™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
1 Introduction
This user's guide contains background information for the TPS5430 and TPS5431 as well as support
documentation for the TPS5430EVM-173 evaluation module (HPA173-001) and the TPS5431EVM-173
evaluation module (HPA173-002) . Also included are the performance specifications, the schematic, and the
bill of materials for the TPS5430EVM-173 and the TPS5431EVM-173.
1.1 Background
The TPS5430 and TPS5431 dc/dc converters are designed to provide up to a 3-A output from an input
voltage source of 5.5 V to 36 V (TPS5430) or 5.5 V to 23 V (TPS5431EVM-173). Rated input voltage and
output current range for the evaluation module is given in Table 1-1. This evaluation module is designed to
demonstrate the small printed-circuit-board areas that may be achieved when designing with the TPS5430 and
TPS5431 regulators. The switching frequency is internally set at a nominal 500 kHz. The high-side MOSFET
is incorporated inside the TPS5430/31 package along with the gate drive circuitry. The low drain-to-source on
resistance of the MOSFET allows the TPS5430/31 to achieve high efficiencies and helps keep the junction
temperature low at high output currents. The compensation components are provided internal to the integrated
circuit (IC), whereas an external divider allows for an adjustable output voltage. Additionally, the TPS5430/31
provides an enable input. The absolute maximum input voltage is 38 V for the TPS5430EVM-173 and 25 V for
the TPS5431EVM-173 .
Table 1-1. Input Voltage and Output Current Summary
EVM INPUT VOLTAGE RANGE OUTPUT CURRENT RANGE
TPS5430EVM-173 VIN = 10 V to 35 V 0 A to 3 A
TPS5431EVM-173 VIN = 9 V to 21 V 0 A to 3 A
1.2 Performance Specification Summary
A summary of the TPS5430EVM-173 performance specifications is provided in Table 1-2. Specifications are
given for an input voltage of VIN = 15 V and an output voltage of 5 V, unless otherwise specified. The
TPS5430EVM-173 is designed and tested for VIN = 10 V to 35 V. The ambient temperature is 25°C for all
measurements, unless otherwise noted.
Table 1-2. TPS5430EVM-173 and TPS5431EVM-173 Performance Specification Summary
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNIT
VIN voltage range TPS5430EVM-173 10 15 35 V
TPS5431EVM-173 9 15 21
Output voltage set point 5.0 V
Output current range VIN = 3.3 V 0 3 A
Line regulation TPS5430EVM-173 IO = 0 A – 3 A, VIN = 10 V – 35 V ±0.07%
TPS5431EVM-173 IO = 0 A – 3 A, VIN = 9 V – 21 V ±0.04%
Load regulation TPS5430EVM-173 VIN = 15 V, IO = 0 A to 3 A ±0.03%
TPS5431EVM-173 ±0.05%
Load transient
response
TPS5430EVM-173
IO = 0.75 A to 2.25 A
Voltage change –50 mV
Recovery time 150 μs
TPS5431EVM-173 Voltage change –40 mV
Recovery time 150 μs
TPS5430EVM-173
IO = 2.25 A to 0.75 A
Voltage change 50 mV
Recovery time 150 μs
TPS5431EVM-173 Voltage change 40 mV
Recovery time 150 μs
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Table 1-2. TPS5430EVM-173 and TPS5431EVM-173 Performance Specification Summary (continued)
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNIT
Loop bandwidth TPS5430EVM-173 VIN = 25 V, IO = 1 A 25.0 kHz
TPS5431EVM-173 VIN = 15 V, IO = 1 A 23.9
Phase margin TPS5430EVM-173 VIN = 25 V , IO = 1 A 50°
TPS5431EVM-173 VIN = 15 V, IO = 1 A 51°
Input ripple voltage TPS5430EVM-173 IO = 3 A 255 300 mVpp
TPS5431EVM-173 295 350
Output ripple voltage TPS5430EVM-173 IO = 3 A 20 mVpp
TPS5431EVM-173 20
Output rise time 8 ms
Operating frequency 500 kHz
Max efficiency TPS5430EVM-173 VIN = 10 V, VO = 5 V, IO = 0.75 A 93.6%
TPS5431EVM-173 VIN = 9 V, VO = 5 V, IO = 0.75 A 94.0%
1.3 Modifications
These evaluation modules are designed to demonstrate the small size that can be attained when designing with
the TPS5430 and TPS5431. A few changes can be made to this module.
1.3.1 Output Voltage Set Point
To change the output voltage of the EVMs, it is necessary to change the value of resistor R2. Changing the
value of R2 can change the output voltage above 1.25 V. The value of R2 for a specific output voltage can be
calculated using Equation 1.
R2 +10 kW 1.221 V
VO*1.221 V
(1)
Table 1-3 lists the R2 values for some common output voltages. Note that VIN must be in a range so that the
minimum on-time is greater than 200 ns, and the maximum duty cycle is less than 87%. The values given in
Table 1-3 are standard values, not the exact value calculated using Equation 1.
Table 1-3. Output Voltages Available
Output Voltage (V) R2 Value (kΩ)
1.8 21.5
2.5 9.53
3.3 5.90
5 3.24
2 Test Setup and Results
This section describes how to properly connect, set up, and use the TPS5430EVM-173 and TPS5431EVM-173
evaluation modules. The section also includes test results typical for the evaluation modules and covers
efficiency, output voltage regulation, load transients, loop response, output ripple, input ripple, and startup.
2.1 Input/Output Connections
The TPS5430EVM-173 and TPS5431EVM-173 are provided with input/output connectors and test points as
shown in Table 2-1. A power supply capable of supplying 3 A must be connected to J1 through a pair of 20 AWG
wires. The load must be connected to J3 through a pair of 20 AWG wires. The maximum load current capability
should be 3 A. Wire lengths must be minimized to reduce losses in the wires. Test-point TP1 provides a place
to monitor the VIN input voltages with TP2 providing a convenient ground reference. TP3 is used to monitor the
output voltage with TP4 as the ground reference.
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Table 2-1. EVM Connectors and Test Points
Reference Designator Function
J1 VIN (see Table 1-1 for Vin range)
J2 OUT, 5 V at 3 A maximum
JP1 2-pin header for enable. Connect EN to ground to disable, open to enable.
TP1 VIN test point at VIN connector
TP2 GND test point at VIN
TP3 Output voltage test point at OUT connector
TP4 GND test point at OUT connector
TP5 Test point between voltage divider network and R3. Used for loop response measurements.
TP6 PH test point
2.2 Efficiency
The efficiency for both EVMs peak at a load current of about 0.75 A and then decrease as the load current
increases towards full load. Figure 2-1 shows the efficiency for the TPS5430EVM-173 at an ambient temperature
of 25°C.
75
80
85
90
95
100
0 0.5 1 1.5 2 2.5 3 3.5
V = 10 V
IN
V = 15 V
IN
V = 20 V
IN
V = 25 V
IN
V = 30 V
IN
V = 35 V
IN
EFFICIENCY
vs
OUTPUT CURRENT
Efficiency - %
I - Output Current - A
O
Figure 2-1. TPS5430 Efficiency
Figure 2-2 shows the efficiency for the TPS5431EVM-173 at an ambient temperature of 25°C.
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75
80
85
90
95
100
0 0.5 1 1.5 2 2.5 3 3.5
EFFICIENCY
vs
OUTPUT CURRENT
Efficiency - %
I - Output Current - A
O
V = 9 V
IN
V = 12 V
IN
V = 15 V
IN
V = 18 V
IN
V = 21 V
IN
Figure 2-2. TPS5431 Efficiency
The efficiency is lower at higher ambient temperatures, due to temperature variation in the drain-to-source
resistance of the MOSFETs.
2.3 Output Voltage Load Regulation
The load regulation for the TPS5430EVM-173 and TPS5431EVM-173 are shown in Figure 2-3 and Figure 2-4.
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.5 1 1.5 2 2.5 3
I - Output Current - A
O
Output Regulation - %
LOAD REGULATION
vs
OUTPUT CURRENT
Figure 2-3. TPS5430 Load Regulation
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-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
0 0.5 1 1.5 2 2.5 3
I - Output Current - A
O
Output Regulation - %
LOAD REGULATION
vs
OUTPUT CURRENT
Figure 2-4. TPS5431 Load Regulation
Measurements are given for an ambient temperature of 25°C.
2.4 Output voltage Line Regulation
The load regulation for the TPS5430EVM-173 and TPS54310EVM-173 are shown in Figure 2-5 and Figure 2-6.
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
10 15 20 25 30 35
I = 0 A
O
I = 1.5 A
O
I = 3 A
O
V - Input Voltage - V
I
Output Regulation - %
LINE REGULATION
vs
INPUT VOLTAGE
Figure 2-5. TPS5430 Line Regulation
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-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
9 12 15 18 21
I = 1.5 A
O
I = 3 A
O
V - Input Voltage - V
I
Output Regulation - %
LINE REGULATION
vs
INPUT VOLTAGE
I = 0 A
O
Figure 2-6. TPS5431 Line Regulation
2.5 Load Transients
The TPS5430EVM-173 and TPS5431EVM-173 response to load transients is shown in Figure 2-7 and Figure
2-8. The current step is from 25% to 75% of maximum rated load. Total peak-to-peak voltage variation is as
shown, including ripple and noise on the output.
V = 50 mV /Div (AC-Coupled)
OUT
I = 1 A/Div
OUT
Time = 200 µs/Div
Figure 2-7. PS5430 Transient Response
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V = 50 mV/Div (AC-Coupled)
OUT
I = 1 A/Div
OUT
Time = 200 µs/Div
Figure 2-8. TPS5431 Transient Response
2.6 Loop Characteristics
The TPS5430EVM-173 and TPS5431EVM-173 loop-response characteristics are shown in Figure 2-9 and
Figure 2-10. Gain and phase plots are shown for VIN voltage of 25 V for the TPS5430EVM-173 and 15 V for the
TPS5431EVM-173. Load current for both measurements is 1 A.
60
-60
100 1 M
180
-180
Gain - dB
f - Frequency - Hz
Phase - deg
Gain
Phase
Figure 2-9. TPS5430 Loop Response
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60
-60
100 1 M
f - Frequency - Hz
Gain - dB
Gain
180
-180
Phase - deg
Phase
Figure 2-10. PS5431 Loop Response
2.7 Output Voltage Ripple
The TPS5430EVM-173 and TPS5431EVM-173 output voltage ripple is shown in Figure 2-11 and Figure 2-12 .
The output current is the rated full load of 3 A. Voltage is measured directly across output capacitors.
Time = 1 µs/Div
V = 20 mV/Div (AC-Coupled)
OUT
V = 20 V/Div
P
Figure 2-11. TPS5430 Output Ripple
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V = 20 mV/Div (AC-Coupled)
OUT
V = 10 V/Div
PH
Time = 1 µs/Div
Figure 2-12. PS5431 Output Ripple
2.8 Input Voltage Ripple
The TPS5430EVM-173 and TPS5431EVM-173 input voltage ripple is shown in Figure 2-13 and Figure 2-14. The
output current for each device is at full rated load of 3 A.
Time = 1 µs/Div
V = 20 V/Div
PH
V = 100 mV/Div (AC-Coupled)
IN
Figure 2-13. TPS5430 Input Ripple
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