Texas Instruments TPS54240EVM-VSON User manual

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TPS54240EVM-VSON Regulator Evaluation Module
User's Guide
SNVU602–May 2019
TPS54240EVM-VSON Regulator Evaluation Module
This user's guide contains information for the TPS54240EVM-VSON evaluation module. Included are the
performance specifications, the schematic, and the bill of materials for the TPS54240EVM-VSON.
Contents
1 Introduction ................................................................................................................... 3
2 Test Setup and Results..................................................................................................... 4
3 Schematic and Bill of Materials........................................................................................... 13
4 Board Layout................................................................................................................ 15
5 Modifications................................................................................................................ 19
List of Figures
1 Top View of TPS54240EVM-VSON....................................................................................... 5
2 TPS54240EVM-VSON Efficiency.......................................................................................... 6
3 TPS54240EVM-VSON Low Current Efficiency .......................................................................... 6
4 TPS54240EVM-VSON Load Regulation.................................................................................. 7
5 TPS54240EVM-VSON Transient Response ............................................................................ 8
6 TPS54240EVM-VSON Output Voltage Ripple in CCM Mode at 2.5-A ILOAD ......................................... 9
7 TPS54240EVM-VSON Output Voltage Ripple in DCM Mode at 200-mA ILOAD ...................................... 9
8 TPS54240EVM-VSON Output Voltage Ripple in Eco-mode™ at 20-mA ILOAD....................................... 9
9 TPS54240EVM-VSON Input Voltage Ripple in CCM mode at 2.5-A ILOAD .......................................... 10
10 TPS54240EVM-VSON Input Voltage Ripple in DCM Mode at 200 mA ILOAD ....................................... 10
11 TPS54240EVM-VSON Input Voltage Ripple in Eco-mode™ at 20 mA ILOAD ....................................... 10
12 TPS54240EVM-VSON Start-Up ......................................................................................... 11
13 TPS54240EVM-VSON Power-Good Output (pulled up to VOUT)..................................................... 11
14 TPS54240EVM-VSON Power-Good Output (Pulled up to external 3.3 V) ......................................... 11
15 TPS54240EVM-VSON Loop Response ................................................................................ 12
16 TPS54240EVM-VSON Schematic ....................................................................................... 13
17 TPS54240EVM-VSON Top-Side Assembly ............................................................................ 15
18 TPS54240EVM-VSON Bottom-Side Assembly ........................................................................ 16
19 TPS54240EVM-VSON Top-Side Layout................................................................................ 16
20 TPS54240EVM-VSON Mid-Layer 1 Layout............................................................................. 17
21 TPS54240EVM-VSON Mid-Layer 2 Layout............................................................................. 17
22 TPS54240EVM-VSON Bottom-Side Layout............................................................................ 18
List of Tables
1 Input Voltage and Output Current Summary............................................................................. 3
2 TPS54240EVM-VSON Performance Specification Summary ......................................................... 4
3 EVM Connectors and Test Points ......................................................................................... 5
4 Bill of Materials ............................................................................................................ 14
5 Output Voltages Available................................................................................................. 19

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Trademarks
Eco-mode is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.

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TPS54240EVM-VSON Regulator Evaluation Module
1 Introduction
This user's guide contains background information for the TPS54240 as well as support documentation for
the TPS54240EVM-VSON evaluation module, which is for the VSON package. Also included are the
performance specifications, the schematic, and the bill of materials for the TPS54240EVM-VSON.
1.1 Background
The TPS54240 DC/DC converter is designed to provide up to a 2.5-A output from an input voltage source
of 3.5 V to 42 V. Rated input voltage and output current range for the evaluation module are given in
Table 1. This evaluation module is designed for VSON package. The switching frequency is internally set
at a nominal 500 kHz. The high-side MOSFET is incorporated inside the TPS54240 package along with
the gate-drive circuitry. The low drain-to-source on-resistance of the MOSFET allows the TPS54240 to
achieve high efficiencies and helps keep the junction temperature low at high output currents. The
compensation components are external to the integrated circuit (IC), and an external divider allows for an
adjustable output voltage. Additionally, the TPS54240 provides adjustable slow start and undervoltage
lockout inputs. The absolute maximum input voltage is 42 V for the TPS54240EVM-VSON.
Table 1. Input Voltage and Output Current Summary
EVM INPUT VOLTAGE RANGE OUTPUT CURRENT RANGE
TPS54240EVM-VSON VIN = 7 V to 24 V 0 A to 2.5 A
Note that EN has an absolute maximum rating of 5 V input and a 1.25-V typical
threshold voltage, the selection of R1and R4limits input voltage range between
7 V and 24 V.
1.2 Performance Specification Summary
A summary of the TPS54240EVM-VSON performance specifications is provided in Table 2. Specifications
are given for an input voltage of VIN = 12 V and an output voltage of 3.3 V, unless otherwise specified. The
TPS54240EVM-VSON is designed and tested for VIN = 7 V to 24 V. The ambient temperature is 25°C for
all measurements, unless otherwise noted. The EVM may be modified by the user to operate from input
voltages up to the 42 V operating limit of the TPS54240.
CAUTION
Risk of electric shock for voltages exceeding 50 VDC.

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Table 2. TPS54240EVM-VSON Performance Specification Summary
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNIT
VIN voltage range 7 12 24 V
Output voltage set point 3.3 V
Output current range VIN = 10 V to 20 V 0 2.5 A
Load regulation VIN = 12 V, IOUT = 0.001 A to 2.5 A ±0.06%
Load transient response IOUT = 0.5 A to 2.5 A Voltage change –30 mV
Recovery time 1 ms
IOUT = 2.5 A to 0.5 A Voltage change 40 mV
Recovery time 1 ms
Loop bandwidth VIN = 12 V, IOUT = 2.5 A 36.9 kHz
Phase margin VIN = 12 V , IOUT =2.5 A 64 °
Input ripple voltage IOUT = 2.5 A 320 mVpp
Output ripple voltage IOUT= 2.5 A 20 mVpp
Slow start time 3 ms
Operating frequency 500 kHz
Peak efficiency TPS54240EVM-VSON, VIN = 12 V, IOUT = 0.7 A 87.7%
CCM/DCM boundary VIN = 12 V 0.4 A
Eco-mode™ threshold VIN = 12 V 45 mA
2 Test Setup and Results
This section describes how to properly connect, set up, and use the TPS54240EVM-VSON evaluation
module. The section also includes test results typical for the evaluation module and covers efficiency,
output voltage regulation, load transients, loop response, output ripple, input ripple, and start-up.
2.1 Input/Output Connections
The TPS54240EVM-VSON is provided with input/output connectors and test points as shown in Table 3.
See Figure 1 for the location of the connectors. A power supply capable of supplying 2.5 A must be
connected to J1 and J3 through a pair of 20 AWG wires. The load must be connected to J2 and J3
through a pair of 20 AWG wires. The maximum load current capability must be 2.5 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 TP3 providing a convenient ground reference. TP2 is used to monitor the output voltage with
TP4 as the ground reference.

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Figure 1. Top View of TPS54240EVM-VSON
Table 3. EVM Connectors and Test Points
REFERENCE DESIGNATOR FUNCTION
J1 VIN (see Table 1 for VIN range)
J2 VOUT, 3.3 V at 2.5 A maximum
J3 Input and output GND
TP1 VIN test point at VIN connector
TP2 Output voltage test point at OUT connector
TP5 Test point between voltage divider network and output. Used for loop response measurements.
TP6 EN test point. Connect EN to ground to disable, open to enable.
TP7 Slow start monitor test point
TP8 RT test point.
TP11 PWRGD test point
TP12 PH test point
TP3,TP4,TP9,TP10 GND test point

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2.2 Efficiency
The efficiency of this EVM peaks at a load current of about 0.7 A with VIN = 12 V, 18 V, and 24 V. And
then decreases as the load current increases towards full load. Figure 2 shows the efficiency for the
TPS54240EVM-VSON at an ambient temperature of 25°C.
Figure 2. TPS54240EVM-VSON Efficiency
Figure 3 shows the efficiency for the TPS54240EVM-VSON at lower output currents between 0.001 A and
0.5 A at an ambient temperature of 25°C.
Figure 3. TPS54240EVM-VSON Low Current Efficiency
The efficiency may be lower at higher ambient temperatures, due to temperature variation in the drain-to-
source resistance of the internal MOSFET.

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2.3 Output Voltage Load Regulation
The load regulation for the TPS54240EVM-VSON is shown in Figure 4.
Figure 4. TPS54240EVM-VSON Load Regulation
Measurements are given for an ambient temperature of 25°C.

Time = 2msec / div
Output Current = 1 A / div (Load Step 0.5 A to 2.5 A)
Vout = 20 mV / div (ac coupled)
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2.4 Load Transients
The TPS54240EVM-VSON response to load transients is shown in Figure 5. The current step is from 0.5
A to 2.5 A . The input voltage is 12 V. Total peak-to-peak voltage variation is as shown, including ripple
and noise on the output.
Figure 5. TPS54240EVM-VSON Transient Response

Time = 50usec / div
Inductance Current = 500 mA / div
PH = 10 V / div
Vout = 20 mV / div (ac coupled)
Time = 2usec / div
Inductance Current = 1 A / div
PH = 10 V / div
Vout = 20 mV / div (ac coupled)
Time = 2usec / div
Inductance Current = 500 mA / div
PH = 10 V / div
Vout = 20 mV / div (ac coupled)
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2.5 Output Voltage Ripple
The output current is the rated full load of 2.5 A and VIN = 12 V. The ripple voltage is measured directly
across the output capacitors.
When the output current is greater than one half the peak-to-peak inductor current, the circuit is operating
in continuous conduction mode (CCM).The TPS54240EVM-VSON output voltage ripple in CCM mode is
shown in Figure 6. The ripple voltage is measured directly across the input capacitors.
When the output current is less than one half the peak to peak inductor current, the circuit is operating in
discontinuous conduction mode (DCM). The circuit enters DCM when the nominal output current falls
below 400 mA. The TPS54240EVM-VSON output voltage ripple in DCM mode is shown in Figure 7
At light load currents, the TPS54240 is designed to operate in the pulse-skipping Eco-mode™ operation.
When the nominal output current falls below 45 mA. typical, the device enters the Eco-mode™ operation.
The TPS54240EVM-VSON output voltage ripple in Eco-mode is shown in Figure 8.
Figure 6. TPS54240EVM-VSON Output Voltage Ripple in
CCM Mode at 2.5-A ILOAD
Figure 7. TPS54240EVM-VSON Output Voltage Ripple in
DCM Mode at 200-mA ILOAD
Figure 8. TPS54240EVM-VSON Output Voltage Ripple in Eco-mode™ at 20-mA ILOAD

Time = 20usec / div
PH = 10 V / div
Vout = 20 mV / div (ac coupled)
Time = 1usec / div
PH = 10 V / div
Vout = 20 mV / div (ac coupled)
Time = 1usec / div
PH = 10 V / div
Vout = 200 mV / div (ac coupled)
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2.6 Input Voltage Ripple
The TPS54240EVM-VSON input voltage ripple in CCM mode is shown in Figure 9. The output current is
the rated full load of 2.5 A and VIN = 12 V. The ripple voltage is measured directly across the input
capacitors. The TPS54240EVM-VSON input voltage ripple in DCM mode is shown in Figure 10. The
output current is 200 mA. The TPS54240EVM-VSON input voltage ripple in Eco-mode is shown in
Figure 11. The output current is 20 mA.
Figure 9. TPS54240EVM-VSON Input Voltage Ripple in
CCM mode at 2.5-A ILOAD
Figure 10. TPS54240EVM-VSON Input Voltage Ripple in
DCM Mode at 200 mA ILOAD
Figure 11. TPS54240EVM-VSON Input Voltage Ripple in Eco-mode™ at 20 mA ILOAD