Texas Instruments TPS62842EVM-103 User manual

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TPS62842EVM-103 User's Guide
User's Guide
SLUUC58–November 2019
TPS62842EVM-103 User's Guide
The TPS62842EVM-103 facilitates the evaluation of the TPS62842DGR of 750-mA, step-down converter
with 60-nA IQin a DGR package. The EVM has output voltages between 1.8 V and 3.6 V from higher input
voltages between 1.8 V and 6.5 V. Due to its extremely low IQ, the TPS6284x provides a long battery
lifetime for systems which have very low current consumption states such as building automation,
metering, and the Internet of Things (IoT).
Contents
1 Introduction ................................................................................................................... 2
2 Setup .......................................................................................................................... 4
3 TPS62842EVM-103 Test Results ......................................................................................... 5
4 Board Layout ................................................................................................................. 6
5 Schematic and List of Materials ......................................................................................... 10
List of Figures
1 Loop Response Measurement Modification.............................................................................. 3
2 TPS62842 Thermal Performance (VIN = 6.5 V, VOUT = 3.6 V, IOUT = 750 mA)........................................ 5
3 Top Assembly................................................................................................................ 6
4 Top Layer..................................................................................................................... 6
5 Internal Layer 1 .............................................................................................................. 7
6 Internal Layer 2 .............................................................................................................. 7
7 Bottom Layer................................................................................................................. 8
8 TPS62842EVM-103 Angled View ......................................................................................... 8
9 TPS62842EVM-103 Top View ............................................................................................. 9
10 TPS62842EVM-103 Schematic .......................................................................................... 10
List of Tables
1 Performance Specification Summary ..................................................................................... 2
2 TPS62842EVM-103 List of Materials.................................................................................... 10
Trademarks

Introduction www.ti.com
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TPS62842EVM-103 User's Guide
1 Introduction
The TPS6284x is a family of synchronous, step-down converters in different packages. The
TPS62842EVM-103 contains the TPS62842DGR device in a DGR package. The DGR package is a
bigger package than DLC (SON) and YBG (WCSP) packages but it has better thermal performance.
1.1 Performance Specification
Table 1 provides a summary of the TPS62842EVM-103 performance specifications.
Table 1. Performance Specification Summary
SPECIFICATION MIN TYP MAX UNIT
Input voltage 1.8 3.6 6.5 V
Output voltage 3.3 V
Output current 0 750 mA
1.2 Modifications
The printed-circuit board (PCB) for this EVM uses the adjustable output voltage version of this integrated
circuit (IC). Additional input and output capacitors can also be added. Finally, the loop response of the IC
can be measured.
1.2.1 Adjusting the Output Voltage
The output voltage is adjusted though the choice of R11 and R14 resistors. Since R11 and R14 are in
parallel, only R11 or R14 should be installed at the same time. R11 and R14 are 0603 sizes to make it
easy to change the output voltage by replacing them. However, 0201 size resistors can also be used to
reduce the total solution size.
1.2.2 Input and Output Capacitors
C14 is provided for an additional input capacitor. This capacitor is not required for proper operation but
can be used to reduce the input voltage ripple.
C15, C16, and C17 are provided for additional output capacitors. These capacitors are not required for
proper operation but can be used to reduce the output voltage ripple and to improve the load transient
response. The total output capacitance must remain within the recommended range in the data sheet for
proper operation.

Cut trace
as shown
-
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1.2.3 Loop Response Measurement
The loop response of the EVM can be measured with two simple changes to the circuitry. First, cut the
trace between the VOS pin and the output capacitor on the top layer. This change is shown in Figure 1.
Second, install a 10-Ωresistor across the resistor pads on the back of the PCB at R13. The pads are
spaced to allow installation of an 0603-sized resistor. With these changes, an ac signal (10-mV, peak-to-
peak amplitude recommended) can be injected into the control loop across the added resistor. Details of
measuring the control loop of DCS-Control devices are found in How to Measure the Control Loop of
DCS-Control™ Devices.
Figure 1. Loop Response Measurement Modification

Setup www.ti.com
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TPS62842EVM-103 User's Guide
2 Setup
This section describes how to properly use the TPS62842EVM-103.
2.1 Input/Output Connector Descriptions
J11, Pin 1 and 2 – VIN Positive input connection from the input supply for the EVM.
J11, Pin 3 and 4 – S+/S- Input voltage sense connections. Measure the input voltage at this point.
J11, Pin 5 and 6 – GND Input return connection from the input supply for the EVM.
J12, Pin 1 and 2 – VOUT Output voltage connection.
J12, Pin 3 and 4 – S+/S- Output voltage sense connections. Measure the output voltage at this point.
J12, Pin 5 and 6 – GND Output return connection.
JP11 – EN EN pin input jumper. Place the supplied jumper across ON and EN to turn
on the IC. Place the jumper across OFF and EN to turn off the IC.
JP12 – MODE
MODE pin input jumper. Place the supplied jumper across PWM and MODE
to operate in forced PWM mode. Place the jumper across PFM and MODE
to operate in power save mode with an automatic transition to PWM mode
at higher load currents.
2.2 Setup
To operate the EVM, set jumpers JP11 through JP13 to the desired position per Section 2.1. Connect the
input supply to J11 and connect the load to J12.

www.ti.com TPS62842EVM-103 Test Results
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3 TPS62842EVM-103 Test Results
The TPS62842EVM-103 was used to take all the data in the 1.8V-6.5V, 750mA, 60nA IQStep-Down
Converter data sheet. See the device data sheet for the performance of this EVM.
Figure 2 shows the thermal performance of the EVM.
Figure 2. TPS62842 Thermal Performance (VIN = 6.5 V, VOUT = 3.6 V, IOUT = 750 mA)

Board Layout www.ti.com
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TPS62842EVM-103 User's Guide
4 Board Layout
This section provides the TPS62842EVM-103 board layout and illustrations in Figure 3 through Figure 9.
Figure 3. Top Assembly
Figure 4. Top Layer

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Figure 5. Internal Layer 1
Figure 6. Internal Layer 2

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Figure 7. Bottom Layer
Figure 8. TPS62842EVM-103 Angled View

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Figure 9. TPS62842EVM-103 Top View

VIN VOUT
VOUT
1.8V - 3.59VVIN
2.2µH
L11
1.8V to 6.5V @ 750 mA
S+S+
5
4
1
2
3
6
J11
5
4
1
2
3
6
J12
S- S-
10.0
R13
4.7µF
C11
47µF
C13
4.7uF
C14
4.7uF
C16
10uF
C17
VOS 1
MODE
3
VSET
4EP 9
EN
5
VIN
6
GND 8
NC 7
SW 2
TPS62842DGRR
U11
GNDGND
GND
GND GND
VIN
ON
EN
OFF
GND
PWM
MODE
PFM/PWM 1
2
3
JP12
1.00MR12
GND
VIN
SW
TP11
GND
1
2
3
JP11
52.3k
R14
52.3k
R11
10uF
C12
10uF
C15
Schematic and List of Materials www.ti.com
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5 Schematic and List of Materials
This section provides the TPS62842EVM-103 schematic and List of Materials.
5.1 Schematic
Figure 10 illustrates the TPS62842EVM-103 schematic.
Figure 10. TPS62842EVM-103 Schematic
5.2 List of Materials
Table 2 lists the TPS62842EVM-103 list of materials.
Table 2. TPS62842EVM-103 List of Materials
REF DES QTY DESCRIPTION PART NUMBER MANUFACTURER
C11 1 Capacitor, ceramic, 4.7 µF, 50 V, ±20%, X7R, 1206 GRM31CR71H475MA12L Murata
C12 1 Capacitor, ceramic, 10 µF, 6.3 V, ±20%, X5R, 0402 GRM155R60J106ME15D Murata
C13 1 Capacitor, ceramic, 47 µF, 10 V, ±20%, X5R, 0805 GRM21BR61A476ME15L Murata
L11 1 Inductor, Unshielded, metal composite, 2.2 µH, 850 mA, 180 mΩ,
SMD CC453232-2R2KL Bourns
R11 1 Resistor, 52.3 kΩ, 1%, 0.05 W, 0201 Std Std
R12 1 Resistor, 1.00 MΩ, 1%, 0.1 W, 0603 Std Std
U11 1 1.8 V to 6.5 V, 750 mA, 60 nA IQStep Down Converter in DGR
Package TPS62842DGR Texas Instruments