Texas Instruments TPS71401DRVEVM-426 User manual

1 Overview
1.1 Related Documentation from Texas Instruments
User's GuideSBVU013 – January 2009
TPS71401DRVEVM-426
This user's guide describes the characteristics, operation, and use of the TPS71401DRVEVM-426evaluation module. This document includes setup instructions, a schematic diagram, thermal guidelines, abill of materials (BOM), and printed circuit board (PCB) layout drawings.
Contents1 Overview ...................................................................................................................... 12 Setup .......................................................................................................................... 23 Operation ..................................................................................................................... 34 Thermal Guidelines .......................................................................................................... 35 Board Layout, Schematic, and Parts List ................................................................................. 4
List of Figures
1 Assembly Layer .............................................................................................................. 52 Top Layer Routing ........................................................................................................... 63 Bottom Layer Assembly ..................................................................................................... 74 Bottom Layer Routing ....................................................................................................... 85 TPS71401DRVEVM-426 Schematic ...................................................................................... 9
This document describes the characteristics, operation, and use of the TPS71401DRVEVM-426evaluation module (EVM). This EVM demonstrates the capabilities and features of Texas Instruments'TPS71401 , a low-dropout (LDO) linear regulator, an 80-mA, low quiescent current linear regulator in a2-mm x 2-mm SON package. The TPS71401DRVEVM-426 EVM helps designers evaluate the operationand performance of the TPS71401 LDO in a variety of configurations.
The following related documents are available through the Texas Instruments web site athttp://www.ti.com .
Table 1. Related Documentation
Part Number Literature Number
TPS71401 SBVS116
All trademarks are the property of their respective owners.
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2 Setup
2.1 Electrostatic Discharge Notice
2.2 Input/Output Connector Descriptions
2.2.1 J1: VIN
2.2.2 J2: VOUT
2.2.3 J3: GND
2.2.4 J4: GND
2.2.5 J5: Output Voltage Selection
Setup www.ti.com
This section describes the jumpers and connectors on the EVM as well as how to properly connect, setup, and use the TPS71401EVM.
CAUTION
Many of the components on the TPS71401EVM are susceptible to damage byelectrostatic discharge (ESD). Customers are advised to observe proper ESDhandling precautions when unpacking and handling the EVM, including the useof a grounded wrist strap at an approved ESD workstation.
Failure to observe proper ESD handling procedures may result in damage toEVM components.
This connector is the positive input supply voltage. The leads to the input supply should be twisted andkept as short as possible to minimize electromagnetic interference (EMI) transmission. Additional bulkcapacitance should be added between J1 and J2 if the supply leads are longer than 6 in (15,24 cm). Anadditional 47uF or greater capacitor improves the transient response of the TPS71401 and helps toreduce ringing on the input when long supply wires are used.
This point is the positive connection from the output. Connect this pin to the positive input of the load.
This is the return connection for the input power supply of the regulator.
This point is the return connection for the output.
This jumper is used to select the output voltage of the TPS71401. The jumper selects different feedbackresistors to change the output voltage setting. The output voltage is set by inserting a shorting jumperacross two pins of J5. The preprogrammed output voltages are configured as shown in Table 2 .
Table 2. Output Voltage Setting
Output Voltage (V) Jumper Between Pins
5.0 1 and 23.3 3 and 42.7 5 and 62.5 7 and 8
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3 Operation
3.1 Power On
3.2 Fixed Output TPS714xx Device Configuration
4 Thermal Guidelines
4.1 Thermal Considerations
T = T + P
J A D JA
´ q
(1)
www.ti.com Operation
Other output voltages can be configured by changing the feedback resistors on the board. The feedbacknetwork is high impedance and sensitive to noise or resistance value changes. The pins of J5 should notbe touched while the device is powered on because the impedance of a human is enough to alter theoutput voltage set point. The output voltage may increase or decrease if J5 is touched, which maydamage any load connected to the EVM.
This section discusses the operation of the TPS71401EVM.
Connect the positive input power supply to J1. Connect the input power return (ground) to J3. TheTPS71401EVM has an absolute maximum input voltage of 11.0 V. The recommended maximum operatingvoltage is 10 V. The actual highest input voltage may be less than 10 V as a result of thermal conditions.See the Thermal Considerations section of this manual to determine the highest input voltage.
Connect the desired load between J2 (positive lead) and J4 (negative or return lead). Configure jumper J5for the desired output voltage. The function of J5 is described in the Setup section of this manual.
The TPS71401 EVM can also be used to evaluate fixed-output voltage versions of the TPS714 LDO. Theboard layout and device footprints are the same for both the adjustable and the fixed-output voltageversions of the TPS714. To evaluate a fixed-output voltage version, the IC on the board must be changedto the desired fixed output voltage (TPS714xx). Note that R
1
must be removed from the EVM board if afixed output voltage version is mounted to the EVM board.
This section presents guidelines for the thermal management of the TPS71401DRVEVM-426 PCB.
Thermal management is a key design component of any power converter application and is especiallyimportant when the power dissipation in the LDO is high. To better help users design the TPS71401 familyinto an application, the following formula should be used to approximate the maximum power dissipationat a particular ambient temperature:
Where:
•T
J
is the junction temperature•T
A
is the ambient temperature•P
D
is the power dissipation in the IC• θ
JA
is the thermal resistance from junction to ambient
All temperatures are in degrees Celsius.
The thermal resistance from junction to ambient for the TPS71401EVM has a typical value of 65 °C/W. Therecommended maximum operating junction temperature specified in the data sheet for the TPS71401family is +125 °C. With these two pieces of information, the maximum power dissipation can be found byusing Equation 1 .
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+125 C = +85 C + P (65 C/W)
D
° ° °
(2)
P = (V V ) I = (-OUTD IN OUT V 3.3 V) 0.08 A = 0.615 W
IN -´ ´
(3)
5 Board Layout, Schematic, and Parts List
5.1 PCB Layouts
Board Layout, Schematic, and Parts List www.ti.com
Example 1. Maximum Power Dissipation Calculation
What is the maximum input voltage that can be applied to a TPS71401 with the output voltageconfigured to 3.3 V if the ambient temperature is +85 °C and the full 80 mA of load current is required?
Given:
T
J
= +125 °C, T
A
= +85 °C, θ
JA
= 65 °C/W
Using Equation 1 , we substitute in the given values above and find that the maximum power dissipationfor the part is P
D
= 0.615 W.
This result means that the total power dissipation of the TPS71401 must be less than 0.615 W. Now theinput voltage can be calculated:
Therefore, the maximum input voltage should be 10.98 V or less in order to maintain a safe junctiontemperature. However, the recommended maximum input voltage is 10.0 V, so the device can be usedover the entire recommended input voltage range.
Similar analyses can be performed to determine the maximum ambient temperature allowed and stillprovide the full output current while maintaining the junction temperature at or below +125 °C. Themaximum ambient temperature depends on the output voltage. Table 3 lists the maximum ambienttemperature allowed for the pre-programmed output voltages.
Table 3. Output Voltage and Maximum AmbientTemperature
Maximum AmbientOutput Voltage (V) Temperature ( °C)
5.0 993.3 902.7 872.5 86
This section provides the TPS71401DRVEVM-426 board layout and illustrations. It also includes theschematic and bill of materials for the EVM.
Figure 1 through Figure 3 show the layout for the TPS71401DRVEVM-426 PCB.
Note: Board layouts are not to scale. These figures are intended to show how the board is laid out;they are not intended to be used for manufacturing TPS71401DRVEVM-426 PCBs.
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www.ti.com Board Layout, Schematic, and Parts List
Figure 1. Assembly Layer
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Board Layout, Schematic, and Parts List www.ti.com
Figure 2. Top Layer Routing
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www.ti.com Board Layout, Schematic, and Parts List
Figure 3. Bottom Layer Assembly
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Board Layout, Schematic, and Parts List www.ti.com
Figure 4. Bottom Layer Routing
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5.2 Schematic and BOM
www.ti.com Board Layout, Schematic, and Parts List
Figure 5 illustrates the TPS71401DRVEVM-426 schematic. Table 4 lists the bill of materials for this EVM.
Figure 5. TPS71401DRVEVM-426 Schematic
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Board Layout, Schematic, and Parts List www.ti.com
Table 4. TPS71401DRVEVM-426 Bill of Materials
(1) (2) (3)
Count RefDes
(4)
Value Description Size Part Number Mfr
1 C1 0.1 µF Capacitor, Ceramic, 0.1- µF, 603 STD Any16-V, X7R, 10%1 C2 2.2 µF Capacitor, Ceramic, 2.2- µF, 603 STD Any10-V, X7R, 10%4 J1, J2, PTC36SAAN Header, Two-pin, 100-mil 0.100 x 2 PTC36SAAN SullinsJ3, J4 spacing1 J5 PTC36DAAN Header, Male 2x4-pin, 0.20 x 0.40 in PTC36DAAN Sullins100-mil spacing1 N/A N/A PCB, 1.5 In x 1.2 In x 0.062 — HPA425 AnyIn1 R1 487 k Resistor, Chip, 1.00M Ω, 603 STD Any1/16-W, 1%1 R2 154 k Resistor, Chip, 1/16W, 5% 603 STD Any1 R3 280 k Resistor, Chip, 1/16W, 5% 603 STD Any1 R4 392 k Resistor, Chip, 1/16W, 5% 603 STD Any1 R5 453 k Resistor, Chip, 1/16W, 5% 603 STD Any1 U1 TPS71401DRV IC, 80-mA, 10-V Quiescent 2mm x 2mm TPS71401DRV TICurrent 3.2- µA LDO LinearRegulator1 — — 100-mm Two-Pin Shunt 0.100 x 2 929957-08 3M
(1)
These assemblies are ESD sensitive. ESD precautions shall be observed.(2)
These assemblies must be clean and free from flux and all contaminants. Use of no-clean flux is not acceptable.(3)
These assemblies must comply with workmanship standards IPC-A-610 Class 2.(4)
Components can be substituted with equivalent manufacturer components.
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EVALUATION BOARD/KIT IMPORTANT NOTICE
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSESONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the product(s) must haveelectronics training and observe good engineering practice standards. As such, the goods being provided are not intended to be completein terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety and environmentalmeasures typically found in end products that incorporate such semiconductor components or circuit boards. This evaluation board/kit doesnot fall within the scope of the European Union directives regarding electromagnetic compatibility, restricted substances (RoHS), recycling(WEEE), FCC, CE or UL, and therefore may not meet the technical requirements of these directives or other related directives.Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, the board/kit may be returned within 30 days fromthe date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY SELLER TO BUYERAND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OFMERCHANTABILITY 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 claimsarising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and allappropriate 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 ANYINDIRECT, 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 orservices described herein.
Please read the User’s Guide and, specifically, the Warnings and Restrictions notice in the User’s Guide prior to handling the product. Thisnotice contains important safety information about temperatures and voltages. For additional information on TI’s environmental and/orsafety programs, please contact the TI application engineer or visit www.ti.com/esh .No license is granted under any patent right or other intellectual property right of TI covering or relating to any machine, process, orcombination in which such TI products or services might be or are used.FCC Warning
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSESONLY and is not considered by TI to be a finished end-product fit for general consumer use. It generates, uses, and can radiate radiofrequency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15 of FCC rules, which aredesigned to provide reasonable protection against radio frequency interference. Operation of this equipment in other environments maycause interference with radio communications, in which case the user at his own expense will be required to take whatever measures maybe required to correct this interference.
EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage range of 2.5 V to 10 V and the output voltage range of 1.2 V to 8.8 V.Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are questionsconcerning 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 +85 °C. The EVM is designed to operateproperly with certain components above +85 °C as long as the input and output ranges are maintained. These components include but arenot limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of devices can be identifiedusing 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.
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