LOW-POWER DC/DC BOOST CONVERTER IN SOT-23 AND SON PACKAGES
Check for Samples: TPS61040, TPS61041
1
FEATURES
•1.8-V to 6-V Input Voltage Range
•Adjustable Output Voltage Range up to 28 V
•400-mA (TPS61040) and 250-mA (TPS61041)
Internal Switch Current
•Up to 1-MHz Switching Frequency
•28-mA Typical No-Load Quiescent Current
•1-mA Typical Shutdown Current
•Internal Soft Start
•Available in SOT23-5, TSOT23-5,
and 2 × 2 × 0.8-mm SON Packages
APPLICATIONS
•LCD Bias Supply
•White-LED Supply for LCD Backlights
•Digital Still Camera
•PDAs, Organizers, and Handheld PCs
•Cellular Phones
•Internet Audio Player
•Standard 3.3-V/5-V to 12-V Conversion
DESCRIPTION
TheTPS61040/41isahigh-frequencyboost
converter dedicated for small to medium LCD bias
supply and white LED backlight supplies. The device
is ideal to generate output voltages up to 28 V from a
dual cell NiMH/NiCd or a single cell Li-Ion battery.
The part can also be used to generate standard
3.3-V/5-V to 12-V power conversions.
TheTPS61040/41operateswithaswitching
frequency up to 1 MHz. This allows the use of small
external components using ceramic as well as
tantalum output capacitors. Together with the thin
SON package, the TPS61040/41 gives a very small
overall solution size. The TPS61040 has an internal
400 mA switch current limit, while the TPS61041 has
a 250-mA switch current limit, offering lower output
voltage ripple and allows the use of a smaller form
factor inductor for lower power applications. The low
quiescent current (typically 28 mA) together with an
optimized control scheme, allows device operation at
very high efficiencies over the entire load current
range.
TYPICAL APPLICATION
1
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
www.ti.com
Table 1. ORDERING INFORMATION
SWITCH CURRENTPACKAGE
T
A
–40°C to
85°C
(1) For the most current package and ordering information, see the Package Option Addendum at the end
of this document, or see the TI website at www.ti.com.
(2) The devices are available in tape and reel and in tubes. Add R suffix to the part number (e.g.,
TPS61040DRVR) to order quantities of 3000 parts in tape and reel or add suffix T (e.g.,
TPS61040DRVT) to order a tube with 250 pieces..
EN43Imode reducing the supply current to less than 1 mA. This pin should not be left floating and needs
FB34I
GND21–Ground
NC–5–No connection
SW16I
V
IN
DDC,
DBV NO.
52ISupply voltage pin
I/ODESCRIPTION
This is the enable pin of the device. Pulling this pin to ground forces the device into shutdown
to be terminated.
This is the feedback pin of the device. Connect this pin to the external voltage divider to program
the desired output voltage.
Connect the inductor and the Schottky diode to this pin. This is the switch pin and is connected to
the drain of the internal power MOSFET.
DETAILED DESCRIPTION
OPERATION
The TPS61040/41 operates with an input voltage range of 1.8 V to 6 V and can generate output voltages up to
28 V. The device operates in a pulse-frequency-modulation (PFM) scheme with constant peak current control.
This control scheme maintains high efficiency over the entire load current range, and with a switching frequency
up to 1 MHz, the device enables the use of very small external components.
The converter monitors the output voltage, and as soon as the feedback voltage falls below the reference voltage
of typically 1.233 V, the internal switch turns on and the current ramps up. The switch turns off as soon as the
inductor current reaches the internally set peak current of typically 400 mA (TPS61040) or 250 mA (TPS61041).
See the Peak Current Control section for more information. The second criteria that turns off the switch is the
maximum on-time of 6 ms (typical). This is just to limit the maximum on-time of the converter to cover for extreme
conditions. As the switch is turned off the external Schottky diode is forward biased delivering the current to the
output. The switch remains off for a minimum of 400 ns (typical), or until the feedback voltage drops below the
reference voltage again. Using this PFM peak current control scheme the converter operates in discontinuous
conduction mode (DCM) where the switching frequency depends on the output current, which results in very high
efficiency over the entire load current range. This regulation scheme is inherently stable, allowing a wider
selection range for the inductor and output capacitor.
SLVS413F –OCTOBER 2002–REVISED DECEMBER 2010
PEAK CURRENT CONTROL
The internal switch turns on until the inductor current reaches the typical dc current limit (I
(TPS61040) or 250 mA (TPS61041). Due to the internal propagation delay of typical 100 ns, the actual current
exceeds the dc current limit threshold by a small amount. The typical peak current limit can be calculated:
The higher the input voltage and the lower the inductor value, the greater the peak.
By selecting the TPS61040 or TPS61041, it is possible to tailor the design to the specific application current limit
requirements. A lower current limit supports applications requiring lower output power and allows the use of an
inductor with a lower current rating and a smaller form factor. A lower current limit usually has a lower output
voltage ripple as well.
All inductive step-up converters exhibit high inrush current during start-up if no special precaution is made. This
can cause voltage drops at the input rail during start up and may result in an unwanted or early system shut
down.
The TPS61040/41 limits this inrush current by increasing the current limit in two steps starting fromfor 256
cycles tofor the next 256 cycles, and then full current limit (see Figure 14).
ENABLE
Pulling the enable (EN) to ground shuts down the device reducing the shutdown current to 1 mA (typical).
Because there is a conductive path from the input to the output through the inductor and Schottky diode, the
output voltage is equal to the input voltage during shutdown. The enable pin needs to be terminated and should
not be left floating. Using a small external transistor disconnects the input from the output during shutdown as
shown in Figure 18.
UNDERVOLTAGE LOCKOUT
An undervoltage lockout prevents misoperation of the device at input voltages below typical 1.5 V. When the
input voltage is below the undervoltage threshold, the main switch is turned off.
www.ti.com
THERMAL SHUTDOWN
An internal thermal shutdown is implemented and turns off the internal MOSFETs when the typical junction
temperature of 168°C is exceeded. The thermal shutdown has a hysteresis of typically 25°C. This data is based
on statistical means and is not tested during the regular mass production of the IC.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature (unless otherwise noted)
Supply voltages on pin V
Voltages on pins EN, FB
Switch voltage on pin SW
Continuous power dissipationSee Dissipation Rating Table
T
Operating junction temperature–40°C to 150°C
J
T
Storage temperature–65°C to 150°C
stg
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltage values are with respect to network ground terminal.
Because the PFM peak current control scheme is inherently stable, the inductor value does not affect the stability
of the regulator. The selection of the inductor together with the nominal load current, input and output voltage of
the application determines the switching frequency of the converter. Depending on the application, inductor
values between 2.2 mH and 47 mH are recommended. The maximum inductor value is determined by the
maximum on time of the switch, typically 6 ms. The peak current limit of 400 mA/250 mA (typically) should be
reached within this 6-ms period for proper operation.
The inductor value determines the maximum switching frequency of the converter. Therefore, select the inductor
value that ensures the maximum switching frequency at the converter maximum load current is not exceeded.
The maximum switching frequency is calculated by the following formula:
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
V
If the selected inductor value does not exceed the maximum switching frequency of the converter, the next step
is to calculate the switching frequency at the nominal load current using the following formula:
= The highest switching frequency occurs at the minimum input voltage(2)
IN(min)
www.ti.com
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
I
= Nominal load current
load
Vd = Rectifier diode forward voltage (typically 0.3V)(3)
A smaller inductor value gives a higher converter switching frequency, but lowers the efficiency.
The inductor value has less effect on the maximum available load current and is only of secondary order. The
best way to calculate the maximum available load current under certain operating conditions is to estimate the
expected converter efficiency at the maximum load current. This number can be taken out of the efficiency
graphs shown in Figure 1 through Figure 4. The maximum load current can then be estimated as follows:
Where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
fS
= Maximum switching frequency as calculated previously
max
h = Expected converter efficiency. Typically 70% to 85%(4)
The maximum load current of the converter is the current at the operation point where the converter starts to
enter the continuous conduction mode. Usually the converter should always operate in discontinuous conduction
mode.
Last, the selected inductor should have a saturation current that meets the maximum peak current of the
converter (as calculated in the Peak Current Control section). Use the maximum value for I
Another important inductor parameter is the dc resistance. The lower the dc resistance, the higher the efficiency
of the converter. See Table 4 and the typical applications for the inductor selection.
Table 4. Recommended Inductor for Typical LCD Bias Supply (see Figure 15)
For battery-powered applications, a high-impedance voltage divider should be used with a typical value for R2 of
≤200 kΩ and a maximum value for R1 of 2.2 MΩ. Smaller values might be used to reduce the noise sensitivity of
the feedback pin.
A feedforward capacitor across the upper feedback resistor R1 is required to provide sufficient overdrive for the
error comparator. Without a feedforward capacitor, or one whose value is too small, the TPS61040/41 shows
double pulses or a pulse burst instead of single pulses at the switch node (SW), causing higher output voltage
ripple. If this higher output voltage ripple is acceptable, the feedforward capacitor can be left out.
The lower the switching frequency of the converter, the larger the feedforward capacitor value required. A good
starting point is to use a 10-pF feedforward capacitor. As a first estimation, the required value for the feedforward
capacitor at the operation point can also be calculated using the following formula:
Where:
R1 = Upper resistor of voltage divider
fS = Switching frequency of the converter at the nominal load current (See the Inductor Selection, Maximum
Load Current section for calculating the switching frequency)
CFF= Choose a value that comes closest to the result of the calculation(6)
The larger the feedforward capacitor the worse the line regulation of the device. Therefore, when concern for line
regulation is paramount, the selected feedforward capacitor should be as small as possible. See the following
section for more information about line and load regulation.
LINE AND LOAD REGULATION
The line regulation of the TPS61040/41 depends on the voltage ripple on the feedback pin. Usually a 50 mV
peak-to-peak voltage ripple on the feedback pin FB gives good results.
Some applications require a very tight line regulation and can only allow a small change in output voltage over a
certain input voltage range. If no feedforward capacitor CFFis used across the upper resistor of the voltage
feedback divider, the device has the best line regulation. Without the feedforward capacitor the output voltage
ripple is higher because the TPS61040/41 shows output voltage bursts instead of single pulses on the switch pin
(SW), increasing the output voltage ripple. Increasing the output capacitor value reduces the output voltage
ripple.
If a larger output capacitor value is not an option, a feedforward capacitor CFFcan be used as described in the
previous section. The use of a feedforward capacitor increases the amount of voltage ripple present on the
feedback pin (FB). The greater the voltage ripple on the feedback pin (≥50 mV), the worse the line regulation.
There are two ways to improve the line regulation further:
1. Use a smaller inductor value to increase the switching frequency which will lower the output voltage ripple,
as well as the voltage ripple on the feedback pin.
2. Add a small capacitor from the feedback pin (FB) to ground to reduce the voltage ripple on the feedback pin
down to 50 mV again. As a starting point, the same capacitor value as selected for the feedforward capacitor
CFFcan be used.
www.ti.com
OUTPUT CAPACITOR SELECTION
For best output voltage filtering, a low ESR output capacitor is recommended. Ceramic capacitors have a low
ESR value but tantalum capacitors can be used as well, depending on the application.
Assuming the converter does not show double pulses or pulse bursts on the switch node (SW), the output
voltage ripple can be calculated as:
where:
IP= Peak current as described in the Peak Current Control section
L = Selected inductor value
I
= Nominal load current
out
fS (I
) = Switching frequency at the nominal load current as calculated previously
out
Vd = Rectifier diode forward voltage (typically 0.3 V)
C
= Selected output capacitor
out
ESR = Output capacitor ESR value(7)
See Table 5 and the typical applications section for choosing the output capacitor.
For good input voltage filtering, low ESR ceramic capacitors are recommended. A 4.7 mF ceramic input capacitor
is sufficient for most of the applications. For better input voltage filtering this value can be increased. See Table 5
and typical applications for input capacitor recommendations.
DIODE SELECTION
To achieve high efficiency a Schottky diode should be used. The current rating of the diode should meet the
peak current rating of the converter as it is calculated in the Peak Current Control section. Use the maximum
value for I
for this calculation. See Table 6 and the typical applications for the selection of the Schottky diode.
LIM
Table 6. Recommended Schottky Diode for Typical LCD Bias Supply (see Figure 15)
DEVICEREVERSE VOLTAGECOMPONENT SUPPLIERCOMMENTS
30 VON Semiconductor MBR0530
TPS61040/41
20 VON Semiconductor MBR0520
20 VON Semiconductor MBRM120LHigh efficiency
30 VToshiba CRS02
LAYOUT CONSIDERATIONS
Typical for all switching power supplies, the layout is an important step in the design; especially at high peak
currents and switching frequencies. If the layout is not carefully done, the regulator might show noise problems
and duty cycle jitter.
The input capacitor should be placed as close as possible to the input pin for good input voltage filtering. The
inductor and diode should be placed as close as possible to the switch pin to minimize the noise coupling into
other circuits. Because the feedback pin and network is a high-impedance circuit, the feedback network should
be routed away from the inductor. The feedback pin and feedback network should be shielded with a ground
plane or trace to minimize noise coupling into this circuit.
Wide traces should be used for connections in bold as shown in Figure 15. A star ground connection or ground
plane minimizes ground shifts and noise.
TPS61040DRVRG4ACTIVESONDRV6TBDCall TICall TI-40 to 85
TPS61040DRVTACTIVESONDRV6250Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CCL
TPS61040DRVTG4ACTIVESONDRV6250Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CCL
TPS61041DBVRACTIVESOT-23DBV53000Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85PHPI
TPS61041DBVRG4ACTIVESOT-23DBV53000 Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85PHPI
TPS61041DRVRACTIVESONDRV63000Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CAW
TPS61041DRVRG4ACTIVESONDRV63000Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CAW
TPS61041DRVTACTIVESONDRV6250Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CAW
TPS61041DRVTG4ACTIVESONDRV6250Green (RoHS
& no Sb/Br)
CU NIPDAULevel-1-260C-UNLIM-40 to 85CAW
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
PACKAGE OPTION ADDENDUM
www.ti.com
17-May-2014
Addendum-Page 2
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF TPS61040, TPS61041 :
•
Automotive: TPS61040-Q1, TPS61041-Q1
NOTE: Qualified Version Definitions:
•
Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
ProductsApplications
Audiowww.ti.com/audioAutomotive and Transportationwww.ti.com/automotive
Amplifiersamplifier.ti.comCommunications and Telecomwww.ti.com/communications
Data Convertersdataconverter.ti.comComputers and Peripheralswww.ti.com/computers
DLP® Productswww.dlp.comConsumer Electronicswww.ti.com/consumer-apps
DSPdsp.ti.comEnergy and Lightingwww.ti.com/energy
Clocks and Timerswww.ti.com/clocksIndustrialwww.ti.com/industrial
Interfaceinterface.ti.comMedicalwww.ti.com/medical
Logiclogic.ti.comSecuritywww.ti.com/security
Power Mgmtpower.ti.comSpace, Avionics and Defensewww.ti.com/space-avionics-defense
Microcontrollersmicrocontroller.ti.comVideo and Imagingwww.ti.com/video
RFIDwww.ti-rfid.com
OMAP Applications Processorswww.ti.com/omapTI E2E Communitye2e.ti.com
Wireless Connectivitywww.ti.com/wirelessconnectivity