TPS5405 [TI]

6.5-V TO 28-V INPUT VOLTAGE, 5-V FIXED OUTPUT, 2-A OUTPUT CURRENT, NON-SYNCHRONOUS STEP-DOWN REGULATOR WITH INTEGRATED MOSFET; 6.5 V至28 V的输入电压,5 -V固定输出, 2 -A的输出电流,集成MOSFET的非同步降压稳压器
TPS5405
型号: TPS5405
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

6.5-V TO 28-V INPUT VOLTAGE, 5-V FIXED OUTPUT, 2-A OUTPUT CURRENT, NON-SYNCHRONOUS STEP-DOWN REGULATOR WITH INTEGRATED MOSFET
6.5 V至28 V的输入电压,5 -V固定输出, 2 -A的输出电流,集成MOSFET的非同步降压稳压器

稳压器 输出元件 输入元件
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TPS5405  
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SLVSBF7A MAY 2012REVISED JUNE 2012  
6.5-V TO 28-V INPUT VOLTAGE, 5-V FIXED OUTPUT, 2-A OUTPUT CURRENT,  
NON-SYNCHRONOUS STEP-DOWN REGULATOR WITH INTEGRATED MOSFET  
Check for Samples: TPS5405  
1
FEATURES  
Fixed 5-V Output  
APPLICATIONS  
6.5-V to 28-V Wide Input Voltage Range  
9-V, 12-V and 24-V Distributed Power Systems  
Up to 2-A Maximum Continuous Output  
Loading Current  
Consumer Applications Such as Home  
Appliances, Set-Top Boxes, CPE Equipment,  
LCD Displays, Peripherals, and Battery  
Chargers  
Pulse Skipping Mode to Achieve High Light  
Load Efficiency  
Industrial and Car Entertainment Power  
Supplies  
Over 80% Efficiency at 10-mA Loading  
Adjustable 50-kHz to 1.1-MHz Switching  
Frequency Set by an External Resistor  
(Leave pin ROSC floating. Set frequency to  
120 kHz and ground connection to 70 kHz)  
Peak Current-Mode Control  
Cycle-by-Cycle Over Current Protection  
Switching Node Anti-Ringing to Ease EMI  
Issue  
External Soft Start  
Available in SOIC8 Package  
DESCRIPTION  
The TPS5405 is a monolithic non-synchronous buck regulator with wide operating input voltage range from 6.5 V  
to 28 V. Current mode control with internal slope compensation is implemented to reduce component count.  
TPS5405 also features a light load pulse skipping mode, which allows for a power loss reduction from the input  
power supply to the system at light loading.  
The switching frequency of the converters can be set from 50 kHz to 1.1 MHz with an external resistor.  
Frequency spread spectrum operation is introduced for EMI reduction.  
LX anti-ringing is added to address high frequency EMI issues.  
A cycle-by-cycle current limit with frequency fold back protects the IC at over loading condition.  
1
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.  
PRODUCTION DATA information is current as of publication date.  
Copyright © 2012, Texas Instruments Incorporated  
Products conform to specifications per the terms of the Texas  
Instruments standard warranty. Production processing does not  
necessarily include testing of all parameters.  
TPS5405  
SLVSBF7A MAY 2012REVISED JUNE 2012  
www.ti.com  
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.  
TYPICAL APPLICATION  
Cboot  
Lo  
Vout  
Cout  
D
1
2
8
7
BOOT  
VIN  
LX  
Cin  
Vin  
GND  
TPS5405  
Rc  
Cc  
3
4
6
5
ROSC  
SS  
COMP  
Rosc  
VSENSE  
Css  
FUNCTIONAL BLOCK DIAGRAM  
VIN  
165°C  
Thermal  
Shutdown  
Shutdown  
Logic  
Shutdown  
Boot  
Charge  
VSENSE  
Boot  
UVLO  
Minimum Clamp  
BOOT  
9A/V  
Current  
Sense  
2.1V  
PWM  
Comparator  
PWM  
Latch  
gm  
Gate  
Drive  
Logic  
R
Q
2µA  
0.8V  
S
Voltage  
Reference  
SS  
Slope  
Compensation  
Σ
LX  
Shutdown  
Discharge  
Logic  
Frequency  
Shift  
Oscillator  
VSENSE  
GND  
COMP  
Maximum  
Clamp  
ROSC  
2
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PCB LAYOUT  
VOUT  
GROUND  
1 BOOT  
LX 8  
2 VIN  
GND 7  
VIN  
3
4
ROSC  
SS  
COMP 6  
VSENSE 5  
ORDERING INFORMATION(1)  
TA  
PACKAGE(2)  
ORDERABLE PART NUMBER  
TOP-SIDE MARKING  
–40°C to 85°C  
8-pin SOIC (D)  
TPS5405DR  
TPS5405  
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI  
web site at www.ti.com.  
(2) Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.  
PIN OUT  
D PACKAGE  
(TOP VIEW)  
BOOT  
VIN  
1
2
8
7
LX  
GND  
3
4
6
5
ROSC  
SS  
COMP  
VSENSE  
TERMINAL FUNCTIONS  
NAME  
BOOT  
NO.  
1
DESCRIPTION  
A 0.1-µF bootstrap capacitor is required between BOOT and LX.  
Input supply voltage, 6.5 V to 28 V  
VIN  
2
Switching frequency program pin. Connect a resistor to this pin to set the switching frequency. Connect the  
pin to ground for a default 70-kHz switching frequency. Leave the pin open for 120-kHz switching  
frequency.  
ROSC  
3
SS  
4
5
Soft start pin. An external capacitor connected to this pin sets the output rise time.  
Output voltage feedback pin  
VSENSE  
Error amplifier output and input to the PWM comparator. Connect frequency compensation components to  
this pin.  
COMP  
6
GND  
LX  
7
8
Ground  
Switching node to external inductor  
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(1)  
ABSOLUTE MAXIMUM RATINGS  
over operating free-air temperature range (unless otherwise noted)  
Voltage range at VIN, LX  
Voltage range at LX (maximum withstand voltage transient < 20 ns)  
Voltage from BOOT to LX  
Voltage at VSENSE  
–0.3 to 30  
–5 to 30  
V
V
–0.3 to 7  
–0.3 to 7  
–0.3 to 3  
–0.3 to 3  
–0.3 to 3  
–0.3 to 0.3  
–40 to 125  
–55 to 150  
V
V
Voltage at SS  
V
Voltage at ROSC  
V
Voltage at COMP  
V
Voltage at GND  
V
TJ  
Operating junction temperature range  
Storage temperature range  
°C  
°C  
TSTG  
(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.  
RECOMMENDED OPERATING CONDITIONS  
over operating free-air temperature range (unless otherwise noted)  
MIN  
6.5  
NOM  
MAX  
28  
UNIT  
V
VIN  
TA  
Input operating voltage  
Ambient temperature  
–40  
85  
°C  
THERMAL INFORMATION  
TPS5405  
D
THERMAL METRIC(1)  
UNITS  
8 PINS  
116.7  
62.4  
θJA  
Junction-to-ambient thermal resistance(2)  
Junction-to-case (top) thermal resistance(3)  
Junction-to-board thermal resistance(4)  
θJCtop  
θJB  
57.0  
°C/W  
ψJT  
Junction-to-top characterization parameter(5)  
Junction-to-board characterization parameter(6)  
Junction-to-case (bottom) thermal resistance(7)  
14.5  
ψJB  
56.5  
θJCbot  
N/A  
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.  
(2) The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, high-K board, as  
specified in JESD51-7, in an environment described in JESD51-2a.  
(3) The junction-to-case (top) thermal resistance is obtained by simulating a cold plate test on the package top. No specific JEDEC-  
standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.  
(4) The junction-to-board thermal resistance is obtained by simulating in an environment with a ring cold plate fixture to control the PCB  
temperature, as described in JESD51-8.  
(5) The junction-to-top characterization parameter, ψJT, estimates the junction temperature of a device in a real system and is extracted  
from the simulation data for obtaining θJA, using a procedure described in JESD51-2a (sections 6 and 7).  
(6) The junction-to-board characterization parameter, ψJB, estimates the junction temperature of a device in a real system and is extracted  
from the simulation data for obtaining θJA , using a procedure described in JESD51-2a (sections 6 and 7).  
(7) The junction-to-case (bottom) thermal resistance is obtained by simulating a cold plate test on the exposed (power) pad. No specific  
JEDEC standard test exists, but a close description can be found in the ANSI SEMI standard G30-88.  
4
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ELECTRICAL CHARACTERISTICS  
TA = -40°C to 125°C, VIN = 12 V (unless otherwise noted)  
PARAMETER  
TEST CONDITIONS  
MIN  
TYP  
MAX UNIT  
INPUT SUPPLY  
VIN  
Input Voltage range  
VIN1 and VIN2  
6.5  
28  
V
Non switching quiescent power supply  
current  
VFB1 = VFB2 = 900 mV,  
LOW_P = high  
IDDQ_nsw  
100  
µA  
Rising VIN  
Hysteresis  
3.5  
V
UVLO  
VIN under voltage lockout  
200  
mV  
FEEDBACK AND ERROR AMPLIFIER  
VSENSE  
Regulated output voltage  
VIN = 12 V  
4.85  
5
5.15  
V
-2 µA < ICOMP < 2 µA,  
VCOMP = 1 V  
Gm_EA  
Error amplifier trans-conductance  
92  
µs  
Igm  
Error amplifier source/sink current  
VCOMP = 1 V, 100 mV overdrive  
VIN = 12 V  
±7  
9
µA  
Gm_SRC  
COMP voltage to inductor current Gm  
A/V  
PFM MODE AND SOFT-START  
Pulse skipping mode switch current  
threshold  
Ith  
300  
2
mA  
µA  
ISS  
Charge current  
OSCILLATOR  
fSW_BK  
Switching frequency range  
Programmable frequency  
Set by external resistor ROSC  
ROSC = GND  
50  
1100  
kHz  
kHz  
70  
120  
300  
fSW  
ROSC = OPEN  
ROSC = 85.5 kΩ  
Frequency spread spectrum in  
percentage of fSW  
fjitter  
VIN = 12 V  
VIN = 12 V  
±6  
%
Jittering swing frequency in percentage  
of fSW  
fswing  
1/512  
tmin_on  
Minimum on time  
VIN = 12 V, TA = 25°C  
VIN = 12 V  
200  
93  
ns  
%
Dmax  
Maximum duty ratio  
CURRENT LIMIT  
ILIMIT  
Peak inductor current limit  
VIN = 12 V  
2.5  
120  
165  
A
MOSFET ON-RESISTANCE  
Rdson_HS  
On resistance of high side FET  
VIN = 12 V  
240  
mΩ  
°C  
THERMAL SHUTDOWN  
TTRIP  
Thermal protection trip point  
Rising temperature  
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TYPICAL CHARACTERISTICS  
TA = 25°C, VIN = 12 V, fSW = 120 kHz (unless otherwise noted)  
Figure 1. Efficiency  
VIN = 12 V, VOUT = 5 V  
Figure 2. Efficiency  
VIN = 12 V, VOUT = 5 V  
Figure 3. Load Regulation  
VIN = 12 V, VOUT = 5 V  
Figure 4. Line Regulation  
VOUT = 5 V  
Figure 5. Startup  
1-A Preset Loading  
Figure 6. Steady State  
IO = 1 A  
6
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TYPICAL CHARACTERISTICS (continued)  
TA = 25°C, VIN = 12 V, fSW = 120 kHz (unless otherwise noted)  
Figure 7. Steady State  
IO = 20 mA  
Figure 8. Load Transient  
IO = 0.1 A to 1 A  
Figure 9. Short Circuit Protection  
Figure 10. Short Circuit Recovery  
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OVERVIEW  
The TPS5405 is a 28-V, 2-A, step-down (buck) converter with an integrated high-side N-channel MOSFET. To  
improve performance during line and load transients, the device implements a constant frequency, current mode  
control which reduces output capacitance and simplifies external frequency compensation design.  
The TPS5405’s switching frequency is adjustable with an external resistor or fixed by connecting the frequency  
program pin to GND or leaving it unconnected.  
The TPS5405 starts switching at VIN equal to 3.5 V. The operating current is 100 μA typically when not switching  
and under no load. When the device is disabled, the supply current is 1 μA typically.  
The integrated 120-mΩ high-side MOSFET allows for high efficiency power supply designs with continuous  
output currents up to 2 A.  
The TPS5405 reduces the external component count by integrating the boot recharge diode. The bias voltage for  
the integrated high-side MOSFET is supplied by an external capacitor on the BOOT to PH pins. The boot  
capacitor voltage is monitored by an UVLO circuit and will turn the high-side MOSFET off when the voltage falls  
below a preset threshold of 2.1 V typically.  
By adding an external capacitor, the slow start time of the TPS5405 can be adjustable which enables flexible  
output filter selection. To improve the efficiency at light load conditions, the TPS5405 enters a special pulse  
skipping mode when the peak inductor current drops below 300 mA typically. The frequency foldback reduces  
the switching frequency during startup and over current conditions to help control the inductor current. The  
thermal shut down gives the additional protection under fault conditions.  
DETAILED DESCRIPTION  
Adjustable Frequency PWM Control  
The TPS5405 uses an external resistor to adjust the switching frequency. Connecting the ROSC pin to ground  
fixes the switching frequency at 70 kHz, leaving it open gives 120-kHz switching frequency.  
Figure 11. ROSC vs Switching Frequency  
-1.167  
ROSC(kW) = 21.82× fSW  
(1)  
For operation at 300 kHz, an 85.5-kresistor is required.  
8
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Pulse Skipping Mode  
The TPS5405 is designed to operate in pulse skipping mode at light load currents to boost light load efficiency.  
When the peak inductor current is lower than 300 mA typically, the COMP pin voltage falls to 0.5 V typically and  
the device enters pulse skipping mode. When the device is in pulse skipping mode, the COMP pin voltage is  
clamped at 0.5 V internally which prevents the high side integrated MOSFET from switching. The peak inductor  
current must rise above 300 mA for the COMP pin voltage to rise above 0.5 V and exit pulse skipping mode.  
Since the integrated current comparator catches the peak inductor current only, the average load current  
entering pulse skipping mode varies with the applications and external output filters.  
Voltage Reference (VSENSE  
)
The voltage reference system produces a ±2% initial accuracy voltage reference (±4% over temperature) by  
scaling the output of a temperature stable bandgap circuit. The typical voltage reference is designed at 0.8 V.  
Bootstrap Voltage (BOOT)  
The TPS5405 has an integrated boot regulator and requires a 0.1-µF ceramic capacitor between the BOOT and  
LX pins to provide the gate drive voltage for the high-side MOSFET. A ceramic capacitor with an X7R or X5R  
grade dielectric is recommended because of the stable characteristics over temperature and voltage. To improve  
drop out, the TPS5405 is designed to operate at 100% duty cycle as long as the BOOT to LX pin voltage is  
greater than 2.1 V typically.  
Programmable Slow Start Using SS Pin  
It is recommended to program the slow start time externally because no slow start time is implemented internally.  
The TPS5405 effectively uses the lower voltage of the internal voltage reference or the SS pin voltage as the  
power supply’s reference voltage fed into the error amplifier and will regulate the output accordingly. A capacitor  
(CSS) on the SS pin to ground implements a slow start time. The TPS5405 has an internal pull-up current source  
of 2 μA that charges the external slow start capacitor. The equation for the slow start time (10% to 90%) is  
shown in Equation 2. The internal Vref is 0.8 V and the ISS current is 2 μA.  
Css(nF)´ Vref (V)  
tss(ms) =  
Iss(mA)  
(2)  
The slow start time should be set between 1 ms to 10 ms to ensure good start-up behavior. The slow start  
capacitor should be no more than 27 nF.  
If during normal operation, the input voltage drops below the VIN UVLO threshold, or a thermal shutdown event  
occurs, the TPS5405 stops switching.  
Error Amplifier  
The TPS5405 has a transconductance amplifier for the error amplifier. The error amplifier compares the  
VSENSE voltage to the internal effective voltage reference presented at the input of the error amplifier. The  
transconductance of the error amplifier is 92 μA/V during normal operation. Frequency compensation  
components are connected between the COMP pin and ground.  
Slope Compensation  
To prevent the sub-harmonic oscillations when operating the device at duty cycles greater than 50%, the  
TPS5405 adds a built-in slope compensation which is a compensating ramp to the switch current signal.  
Overcurrent Protection and Frequency Shift  
The TPS5405 implements current mode control that uses the COMP pin voltage to turn off the high-side  
MOSFET on a cycle by cycle basis. Every cycle the switch current and the COMP pin voltage are compared;  
when the peak inductor current intersects the COMP pin voltage, the high-side switch is turned off. During  
overcurrent conditions that pull the output voltage low, the error amplifier responds by driving the COMP pin high,  
causing the switch current to increase. The COMP pin has a maximum clamp internally, which limits the output  
current.  
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The TPS5405 provides robust protection during short circuits. There is potential for overcurrent runaway in the  
output inductor during a short circuit at the output. The TPS5405 solves this issue by increasing the off time  
during short circuit conditions by lowering the switching frequency. The switching frequency is divided by 8, 4, 2,  
and 1 as the voltage ramps from 0 V to 5V on the VSENSE pin. The relationship between the switching  
frequency and the VSENSE pin voltage is shown in Table 1.  
Table 1. Switching Frequency Conditions  
SWITCHING FREQUENCY  
VSENSE PIN VOLTAGE  
SENSE 3.75 V  
fSW  
V
fSW/2  
fSW/4  
fSW/8  
3.75 V > VSENSE 2.5 V  
2.5 V > VSENSE 1.25 V  
1.25 V > VSENSE  
Spread Spectrum  
In order to reduce EMI, TPS5405 introduces frequency spread spectrum. The jittering span is ±6% of the  
switching frequency with 1/512 swing frequency.  
Switching Node Anti-Ringing  
When the non-synchronous buck converter operates in DCM mode, the filter inductor and the parasitic  
capacitance in the switching node (LX) form an LC resonant circuit; due to its high Q factor, lengthy high  
frequency oscillation can be observed in the switching node. This ringing could cause radiated EMI issues in  
some systems. TPS5405 adds an anti-ringing circuit to prevent the ringing from happening, when the inductor  
current crosses zero and LX starts to climb up, an internal MOSFET between LX and VSENSE is turned on,  
providing a damping path for the resonant circuit so as to eliminate the ringing.  
Overvoltage Transient Protection  
The TPS5405 incorporates an overvoltage transient protection (OVTP) circuit to minimize output voltage  
overshoot when recovering from output fault conditions or strong unload transients. The OVTP circuit includes an  
overvoltage comparator to compare the VSENSE pin voltage and internal thresholds. When the VSENSE pin  
voltage goes above 109% × Vref, the high-side MOSFET will be forced off. When the VSENSE pin voltage falls  
below 107% × Vref, the high-side MOSFET will be enabled again.  
Inductor Selection  
The higher operating frequency allows the use of smaller inductor and capacitor values. A higher frequency  
generally results in lower efficiency because of switching loss and MOSFET gate charge losses. In addition to  
this basic trade-off, the effect of the inductor value on ripple current and low current operation must also be  
considered. The ripple current depends on the inductor value. The inductor ripple current (iL) decreases with  
higher inductance or higher frequency and increases with higher input voltage (VIN). Accepting larger values of iL  
allows the use of low inductances, but results in higher output voltage ripple and greater core losses.  
To calculate the value of the output inductor, use Equation 3. LIR is a coefficient that represents inductor peak-  
to-peak ripple to DC load current. It is recommended to set LIR to 0.1 ~ 0.3 for most applications.  
Actual core loss of the inductor is independent of core size for a fixed inductor value, but it is very dependent on  
the inductance value selected. As inductance increases, core losses go down. Unfortunately, increased  
inductance requires more turns of wire and therefore copper losses will increase. Ferrite designs have very low  
core loss and are preferred for high switching frequencies, so design goals can concentrate on copper loss and  
preventing saturation. Ferrite core material saturates hard, which means that inductance collapses abruptly when  
the peak design current is exceeded. It results in an abrupt increase in inductor ripple current and consequent  
output voltage ripple. Do not allow the core to saturate. It is important that the RMS current and saturation  
current ratings are not exceeding the inductor specification. The RMS and peak inductor current can be  
calculated from Equation 5 and Equation 6.  
10  
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VIN - VOUT  
VOUT  
×
L =  
IO ×LIR  
IN - VOUT  
V
IN × fsw  
(3)  
(4)  
V
VOUT  
DiL =  
×
IO  
VIN × fsw  
V
OUT ×(V  
- VOUT )  
2
INmax  
(
)
V
×L × fsw  
iLRMS  
=
IO2 +  
INmax  
12  
(5)  
(6)  
DiL  
ILpeak = IO2 ×  
2
For this design example, use LIR = 0.3 and the inductor is calculated to be 5.40 µH with VIN = 12 V. Choose  
4.7 µH value for the standard inductor and the peak to peak inductor ripple is about 34% of 1-A DC load current.  
Output Capacitor Selection  
There are two primary considerations for selecting the value of the output capacitor. The output capacitors are  
selected to meet load transient and output ripple’s requirements.  
Equation 7 gives the minimum output capacitance to meet the transient specification. For this example,  
L = 4.7 µH, ΔIOUT = 1 A – 0.0 A = 1 A and ΔVOUT = 500 mV (10% of regulated 5 V). Using these numbers gives a  
minimum capacitance of 1 µF. A standard 22-µF ceramic is chosen in the design.  
DIOUT2 ×L  
Co >  
2× VOUT × DVOUT  
(7)  
The selection of CO is driven by the effective series resistance (ESR). Equation 8 calculates the minimum output  
capacitance needed to meet the output voltage ripple specification. Where fSW is the switching frequency, ΔVOUT  
is the maximum allowable output voltage ripple, and ΔiL is the inductor ripple current. In this case, the maximum  
output voltage ripple is 50 mV (1% of regulated 5 V). From Equation 4, the output current ripple is 1 A. From  
Equation 8, the minimum output capacitance meeting the output voltage ripple requirement is 2.5 µF with 3-mΩ  
ESR resistance.  
1
1
Co >  
×
DVOUT  
8 × fsw  
- ESR  
DiL  
(8)  
After considering both requirements, for this example, one 22-µF, 6.3-V X7R ceramic capacitor with 3-mESR  
should be used.  
Input Capacitor Selection  
A minimum 10-µF X7R/X5R ceramic input capacitor is recommended to be added between VIN and GND. These  
capacitors should be connected as close as physically possible to the input pins of the converters as they handle  
the RMS ripple current shown in Equation 9. For this example, IOUT = 1 A, VOUT = 5 V, minimum VINmin = 9.6 V,  
from Equation 9, the input capacitors must support a ripple current of 1-A RMS.  
V
- VOUT  
(
)
VOUT  
INmin  
I
= IOUT  
×
×
INRMS  
V
V
INmin  
INmin  
(9)  
The input capacitance value determines the input ripple voltage of the regulator. The input voltage ripple can be  
calculated using Equation 10. Using the design example values, IOUTmax = 1 A, CIN = 10 µF, fSW = 300 kHz, yields  
an input voltage ripple of 83 mV.  
IOUTmax ×0.25  
DV  
=
IN  
CIN × fSW  
(10)  
To prevent large voltage transients, a low ESR capacitor sized for the maximum RMS current must be used.  
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11  
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TPS5405  
SLVSBF7A MAY 2012REVISED JUNE 2012  
www.ti.com  
Bootstrap Capacitor Selection  
An external bootstrap capacitor connected to the BST pins supplies the gate drive voltages for the topside  
MOSFETs. The capacitor between BST pin and LX pin is charged though internal diode from V7V when the LX  
pin is low. When a high side MOSFET is to be turned on, the driver places the bootstrap voltage across the gate-  
source of the desired MOSFET. This enhances the top MOSFET switch and turns it on. The switch node voltage,  
LX, rises to VIN and the BST pin follows. With the internal high side MOSFET on, the bootstrap voltage is above  
the input supply: VBST = VIN + V7V. The selection on bootstrap capacitance is related with internal high side  
power MOSFET gate capacitance. A 0.047-μF ceramic capacitor is recommended between the BST pin and LX  
pin for proper operation. It is recommended to use a ceramic capacitor with X5R or better grade dielectric. The  
capacitor should have 10-V or higher voltage rating.  
Thermal Shutdown  
The device implements an internal thermal shutdown to protect itself if the junction temperature exceeds 165°C.  
The thermal shutdown forces the device to stop switching when the junction temperature exceeds the thermal  
trip threshold. Once the die temperature decreases below 165°C, the device reinitiates the power up sequence.  
12  
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Product Folder Link(s): TPS5405  
PACKAGE OPTION ADDENDUM  
www.ti.com  
2-Jul-2012  
PACKAGING INFORMATION  
Status (1)  
Eco Plan (2)  
MSL Peak Temp (3)  
Samples  
Orderable Device  
Package Type Package  
Drawing  
Pins  
Package Qty  
Lead/  
Ball Finish  
(Requires Login)  
TPS5405DR  
ACTIVE  
SOIC  
D
8
3000  
Green (RoHS  
& no Sb/Br)  
CU NIPDAU Level-1-260C-UNLIM  
(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.  
(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.  
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.  
Addendum-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
2-Jul-2012  
TAPE AND REEL INFORMATION  
*All dimensions are nominal  
Device  
Package Package Pins  
Type Drawing  
SPQ  
Reel  
Reel  
A0  
B0  
K0  
P1  
W
Pin1  
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant  
(mm) W1 (mm)  
TPS5405DR  
SOIC  
D
8
3000  
330.0  
12.4  
6.4  
5.2  
2.1  
8.0  
12.0  
Q1  
Pack Materials-Page 1  
PACKAGE MATERIALS INFORMATION  
www.ti.com  
2-Jul-2012  
*All dimensions are nominal  
Device  
Package Type Package Drawing Pins  
SOIC  
SPQ  
Length (mm) Width (mm) Height (mm)  
340.5 338.1 20.6  
TPS5405DR  
D
8
3000  
Pack Materials-Page 2  
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