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型号: | TPS5405 |
厂家: | 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 |
文件: | 总18页 (文件大小:719K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED 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 2012–REVISED 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
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): TPS5405
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED JUNE 2012
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
Copyright © 2012, Texas Instruments Incorporated
Submit Documentation Feedback
3
Product Folder Link(s): TPS5405
TPS5405
SLVSBF7A –MAY 2012–REVISED JUNE 2012
www.ti.com
(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
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): TPS5405
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED JUNE 2012
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
Copyright © 2012, Texas Instruments Incorporated
Submit Documentation Feedback
5
Product Folder Link(s): TPS5405
TPS5405
SLVSBF7A –MAY 2012–REVISED JUNE 2012
www.ti.com
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
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): TPS5405
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED JUNE 2012
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
Copyright © 2012, Texas Instruments Incorporated
Submit Documentation Feedback
7
Product Folder Link(s): TPS5405
TPS5405
SLVSBF7A –MAY 2012–REVISED JUNE 2012
www.ti.com
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-kΩ resistor is required.
8
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): TPS5405
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED JUNE 2012
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.
Copyright © 2012, Texas Instruments Incorporated
Submit Documentation Feedback
9
Product Folder Link(s): TPS5405
TPS5405
SLVSBF7A –MAY 2012–REVISED JUNE 2012
www.ti.com
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
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): TPS5405
TPS5405
www.ti.com
SLVSBF7A –MAY 2012–REVISED JUNE 2012
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 ×
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-mΩ ESR
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.
Copyright © 2012, Texas Instruments Incorporated
Submit Documentation Feedback
11
Product Folder Link(s): TPS5405
TPS5405
SLVSBF7A –MAY 2012–REVISED 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
Submit Documentation Feedback
Copyright © 2012, Texas Instruments Incorporated
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
IMPORTANT NOTICE
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 JESD46C and to discontinue any product or service per JESD48B. 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 which meet ISO/TS16949 requirements, mainly for automotive use. Components which
have not been so designated are neither designed nor intended for automotive use; and TI will not be responsible for any failure of such
components to meet such requirements.
Products
Audio
Applications
www.ti.com/audio
amplifier.ti.com
dataconverter.ti.com
www.dlp.com
Automotive and Transportation www.ti.com/automotive
Communications and Telecom www.ti.com/communications
Amplifiers
Data Converters
DLP® Products
DSP
Computers and Peripherals
Consumer Electronics
Energy and Lighting
Industrial
www.ti.com/computers
www.ti.com/consumer-apps
www.ti.com/energy
dsp.ti.com
Clocks and Timers
Interface
www.ti.com/clocks
interface.ti.com
logic.ti.com
www.ti.com/industrial
www.ti.com/medical
www.ti.com/security
Medical
Logic
Security
Power Mgmt
Microcontrollers
RFID
power.ti.com
Space, Avionics and Defense www.ti.com/space-avionics-defense
microcontroller.ti.com
www.ti-rfid.com
Video and Imaging
www.ti.com/video
OMAP Mobile Processors www.ti.com/omap
Wireless Connectivity www.ti.com/wirelessconnectivity
TI E2E Community
e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2012, Texas Instruments Incorporated
相关型号:
TPS5405DR
6.5-V TO 28-V INPUT VOLTAGE, 5-V FIXED OUTPUT, 2-A OUTPUT CURRENT, NON-SYNCHRONOUS STEP-DOWN REGULATOR WITH INTEGRATED MOSFET
TI
©2020 ICPDF网 联系我们和版权申明