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Vout(50mV/div)

Iout(2A/div)

100us/div

TPS54428DDA

TPS54428

www.ti.com

SLVSB42B –NOVEMBER 2011–REVISED MARCH 2013

4.5V to 18 V Input, 4-A Synchronous Step-Down Converter with Eco-mode™

Check for Samples: TPS54428

FEATURES

DESCRIPTION

The TPS54428 is an adaptive on-time D-CAP2™

• D-CAP2™ Mode Enables Fast Transient

mode synchronous buck converter.

Response

The TPS54428 enables system designers to

• Low Output Ripple and Allows Ceramic Output

complete the suite of various end-equipment power

Capacitor

bus regulators with a cost effective, low component

• Wide V

Input Voltage Range: 4.5 V to 18 V

count, low standby current solution.

• Output Voltage Range: 0.76 V to 7.0 V

The main control loop for the TPS54428 uses the D-

• Highly Efficient Integrated FETs Optimized

CAP2™ mode control that provides a fast transient

for Lower Duty Cycle Applications

response with no external compensation

– 70 mΩ (High Side) and 53 mΩ (Low Side)

components.

• High Efficiency, Less Than 10 μA at Shutdown

The adaptive on-time control supports seamless

• High Initial Bandgap Reference Accuracy

transition between PWM mode at higher load

conditions and Eco-mode™ operation at light loads.

• Adjustable Soft Start

• Pre-Biased Soft Start

Eco-mode™ allows the TPS54428 to maintain high

efficiency during lighter load conditions.

• 650-kHz Switching Frequency (f

)

• Cycle By Cycle Over Current Limit

The TPS54428 also has a proprietary circuit that

enables the device to adopt to both low equivalent

• Auto-Skip Eco-mode™ for High Efficiency at

series resistance (ESR) output capacitors, such as

Light Load

POSCAP or SP-CAP, and ultra-low ESR ceramic

capacitors. The device operates from 4.5-V to 18 V

APPLICATIONS

VIN input.

• Wide Range of Applications for Low Voltage

The output voltage can be programmed between

System

0.76 V and 7.0 V.

– Digital TV Power Supply

The device also features an adjustable soft start time.

– High Definition Blu-ray Disc™ Players

The TPS54428 is available in 8-pin DDA package

– Networking Home Terminal

and 10-pin DRC packages, and is designed to

– Digital Set Top Box (STB)

operate over the ambient temperature range of –40°C

to 85°C.

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.

2D-CAP2 is a trademark of Texas Instruments.

3Blu-ray Disc is a trademark of Blu-ray Disc Association.

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.

Summary of content (26 pages)

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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 4.5V to 18 V Input, 4-A Synchronous Step-Down Converter with Eco-mode™ Check for Samples: TPS54428 FEATURES DESCRIPTION • The TPS54428 is an adaptive on-time D-CAP2™ mode synchronous buck converter. 1 23 • • • • • • • • • • • D-CAP2™ Mode Enables Fast Transient Response Low Output Ripple and Allows Ceramic Output Capacitor Wide VIN Input Voltage Range: 4.5 V to 18 V Output Voltage Range: 0.76 V to 7.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 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.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 RECOMMENDED OPERATING CONDITIONS over operating free-air temperature range (unless otherwise noted) VIN Supply input voltage range VBST VI Input voltage range MIN MAX 4.5 18 –0.1 24 VBST (10 ns transient) -0.1 27 VBST(vs SW) –0.1 5.7 SS –0.1 5.7 EN –0.1 18 VFB –0.1 5.5 SW –1.8 18 SW (10 ns transient) UNIT V V –3 21 GND –0.1 0.1 –0.1 5.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com ELECTRICAL CHARACTERISTICS (continued) over operating free-air temperature range, VIN = 12 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT THERMAL SHUTDOWN TSDN Shutdown temperature (2) Thermal shutdown threshold 170 Hysteresis (2) °C 35 ON-TIME TIMER CONTROL tON On time VIN = 12 V, VO = 1.05 V 150 tOFF(MIN) Minimum off time TA = 25°C, VFB = 0.7 V 260 310 ns 7.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 PIN FUNCTIONS PIN NAME DESCRIPTION DDA DRC EN 1 1 Enable input control. Active high. VFB 2 2 Converter feedback input. Connect to output voltage with feedback resistor divider. VREG5 3 3 5.5 V power supply output. A capacitor (typical 1 µF) should be connected to GND. VREG5 is not active when EN is low. SS 4 4 Soft-start control. An external capacitor should be connected to GND. GND 5 Ground pin.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com OVERVIEW The TPS54428 is a 4-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs. It operates using D-CAP2™ mode control. The fast transient response of D-CAP2™ control reduces the output capacitance required to meet a specific level of performance. Proprietary internal circuitry allows the use of low ESR output capacitors including ceramic and special polymer types.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 Current Protection The output over-current protection (OCP) is implemented using a cycle-by-cycle valley detect control circuit. The switch current is monitored by measuring the low-side FET switch voltage between the SW pin and GND. This voltage is proportional to the switch current. To improve accuracy, the voltage sensing is temperature compensated.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com TYPICAL CHARACTERISTICS (continued) VIN = 12 V, TA = 25°C (unless otherwise noted) 50 1.1 VI = 18 V 45 40 VO - Output Voltage - V EN Input Current - mA 1.075 35 30 25 20 15 VI = 18 V 1.05 VI = 12 V VI = 5 V 1.025 10 5 1 0 5 0 10 EN Input Voltage - V 15 20 0 1 2 3 4 IO - Output Current - A Figure 3. EN CURRENT vs EN VOLTAGE Figure 4. 1.05V OUTPUT VOLTAGE vs OUTPUT CURRENT 1.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 TYPICAL CHARACTERISTICS (continued) VIN = 12 V, TA = 25°C (unless otherwise noted) 100 900 850 90 VO = 3.3 V fsw - Switching Frequency - kHz 80 VO = 2.5 V Efficiency - % 70 VO = 1.8 V 60 50 40 30 20 10 800 VO = 5 V VO = 3.3 V VO = 2.5 V V = 1.8 V O 750 700 650 VO = 1.5 V 600 VO = 1.2 V VO = 1.05 V 550 500 450 0 0.001 0.01 IO - Output Current - A 400 0.1 5 0 Figure 9.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com DESIGN GUIDE Step By Step Design Procedure To • • • • • begin the design process, you must know a few application parameters: Input voltage range Output voltage Output current Output voltage ripple Input voltage ripple 4.5 to 18 V Δ 1 TPS54428DDA 1.05 V 4 A 8200 pF Figure 15. Schematic Diagram for This Design Example.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 Table 1. Recommended Component Values C4 (pF) (1) Output Voltage (V) R1 (kΩ) R2 (kΩ) L1 (µH) C8 + C9 (µF) 1 6.81 22.1 1.5 22 - 68 1.05 8.25 22.1 1.5 22 - 68 1.2 12.7 22.1 1.5 22 - 68 1.5 21.5 22.1 1.5 22 - 68 1.8 30.1 22.1 5 - 22 2.2 22 - 68 2.5 49.9 22.1 5 - 22 2.2 22 - 68 3.3 73.2 22.1 5 - 22 2.2 22 - 68 5 124 22.1 5 - 22 3.3 22 - 68 6.5 165 22.1 5 - 22 3.
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TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com VREG5 Capacitor Selection A 1-µF ceramic capacitor must be connected between the VREG5 to GND pin for proper operation. It is recommended to use a ceramic capacitor THERMAL INFORMATION This 8-pin DDA package incorporates an exposed thermal pad that is designed to be directly to an external heatsink. The thermal pad must be soldered directly to the printed board (PCB). After soldering, the PCB can be used as a heatsink.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 LAYOUT CONSIDERATIONS 1. Keep the input switching current loop as small as possible. 2. Keep the SW node as physically small and short as possible to minimize parasitic capacitance and inductance and to minimize radiated emissions. Kelvin connections should be brought from the output to the feedback pin of the device. 3. Keep analog and non-switching components away from switching components. 4.
PAGE 14
TPS54428 SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 www.ti.com VIN FEEDBACK RESISTORS TO ENABLE CONTROL EN VIN HIGH FREQENCY BYPASS VIN CAPACITOR VFB VIN VREG5 BIAS CAP SLOW START CAP ANALOG GROUND TRACE VIN INPUT BYPASS CAPACITOR VBST SS SW GND SW BOOST CAPACITOR OUTPUT INDUCTOR OUTPUT FILTER CAPACITOR EXPOSED THERMAL PAD AREA Connection to POWER GROUND on internal or bottom layer VOUT POWER GROUND VIA to Ground Plane Figure 18.
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TPS54428 www.ti.com SLVSB42B – NOVEMBER 2011 – REVISED MARCH 2013 REVISION HISTORY Changes from Original (November 2011) to Revision A • Page Deleted TA = –20ºC to 85ºC from ELEC CHARA table, CURRENT LIMIT section, Test Conditions statement .................. 3 Changes from Revision A (January 2012) to Revision B Page • Changed the Description text to include the DRC package .................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 2-May-2014 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.
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PACKAGE MATERIALS INFORMATION www.ti.com 30-Apr-2014 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TPS54428DDAR SO Power PAD DDA 8 2500 330.0 12.8 6.4 5.2 2.1 8.0 12.0 Q1 TPS54428DRCR SON DRC 10 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS54428DRCT SON DRC 10 250 180.0 12.4 3.3 3.3 1.1 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 30-Apr-2014 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS54428DDAR SO PowerPAD DDA 8 2500 366.0 364.0 50.0 TPS54428DRCR SON DRC 10 3000 367.0 367.0 35.0 TPS54428DRCT SON DRC 10 250 210.0 185.0 35.
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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 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.