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Summary of Contents for Texas Instruments TPS40003
- Page 1 User’s Guide TPS40003 Based 5–A Converter in Less Than One Square Inch User’s Guide...
- Page 2 Texas Instruments (TI) provides the enclosed product(s) under the following conditions: This evaluation kit being sold by TI is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not considered by TI to be fit for commercial use. As such, the goods being provided may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including product safety measures typically found in the end product incorporating the goods.
- Page 3 EVM User’s Guide. When placing measurement probes near these devices during operation, please be aware that these devices may be very warm to the touch. Copyright Mailing Address: Texas Instruments Post Office Box 655303 Dallas, Texas 75265 2003, Texas Instruments Incorporated...
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Page 4: Table Of Contents
This user’s guide provides details on a 5-A buck converter that converts 3.3 V down to a 1.2-V level utilizing the TPS40003 controller, with less than one square inch board area. A schematic for the board is shown in Figure 1. A list of material is provided in the final section. -
Page 5: Schematic
SLUU130A – September 2002 – Revised February 2003 Schematic Figure 1. Application Diagram for the TPS40002/3 TPS40003-Based 5-A Converter in Less Than One Square Inch... -
Page 6: Design Procedure
TPS4000X family involves the selection of Discontinuous Current Mode (DCM) operation or Continuous Current Mode (CCM) operation at lighter loads. In this design the TPS40003 is selected to keep the current continuous all the way to zero load, to provide robust control characteristics. - Page 7 Short Circuit Protection The TPS40003 implements short circuit protection by comparing the voltage across the topside MOSFET while it is on to a voltage dropped from VDD by R tolerances in the current source and variations in the power MOSFET on-voltage versus temperature, the short circuit level can protect against gross overcurrent conditions only, and should be set higher than rated load.
- Page 8 SLUU130A – September 2002 – Revised February 2003 Compensation Design The TPS40003 uses voltage mode control in conjunction with a high frequency error amplifier. For the fastest transient response, the loop crossover frequency is set at 1/10 f corner frequency f is situated at 24 kHz, and the output capacitor ESR zero is far higher at approximately 1MHz.
- Page 9 Q1:B. Since C is 440 pF for Q1:B, C9 is chosen to be 3.3 nF. f , is relatively small at 24 mW. TPS40003-Based 5-A Converter in Less Than One Square Inch = 4.4 A. At the crossover –50 –100...
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Page 10: Powerpad Packaging
A typical construction utilizes a few vias of 0.013” diameter plated with 1 ounce copper in the land under the TPS40003. A typical layout pattern is shown in Figure 2, but does not show the copper land which would encompass the vias above and below the device. -
Page 11: Test Results/Performance Data
SLUU130A – September 2002 – Revised February 2003 DC Power Supply Input wires 18 gauge or larger short as feasible (–) SLUP182 VOUT LOAD (–) Figure 4. TPS40003-Based 5-A Converter in Less Than One Square Inch DVM1 SCOPE DVM2 (–) -
Page 12: Output Current
MOSFET drive circuit to account for variations in line, load, and between devices. 2 V/div TPS40003-Based 5-A Converter in Less Than One Square Inch EFFICIENCY OUTPUT CURRENT I OUT – Output Current – A Figure 5. -
Page 13: Short Circuit Operation
10 mV/div SLUU130A – September 2002 – Revised February 2003 SHORT CIRCUIT OPERATION t – Time – 1 ms/div Figure 7. OUTPUT VOLTAGE RIPPLE t – Time – 500 ns/div Figure 8. TPS40003-Based 5-A Converter in Less Than One Square Inch... -
Page 14: Transient Response
500 mV/div Figure 10 shows the transient response for a fast load step from 1 A to 2 A. 50 mV/div TPS40003-Based 5-A Converter in Less Than One Square Inch STARTUP WAVEFORM t – Time – 200 s/div Figure 9. -
Page 15: Pcb Layout
SLUU130A – September 2002 – Revised February 2003 PCB Layout Figures 11 through13 show the top copper layer, the bottom copper layer, and top assembly layer, of SLUP182. Figure 12 Figure 13 TPS40003-Based 5-A Converter in Less Than One Square Inch... -
Page 16: List Of Material
TP1, TP3, TP4, JACK TP2, TP6 Adaptor Device TPS40003-Based 5-A Converter in Less Than One Square Inch Description Ceramic, 22 F, 6.3 V, X5R, 20%, 1210 Ceramic, 0.001 F, 10 V, X5R, 10%, 805 Ceramic, 0.0047 F, 50 V, X7R, 10% Ceramic, 470 pF, 50 V, X7R, 10% Ceramic, 0.1 F, 50 V, X5R, 10%... -
Page 17: Important Notice
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.
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