Hi,
I am attempting to use the TPS53353 in a design generated by webbench (design attached).
The components have been assembled on the PCB per recommended layouts. However the
TPS53353 appears to go into a shut down mode. When the input power (12V) is turned ON, there is no
powergood ( is being pulled low I suspect), En is at 4V, Should EN be above 4.2V to turn on?
Also I have a Resistor+LED to indicate power on and it is drawing above 10mA on power ON,
There is significant Capacitive load ( greater than 300 uF) on the output. Will this cause a
current spike and shut down the TPS53353 ?
Any pointers to debug this is appreciated, Thanks in advance for any support/help.
HK
============== Design parameters and design outputs of web bench ( no ckt diag sorry)
Electrical BOM
# Name Manufacturer Part Number QuantiPtyrice Properties Footprint
1. Cbias Kemet C0603C104K5RACTU
Series= X7R
1 $0.01 Cap= 100.0 nF
VDC= 50.0 V
IRMS= 0.0 A
0603 10mm2
2. Cbst Kemet C0603C222K5RAC
Series= X7R
1 $0.01 Cap= 2.2 nF
VDC= 50.0 V
IRMS= 0.0 A
0603 10mm2
3. Cbyp Kemet C0603C102J5GAC
Series= C0G/NP0
1 $0.01 Cap= 1.0 nF
VDC= 50.0 V
IRMS= 0.0 A
0603 10mm2
4. Cin TDK C4532X7R1C226M
Series= X7R
4 $0.41 Cap= 22.0 μF
ESR= 1.9 mOhm
VDC= 16.0 V
IRMS= 3.6 A
1812 39mm2
5. Cout TDK C4532X5R0J107M
Series= X5R
4 $0.74 Cap= 100.0 μF
ESR= 1.2 mOhm
VDC= 6.3 V
IRMS= 4.6 A
1812 39mm2
6. Covth1 AVX 08055C563KAT2A
Series= X7R
1 $0.02 Cap= 56.0 nF
ESR= 32.0 mOhm
VDC= 50.0 V
IRMS= 0.0 A
0805 13mm2
7. Creg TDK C3216X7R1H105K
Series= X7R
1 $0.04 Cap= 1.0 μF
ESR= 10.0 mOhm
VDC= 50.0 V
IRMS= 3.2 A
1206 19mm2
8. Cvdd MuRata GRM21BC81E475KA12L
Series= 379
1 $0.05 Cap= 4.7 μF
VDC= 25.0 V
IRMS= 0.0 A
0805 13mm2
9. L1 Wurth Elektronik eiSos 7443556082 1 $6.34 L= 820.0 nH
DCR= 500.0 μOhm
WE-HCB-18X8.9 410mm2
WEBENCH® Design
Copyright © 2012, Texas Instruments Incorporated 2 ti.com/webench
WEBENCH® Design Report TPS53353DQPR : TPS53353DQPR 8.0V-14.0V to 4.5V @ 20.0A
# Name Manufacturer Part Number QuantiPtyrice Properties Footprint
10. Rbst Vishay-Dale CRCW04023R00JNED
Series= CRCW..e3
1 $0.07 Res= 3.0 Ohm
Power= 63.0 mW
Tolerance= 5.0%
0402 8mm2
11. RenB Vishay-Dale CRCW0402100KFKED
Series= CRCW..e3
1 $0.01 Res= 100.0 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
12. RenT Vishay-Dale CRCW0402200KFKED
Series= CRCW..e3
1 $0.01 Res= 200.0 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
13. Renable Vishay-Dale CRCW04021K00FKED
Series= CRCW..e3
1 $0.01 Res= 1,000 Ohm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
14. Rfbb Vishay-Dale CRCW040210K0FKED
Series= CRCW..e3
1 $0.01 Res= 10.0 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
15. Rfbt Vishay-Dale CRCW040264K9FKED
Series= CRCW..e3
1 $0.01 Res= 64.9 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
16. Rpgood Vishay-Dale CRCW0402100KFKED
Series= CRCW..e3
1 $0.01 Res= 100.0 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
17. Rss Vishay-Dale CRCW0603200KFKEA
Series= CRCW..e3
1 $0.01 Res= 200.0 kOhm
Power= 100.0 mW
Tolerance= 1.0%
0603 10mm2
18. Rsync Vishay-Dale CRCW04024K53FKED
Series= CRCW..e3
1 $0.01 Res= 4.53 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
19. Rtrip Vishay-Dale CRCW0402107KFKED
Series= CRCW..e3
1 $0.01 Res= 107.0 kOhm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
20. Rvdd Vishay-Dale CRCW04022R05FKED
Series= CRCW..e3
1 $0.01 Res= 2.05 Ohm
Power= 63.0 mW
Tolerance= 1.0%
0402 8mm2
21. U1 Texas Instruments TPS53353DQPR 1 $3.95
R-PSON-N22 58mm2
Operating Values
# Name Value Category Description
1. Cin IRMS 2.53 A Current Input capacitor RMS ripple current
2. Cout IRMS 680.0 m A Current Output capacitor RMS ripple current
3. IC Irms 20.2 A Current Calculated current across IC
4. L Ipp Max 9.408 A Current Inductor Peak to Peak Current calculated Max
5. L Ipp Min 6.03 A Current Inductor Peak to Peak Current calculated Min
6. L1 Irms 20.2 A Current Inductor ripple current
7. BOM Count 27.0 General Total Design BOM count
8. FootPrint 937.0 mm2 General Total Foot Print Area of BOM components
9. Frequency 500.0 k Hz General Switching frequency
10. IC Tolerance 600.0 m V General IC Feedback Tolerance
11. Pout 90.0 W General Total output power
12. Total BOM $15.2 General Total BOM Cost
13. Cin Vdrop 14.1 V Op_Point Calculated voltage across input cap
14. Cout Vdrop 4.52 V Op_Point Calculated voltage across output capacitor
15. IC Vdrop 14.1 V Op_Point Calculated voltage across IC
16. Vout OP 4.5 V Op_Point Operational Output Voltage
17. Duty Cycle 32.7 % Op_point Duty cycle
18. Efficiency 95.978 % Op_point Steady state efficiency
19. IC Tj 79.0 degC Op_point IC junction temperature
20. IOUT_OP 20.0 A Op_point Iout operating point
21. VIN_OP 14.0 V Op_point Vin operating point
22. Vout p-p 11.7 m V Op_point Peak-to-peak output ripple voltage
23. Cin Pd 48.0 m W Power Input capacitor power dissipation
24. Cout Pd 2.0 m W Power Output capacitor power dissipation
25. IC Pd 3.1 W Power IC power dissipation
26. M1 Rdson Max 5.0 m Ohm Power High side FET Rdson max
27. M1 Rdson Min 5.0 m Ohm Power High side FET Rdson min
WEBENCH® Design
Copyright © 2012, Texas Instruments Incorporated 3 ti.com/webench
WEBENCH® Design Report TPS53353DQPR : TPS53353DQPR 8.0V-14.0V to 4.5V @ 20.0A
# Name Value Category Description
28. M2 Rdson Max 2.0 m Ohm Power Low side FET Rdson Max
29. M2 Rdson Min 2.0 m Ohm Power Low side FET Rdson Min
30. Total Pd 3.1 W Power Total Power Dissipation
Design Inputs
# Name Value Description
1. Iout 20.0 A Maximum Output Current
2. Iout1 20.0 Amps Output Current #1
3. VinMax 14.0 V Maximum input voltage
4. VinMin 8.0 V Minimum input voltage
5. Vout 4.5 V Output Voltage
6. Vout1 4.5 Volt Output Voltage #1
7. base_pn TPS53353 National Based Product Number
8. Ta 30.0 degC Ambient temperature
