PT8100 Datasheet, PDF (9/14 Pages) Texas Instruments – 40-A 3.3/5-V Input Programmable Integrated Switching Regulator

Application Notes
PT8100
Capacitor Recommendations for the Non-Isolated
40-A Excalibur™ Series of Regulators
Input Capacitors
The recommended input capacitance is determined by the
1.0 ampere minimum ripple current rating and 1500µF
minimum capacitance. Capacitors listed below must be
rated for a minimum of 2× the input voltage with +5V
operation. Ripple current and ≤100mΩ equivalent series
resistance (ESR) values are the major considerations along
with temperature when selecting the proper capacitor.
Output Capacitors
The minimum required output capacitance is either 660µF
Oscon/Tantalum or 1200µF Alunimun Electrolytic with
a maximum ESR less than or equal to 100mΩ. Failure
to observe this requirement may lead to regulator insta-
bility or oscillation. Electrolytic capacitors have poor
ripple performance at frequencies greater than 400kHz,
but excellent low frequency transient response. Above
the ripple frequency ceramic decoupling capacitors are
necessary to improve the transient response and reduce
any high frequency noise components apparent during
higher current excursions. Preferred low ESR type
capacitor part numbers are identified in Table 1 below.
Tantalum Characteristics
Tantalum capacitors with a minimum 10V rating are
recommended on the output bus, but only the AVX TPS,
Sprague 594/595, or Kemet T495/T510 product series.
The AVX TPS, Sprague, or Kemet series capacitors are
specified over other types due to their higher surge current,
excellent power dissipation, and ripple current ratings.
As a caution, the TAJ Series by AVX is not recommended.
This series exhibits considerably higher ESR, reduced
power dissipation and lower ripple current capability.
The TAJ series is also less reliable compared to the TPS
series when determining power dissipation capability.
Capacitor Table
Table 1 identifies the characteristics of capacitors from a
number of vendors with acceptable ESR and ripple current
(rms) ratings. The suggested minimum quantities per regu-
lator for both the input and output buses are identified.
This is not an extensive capacitor list. The table below is a
suggested selection guide for input and output capacitors. Other
capacitor vendors are available with comparable RMS ripple
current rating and ESR (Equivalent Series Resistance at 100kHz).
These critical parameters are necessary to insure both opti-
mum regulator performance and long capacitor life.
Table 1 Capacitors Characteristic Data
Capacitor Vendor
Series
Capacitor Characteristics
Quantity
Working
Voltage
Panasonic
FC/FK (Surface Mount)
FC (Radial)
United Chemi-Con
LXZ (Radial)
FX
Nichicon
PL Series
UD Series
Os-con:
SS
SVP (Surface Mount)
SVP (Surface Mount)
AVX Tanatalum
TPS Series
(Surface (Mount)
Vishay/Sprague Tantalum
595D/594D Series
(Surface Mount)
Kemet Tantalum
T510/T495 /T520
(Surface Mount)
Sanyo Poscap
TPB (Surface Mount)
16V
16V
16V
16V
25V
6.3V
10V
10V
10V
10V
10V
10V
10V
10V
10V
10V
10V
10V
10V
10V
Value(µF) (ESR) Equivalent
Series Resistance
1500
2200
1500
1500
1800
1000
680
1500
1800
1000
0.060Ω
0.038Ω
0.043Ω
0.038Ω
0.029Ω
0.013Ω
0.015Ω÷2 =0.007Ω
0.050Ω
0.044Ω
0.09Ω
330 0.025Ω÷3 =0.008Ω
330 0.017Ω÷3 =0.006Ω
560 0.013Ω÷2 =0.065Ω
330 0.100Ω÷3 =0.034Ω
330 0.060Ω÷3 =0.020Ω
330 0.045Ω÷3 =0.015Ω
680 0.090Ω÷4 =0.023Ω
330 0.035Ω÷3 =0.012Ω
220 0.070Ω÷5 =0.035Ω
220 0.040Ω÷5 =0.008Ω
85°C Maximum
Ripple
Current(Irms)
1100mA
2000mA
1690mA
1660mA
2200mA
4935mA
>7000mA
1190mA
1420mA
670mAx2
>7000mA
>7000mA
>7000mA
>3500mA
>3500mA
>4600mA
>2500mA
>5000mA
>3000mA
>3000mA
Physical
Size(mm)
12.5×13.5
18x16.5
16x15
12.5x20
16x20
10×10.5
10×10.5
16x15
16x15
10×10
10×10.5
10.3×12.6
10×12.7
7.0 L
×5.97 W
×3.45 H
7.2 L
×6.0 W
×3.5 H
7.3 L
×4.3 W
×4.0 H
7.2 L
×4.3 W
×3.1 H
Input
Bus
Output
Bus
Vendor Number
1
1 EEVFK1C152Q
1
1 EEVFC1C222N
1
1 EEUFC1C152S
1
1 LXZ16VB155M12X20LL
1
1 LXZ25VB182M16X20LL
1
1 6FX1000M (Vin =3.3V)
2
1 10FX680M (Os-con)
1
1 UPM1A152MHH6
1
1 UPM1A182MHH6
2
2 UUD1A102MCR1GS
3
2 10SS330M
3
2 10SVP330M
2
2 10SVP560M
3
2 TPSV337M010R0100
3
2 TPSV337M010R0060
3
2 594D337X0010R2T
2
1 595D687X0010R2T
3
1 T510X337M010AS
5
2 T495X227M010AS
5
2 10TPB220M
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