Datasheet
PTH08T241W - Type A Ceramic Capacitors
20
10
9
8
7
6
5
4
3
30
4000
3000
2000
1000
500
400
300
200
5000
900
600
700
800
C − Capacitance − µF
Transient − mV/A
WIth TurboTrans
Without TurboTrans
PTH08T241W
Type A Ceramic Capacitors
20
10
9
8
7
6
5
4
3
30
4000
3000
2000
1000
500
400
300
200
5000
900
600
700
800
C − Capacitance − µF
Transient − mV/A
WIth TurboTrans
Without TurboTrans
PTH08T241W
Type A Ceramic Capacitors
R
TT
+ 40
ƪ
1 *
ǒ
C
O
ń1500
Ǔƫ
ƪ
ǒ
5 C
O
ń1500
Ǔ
* 1
ƫ
(
kW
)
(2)
PTH08T240W , PTH08T241W
SLTS264J – NOVEMBER 2005 – REVISED JUNE 2009 ...................................................................................................................................................
www.ti.com
12-V Input 5-V Input
Figure 12. Capacitor Type A, 100 ≤ C( µ F) × ESR(m Ω ) ≤ Figure 13. Capacitor Type A, 100 ≤ C( µ F)xESR(m Ω ) ≤
1000 (e.g. Ceramic) 1000 (e.g. Ceramic)
Table 4. Type A TurboTrans C
O
Values and Required R
TT
Selection Table
Transient Voltage Deviation (mV) 12-V Input 5-V Input
25% load step 50% load step 75% load step C
O
R
TT
C
O
R
TT
(2.5 A) (5 A) (7.5 A) Minimum Required Minimum Required
Required Output TurboTrans Required Output TurboTrans
Capacitance ( µ F) Resistor (k Ω ) Capacitance ( µ F) Resistor (k Ω )
50 100 150 300 open 300 open
45 90 135 310 1180 370 140
40 80 120 380 118 470 49.9
35 70 105 470 47.5 610 23.2
30 60 90 610 22.6 830 10.0
25 50 75 830 10.0 1200 2.61
20 40 60 1220 2.49 3050 short
R
TT
Resistor Selection
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming, see Equation 2
Where C
O
is the total output capacitance in µ F. C
O
values greater than or equal to 1500 µ F require R
TT
to be a
short, 0 Ω .
To ensure stability, a minimum amount of output capacitance is required for a given R
TT
resistor value. The value
of R
TT
must be calculated using the minimum required output capacitance determined from the capacitor
transient response charts above.
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