Datasheet

PTH08T240W Type C Capacitors
C − Capacitance − µF
Transient − mV/A
6000
5000
4000
3000
2000
1000
500
300
200
30
20
10
9
8
7
6
5
4
3
2
10000
WIth TurboTrans
Without TurboTrans
6000
5000
4000
3000
2000
1000
500
300
200
30
20
10
9
8
7
6
5
4
3
2
10000
WIth TurboTrans
Without TurboTrans
C − Capacitance − µF
Transient − mV/A
R
TT
+
40
ƪ
1 *
ǒ
C
O
ń1980
Ǔƫ
ƪ
ǒ
ǒ
ǒ
5 C
O
Ǔ
) 880
Ǔ
ń1980
Ǔ
* 1
ƫ
(
kW
)
(4)
PTH08T240W , PTH08T241W
SLTS264J – NOVEMBER 2005 – REVISED JUNE 2009 ................................................................................................................................................... www.ti.com
12-V Input 5-V Input
Figure 16. Cap Type C, 5000 < C( µ F) × ESR(m Ω ) ≤ 10,000 Figure 17. Cap Type C, 5000 < C( µ F) × ESR(m Ω ) ≤ 10,000
(e.g. OS-CON) (e.g. OS-CON)
Table 6. Type C 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 )
75 150 225 220 open 250 1300
60 120 180 270 294 330 133
45 90 135 400 68.1 480 45.3
35 70 105 580 31.6 700 21.5
30 60 90 720 20.0 860 13.7
25 50 75 950 11.8 1150 7.68
20 40 60 1300 5.23 1550 2.61
15 30 45 2000 short 2800 short
10 20 30 7400 short exceeds limit —
R
TT
Resistor Selection
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming, see Equation 4 . For
V
O
> 3.45V please contact TI for C
O
and R
TT
values.
Where C
O
is the total output capacitance in µ F. C
O
values greater than or equal to 1980 µ F require R
TT
to be a
short, 0 Ω . (R
TT
results in a negative value when C
O
> 1980 µ F).
To ensure stability, the value of R
TT
must be calculated using the minimum required output capacitance
determined from the capacitor transient response charts above.
20 Submit Documentation Feedback Copyright © 2005 – 2009, Texas Instruments Incorporated
Product Folder Link(s): PTH08T240W PTH08T241W