Datasheet

PTH04T240W Type C Capacitors
9
8
20
10
30
7
6
5
4
3
6000
5000
4000
3000
2000
1000
500
300
200
10000
400
700
600
800
900
7000
8000
9000
C − Capacitance − µF
Transient − mV/A
Without TurboTrans
With TurboTrans
C − Capacitance − µF
Transient − mV/A
9
8
20
10
30
7
6
5
4
3
6000
5000
4000
3000
2000
1000
500
300
200
10000
400
700
600
800
900
7000
8000
9000
Without TurboTrans
With TurboTrans
R
TT
+
40
ƪ
1 *
ǒ
C
O
ń1100
Ǔƫ
ƪ
ǒǒ
C
O
Ǔ
ń220
Ǔ
* 1
ƫ
(
kW
)
(4)
PTH04T240W , PTH04T241W
www.ti.com ...................................................................................................................................................... SLTS276D – OCTOBER 2006 – REVISED JULY 2009
5-V Input 3.3-V Input
Figure 14. Capacitor Type C, Figure 15. Capacitor Type C,
5000 < C( µ F) × ESR(m Ω ) ≤ 10,000 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) 5-V Input 3.3-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 220 open
60 120 180 270 137 290 95.3
50 100 150 350 49.9 360 42.2
40 80 120 460 21.5 480 19.1
30 60 90 680 7.32 680 7.32
25 50 75 860 3.09 860 3.09
20 40 60 1150 short 1200 short
15 30 45 2750 short 3000 short
10 20 30 9300 short above maximum N/A
R
TT
Resistor Selection
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming, see Equation 4 .
Where C
O
is the total output capacitance in µ F. C
O
values greater than or equal to 1100 µ F require R
TT
to be a
short, 0 Ω . (R
TT
results in a negative value when C
O
> 1100 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.
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