Datasheet

C-Capacitance- Fm
Transient-mV/A
400
500
600
700
800
900
1000 2000 3000 4000
5000
6000
7000
8000
9000
10000
20
10
9
8
7
6
5
4
3
2
WithTurboTrans
V =12V
I
WithoutTurboTrans
C-Capacitance- Fm
Transient-mV/A
400
500
600
700
800
900
1000 2000 3000 4000
5000
6000
7000
8000
9000
10000
20
10
9
8
7
6
5
4
3
2
WithTurboTrans
V =8V
I
WithoutTurboTrans
R
TT
Resistor Selection
PTH08T210W
SLTS262I – OCTOBER 2005 – REVISED MARCH 2009 ................................................................................................................................................... www.ti.com
Type C Capacitor Type C Capacitor
12 V Input 8 V Input
Figure 15. Cap Type C, 5000 ≤ C( µ F)xESR(m Ω ) ≤ 10,000 Figure 16. Cap Type C, 5000 ≤ C( µ F)xESR(m Ω ) ≤ 10,000
(e.g. Os-Con) (e.g. Os-Con)
Table 4. Type C TurboTrans C
O
Values & Required R
TT
Selection Table
Transient Voltage Deviation (mV) 12 V Input 8 V Input
25% 50% 75% C
O
R
TT
C
O
R
TT
Load Step Load Step Load Step Minimum Required Required TurboTrans Minimum Required Required TurboTrans
(7.5 A) (15 A) (22.5 A) Output Capacitance Resistor ( Ω ) Output Capacitance Resistor ( Ω )
( µ F) ( µ F)
80 160 240 470 open 520 294 k
70 140 210 560 158 k 620 93.1 k
60 120 180 680 63.4 k 750 45.3 k
50 100 150 850 31.6 k 940 24.3 k
40 80 120 1100 15.8 k 1300 10.2 k
35 70 105 1300 10.2 k 1500 6.65 k
30 60 90 1600 5.36 k 1800 3.32 k
25 50 75 2000 1.82 k 2200 698
20 40 60 4000 0 5400 0
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming equation, see
Equation 1 .
C
O
values greater than or equal to 2350 µ F require R
TT
to be a short, 0 Ω . (Equation 1 will result in a negative
value for R
TT
when C
O
≥ 2350 µ F.)
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