Datasheet

C − Capacitance − µF
Transient − mV/A
1000
500 400 300 200 600 700 100
5000
4000
3000
2000
10000
6000
20
10
9
8
7
30
40
50
60
Without TurboTrans
With TurboTrans
C − Capacitance − µF
Transient − mV/A
1000
500 400 300 200
600 700 100
5000
4000
3000
2000
10000
6000
20
10
9
8
7
30
40
50
60
Without TurboTrans
With TurboTrans
R
TT
=40x
1-(C /1000)
O
5 x(C /1000)-1
O
(k )W
[]
PTH08T230W, PTH08T231W
www.ti.com SLTS265L –NOVEMBER 2005– REVISED AUGUST 2011
PTH08T230W Type C Capacitors
12-V INPUT 5-V INPUT
Figure 16. Capacitor Type C, 5000 < C(μF) x Figure 17. Capacitor Type C, 5000 < C(μF) x
ESR(mΩ) ≤ 10,000 ESR(mΩ) ≤ 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
C
O
R
TT
C
O
R
TT
25% load step 50% load step 75% load step Minimum Required Minimum Required
(1.5 A) (3 A) (4.5 A) Required Output TurboTrans Required Output TurboTrans
Capacitance (μF) Resistor (kΩ) Capacitance (μF) Resistor (kΩ)
75 150 225 200 open 200 open
60 120 180 230 205 250 121
50 100 150 300 56.2 310 49.9
40 80 120 390 25.5 400 24.3
30 60 90 570 9.31 580 8.87
25 50 75 720 4.32 730 4.12
20 40 60 960 0.422 980 0.205
15 30 45 3100 short 4000 short
R
TT
Resistor Selection
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming equation:
(4)
Where C
O
is the total output capacitance in μF. C
O
values greater than or equal to 1000 μF 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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