Datasheet

C − Capacitance − µF
Transient − mV/A
20
10
9
8
7
30
40
Without TurboTrans
With TurboTrans
1000
500 400 300 200 600 700 100
5000
4000
3000
2000
10000
6000
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
R
TT
=40x
1-(C /1000)
O
5 x(C /1000)-1
O
(k )W
[]
PTH08T260W, PTH08T261W
www.ti.com SLTS272G –DECEMBER 2006– REVISED AUGUST 2011
PTH08T260W Type C Capacitors
12-V INPUT 5-V INPUT
Figure 14. Capacitor Type C, 5000 < C(μF) x Figure 15. 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)
30 55 85 200 open 200 open
25 50 75 200 open 220 309
20 40 60 240 150 270 82.5
18 35 55 290 63.4 330 41.2
15 30 45 440 18.7 520 12.1
13 25 40 580 8.87 690 5.11
10 20 30 820 2.32 980 0.205
8 15 25 2300 short 6800 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.
Copyright © 2006–2011, Texas Instruments Incorporated Submit Documentation Feedback 21
Product Folder Link(s): PTH08T260W PTH08T261W