Datasheet

PTH08T240F Type C Capacitors
6000 5000 4000 3000 2000 1000
10
7
6
5
4
3
2
1
10000
8000 9000 7000
9
8
Transient (mV/A)
C - Capacitance - mF
6000 5000 4000 3000 2000 1000
10
7
6
5
4
3
2
1
10000
8000 9000 7000
9
8
Transient (mV/A)
C - Capacitance - mF
( )
( )
( )
O
TT
O
40 1 C 5000
R k
C 1000 1
é ù
´ -
ë û
= W
é ù
-
ë û
(4)
PTH08T240F
www.ti.com ............................................................................................................................................... SLTS277D – DECEMBER 2006 – REVISED MARCH 2009
8-V Input 5-V Input
Figure 18. Capacitor Type C, Figure 19. 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) 8-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 )
20 40 60 1000 open 1040 787
18 36 54 1000 open 1180 169
16 32 48 1100 340 1350 82.5
14 28 42 1300 97.6 1600 45.3
12 24 36 1600 45.3 1930 26.7
10 20 30 2050 22.6 2420 14.7
8 16 24 2750 10.5 3200 6.49
6 12 18 4050 2.49 4560 1.0
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 5000 µ F require R
TT
to be a
short, 0 Ω . (R
TT
results in a negative value when C
O
> 5000 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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