Datasheet

C − Capacitance − µF
Transient − mV/A
Without TurboTrans
With TurboTrans
40
30
20
4
5000
4000
3000
1000
900
300
200
500
400
700
600
800
2000
10
6
5
8
7
9
C − Capacitance − µF
Transient − mV/A
Without TurboTrans
With TurboTrans
40
30
20
4
5000
4000
3000
1000
900
300
200
500
400
700
600
800
2000
10
6
5
8
7
9
R
TT
+ 40
1 *
ǒ
C
O
ń1250
Ǔ
ǒ
C
O
ń250
Ǔ
* 1
kW
(4)
PTH04T230W , PTH04T231W
SLTS271C – SEPTEMBER 2006 – REVISED MARCH 2009 ............................................................................................................................................. www.ti.com
PTH04T230W Type C Capacitors
5-V Input 3.3-V Input
Figure 14. Capacitor Type C, 5000 < C( µ F) x ESR(m Ω ) ≤ Figure 15. Capacitor Type C, 5000 < C( µ F) x ESR(m Ω ) ≤
10,000 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
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 ( µ F) Resistor (k Ω ) Capacitance ( µ F) Resistor (k Ω )
50 100 150 270 487 250 open
40 80 120 360 66.5 350 76.8
35 70 105 430 36.5 420 39.2
30 60 90 520 21.5 520 21.5
25 50 75 660 11.5 670 11.0
20 40 60 890 4.53 920 3.83
15 30 45 1420 short 1630 short
12 20 30 3050 short 3700 short
R
TT
Resistor Selection
The TurboTrans resistor value, R
TT
can be determined from the TurboTrans programming equation:
Where C
O
is the total output capacitance in µ F. C
O
values greater than or equal to 1250 µ F 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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