Datasheet
C − Capacitance − µF
Transient − mV/A
40
30
20
4
5000
4000
3000
1000
900
300
200
500
400
700
600
800
2000
10
6
5
8
7
9
PTH04T261 Type A
Ceramic Capacitors
Without TurboTrans
With TurboTrans
C − Capacitance − µF
Transient − mV/A
40
30
20
4
5000
4000
3000
1000
900
300
200
500
400
700
600
800
2000
10
6
5
8
7
9
PTH04T261 Type A
Ceramic Capacitors
Without TurboTrans
With TurboTrans
R
TT
+ 40
1 *
ǒ
C
O
ń1500
Ǔ
ǒ
C
O
ń300
Ǔ
* 1
kW
(2)
PTH04T260W , PTH04T261W
SLTS273E – SEPTEMBER 2006 – REVISED JULY 2009 ..................................................................................................................................................
www.ti.com
PTH04T261W - Type A Ceramic Capacitors
5-V Input 3.3-V Input
Figure 10. Capacitor Type A, 100 < C( µ F) x ESR(m Ω ) ≤ Figure 11. Capacitor Type A, 100 < C( µ F) x ESR(m Ω ) ≤
1000 1000
(e.g. Ceramic) (e.g. Ceramic)
Table 4. Type A 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
(0.75 A) (1.5 A) (2.25 A) Required Output TurboTrans Required Output TurboTrans
Capacitance ( µ F) Resistor (k Ω ) Capacitance ( µ F) Resistor (k Ω )
25 50 75 300 open 300 open
20 40 60 300 open 300 open
15 30 45 400 93.1 340 226
10 20 30 700 15.8 610 23.2
8 16 24 960 6.49 840 9.76
6 12 18 1500 short 1300 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 1500 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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