Datasheet

TPS60200, TPS60201, TPS60202, TPS60203
REGULATED 3.3 V, 100-mA LOW-RIPPLE CHARGE PUMP
LOW POWER DC/DC CONVERTERS
SLVS274 – MARCH 2000
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
TPS60200
PEAK OUTPUT CURRENT
vs
INPUT VOLTAGE
150
100
50
0
1.6 2.0 2.4 2.8
200
250
350
3.2 3.6
300
V
I
– Input Voltage – V
I – Output Current – mA
Figure 17
O
APPLICATION INFORMATION
capacitor selection
The TPS6020x devices require only four external capacitors to achieve a very low output voltage ripple. The
capacitor values are closely linked to the required output current. Low ESR (<0.1 Ω) capacitors should be used
at input and output. In general, the transfer capacitors (C1 and C2) will be the smallest, a 1-µF value is
recommended for maximum load operation. With smaller capacitor values, the maximum possible load current
is reduced and the LinSkip threshold is lowered.
The input capacitor improves system efficiency by reducing the input impedance. It also stabilizes the input
current of the power source. The input capacitor should be chosen according to the power supply used and the
distance from the power source to the converter IC. C
i
is recommended to be about two to four times as large
as the flying capacitors C1 and C2.
The output capacitor (C
o
) should be at minimum the size of the input capacitor. The minimum required
capacitance is 2.2 µF. Larger values will improve the load transient performance and will reduce the maximum
output ripple voltage.
Only ceramic capacitors are recommended for input, output, and flying capacitors. Depending on the material
used to manufacture them, ceramic capacitors might lose their capacitance over temperature and voltage.
Ceramic capacitors of type X7R or X5R material will keep their capacitance over temperature and voltage,
whereas Z5U- or Y5V-type capacitors will decrease in capacitance. Table 2 lists recommended capacitor
values.