TPS60210_17 Datasheet, PDF (14/26 Pages) Texas Instruments – SINGLE-CELL TO 3-V/3.3-V, 20-mA DUAL OUTPUT, HIGH-EFFICIENCY CHARGE PUMP WITH SNOOZE MODE

TPS60210, TPS60211, TPS60212, TPS60213
REGULATED 3.3 V, LOWĆRIPPLE CHARGE PUMP
WITH ULTRALOW OPERATING CURRENT
SLVS296 − JUNE 2000
APPLICATION INFORMATION
capacitor selection
The TPS6021x 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 the input and output of the charge pump. In general, the transfer capacitors (C1 and C2) will be the smallest.
A 1-µF value is recommended if full load current performance is needed. 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, 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 minimum required capacitance is 2.2 µF. Larger values will improve the load transient performance and
will reduce the maximum output ripple voltage. The larger the output capacitor, the better the output voltage
accuracy, and the more output current can be drawn from the converter when programmed into snooze mode.
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 1 lists recommended capacitor
values.
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