Datasheet

OUT OUT
FB
V V
R1 = R2 1 = R2 1
V 0.8V
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FB
FB
V
0.8 V
R2 = = 160 kΩ
I 5 μA
»
OUT FB
R1 R1
V = V 1 + = 0.8 V 1 +
R2 R2
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TPS62090 , TPS62091 , TPS62092 , TPS62093
SLVSAW2B –MARCH 2012–REVISED APRIL 2014 www.ti.com
10.2.2.2 Input and Output Capacitor Selection
For best output and input voltage filtering, low ESR ceramic capacitors are recommended. The input capacitor
minimizes input voltage ripple, suppresses input voltage spikes and provides a stable system rail for the device.
A 22 µF or larger input capacitor is recommended for 1.4 MHz operation frequency. For 2.8 MHz operation
frequence a 10 µF input capacitor or larger is recommended. The output capacitor value can range from 10 µF
up to 150 µF and beyond. The recommended typical output capacitor value is 22 µ F and can vary over a wide
range as outline in the output filter selection table.
Table 4. Input Capacitor Selection
INPUT CAPACITOR COMMENT
10 µF FREQ=low, f=2.8 MHz
22 µF FREQ=high, f=1.4 MHz
10.2.2.3 Setting the Output Voltage
The output voltage is set by an external resistor divider according to the following equations:
(10)
(11)
(12)
When sizing R2, in order to achieve low quiescent current and acceptable noise sensitivity, use a minimum of 5
µA for the feedback current I
FB
. Larger currents through R2 improve noise sensitivity and output voltage
accuracy. Lowest quiescent current and best output voltage accuracy can be achieved with the fixed output
voltage versions. For the fixed output voltage versions, the FB pin can be left floating or connected to GND to
improve the thermal package performance.
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