ams Datasheet Page 23
[v1-11] 2015-Jan-28 Document Feedback
AS1310 − Application Information
Capacitor Selection
The convertor requires three capacitors. Ceramic X5R or X7R
types will minimize ESL and ESR while maintaining capacitance
at rated voltage over temperature. The V
IN
capacitor should be
22μF. The V
OUT
capacitor should be between 22μF and 47μF. A
larger output capacitor should be used if lower peak to peak
output voltage ripple is desired. A larger output capacitor will
also improve load regulation on V
OUT
. See Figure 23 for a list of
capacitors for input and output capacitor selection.
Figure 23:
Recommended Input and Output Capacitors
On the pin REF a 10nF capacitor with an Insulation resistance
>1GΩ is recommended.
Figure 24:
Recommended Capacitors for REF
Layout Considerations
Relatively high peak currents of 480mA (max) circulate during
normal operation of the AS1310. Long printed circuit tracks can
generate additional ripple and noise that mask correct
operation and prove difficult to “de-bug” during production
testing. Referring to Figure 2, the input loop formed by C1, V
IN
and GND pins should be minimized. Similarly, the output loop
formed by C2, V
OUT
and GND should also be minimized. Ideally
both loops should connect to GND in a “star” fashion. Finally, it
is important to return C
REF
to the GND pin directly.
Part Number C
TC
Code
Rated
Voltage
Dimensions
(L/W/T)
Manufacturer
GRM21BR60J226ME99 22μF X5R 6.3V 0805, T=1.25mm
Murata
www.murata.com
GRM31CR61C226KE15 22μF X5R 16V 1206, T=1.6mm
GRM31CR60J475KA01 47μF X5R 6.3V 1206, T=1.6mm
Part Number C
TC
Code
Insulation
Resistance
Rated
Voltage
Dimensions
(L/W/T)
Manufacturer
GRM188R71C104KA01 100nF X7R >5GΩ 16V
0603,
T=0.8mm
Murata
www.murata.com
GRM31CR61C226KE15 100nF X7R >5GΩ 50V
0805,
T=1.25mm
