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AS1341

Datasheet - A p p l i c a t i o n I n f o r m a t i o n

9.5 Maximum Output Current

The AS1341 output current determines the regulator’s switching frequency. When the converter approaches continuous mode, the output

voltage falls out of regulation. For the typical application, the maximum output current is approximately:

(EQ 5)

For low-input voltages, the maximum on-time may be reached and the load current is limited by:

(EQ 6)

9.6 Output Capacitor

Choose the output capacitor to service the maximum load current with acceptable voltage ripple. The output ripple has two components:

variations in the charge stored in the output capacitor with each LX pulse, and the voltage drop across the capacitor’s equivalent series

resistance (ESR) caused by the current into and out of the capacitor:

(EQ 7)

The output voltage ripple as a consequence of the ESR and output capacitance is:

(EQ 8)

(EQ 9)

Where:

Equations EQ 7, EQ 8, and EQ 9 are suitable for initial capacitor selection, but actual values should be set by testing a prototype or evaluation

circuit. As a general rule, a smaller amount of charge delivered in each pulse results in less output ripple. Since the amount of charge delivered

in each oscillator pulse is determined by the inductor value and input voltage, the voltage ripple increases with larger inductance, and as the

input voltage decreases.

Table 6. Recommended Output Capacitor

Part Number

C

ESR

Rated Voltage

Manufacturer

T520V107M010ATE018

100µF

18m

Ω

10V

Kemet

www.kemet.com

A700V826M006ATE018

82µF

18m

Ω

6.3V

T520B107M006ATE040

100µF

40m

Ω

6V

T520A336M006ATE070

33µF

70m

Ω

6.3V

A700V226M006ATE028

22µF

28m

Ω

6.3V

510X107M020ATE040

10µF

40m

Ω

20V

EEFUD0J101R

100µF

15m

Ω

6.3V

Panasonic

www.panasonic.com

EEFCD0K330R

33µF

18m

Ω

8V

10TPB100ML

100µF

55m

Ω

10V

Sanyo

www.edc.sanyo.com

6TPB47M

47µF

70m

Ω

6.3V