LM25010MH datasheet(14/17 Pages) NSC

14 / 17 page

Applications Information (Continued)

Item

Description

Value

Ceramic Capacitor

(2) 2.2 µF, 50V

Ceramic Capacitor

22 µF, 16V

Ceramic Capacitor

0.47 µF, 16V

C4, C6

Ceramic Capacitor

0.022 µF, 16V

Ceramic Capacitor

0.1 µF, 50V

Schottky Diode

60V, 2A

Inductor

100 µH

Resistor

1.0 k

Ω

Resistor

1.0 k

Ω

Resistor

1.5

Ω

Resistor

200 k

Ω

National Semi LM25010

MINIMUM LOAD CURRENT

The LM25010 requires a minimum load current of 500 µA. If

the load current falls below that level, the bootstrap capacitor

(C4) may discharge during the long off-time, and the circuit

will either shutdown, or cycle on and off at a low frequency.

If the load current is expected to drop below 500 µA in the

application, R1 and R2 should be chosen low enough in

value so they provide the minimum required current at nomi-

nal V

OUT.

LOW OUTPUT RIPPLE CONFIGURATIONS

For applications where low output voltage ripple is required

the output can be taken directly from the low ESR output

capacitor (C2) as shown in Figure 9. However, R3 slightly

degrades the load regulation. The specific component val-

ues, and the application determine if this is suitable.

Where the circuit of Figure 9 is not suitable, the circuits of

Figure 10 or Figure 11 can be used.

20172735

FIGURE 7. Efficiency vs Load Current and V

Circuit of Figure 6

20172737

FIGURE 8. Frequency vs V

Circuit of Figure 6

20172715

FIGURE 9. Low Ripple Output

20172748

FIGURE 10. Low Output Ripple Using a Feedforward

Capacitor

LM25010MH Datasheet(PDF) 14 Page - National Semiconductor (TI)

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