15

 2005 Semtech Corp.

www.semtech.com

POWER MANAGEMENT

SC2434

Applications Information (Cont.)

Efficency (%)

65.00

70.00

75.00

80.00

85.00

90.00

95.00

0

102030

40506070

I_out(A)

The reference design implemented 1.5mOhm output droop impedance as shown in Fig. 9.

Fig. 9 - Measured output drooping characteristics of the 60A design.

The efficiency of the design is depends on the MOSFET being used and thermal management requirements of

controlling the PCB temperature and the MOSFET junction temperature. The following efficiency curve is corresponding

to 4mOhm bottom FET, while the top FET has 12 mOhm Rdson.

Fig. 10 - Typical efficiency curve for 12 mOhm top FETs and 4 Ohm bottom FETs.

Load Line (Vin=12V, VID=00100)

1.6

1.62

1.64

1.66

1.68

1.7

1.72

1.74

1.76

0

10

20

3040

5060

I (A)

Vo

Spec_H

Spec_L