Fairchild RC5051, RC5050 specifications Mosfet Selection Cosiderations, Mosfet Selection Table

APPLICATION NOTE AN50

MOSFET Selection Cosiderations

MOSFET Selection

This application requires N-channel Logic Level Enhance- ment Mode Field Effect Transistors. Desired characteristics are as follows:

•Low Static Drain-Source On-Resistance, RDS,ON < 37 mΩ (lower is better)

•Low gate drive voltage, VGS ≤ 4.5V

•Power package with low Thermal Resistance

•Drain current rating of 20A minimum

•Drain-Source voltage > 15V.

The on-resistance (RDS,ON) is the primary parameter for MOSFET selection. It determines the power dissipation

within the MOSFET and, therefore, significantly affects the efficiency of the DC-DC converter. Table 5 is a selection table for MOSFETs.

Table 3. MOSFET Selection Table

	Conditions1		RDS,ON(mΩ)			Thermal
Manufacturer & Model #			Typ.	Max.	Package	Resistance
Fuji	VGS = 4V, ID = 17.5A	TJ = 25°C	25	37	TO-220	ΦJA = 75
2SK1388
		TJ = 125°C	37	—
Siliconix	VGS = 4.5V, ID = 5A	TJ = 25°C	16.5	20	SO-8	ΦJA = 50
SI4410DY					(SMD)
		TJ = 125°C	28	34
National Semiconductor	VGS = 5V, ID = 40A	TJ = 25°C	13	15	TO-220	ΦJA = 62.5
NDP706AL						ΦJC = 1.5
NDP706AEL		TJ = 125°C	20	24
National Semiconductor	VGS = 4.5V, ID = 10A	TJ = 25°C	31	40	TO-220	ΦJA = 62.5
NDP603AL		TJ = 125°C	42	54		ΦJC= 2.5
National Semiconductor	VGS = 5V, ID = 24A	TJ = 25°C	22	25	TO-220	ΦJA= 62.5
NDP606AL		TJ = 125°C	33	40		ΦJC = 1.5
Motorola	VGS = 5V, ID = 37.5A	TJ = 25°C	6	9	TO-263	ΦJA = 62.5
MTB75N03HDL		T = 125°C	9.3	14	(D2 PAK)	Φ	JC	= 1.0
		J
Int. Rectifier	VGS = 5V, ID = 31A	TJ = 25°C	—	28	TO-220	ΦJA = 62.5
IRLZ44		TJ = 125°C	—	46		ΦJC = 1.0
Int. Rectifier	VGS = 4.5V, ID = 28A	TJ = 25°C	—	19	TO-220	ΦJA = 62.5
IRL3103S		TJ = 125°C	—	31		ΦJC = 1.0
Intl Rectifier	VGS = 4.5V,	TA = 25°C		18	SO-8	ΦJA = 50
IRF7413	ID = 3.7A				SMD

Note:

1.RDS,ON values at Tj = 125°C for most devices were extrapolated from the typical operating curves supplied by the manufacturers and are approximations only.

7