SI1406DH-T1 Vishay/Siliconix, SI1406DH-T1 Datasheet - Page 7

• Manufacturer Part Number: SI1406DH-T1
• Description: MOSFET 20V 3.9A 1.0W
• Manufacturer: Vishay/Siliconix

Specifications of SI1406DH-T1

• Product Category: MOSFET
• Rohs: yes
• Transistor Polarity: N-Channel
• Drain-source Breakdown Voltage: 20 V
• Gate-source Breakdown Voltage: +/- 8 V
• Continuous Drain Current: 3.1 A
• Resistance Drain-source Rds (on): 0.065 Ohms
• Configuration: Single
• Maximum Operating Temperature: + 150 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-363-6
• Fall Time: 47 ns
• Minimum Operating Temperature: - 55 C
• Power Dissipation: 1 W
• Rise Time: 47 ns
• Factory Pack Quantity: 3000
• Typical Turn-off Delay Time: 54 ns

AN815
Vishay Siliconix
THERMAL PERFORMANCE
Junction-to-Foot Thermal Resistance
(Package Performance)
The junction to foot thermal resistance is a useful method of
comparing different packages thermal performance.
A helpful way of presenting the thermal performance of the
6-Pin SC-70 copper leadframe device is to compare it to the
traditional Alloy 42 version.
Thermal performance for the 6-pin SC-70 measured as
junction-to-foot thermal resistance, where the “foot” is the
drain lead of the device at the bottom where it meets the PCB.
The junction-to-foot thermal resistance is typically 40_C/W in
the copper leadframe and 163_C/W in the Alloy 42 leadframe
— a four-fold improvement. This improved performance is
obtained by the enhanced thermal conductivity of copper over
Alloy 42.
Power Dissipation
The typical Rq
leadframe is 103_C/W steady-state, compared with 212_C/W
for the Alloy 42 version. The figures are based on the 1-inch
FR4 test board. The following example shows how the thermal
resistance impacts power dissipation for the two different
leadframes at varying ambient temperatures.
www.vishay.com
2
ALLOY 42 LEADFRAME
Room Ambient 25 _C
P
P
P
D
D
D
+
+ 150
+ 590 mW
T
J(max)
JA
212
Rq
o
C * 25
for the single 6-pin SC-70 with copper
o
JA
* T
C W
Front of Board SC70-6
A
o
C
Elevated Ambient 60 _C
P
P
P
D
D
D
+
+ 150
+ 425 mW
T
J(max)
212
Rq
o
C * 25
o
JA
* T
C W
A
o
C
FIGURE 3.
2
As can be seen from the calculations above, the compact 6-pin
SC-70 copper leadframe LITTLE FOOT power MOSFET can
handle up to 1 W under the stated conditions.
Testing
To further aid comparison of copper and Alloy 42 leadframes,
Figure 5 illustrates single-channel 6-pin SC-70 thermal
performance on two different board sizes and two different pad
patterns. The measured steady-state values of Rq
two leadframes are as follows:
The results indicate that designers can reduce thermal
resistance (Rq
leadframe device rather than the Alloy 42 version. In this
example, a 121_C/W reduction was achieved without an
increase in board area. If increasing in board size is feasible,
a further 105_C/W reduction could be obtained by utilizing a
1-inch
The copper leadframe versions have the following suffix:
COOPER LEADFRAME
LITTLE FOOT 6-PIN SC-70
1) Minimum recommended pad pattern on
the EVB board V (see Figure 3.
2) Industry standard 1-inch
maximum copper both sides.
Room Ambient 25 _C
2
P
P
P
square PCB area.
D
D
D
+
+ 150
+ 1.01 W
T
vishay.com
J(max)
124
JA
Back of Board SC70-6
Rq
o
C * 25
) by 36% simply by using the copper
Single:
Dual:
Complementary: Si15xxEDH
o
JA
* T
C W
2
PCB with
A
o
C
Elevated Ambient 60 _C
Si14xxEDH
Si19xxEDH
P
P
P
Alloy 42
329.7_C/W
211.8_C/W
D
D
D
Document Number: 71334
+
+ 150
+ 726 mW
T
J(max)
124
Rq
o
C * 60
o
JA
* T
C W
208.5_C/W
103.5_C/W
Copper
JA
12-Dec-03
A
o
for the
C