tp2150b Tripath Technology Inc., tp2150b Datasheet - Page 13

• Manufacturer Part Number: tp2150b
• Description: Dual High Side And Low Side Mosfet Driver
• Manufacturer: Tripath Technology Inc.

Output Transistor Selection
The key parameters to consider when selecting what MOSFET to use with the TP2150B are drain-
source breakdown voltage (BVdss), gate charge (Qg), and on-resistance (R
The BVdss rating of the MOSFET needs to be selected to accommodate the voltage swing
between V
transients. With a ‘good’ circuit board layout, a BVdss that is 50% higher than the VPP and VNN
voltage swing is a reasonable starting point. The BVdss rating should be verified by measuring
the actual voltages experienced by the MOSFET in the final circuit.
Ideally a low Qg (total gate charge) and low R
Unfortunately, these are conflicting requirements since R
typical MOSFET. The design trade-off is one of cost versus performance. A lower R
lower I
= Qg x 10 x 1.2MHz). A lower R
R
Gate Resistor Selection
The gate resistors, R
voltage overshoots. They also dissipate a portion of the power resulting from moving the gate
charge each time the MOSFET is switched. If R
the driver. Large gate resistors lead to slower MOSFET switching, which can lead to higher idle
current.
Recommended MOSFETs
The following devices are capable of achieving full performance, both in terms of distortion and
efficiency, for the specified load impedance and voltage range.
Device Information – Recommended MOSFETs
Note: The devices are listed in ascending current capability not in order of recommendation.
The following information represents qualitative data from system development using the
TP2150B along with the Tripath TC2001 processor and the associated MOSFETs.
Recommendations such as maximum supply voltages and gate resistor values are dependent on
the PCB layout and component location. The gate resistor values were chosen to achieve about
18-80mA of idle current from the VPP supply. This value of supply current is a good compromise
between low power efficiency and high frequency THD+N performance. As shown in Table 2
below, increasing the gate resistor value will improve high frequency THD+N performance at the
expense of idle current draw. The BBM setting was 40nS in all cases. It should be understood
that different MOSFETs will have different characteristics and will require some adjustment to the
gate resistor to achieve the same idle current.
13
BUK7575-100A
Part Number
DS(ON)
STP14NF10
STP24NF10
FQP13N10
FQP16N15
FQP19N10
FDP2572
IRF520N
IRF530N
2
means lower cost and lower switching losses but higher I
R
DS(ON)
SPOS
losses but the associated higher Qg translates into higher switching losses (losses
and V
Fairchild Semiconductor
Fairchild Semiconductor
Fairchild Semiconductor
Fairchild Semiconductor
Philips Semiconductor
International Rectifier
International Rectifier
ST Microelectronics
ST Microelectronics
Manufacturer
G
SNEG
, are used to control MOSFET switching rise/fall times and thereby minimize
as well as any voltage peaks caused by voltage ringing due to switching
DS(ON)
BV
also means a larger silicon die and higher cost. A higher
100
DSS
100
100
100
100
100
150
100
150
(V)
DS(ON)
G
I
12.8
16.4
is too small, excessive heat can be generated in
D
9.7
14
17
23
26
19
29
T r i p a t h T e c h n o l o g y , I n c . - T e c h n i c a l I n f o r m a t i o n
(A)
are desired for the best amplifier performance.
DS(ON)
25(max.)
37(max.)
Q
15.5
g
12
25
30
23
19
27
(nC)
is inversely proportional to Qg for a
2
R
DSON
0.20 (max.)
0.09 (max.)
R
DS(on)
0.142
0.064
0.055
0.123
0.045
0.16
0.1
TP2150B - MC/ 1.7/06.04
losses.
(:)
DS(ON)
P
).
D
108
135
48
65
60
70
99
85
75
(W)
DS(ON)
Package
TO220
TO220
TO220
TO220
TO220
TO220
TO220
TO220
TO220
means