TC429EOA View Datasheet(PDF) - Microchip Technology
Part Name
Description
MFG CO.
'TC429EOA' PDF : 18 Pages View PDF
TC429
The device capacitive load dissipation is:
EQUATION
PC
=
2
fCVS
Where:
f = Switching frequency
C = Capacitive load
VS = Supply voltage
Quiescent power dissipation depends on input signal
duty cycle. A logic low input results in a low-power
dissipation mode with only 0.5 mA total current drain.
Logic-high signals raise the current to 5 mA maximum.
The quiescent power dissipation is:
EQUATION
PQ = VS(D(IH) + (1 – D)IL)
Where:
IH = Quiescent current with input high
(5 mA max)
IL = Quiescent current with input low
(0.5 mA max)
D = Duty cycle
Transition power dissipation arises because the output
stage N- and P-channel MOS transistors are ON
simultaneously for a very short period when the output
changes.
The device transition power dissipation is approxi-
mately:
EQUATION
PT
=
f
VS
3.3
×
–
10
9A
•
Sec
An example shows the relative magnitude for each
item.
C = 2500 pF
VS = 15V
D = 50%
f = 200 kHz
PD = Package power dissipation:
= PC + PT + PQ
= 113 mW + 10 mW + 41 mW
= 164 mW
Maximum ambient operating temperature:
= TJ – θJA (PD)
= 150ºC - (150ºC/W)(0.164W)
= 125°C
Where:
TJ = Maximum allowable junction temperature
(+150°C)
θJA = Junction-to-ambient thermal resistance
(150°C/W, CERDIP)
DS21416C-page 10
Note:
Ambient operating temperature should not
exceed +85ºC for EPA or EOA devices or
+125ºC for MJA devices.
TABLE 4-1: MAXIMUM OPERATING
FREQUENCIES
VS
fMAX
18V
500 kHz
15V
700 kHz
10V
1.3 MHz
5V
>2 MHz
Conditions:
1. CERDIP Package (θJA =150°C/W)
2. TA = +25°C
3. CL = 2500 pF
5V/DIV
INPUT
500mV/DIV
(5 AMP/DIV)
OUTPUT
VS = 18V
RL = 0.1Ω
5V
500mV
5µs
TIME (5µs/DIV)
FIGURE 4-5:
Capability.
Peak Output Current
4.5 POWER-ON OSCILLATION
Note:
It is extremely important that all MOSFET
driver applications be evaluated for the
possibility of having high-power oscillations
occur during the power-on cycle.
Power-on oscillations are due to trace size, layout and
component placement. A ‘quick fix’ for most applica-
tions that exhibit power-on oscillation problems is to
place approximately 10 kΩ in series with the input of
the MOSFET driver.
2003 Microchip Technology Inc.
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