TDA2003
LINEAR INTEGRATED CIRCUIT
BUILT-IN PROTECTION SYSTEMS(Cont.)
THERMAL SHUT-DOWN
The presence of a thermal limiting circuit offers the following advantages:
(1) An overload on the output (even if it is permanent),or an excessive ambient temperature can be easily withstood.
(2) The heat-sink can have a smaller factor compared with that of a conventional circuit. There is no device damage
in case of excessive junction temperature: all that happens is that Po ( and therefore PD) and Id are reduced.
COMPONENTS USAGE SUGGESTION
The recommended values of the components are those shown on typical application circuit Different values can
be used. The following table can help the designer.
COMPONENT RECOMMENDED
VALUE
PURPOSE
LARGE THAN
SMALLER THAN
RECOMMENDED VALUE RECOMMENDED VALUE
increase of drain current
Decrease of SVR
R1
R2
(Gv-1)*R2
gain setting.
2.2Ω
gain and SVR setting.
Danger of oscillation at high
frequencies with inductive
loads.
R3
1Ω
Frequency stability
Poor high frequencies
Danger of oscillation
attenuation
Rx
C1
≈20R2
2.2μF
Upper frequency cutoff
Input DC decoupling
Noise at switch-on
switch-off
C2
C3
470μF
0.1μF
Ripple rejection
Decrease of SVR
Danger of oscillation
Higher low frequency
cutoff
Supply voltage bypass
C4
1000μF
Supply voltage bypass
Danger of oscillation at
high frequencies with
inductive loads.
C5
Cx
0.1μF
Frequency stability
≈1/(2π*B*R1)
Upper frequency cutoff
Lower bandwidth
Larger bandwidth
UNISONIC TECHNOLOGIES CO., LTD
7 of 10
QW-R107-002,F
www.unisonic.com.tw
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