PA2005 Datasheet, PDF (12/16 Pages) Unisonic Technologies – 20W BRIDGE AMPLIFIER FOR CAR RADIO

PA2005
„ BUILT-IN PROTECTION SYSTEMS
LINEAR INTEGRATED CIRCUIT
LOAD DUMP VOLTAGE SURGE
The UTC PA2005 has a circuit which enables it to withstand a voltage pulse train, on pin9, of the type shown in
Figure 3.
If the supply voltage peaks to more than 40V, then an LC filter must be inserted between the supply and pin9, in
order to assure that the pulses at pin 9 will be held withing the limits shown.
A suggested LC network is shown in Figure 2, With this network, a train of pulses with amplitude up to 120V and
width of 2ms can be applied at point A, This type of protection is ON when the supply voltage (pulse or DC) exceeds
18V. For this reason the maximum operating supply voltage is 18V.
FROM A
SUPPLY
LINE
Figure 2
L=2mH
C
3000μ F
16V
TO PIN 9
Vs(V)
40
14.4
t1
t2
Figure 3
t1=50ms
t2=1000ms
t
SHORT CIRCUIT (AC AND DC CONDITIONS)
The UTC PA2005 can withstand a permanent short circuit on the output for a supply voltage up to 16V.
POLARITY INVERSION
High current (up to 10A) can be handled by the device with no damage for a longer period than the blow-out time
of a quick 2A fuse (normally connected in series with the supply). This feature is added to avoid destruction, if during
fitting to the car, a mistake on the connection of the supply is made.
OPEN GROUND
When the ratio is in the ON condition and the ground is accidentally opened, a standard audio amplifier will be
damaged. On the UTC PA2005 protection diodes are included to avoid any damage.
INDUCTIVE LOAD
A protection diode is provided to allow use of the UTC PA2005 with inductive loads.
DC VOLTAGE
The maxim operating DC voltage for the UTC PA2005 is 18V.
However the device can withstand a DC voltage up to 28V with no damage. This could occur during winter if two
batteries are series connected to crank the engine.
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 heatsink can have a smaller factor of safety compared with that of a conventional circuit. There is no
device damage in the case of excessive junction temperature; all that happens is that Po (and therefore Ptot) and Id
are reduced.
The maximum allowable power dissipation depends upon the size of the external heatsink (i.e. its thermal
resistance); Figure 4 shows the dissipation power as a function of ambient temperature for different thermal
resistance.
LOUDSPEAKER PROTECTION
The circuit offers loudspeaker protection during short circuit for one wire to ground.
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
12 of 16
QW-R107-035,D