Philips Semiconductors
Product specification
4
×
40 W BTL quad car radio power
amplifier
FEATURES
•
Requires very few external components
•
High output power
•
Low output offset voltage
•
Fixed gain
•
Diagnostic facility (distortion, short-circuit and
temperature pre-warning)
•
Good ripple rejection
•
Mode select switch (operating, mute and standby)
•
Load dump protection
•
Short-circuit safe to ground and to V
P
and across the
load
•
Low power dissipation in any short-circuit condition
•
Thermally protected
•
Reverse polarity safe
•
Electrostatic discharge protection
•
No switch-on/switch-off plop
•
Flexible leads
•
Low thermal resistance
•
Pin compatible with the TDA8568Q, except for the gain.
QUICK REFERENCE DATA
SYMBOL
V
P
I
ORM
I
q(tot)
I
stb
I
sw
Z
i
P
o(EIAJ)
SVRR
α
cs
G
v(cl)
V
n(o)
V
OS
∆V
OS
PARAMETER
operating supply voltage
repetitive peak output current
total quiescent current
standby current
switch-on current
input impedance
EIAJ output power
supply voltage ripple rejection
channel separation
closed-loop voltage gain
noise output voltage
DC output offset voltage
delta DC output offset voltage
R
s
= 0
Ω
MUTE
ON
↔
MUTE
THD = maximum
R
s
= 0
Ω
R
s
= 10 kΩ
CONDITIONS
MIN.
6
−
−
−
−
25
−
−
−
33
−
−
−
TYP.
14.4
−
200
0.2
−
30
40
50
50
34
−
−
−
GENERAL DESCRIPTION
TDA8571J
The TDA8571J is a integrated class-B output amplifier
contained in a 23-lead Single-In-Line (SIL) plastic power
package. It contains four amplifiers in a BTL configuration,
each with a gain of 34 dB. The output power is 4
×
40 W
(EIAJ) into a 4
Ω
load.
APPLICATIONS
•
Primarily developed for car radio applications.
MAX.
18
7.5
−
100
80
−
−
−
−
35
170
80
80
UNIT
V
A
mA
µA
µA
kΩ
W
dB
dB
dB
µV
mV
mV
ORDERING INFORMATION
TYPE
NUMBER
TDA8571J
2002 Mar 05
PACKAGE
NAME
DBS23P
DESCRIPTION
plastic DIL-bent-SIL power package; 23 leads (straight lead length 3.2 mm)
2
VERSION
SOT411-1
Philips Semiconductors
Product specification
4
×
40 W BTL quad car radio power
amplifier
FUNCTIONAL DESCRIPTION
The TDA8571J contains four identical amplifiers which can
be used for bridge applications. The gain of each amplifier
is fixed at 34 dB.
Mode select switch (pin MODE)
•
Standby: low supply current (<100
µA)
•
Mute: input signal suppressed
•
Operating: normal on condition.
Since this pin has a low input current (<80
µA),
a low cost
supply switch can be applied.
To avoid switch-on plops, it is advised to keep the amplifier
in the mute mode during
≥150
ms (charging of the input
capacitors at pins IN1, IN2, IN3 and IN4. When switching
from standby to mute, the slope should be at least 18 V/s.
This can be realized by:
•
Microprocessor control
•
External timing circuit (see Fig.3).
Diagnostic output (pin V
DIAG
)
D
YNAMIC
D
ISTORTION
D
ETECTOR
(DDD)
At the onset of clipping of one or more output stages, the
dynamic distortion detector becomes active and pin V
DIAG
goes LOW. This information can be used to drive a sound
processor or DC volume control to attenuate the input
signal and so limit the distortion. The output level of
pin V
DIAG
is independent of the number of channels that
are clipping (see Fig.4).
S
HORT
-
CIRCUIT DIAGNOSTIC
TDA8571J
When a short-circuit occurs at one or more outputs to
ground or to the supply voltage, the output stages are
switched off until the short-circuit is removed and the
device is switched on again, with a delay of approximately
10 ms after removal of the short-circuit. During this
short-circuit condition, pin V
DIAG
is continuously LOW.
When a short-circuit occurs across the load of one or more
channels, the output stages are switched off during
approximately 10 ms. After that time it is checked during
approximately 50
µs
to determine whether the short-circuit
is still present. Due to this duty cycle of 50
µs/10
ms the
average current consumption during this short-circuit
condition is very low.
During this short-circuit condition, pin V
DIAG
is LOW for
10 ms and HIGH for 50
µs
(see Fig.5). The protection
circuits of all channels are coupled. This means that if a
short-circuit condition occurs in
one
of the channels,
all
channels are switched off. Consequently, the power
dissipation in any short-circuit condition is very low.
T
EMPERATURE PRE
-
WARNING
When the virtual junction temperature T
vj
reaches 145
°C,
pin V
DIAG
goes LOW.
O
PEN
-
COLLECTOR OUTPUTS
The diagnostic pin has an open-collector output, so more
devices can be tied together. An external pull-up resistor is
needed.
handbook, halfpage
Vo
handbook, halfpage
P
MGG155
+V
10 kΩ
MODE
0
47
µF
BZX79C/3.9V
MGD959
V9
VP
0
t
Fig.3 Mode select switch circuitry.
Fig.4 Distortion detector waveform.
2002 Mar 05
5
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
