tfa9843j-02 NXP Semiconductors, tfa9843j-02 Datasheet - Page 6

• Manufacturer Part Number: tfa9843j-02
• Description: Tfa9843j 2-channel Audio Amplifier Se 1 W To 20 W Or Btl 4 W To 40 W
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 12587
Preliminary data
8.4 Supply voltage ripple rejection
8.5 Built-in protection circuits
Standby — In this mode the current consumption is very low and the outputs are
floating. The device is in standby mode when V
grounded.
Mute — In this mode the amplifier is DC-biased but not operational (no audio output).
This allows the input coupling capacitors to be charged to avoid pop-noise. The
device is in mute mode when 4.5 V < V
On — In this mode the amplifier is operating normally. The operating mode is
activated at V
The supply voltage ripple rejection (SVRR) is measured with an electrolytic capacitor
of 150 F on pin SVR using a bandwidth of 20 Hz to 22 kHz.
SVRR as function of the frequency. A larger capacitor value on pin SVR improves the
ripple rejection behavior at the lower frequencies.
The TFA9843J contains two types of temperature sensors; one measures local
temperatures of the power stages and one measures the global chip temperature. At
a local temperature of the power stage of approximately 185
temperature of approximately 150
stages for 2 ms. High impedance of the outputs is the result. After this time period the
power stages switch on automatically and the detection will take place again; still a
too high temperature switches off the power stages immediately. This protects the
TFA9843J against shorts to ground, to the supply voltage, across the load and too
high chip temperatures.
The protection will only be activated when necessary, so even during a short-circuit
condition, a certain amount of (pulsed) current will still be flowing through the short,
just as much as the power stage can handle without exceeding the critical
temperature level.
Fig 3. Mode selection.
MODE
standby
Rev. 02 — 19 January 2004
> (V
0.8
CC
4.5
2.0 V).
o
C this detection circuit switches off the power
2-channel audio amplifier (2 x SE or 1 x BTL)
all mute
MODE
< (V
MODE
V CC 3.5
CC
< 0.8 V, or when pin MODE is
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
3.5 V).
V CC 2.0
1/2 on
Figure 17
o
V MODE (V)
C or a global
TFA9843J
V CC
MCE502
illustrates the
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