TDA8595TH/N2S,118 NXP Semiconductors, TDA8595TH/N2S,118 Datasheet - Page 18

• Manufacturer Part Number: TDA8595TH/N2S,118
• Description: Audio Amplifiers GEN PURP 64W 65dB
• Manufacturer: NXP Semiconductors

Specifications of TDA8595TH/N2S,118

• Rohs: yes
• Product: General Purpose Audio Amplifiers
• Output Type: Fixed
• Output Power: 64 W
• Maximum Power Dissipation: 80 W
• Mounting Style: SMD/SMT
• Package / Case: HSOP-36
• Common Mode Rejection Ratio (min): 65 dB
• Factory Pack Quantity: 500

NXP Semiconductors
TDA8595
Product data sheet
7.16 AC load detection
If the amplifier is used as line driver and the external booster has an input impedance of
more than 100  and less than 800  (DC-coupled), the DC load bits will contain
DBx[D5:D4] = 10, independent of the gain setting (see
Table 5.
By reading the I
amplifier, whether a speaker or an external booster is connected.
Depending on these bits, the amplifier gain can be selected, 26 dB for normal mode or
16 dB for line driver mode. If the gain select is performed when the amplifier is muted, the
gain select will be pop free.
The DC load bits are combined with the AC load bits and are only valid when the AC load
detection is disabled. When the AC load detection is enabled (IB1[D2] = 1), the bits
DBx[D4] will show the content of the AC load detection. When the AC load detection is
disabled again, bit DBx[D4] will show the content of the DC load measurement, which was
stored during the AC load measurement. The AC load detection can only be performed
after the amplifier has completed its start-up cycle and will not conflict with the DC load
detection.
The AC load detection, enabled with IB1[D2] = 1, is used to detect if AC coupled
speakers, for example tweeters, are connected correctly during assembly. The detection
is audible because a sine wave of a certain frequency (e.g. 19 kHz) needs to be applied to
the inputs of the amplifier. The output voltage over the load impedance will generate an
amplifier current. If the amplifier peak current triggers a 460 mA (peak) threshold detector
three times, the AC load detection bit will be set. A three ‘threshold cross’ counter is used
to prevent false AC load detection when switching the input signal on or off.
An AC coupled speaker will reduce the impedance at the output of the amplifier in a
certain frequency band. The presence of an AC coupled speaker can be determined using
460 mA (peak) and 230 mA (peak) threshold current detection. For instance, at an output
voltage of 2 V (peak) the total impedance must be less than 4  to detect the AC coupled
load, or more than 8  to guarantee only a DC connection is detected.
DC load bits
DBx[D5]
0
1
1
0
Fig 13. DC load detection levels
DC load detection
DETECTION
LEVEL
LOAD
All information provided in this document is subject to legal disclaimers.
2
C-bus bits the microprocessor can determine, after the start-up of the
Rev. 4 — 26 February 2013
DBx[D4]
0
0
1
1
NORMAL
20
I
2
C-bus controlled 4  45 W power amplifier
100
LINE DRIVER MODE
Table
800
Meaning (when IB1[D2] = 0)
normal load
line driver load
open load
not valid
5).
5 k
OPEN-CIRCUIT
TDA8595
© NXP B.V. 2013. All rights reserved.
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