ADAU1590ASVZ AD [Analog Devices], ADAU1590ASVZ Datasheet - Page 16

• Manufacturer Part Number: ADAU1590ASVZ
• Description: Class-D Audio Power Amplifier
• Manufacturer: AD [Analog Devices]

ADAU1590
The slicer threshold can be set externally using a resistor as
follows:
where:
AVDD = 3.3 V typical.
V
The following equation can be used to calculate the input signal
at which the slicer becomes active:
Therefore, for AVDD = 3.3 V typical and V
Thus, the slicer is activated at and above 0.864 V
This feature allows the user to set the slicer and, in turn, reduces
the output power at a given supply voltage.To disable the slicer,
SLC_TH should be connected to AGND. Table 9 shows the
typical values for R
Table 9. Typical R
V
1.1
1.17
1.24
1.32
POWER STAGE
The ADAU1590 power stage comprises a high-side PMOS and
a low-side NMOS. The typical R
NMOS stage does not need an external bootstrap capacitor and
simplifies the high-side driver design. The power stage also has
comprehensive protection circuits to detect the faults in typical
applications. See the Protection Circuits section for further details.
TH
TH
(V)
is the voltage threshold at which the slicer is activated.
V
R
V
V
EXTERNAL
TH
IN RMS
IN RMS
= (AVDD/2) × (50 kΩ/50 kΩ + R
Figure 40. Block for Slicer Threshold Adjust, SLC_TH
= 0.864 V
V
=
CM
= 24.9 kΩ
1.414 ×
SLICER_LEVEL
R
24.9
20.5
16.5
12.4
V
EXTERNAL
EXTERNAL
TH
EXTERNAL
0.9
(kΩ)
.
Values
50kΩ
V
R
TH
EXTERNAL
DS-ON
is ~300 mΩ. The PMOS-
PIN 24 (SLC_TH)
EXTERNAL
TH
V
0.864
0.919
0.974
1.037
= 1.1 V,
IN RMS
IN RMS
)
(V)
.
Rev. 0 | Page 16 of 24
GAIN
The gain of the amplifier is set internally using feedback resis-
tors optimized for 12 V nominal operation. The typical gain
values are tabulated in Table 1. The typical gain is 17 dB with
PGA set to 0 dB. PGA0 (Pin 14) and PGA1 (Pin 13) are used
for setting the desired gain.
The gain can be set according to Table 10. Note that the ampli-
fier full-scale input level changes as per the PGA gain setting.
Table 10. Gain Settings
PGA1
(Pin 13)
0
0
1
1
PROTECTION CIRCUITS
The ADAU1590 includes comprehensive protection circuits. It
includes thermal warning, thermal overheat, and overcurrent or
short-circuit protection on the outputs. The ERR and OTW
outputs are open drain and require external pull-up resistors.
The outputs are capable of sinking 10 mA. The open-drain
outputs are useful in multichannel applications where more
than one ADAU1590 is used. The error outputs of multiple
ADAU1590s can be OR’ e d to simplify the system design.
The logic outputs of the error flags ease the system design of
using a microcontroller.
THERMAL PROTECTION
Thermal protection in the ADAU1590 is categorized into two
error flags: one as thermal warning and the other as thermal
shutdown. When the device junction temperature reaches near
135°C (±5°C), the ADAU1590 outputs a thermal warning error
flag by pulling OTW (Pin 10) low. This flag can be used by the
microcontroller in the system for indication to the user or can
be used to lower the input level to the amplifier to prevent
thermal shutdown. The device continues operation until
shutdown temperature is reached.
When the device junction temperature exceeds 150°C, the
device outputs an error flag by pulling ERR (Pin 9) low. This
error flag is latched. To restore the operation, MUTE (Pin 15)
needs to be toggled to low and then to high again.
OVERCURRENT PROTECTION
The overcurrent protection in the ADAU1590 is set internally at
a 5 A peak output current. The device protects the output
devices against excessive output current by pulling ERR (Pin 9)
low. This error flag is latched. To restore the normal operation,
MUTE (Pin 15) needs to be toggled to low and then to high
again. The error flag is useful for the microcontroller in the
system to indicate abnormal operation and to initiate the audio
MUTE sequence. The device senses the short-circuit condition
PGA0
(Pin14)
0
1
0
1
PGA
Gain (dB)
0
6
12
18
Amplifier
Gain (dB)
17
23
29
35
Full-Scale
Input Level
(V
1
0.5
0.25
0.125
RMS
)