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92HD75B
V 1.0 01-09
4-CHANNEL HD AUDIO CODECS OPTIMIZED FOR LOW POWER
92HD75B
4-CHANNEL HD AUDIO CODECS OPTIMIZED FOR LOW POWER
PC AUDIO
1.4.
Detailed Description
1.4.1.
Low-voltage High Definition Audio Link Signaling
The 92HD75B is compatible with either 1.5 V or 3.3 V High Definition Audio Link signaling; the volt-
age selection is performed dynamically based on the input voltage of DVDD_IO in 48 pad package.
Note that DVDD_IO is not a logic configuration pin but provides the digital power supply to be used
for the High Definition Audio Link signals. Different oderable part numbers are assigned.The 32 pad
package does not have DVDD_IO so selection of 1.5V or 3.3V Hight Definition Audio Link signaling
is by two different orderable parts. Please see the orderable part number section for more details.
When in 1.5 V mode, the 92HD75B can correctly decode BITCLK, SYNC, RESET# and SDO
because they operate at 1.5 V. Additionally, it will drive SDI_CODEC at 1.5 V. None of the GPIOs are
affected, as they always function at their nominal voltage (DVDD or AVDD).
1.4.2.
Port Functionality
Single function (Input only / output only) ports allow for the highest possible performance.
Port A supports
Headphone Out
Line Out
Ports B and C support
Line In
Mic with0/10/20/30/40 dB boost
Port D supports
Line Out
Port E supports
Line In
Mic with0/10/20/30/40 dB boost
Port F supports (48 version only)
Line Out
Note4: 40dB boost requires using the IDT driver. When the 40dB mic boost feature is enabled, addi-
tional gain increases greater than 6dB may result in significant audio quality degradation of the
microphone audio input. In particular, when the 40dB MIC boost is active, the SNR, THD+N and DC
offset will significantly degrade regardless of the input signal level.
1.4.3.
Port Characteristics
Ports are designed to be dedicated inputs or outputs only. Universal (Bi-directional) jacks are not
supported. Port A is designed to drive a set of 32 ohm (nominal) headphones or a 10K (nominal)
load with on board shunt resistance as low as 20K ohms (typical - used to maintain coupling CAP
bias.) Line Level outputs are intended to drive an external 10K speaker load (nominal) and an on
board shunt resistor of 20-47K (nominal). However, applications may support load impedances of 5K
ohms and above. Input ports are 47K impedance (nominal) at the pin.
DAC full scale outputs and intended full scale input levels are 1V rms. Line output ports and Head-on
output ports on the 92HD75B may be configured for +3dBV full scale output levels by using a vendor
specific verb.