92HD71B7 Datasheet, PDF (12/216 Pages) Integrated Device Technology – 4-CHANNEL HD AUDIO CODEC OPTIMIZED FOR LOW POWER

92HD71B7
4-CHANNEL HD AUDIO CODEC OPTIMIZED FOR LOW POWER
PC AUDIO
1.4. Detailed Description
1.4.1. Low-voltage High Definition Audio Link Signaling
The 92HD71B 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. 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.
When in 1.5 V mode, the 92HD71B 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
• Port D supports
• Line Out
• Ports B and C support
• Line In
• Mic with 0/10/20/30/40 dB Mic boost⁴
• Mono Output cannot be reconfigured
• Port E supports
• Line In
• Mic with 0/10/20/30/40 dB Mic boost⁴
• Port F supports
• 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 92HD71B7 may be configured for +3dBV full scale output levels by using a ven-
dor specific verb.
IDT™ CONFIDENTIAL AND PROPRIETARY
12
4-CHANNEL HD AUDIO CODEC OPTIMIZED FOR LOW POWER
92HD71B7
V 0.9 07/07