Product Description
High quality audio systems have become standard for most personal computers. Furthermore, the audio functions have been migrating to the motherboard, putting pressure on available board space. The PACAC97 provides the components necessary for signal conditioning of analog audio inputs for an AC97 compliant Codec as well as gain setting resistors for headphone and microphone amplifiers. Since analog signal levels can be as high as 2Vrms, the PACAC97 provides 6dB of attenuation (to 1Vrms) for LINE-IN, AUX, and CD inputs. The CD line level inputs of the PACAC97 have an additional ground signal, CD_GND, that supports the pseudo differential amplifier present in AC97 Codecs.

FEATUREs
• Signal conditioning and gain setting resistors for all standard audio functions
• Low noise thin film resistors ±1% match
• Better than 1% matching between channels
• Gain modification by changing resistors externally
• Better than –90dB inter-channel and channel-tochannel crosstalk
• Single 28-pin QSOP package
• Saves board space and reduces assembly cost

APPLICATIONs
• Analog audio system for Pentium II Class personal computers, used in conjunction with Audio Codec, CS4297 or AD1819A.