TECHNICAL NOTE Audio Accessory ICs Karaoke/Surround Digital Echo BU9253AS/FS, BU9262AFS Description The Karaoke/Surround Digital Echo IC incorporates a digital delay circuit, an input/output mixing circuit, supporting Karaoke echo and surround system, all in a single chip. BU9253AS/FS has functions required by Karaoke echo system, and BU9262AFS has various functions required for surround / echo system. Features BU9253AS/FS 1) Digital delay time : 131ms (fCLK = 375kHz) 2) Built-in mixing circuit for adding original sound and echo sound 3) Echo mix ratio settable by DC voltage 4) Built-in amplifier circuit for structuring input/output secondary LPF 5) Microphone mute function (mute of mixing sound of original sound + echo sound) 6) Built-in CR oscillation circuit BU9262AFS 1) Digital delay time : 8-stage setting from 9.2ms to 192ms 2) Built-in input/output mixing circuit 3) Built-in feedback, delay volume circuit 4) Built-in input/output LPF 5) Serial interface 6) Auto mute circuit built in (action at power on, mode switching) 7) Built-in auto reset circuit at power on Applications Radio cassette recorder, mini-component and karaoke systems. Product lineup Parameter BU9253AS BU9253FS BU9262AFS Supply voltage 4.0V5.5V 4.0V5.5V 4.5V5.5V Oscillation frequency 375kHz 375kHz 2MHz Current consumption 6mA 6mA 20mA Operating temperature range -10+70 -10+70 -10+70 Package SDIP18 SSOP-A16 SSOP-A32 Digital delay Fixed Fixed Variable Echo level Fixed Fixed Variable Ver.B Oct.2005 Absolute maximum ratings BU9253AS Parameter Symbol Ratings Unit Supply voltage VCCMAX 7.0 V Terminal voltage VIN -0.3 VCC+0.3 V Power dissipation PD 600* mW Storage temperature TSTG -55 +125 * Reduce by 6.0 mW/ C over 25C BU9253FS Parameter Symbol Ratings Unit Supply voltage VCCMAX 7.0 V Terminal voltage VIN -0.3 VCC+0.3 V Power dissipation PD 500* mW Storage temperature TSTG -55 +125 * Reduce by 5.0 mW/ C over 25C BU9262AFS Parameter Symbol Ratings Unit Supply voltage VCC 0.3 7.0 V Terminal voltage VIN VSS 0.3 VCC + 0.3 V Power dissipation PD 800* mW Storage temperature TSTG -55 +125 * Reduce by 8.0 mW/ C over 25C Note: This IC is not designed to be radiation-resistant. Note: Operation is not guaranteed. Operating conditions BU9253AS/FS Parameter Symbol Limits Unit Supply voltage VCC 4.0 5.5 V Operating temperature Ta -10 +70 Operating frequency fC 375 kHz BU9262AFS Parameter Symbol Limits Unit Operating supply range VCC 4.5 5.5 V Operating temperature Ta -10 +70 Operating frequency fC 2 MHz 2/16