BA3840KV

Audio ICs Preset graphic equalizer for headphone stereos BA3840KV The BA3840KV is a preset graphic equalizer IC for headphone stereos. It combines two equalizer circuit channels on a single chip, and also includes a dynamic sound leak reduction circuit. FApplications Headphone stereos Portable CD players FFeatures 1) Four sound quality settings are possible by DC control. 2) High-frequency sounds can be cut off based on the volume. FBlock diagram 3) The sound leak reduction circuit can be turned on and off by DC control. 555 Audio ICs FAbsolute maximum ratings (Ta = 25_C) BA3840KV FRecommended operating conditions (Ta = 25_C) FElectrical characteristics(unless otherwise noted, Ta = 25_C, VCC = 2V, f = 1kHz, VIN = 100mVrms, F flat position on, sound leak reduction circuit off) 556 Audio ICs FPin descriptions BA3840KV 557 Audio ICs BA3840KV 558 Audio ICs BA3840KV 559 Audio ICs FMeasurement circuit BA3840KV FCircuit operation (1) Preset graphic equalizer (1) Flat position By pulling up the FLAT pin to VCC, frequency characteristics become flat. (2) Rock position By pulling up the ROCK pin to VCC, low frequencies are boosted by about 7dB. High frequencies are also adjusted to balance the subjectively heard sound. (3) Pop position By pulling up the POPS pin to VCC, mid-range frequencies are boosted by about 6dB and combined with the rock position characteristics. (4) Jazz position By open-circuiting the above three pins, low frequencies are boosted by 14dB. High frequencies are also adjusted to balance the subjectively heard sound. (2) Sound leak reduction circuit If the stereo output signal from the power amplifier is mixed and input to the DET 1 pin and the PLSS pin pulled up to VCC, the sound frequencies close to 5kHz that leak easily will be cut off in accordance with the volume. (3) MUTE pin If the MUTE pin is pulled up to VCC, the effective graphic equalizer position will be FLAT regardless of the selected position. (However, if the pop position has been selected, the mid-range boost will be maintained.) (4) DET 2 pin If the stereo output signal from the power amplifier is mixed and input to the DET 2 pin, the effective graphic equalizer position will be FLAT during high level output regardless of the selected position. (However, if the pop position has been selected, the mid-range boost will be maintained.) 560 Audio ICs FApplication example BA3840KV FOperation notes (1) Graphic equalizer positions When selecting a position, be sure to open-circuit the non-selected pins. If any are pulled down to ground, over-current can result. (2) Test pins The test pins are all connected to internal circuits. They are not N.C. pins, therefore open-circuit them, do not ground them. (3) Recommended operating conditions Furthermore, if a condition for an electrical characteristic is not satisfied while within the ambient operating temperature range, the standard value for that electrical characteristic cannot be guaranteed. Despite this, however, no abrupt changes to the electrical characteristic will occur. 561 Audio ICs FElectrical characteristic curves BA3840KV FExternal dimensions (Units: mm) 562