BA3826S Datasheet | ROHM

Audio ICs Band-pass filter for spectrum analyzer The BA3826S is a 7-band ( 2), band-pass filter that uses microprocessor time division to output in serial to left and right stereo channels. To minimize the number of external ponents required and enable pact and reliable designs, all of the capacitors for the filters are on the chip. FApplications CD radio cassette players, mini-ponent stereo systems, car stereos FFeatures 1) Seven band-pass filter elements for spectrum analyzer displays. 2) Microprocessor time division used for serial output on L and R channels. 3) All filter capacitors are built-in to minimize external attached requirements. FAbsolute maximum ratings (Ta = 25_C) 4) Low current dissipation (8m A Typ.). 5) Ideal for mini-ponent stereos and other stereo equipment. FRemended operating conditions (Ta = 25_C) Audio ICs FBlock diagram FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5V, Vee = - 5V, RL = 10kΩ, and Rφ = 120kΩ) Audio ICs FMeasurement circuit FCircuit operation (1) Input switch circuit The BA3826S alternately switches between the left and right stereo channel signals using time division to serialize and process the signals. Audio ICs (2) Band-pass filter circuit This circuit extracts the required frequency range from the input signal and amplifies it. The center frequency is determined by the value of the current flowing through the resistor connected to pin 14. Q is set to 3.5 (Typ.). Due to the characteristics of the band-pass filter circuit, the circuit has a transition rise and fall characteristic. Due to the transition rise characteristic, five input cycles are required until peak output is reached. When RESET is input, a built-in circuit cancels the fall transition characteristic (input the reset signal for 0.5ms). (4) Timing (3) DET circuit The DET circuit detects the signal selected by the band pass filter and performs peak hold. The RESET Driver discharges...