BH3540AFS

Optical disc ICs Headphone amplifier with internal LPF and EVR for CD-ROM BH3540AFS The BH3540AFS is an H / P amplifier with internal secondary LPF and EVR circuits. When multibit output from a D / A converter is input, the secondary LPF outputs an audio signal. Output level for headphones can be changed with the EVR circuit. This IC also has independent internal mute circuits for the left and right channels. FApplications CD-ROM drives and other products (with line and headphone output pins) that process digital audio signals FFeatures 1) Internal LPF, line amplifier and EVR. 2) Internal mute function. 3) Internal thermal shutdown circuit. 4) No attached oscillation prevention components are needed, even at a load of 8Ω. 5) Mute function reduces the popping noises that can occur when the power is turned on and off. FBlock diagram 146 Optical disc ICs FAbsolute maximum ratings (Ta = 25_C) BH3540AFS FRecommended operating conditions FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5.0V, line RL1 = 50kΩ, H / P RL2 = 32Ω, VIN = 1.8dBV, f = 1kHz, EVR = Max.) 147 Optical disc ICs FMeasurment circuit BH3540AFS 148 Optical disc ICs FApplication example BH3540AFS 149 Optical disc ICs FOperation notes (1) Preventing popping noises The BH3540AFS has a mute function that reduces the popping noises that can occur when the power is turned on or off. To further reduce these popping noises, attach a capacitor and resistor to the mute pin (pins 3 and 14). BH3540AFS (2) Recommended time chart FElectrical characteristic curves FExternal dimensions (Units: mm) 150