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. Applications CD-ROM drives and other products (with line and headphone output pins) that process digital audio signals Features 1) Internal LPF, line amplifier and EVR. 2) Internal mute function. 3) Internal thermal shutdown circuit. Block diagram 146 4) No attached oscillation prevention components are needed, even at a load of 8. 5) Mute function reduces the popping noises that can occur when the power is turned on and off. 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 = 50k, H / P RL2 = 32, VIN = 1.8dBV, f = 1kHz, EVR = Max.) 147 Optical disc ICs Measurment circuit 148 BH3540AFS Optical disc ICs BH3540AFS Application example 149 Optical disc ICs Operation 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). Electrical characteristic curves External dimensions (Units: mm) 150 BH3540AFS (2) Recommended time chart Appendix Notes No technical content pages of this document may be reproduced in any form or transmitted by any means without prior permission of ROHM CO.,LTD. The contents described herein are subject to change without notice. The specifications for the product described in this document are for reference only. Upon actual use, therefore, please request that specifications to be separately delivered. Application circuit diagrams and circuit constants contained herein are shown as examples of standard use and operation. Please pay careful attention to the peripheral conditions when designing circuits and deciding upon circuit constants in the set. Any data, including, but not limited to application circuit diagrams information, described herein are intended only as illustrations of such devices and not as the specifications for such devices. ROHM CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any third party's intellectual property rights or other proprietary rights, and further, assumes no liability of whatsoever nature in the event of any such infringement, or arising from or connected with or related to the use of such devices. Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or otherwise dispose of the same, no express or implied right or license to practice or commercially exploit any intellectual property rights or other proprietary rights owned or controlled by ROHM CO., LTD. is granted to any such buyer. Products listed in this document use silicon as a basic material. Products listed in this document are no antiradiation design. The products listed in this document are designed to be used with ordinary electronic equipment or devices (such as audio visual equipment, office-automation equipment, communications devices, electrical appliances and electronic toys). Should you intend to use these products with equipment or devices which require an extremely high level of reliability and the malfunction of with would directly endanger human life (such as medical instruments, transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other safety devices), please be sure to consult with our sales representative in advance. About Export Control Order in Japan Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control Order in Japan. In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause) on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction. Appendix1-Rev1.0