BA6820F Datasheet | ROHM

feature a power-on mute, so steps to prevent erroneous LED lighting at power on are not required. The input resistance of the AC inputs is 3kΩ (Typ.) for the BA6820F and 0.3kΩ (Typ.) for the BA6822S / F. FApplications Level meters for VCRs, stereo cassette players, audio amplifiers and karaoke equipment. FFeatures 1) Uses dynamic-drive system to display two 12-point channels. 22-pin SOP and 22-pin shrink DIP packages. 2) Independent AC and DC inputs provided (one input displays one channel). Switching function allows two-mode display. 3) Upper 8 points have peak hold function in AC mode (two seconds). A peak-hold cancel function is also provided. 4) A mute function is provided, and muting can be applied externally. 5) Power on mute function. Audio ICs FBlock diagram BA6820F / BA6822S / BA6822F FAbsolute maximum ratings (BA6820F / BA6822F) (Ta = 25_C) (BA6822S) (Ta = 25_C) FRemended operating conditions (Ta = 25_C) Audio ICs BA6820F / BA6822S / BA6822F FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5.0V and f = 1k Hz) Audio ICs BA6820F / BA6822S / BA6822F Audio ICs FMeasurement circuit BA6820F / BA6822S / BA6822F FApplication example Audio ICs FAttached ponents S C1 and C2: 1µF input coupling capacitors (electrolytic) for the square-root pression amplifier. The rectified voltage output from pins 2 and 4 is attenuated by 1.5d B at the frequency determined by the following formula (refer to the data for the relationship between the pin 2 and 4 DC voltage frequency characteristics and the LED lighting level). f C = 1 2π S C1 (RIN)VR1) (RIN = input resistance) BA6820F / BA6822S / BA6822F S Q1 to Q4: 2SA854S Transistors for display switching. If the current for one LED is ILED, the values of IC and PC for each of Q1 to Q4 when all LEDs are lit are given by: IC = 6 PC = 6 ILED (for duty cycle of 7 / 32) ILED Vsat 7 32 When the LEDs light due to low-frequency mechanical noise or induced hum, reduce the values...