BA6803S Datasheet | ROHM

features a power-on mute, and the output block can directly drive fluorescent display tubes, so few external ponents are required. The grid output duty cycle is 1 / 8. FApplications Level meters for all types of AV equipment FFeatures 1) Uses dynamic-drive system to display two 16-point channels. 30-pin SDIP package. 2) AC and DC inputs provided. Switching function allows two-mode display. 3) Upper 12 points have peak hold function in AC mode (two seconds typ.). 4) Power-on mute function. 5) Dynamic-drive system reduces the power dissipation of the fluorescent display tube power supply. 6) Square root pression amplifier built in. FAbsolute maximum ratings (Ta = 25_C) Audio ICs FBlock diagram FElectrical characteristics (unless otherwise noted, Ta = 25_C) Audio ICs Audio ICs FMeasurement circuit FApplication example Audio ICs FCircuit operation (1) Input block The AC input pins are pins 1 and 3, and the DC input pins are pins 6 and 7. Pin 8 is used to switch between the AC and DC inputs. When the input to pin 8 is “H”, AC input is selected (pins 1 and 3). Therefore, by using pin 8 to switch between the AC and DC modes, the IC can do two jobs, using one fluorescent tube. For example, pins 1 and 3 can be used for audio signal input, and pins 6 and 7 can be used as the input for the signal meter output from a tuner (DC). The AC input impedance of pins 1 and 3 is a low 250Ω (typ.), so connect potentiometers (VR1 and VR2) in series with the inputs to adjust the sensitivity and ch1 and ch2 balance. (2) Peak hold circuit The BA6803S features a peak hold circuit that temporarily holds peak signal levels in AC input mode. The peak hold function can be used with the upper 12 points (5 to 16). The peak hold time depends on the oscillator frequency. It is 2 sec. (typ.) for an oscillator frequency of 2k Hz. DC mode does not have a peak hold function. (3) Grid output The pin 10 and 11 grid outputs are open-collector NPN...