BA682A Datasheet | ROHM

Audio ICs LED level meter driver, 12- point, VU scale, dot or bar display The BA682A is a monolithic IC for LED level meter applications. The display level range is 13m Vrms to 327m Vrms (Typ.), the 0d B level is 130m Vrms (Typ.) and the VU display is -20d B to +8d B. The constant current outputs can be set using external ponents allowing use of different color LEDs in various binations. FApplications Level meters for all types of audio equipment applications FFeatures 1) 12-point VU display meter driver for bar / dot displays. 2) Fixed-current outputs that can directly drive LEDs. 3) Output current can be set using external resistors allowing different types of LEDs to be used in bination. 4) Built-in half-wave rectifier amplifier. 5) LED on and off timing can be set using an external capacitor and resistor. 6) With bar-type display, by connecting four LEDs in series, power dissipation is reduced. FAbsolute maximum ratings (Ta = 25_C) Audio ICs FBlock diagram FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 12V) Audio ICs FMeasurement circuit Fparator level vs. AC and DC input levels FApplication example Fig.2 Audio ICs FAttached ponents (1) LED current setting resistor (R1) This resistor sets the LED current value. Refer to Fig. 3 for the relationship between the value of this resistor and the current value. The remended value is 27kΩ for green LEDs, and 39kΩ for red LEDs. If the LED current is set too high, the allowable power dissipation of the package may be exceeded, so exercise due caution. (2) Input coupling capacitor (C1) This capacitor connects the BA682A to external input circuits. The remended value is 2.2µF. (3) Input bias resistor (R2) This resistor is the input impedance. If the value is set too large, the DC bias voltage will increase, and the input offset will increase and have an effect on the parators. The remended value is 10kΩ. (4) Resistor and capacitor that set the LED operation...