View ba681a datasheet:

Audio ICs LED level meter driver, 12–point, power scale, dot or bar display BA681A The BA681A is a monolithic IC for LED power meter applications. The display level range is 6mVrms to 359mVrms (Typ.) divided into 12 points with repeated interval spacings of 3dB, 3dB and 4dB. The 0dB level is 180mVrms (Typ.) and the range is *30dB to +16dB. The constant current outputs can be set using external components allowing use of different color LEDs in various combinations. FApplications Level meters for radio cassettes, car stereos, and home stereos FFeatures 1) 12-point power meter driver for bar/dot displays. 5) LED on and off timing can be set using an external 2) Fixed-current outputs that can directly drive LEDs. capacitor and resistor. 3) Output current can be set using externa