Communication ICs PLL tone decoder IC BA1604 / BA1604F The BA1604 and BA1604F are tone decoder ICs that enable the frequency to be selected in precise detail, using a PLL system. These ICs are configured of a PLL circuit, a detection circuit, a voltage comparator circuit and an output logic drive circuit. When the input signal is within the transmission range of the circuit, PLL is synchronized (locked) to the input signal. At this point, the output voltage of the decoder drops, and the change turns on the transistors for the voltage comparator and output logic drive circuits. A load of up to 100mA can be driven.The center frequency (f0) of the decoder is set by the mobile oscillation frequency of the current control oscillator. This frequency is determined by selecting a CR con- nected to Pins 5 and 6. Applications Telephones Data communication systems Remote control systems Features 1) The detection bandwidth can be varied independent- 5) Frequency can be changed over a range of 20 : 1 us- ly between 0 and 14%. ing an external resistor. 2) The output circuit can withstand a load current of up 6) Compatible with EXAR XR-567 and Signetics to 100mA, and is directly coupled to the logic circuit. NE567. 3) The center frequency offers a high level of stability. 4) High out-of-band signal and noise rejection capabili- ty. Block diagram 212Communication ICs BA1604 / BA1604F Absolute maximum ratings (Ta=25 C) Recommended operating conditions (Ta=25 C) Electrical characteristics (unless otherwise noted, Ta=25 C, VCC=5V) 213