DESCRIPTION
A tri-state, 3-bit output code indicates the presence of dial tone, audible ring-back, busy signal, or re-order tones. A front-end bandpass filter is accomplished with switched capacitors. In addition to the three data bits, a buffered bandpass output and envelope output are available. All logic inputs and outputs can interface with LSTTL, CMOS and NMOS. Circuit features include low power consumption and easy application. Few and inexpensive external components are required. A typical application requires a 3.58MHz crystal or clock, 470kΩ resistor, and two bypass capacitors. The NE5900 is effective where traditional call progress tones, PBX tones, and precision call progress tones must be correctly interpreted with a single circuit. PIN CONFIGURATION D1 and N Packages INPUT VREF EXT CLOCK IN/XTAL1 XTAL2 TEST IN CLEAR IN COUNT IN PROGRESS 0V 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 5V ANALOG OUT TRI-STATE ENABLE ENVELOPE BIT 1 BIT 2 BIT 3 DATA VALID TOP VIEW NOTE: 1. SOL — Released in large SO package only.