CD22202

November 2002 UC T NT P RO D E T E CEME L OBSO DED REPLA enter at EN rt C /tsc COMM S uppo NO RE r Technical .intersil.com u ww to contac TERSIL or w IN 8 8 1-8 ® CD22202, CD22203 5V Low Power DTMF Receiver Features Central Office Quality No Front End Band Splitting Filters Required Single, Low Tolerance, 5V Supply Detects Either 12 or 16 Standard DTMF Digits Uses Inexpensive 3.579545MHz Crystal for Reference Excellent Speech Immunity Output in Either 4-Bit Hexadecimal Code or Binary Coded 2-of-8 Synchronous or Handshake Interface Three-State Outputs Excellent Latch-Up Immunity Description The CD22202 and CD22203 complete dual-tone multiple frequency (DTMF) receivers detect a selectable group of 12 or 16 standard digits. No front-end pre-filtering is needed. The only externally required components are an inexpensive 3.579545MHz TV “colorburst’’ crystal (for frequency reference) and a bias resistor. Extremely high system density is possible through the use of the clock output of a crystal connected CD22202/CD22203 receiver to drive the time bases of additional receivers. This is a monolithic integrated circuit fabricated with low-power, complementary symmetry CMOS processing. It only requires a single low tolerance power supply. The CD22202 and CD22203 employ state-of-the-art circuit technology to combine the digital and analog functions on the same CMOS chip using a standard digital semiconductor process. The analog input is preprocessed by 60Hz reject...