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.

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