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