M-88L70

• Telephone switch equipment
• Mobile radio
• Remote control
• Paging systems
• PCMCIA
• Portable TAD
• Remote data entry

The M-88L70 is a full DTMF Receiver that integrates both bandsplit filter and decoder functions into a single 18-pin DIP or SOIC package. Manufactured using CMOS process technology, the M-88L70 offers low power consumption (18 mW max), precise data handling and 3V operation. Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code. External component count is minimized by provision of an on-chip differential input amplifier, clock generator, and latched tri-state interface bus. Minimal external components required include a low-cost 3.579545 MHz color burst crystal, a timing resistor, and a timing capacitor.

The M-88L70 monolithic DTMF receiver offers small size, low power consumption and high performance, with 3 volt
operation. Its architecture consists of a bandsplit filter section, which separates the high and low group tones,
followed by a digital counting section which verifies the frequency and duration of the received tones before passing the corresponding code to the output bus.