[GEC PLESSEY SEMI]

The MV5087 is fabricated using ISO-CMOS high density technology and offers low power and wide voltage operation. An inexpensive 3.58MHz TV crystal completes the reference oscillator. From this frequency are derived 8 different sinusoidal frequencies which, when appropriately mixed, provide Dual-Tone Multi-Frequency (DTMF) tones.

Inputs are compatible with either a standard 2-of-8 or a single contact (form A) keyboard. The keyboard entries determine the correct division of the reference frequency by the row and column counters.

D-to-A conversion, using R-2R ladder networks, results in a staircase approximation of a sinewave with low total distortion. Frequency and amplitude stability over operating voltage and temperature range are maintained within industry specifications.

FEATURES

■ Pin-for-Pin Replacement for MK5087

■ Low Standby Power

■ Minimum External Parts Count

■ 3.5V to 10V Operatlon

■ 2-of-8 Keyboard or Calculator-Type Single Contact (Form A) Keyboard Input

■ On-Chip Regulation of Output Tone

■ Mute and Transmitter Drivers On-Chip

■ High Accuracy Tones Provided by 3.58MHz Crystal Oscillator

■ Pin-Selectable Inhibit of Single Tone Generation

APPLICATIONS

DTMF Signalling for

■ Telephone Sets

■ Mobile Radio

■ Remote Control

■ Point-of-Sale and Banking Terminals

■ Process Control