DESCRIPTION
The LT®1684 is a telecommunication ring tone generator. The IC takes a user-generated pulse width modulated (PWM) input and converts it to a high voltage sine wave suitable for telephone ringing applications.

FEATURES
■ Allows Dynamic Control of Output Frequency, Cadence, Amplitude and DC Offset
■ Active Tracking Supply Configuration Allows Linear Generation of Ring Tone Signal
■ No High Voltage Post-Filtering Required
■ Capacitive Isolation Eliminates Optocouplers
■ Low Distortion Output Meets International PTT Requirements
■ Differential Input Signal for Noise Immunity
■ User Adjustable Active Output Current Limit
■ Powered Directly From High Voltage Ringer Supply—No Additional Supplies Necessary
■ Supply Current: <1mA
■ 2% Signal Amplitude Reference
■ Available in 14-Pin SO and DIP Packages

APPLICATIONS
■ Wireless Local Loop Telephones
■ Key System/PBX Equipment
■ Fiber to the Curb Telecom Equipment