Description
The L7590C Telephone Ringing Driver produces a low-frequency sinusoidal ringing signal for analog telephone loops. This is accomplished by producing an output pulse stream that is an amplified replica of the digital input. The output is then filtered to produce a sine wave. The peak-to-peak output level is determined by the magnitude of the negative high-voltage dc applied to the device (up to –170 V).

Features
■ Applies a battery-backed, single-ended, sinusoidal ringing signal to the telephone loop
■ Ringing capability:
    — 40 Vrms into 5 North American REN
    — 30 mApeak into 4 German REN
■ Built-in current limiting
■ Low power dissipation in idle and ringing modes
■ Requires 5 V, a high-value negative dc supply, and a digital input sequence