Data Sheet June 1998
L7590C Telephone Ringing Driver
Features
s
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).
The required input is a 100 kHz CMOS-compatible pulse stream, pulse-width modulated (PWM) at the desired ringing frequency.
The output stage consists of one upper and one lower drive
transistor with an internal control...