HT9020B

Supply Voltage.............................V_SS-0.3V to V_DD+6V
Input Voltage .......................... V_SS-0.3V to V_DD+0.3V
Storage Temperature ...........................-55to 150
Operating Temperature .........................-20 to 75
Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maximum Ratings may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.

The HT9020B call progress tone detector is a telecom peripheral for Auto-dialing system use.

Switched capacitors technology is implemented into the chip HT9020B to get good performance characteristics of band pass filter in the range of 305 to 640Hz call progress tone which is dual tone multi-frequency signal. When it detected CPT signal then it generates relative envelopes for external microcontroller decision to finish different kinds of CPT signal detection such as dial tone, busy tone, ring-back tone and reorder tone.