HT9020B

www.DataSheet4U.com HT9020B Call Progress Tone Detector Features · Operating voltage: 2.5V~5.5V · Low power consumption · Low cost 32768Hz crystal · CPT Band: 305~640Hz detection · Good performance: -8 ~ -39 dBm at VDD=2.5V 0 ~ -27 dBm at VDD=5V · 8-pin DIP package General Description The HT9020B call progress tone detector is a telecom peripheral for Auto-dialing system use. Switched capacitors technology is implemented into the chip 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. Block Diagram X 1 X 2 3 2 7 6 8 H z O s c illa to r C lo c k G e n e ra to r V R E . G e n e ra to r V R E . E N S IN B a n d p a s s . ilte r L e v e l S e n s e C K T D ig ita l C o n tro l C K T E N V V S S V D D Pin Assignment E N V V R E . 2 7 3 6 4 5 S IN V S S 1 8 V D D E N X 2 X 1 H T 9 0 2 0 B 8 D IP -A Rev. 1.20 1 March 31, 2003 HT9020B Pin Description Pin Name ENV VREF SIN VSS VDD EN I/O O O I ¾ ¾ I Internal Connection CMOS OUT CMOS OUT CMOS IN ¾ ¾ CMOS IN Description While an input signal is within specification, this pin will output the envelope relative to the input signal with a typical 40ms timing delay. 1/2 VDD reference voltage output pin When EN=VD...