HT9020B Datasheet, PDF (1/7 Pages) Holtek Semiconductor Inc – Call Progress Tone Detector

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 V_DD=2.5V
0 ~ -27 dBm at V_DD=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
X1
32768H z
X2
O s c illa to r
S IN
B andpass
. ilte r
C lo c k
G e n e ra to r
Level
S ense C K T
VRE.
VRE.
G e n e ra to r
EN
D ig ita l
ENV
C o n tro l C K T
VSS
VDD
Pin Assignment
ENV 1
8 VDD
VRE. 2
S IN 3
VSS ⁴
7
EN
6
X2
5
X1
H T9020B
8 D IP -A
Rev. 1.20
1
March 31, 2003