BU8877 Datasheet, PDF (2/3 Pages) List of Unclassifed Manufacturers – Call Progress Tone Decoder for Telephone

Electrical characteristics (Unless otherwise noted, Ta=25˚C, V_DD= 5.0V, Xtal frequency=3.58MHz)
Parameter
Symbol Min. Typ. Max. Unit
Conditions
Supply current operation 2-1
IDD2-1
-
3.7
5.0
mA ENABLE="H"(VDD=5.0V)
Minimum input signal level
Maximum input signal level
Must not detect signal level
VRECL -38
-
VRECH
-
-
VREJ -50
-
-
dBm ^{Input frequency:}
2
dBm ^{Must detect frequency range}
VRECL, VRECH are proportional
-
dBm _{to VDD.}
350Hz fV350 345
350
355
Hz
Must detect frequency range
Input signal level: 0dBm
440Hz fV440 435
440
445
Hz
Input Impedance
Zin
-
100
-
Call progress tone response time
tRES
28
-
56
Call pogress tone de-response time
tDRES
28
-
56
Detect duty ratio ^*
WDU
35
50
65
*Detect Duty Ratio which input signal (350Hz+440Hz) burst at 5Hz (Duty Ratio=50%)
kΩ Input frequency: 100Hz~2000Hz
ms
ms
%
Block Diagram
VDD
VSS
ENABLE
INPUT
XIN
XOUT
VDD
VSS
ENABLE
AGC AAF
BPF
(350Hz) ^Comparator
BPF
(440Hz) ^Comparator
Timer
DETECT
OSC
CLOCK
GENERATOR
CLOCK
VREF
VREF
BU8877/F