75T2090 Datasheet, PDF (1/9 Pages) TDK Electronics – DTMF Transceivers

DESCRIPTION
TDK Semiconductor’s 75T2089/2090/2091 are
complete Dual-Tone Multifrequency (DTMF)
Transceivers that can both generate and detect all
16 DTMF tone-pairs. These ICs integrate the
performance-proven 75T202 DTMF receiver with a
DTMF generator circuit.
The DTMF receiver electrical characteristics are
identical to the standard 75T202 device
characteristics. The DTMF generator provides
performance similar to the Mostek MK5380, but with
an improved (tighter) output amplitude range
specification and with the addition of independent
latch and reset controls.
An additional feature of the 75T2090/2091 is
"imprecise" call progress detector. The detector
detects the presence of signals in the 305-640 Hz
band.
(continued)
75T2089/2090/2091
DTMF Transceivers
FEATURES
April 2000
• DTMF Generator and Receiver on one-chip
• Call progress detection (2090/2091 only)
• Early detect output (2091 only)
• DTMF Receiver exhibits excellent speech
immunity
• Analog input range from -32 to -2 dBm
(ref 600Ω )
• Three-state outputs (4-bit hexadecimal) from
DTMF Receiver
• AC coupled, internally biased analog input
• Latched DTMF Generator inputs
• DTMF output typ. -8 dBm (Low Band) and
-5.5 dBm (High Band)
• Easy interface for microprocessor dialing
• Uses inexpensive 3.579545 MHz crystal for
reference
• Low-power 5 volt CMOS
BLOCK DIAGRAM
LIN
(2090/2091 only)
D7
D6
D5
D4
Vp
LATCH
Vp
RESET
DIN
XIN
DQ
DQ
DQ
DQ
CK
RS
X1
XOUT
XEN ATB
Vp
8
BANDSPLIT
FILTERS
INTERNAL
CLOCK
ENERGY
DETECTOR
Vp
DTMF
GENERATOR
CK Q
Vp D CLR
BANDPASS
FILTERS
BANDPASS
697
FILTERS
BS1
770
852
AMPLITUDE
DETECTORS
TIMING
CIRCUITRY
941
1209
BS2
1336
DV
STROBE
DV
F.F.
1477
1633
POWER REGULATOR
VOLTAGE
REF
OUTPUT
DECODER
AND
REGISTER
Vp Vn
DE
DET
(2090/2091 only)
DTMF
OUT
ED
(2091 only)
DV
D3
D2
D1
D0