CM88L70/70C
CALIFORNIA MICRO DEVICES
CMOS Integrated DTMF Receiver, 3V Version
Applications
• 2.7V to 3.6V operating range
• PCMCIA
• Full DTMF receiver
• Portable TAD
• Less than 18mW power consumption
• Mobile radio
• Industrial temperature range
• Remote control
• Uses quartz crystal or ceramic resonators
• Remote data entry
• Adjustable acquisition and release times
• Call limiting
• 18-pin DIP, 20-pin QSOP, 18-pin SOIC,
• Telephone answering systems
O
bs
Pr o
od le
uc te
t
Features
20-pin PLCC, 20-pin TSSOP
• Paging systems
• CM88L70
–
Power down mode
–
Inhibit mode
–
Buffered oscillator output (OSC 3) to
drive other devices
Product Description
CM88L70/70C decoder uses digital counting techniques
for the detection and decoding of all 16 DTMF tone pairs
into a 4-bit code. This DTMF receiver minimizes external
component count by providing an on-chip differential
input amplifier, clock generator, and a latched three-state
interface bus. The on-chip clock generator requires only
a low cost TV crystal or ceramic resonator as an external
component.
The CAMD CM88L70/70C provides full DTMF receiver
capability by integrating both the band-split filter and
digital decoder functions into a single 18-pin DIP,
SOIC, or 20-pin PLCC, TSSOP, or QSOP package. The
CM88L70/70C is manufactured using state-of-the-art
CMOS process technology for low power consumption
(35mW, MAX.) and precise data handling. The filter
section uses a switched capacitor technique for both
high and low group filters and dial tone rejection. The
Block Dia g ra m
VSS
VDD
VREF
INH
–
BIAS
CIRCUIT
PD
CHP
POWER
IN+
Q1
CHP
BIAS
CHIP
REF
DIAL
TONE
FILTER
+
IN–
+
–
HIGH
GROUP
FILTER
Q2
ZERO
CROSSING DETECTORS
DIGITAL
DETECTION
ALGORITHM
CODE
CONVERTER
AND
LATCH
Q3
LOW
GROUP
FILTER
GS
Q4
TO ALL
CHIP
CLOCKS
St
GT
OSC 1
OSC 2
OSC 3
St/GT
ESt
STEERING
LOGIC
StD
TOE
C1581000
© 2001, 2002 California Micro Devices Corp. All rights reserved.
215 Topaz Street, Milpitas, California 95035
12/31/2001
Tel: (408) 263-3214
Fax: (408) 263-7846
www.calmicro.com
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