CD22204E [INTERSIL]
5V Low Power Subscriber DTMF Receiver; 5V低功耗用户的DTMF接收器
| 型号： | CD22204E |
| 厂家： | 
Intersil |
| 描述： | 5V Low Power Subscriber DTMF Receiver |
| 文件： | 总5页 (文件大小：47K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CD22204
Data Sheet
February 1999
File Number 1696.4
5V Low Power Subscriber DTMF Receiver
Features
The CD22204 complete dual tone multiple frequency (DTMF)
receiver detects a selectable group of 12 or 16 standard digits.
No front-end pre-filtering is needed. The only externally
required components are an inexpensive 3.579545MHz TV
‘‘colorburst’’ crystal (for frequency reference) and a bias
resistor. Extremely high system density is possible through
the use of the Alternate Time Base (ATB) output of a crystal
connected CD22204 receiver to drive the time bases of up to
10 additional receivers. This is a monolithic integrated circuit
fabricated with low power, complementary symmetry CMOS
processing. It only requires a single power supply.
• No Front End Band Splitting Filters Required
• Single Low Tolerance 5V Supply
• Three-State Outputs for Microprocessor Based
Systems
• Detects all 16 Standard DTMF Digits
• Uses Inexpensive 3.579545MHz Crystal
• Excellent Speech Immunity
• Output in 4-Bit Hexadecimal Code
• Excellent Latch-Up Immunity
The CD22204 employs state-of-the-art ‘‘switched-capacitor’’
filter technology, resulting in approximately 40 poles of filtering
and digital circuitry on the same CMOS chip. The analog input
is preprocessed by 60Hz reject and bandsplitting filters and
then zero-cross detected to provide AGC. Eight bandpass
filters detect the individual tones. Digital processing is used to
measure the tone and pause durations and provides the
correctly coded and timed digital outputs. The outputs
interface directly to standard CMOS circuitry and are three-
state enabled to facilitate bus oriented architectures.
Pinouts
CD22204 (PDIP)
TOP VIEW
1
2
3
4
5
6
7
14
13
12
11
10
9
D2
D1
EN
D4
D8
DV
V
ATB
XIN
XOUT
DD
Ordering Information
NC
PART
NUMBER
TEMP.
RANGE ( C)
XEN
o
PACKAGE
14 Ld PDIP
PKG. NO.
E14.3
ANALOG
IN
8
V
SS
CD22204E
0 to 70
Functional Diagram
5
NC
DV
D1
D2
LOW B/P
FILTERS
12
2
7
ANALOG IN
HIGH B/P
FILTERS
1
11
ATB
6
14
13
3
CHIP
D4
D8
EN
XEN
CLOCKS
XIN
10
VOLTAGE
REG./REF.
9
XOUT
4
8
V
V
SS
DD
NOTE: Pin numbers are for PDIP.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999
67
CD22204
Absolute Maximum Ratings (Note 1)
Thermal Information
o
DC Supply Voltage (V ) (Referenced to V Terminal) . . . . . . .7V
DD SS
Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .175 C
o
o
Power Dissipation
Maximum Storage Temperature Range. . . . . . . . . . -65 C to 150 C
o
o
o
o
T = 25 C (Derate above T = 25 C at 6.25mW/ C . . . . . . . .65mW
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300 C
A
A
Input Voltage Range
All Inputs Except Analog In . . . . . . . . . . . . . . (V
Operating Conditions
0.5V) to -0.5V
0.5V) to (V -10V)
DD
o
o
Analog in Voltage Range . . . . . . . . . . . . . (V
DD
DD
DC Current into any Input or Output . . . . . . . . . . . . . . . . . . . . . .±20mA
Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 C to 70 C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
o
o
Electrical Specifications 0 C ≤ T ≤ 70 C, V = 5V ±10%
A
DD
PARAMETER
Frequency Detect Bandwidth
Amplitude for Detection
TEST CONDITIONS
MIN
TYP
±2.3
-
MAX
±3.5
-2
UNITS
±(1.5 + 2Hz)
% of f
O
Each Tone
-32
dBm Referenced to 600Ω
(Note 3)
Minimum Acceptable Twist
-8
-
+4
dB
High Tone
Twist = ---------------------------
Low Tone
60Hz Tolerance
-
-
-
-
0.8
0
V
RMS
Dial Tone Tolerance
“Precise” Dial Tone
dB Referenced to Lower
Amplitude Tone
Talk Off
MITEL Tape #CM7291
“0” Level, 400µA Load
“1” Level, 200µA Load
“0” Level
-
2
-
-
Hits
V
Digital Outputs (except XOUT)
0
0.5
V
-0.5
-
V
V
DD
DD
Digital Inputs
0
-
0.3V
V
DD
“1” Level
o
0.7V
-
V
V
DD
DD
Supply Current
Noise Tolerance
T = 25 C
A
-
-
10
-
20
mA
MITEL Tape #CM7291
(Note 2)
-12
dB Referenced to Lowest
Amplitude Tone
Input Impedance
NOTES:
V
≥ V ≥ (V
IN
-10)
DD
100kΩ//15pF
300kΩ
-
DD
1. Unused inputs must be connected to V
DD
or V as appropriate.
SS
2. Bandwidth limited (3kHz) Gaussian noise.
3. Lower minimum available, please contact sales office.
(-32dBm = 19.45mV
, -2dBm = 0.615mV )
RMS
RMS
68
CD22204
Functional Block Diagram
BANDPASS
FILTERS
697
770
BAND
SPLIT
FILTERS
ZERO
CROSSING
DETECTORS
AMPLITUDE
DETECTORS
ANALOG
PREPROCESSOR
IN
60Hz
REJECT
7
PRE EMP
BS1
852
941
TIMING
BS2
CIRCUITRY
1209
1336
1477
1633
11
6
ATB
XEN
DV
12
DATA STROBE
CLOCK
GENERATOR
10
÷8
CHIP CLOCKS
XIN
2
1
D1
D2
1M
OUTPUT
DECODER
OUTPUT
REGISTER
XOUT
9
14
D4
VOLTAGE
REF
POWER REGULATOR
13
3
D8
EN
DATA CLEAR
4
8
V
V
SS
DD
NOTE: Pin numbers are for plastic DIP.
The CD22204 is designed to accept sinusoidal input wave-
forms, but will operate satisfactorily with any input that has
the correct fundamental frequency with harmonics that are
at least 20dB below the fundamental.
System Functions
Analog In
The Analog In pin accepts the analog input. It is internally
biased so that the input signal may be either AC or DC cou-
pled, as long as it does not exceed the positive supply volt-
age. Proper input coupling is illustrated below.
Crystal Oscillator
The CD22204 contains an on-board inverter with sufficient
gain to provide oscillation when connected to a low cost tele-
vision “color-burst” (3.579545MHz) crystal. The crystal oscil-
lator is enabled by tying XEN high. The crystal is connected
between XIN and XOUT. A 1MΩ resistor is also connected
between these pins in this mode. ATB is a clock frequency
output. Other CD22204 devices may use the same fre-
quency reference by tying their ATB pins to the ATB output of
a crystal connected device. XIN and XEN of the auxiliary
devices must then be tied high and low, respectively. Up to
ten devices may be run from a single crystal connected
CD22204 as shown in Figure 2.
CD22204E
0.01µF
V
DD
AUDIO
INPUT
(+4dBm OR
270kΩ
1.22V
RMS
MAXIMUM)
1500pF
10pF
(ON CHIP)
7
ANALOG
IN
>100kΩ
33kΩ
V
SS
OPTIONAL
HIGH FREQUENCY
NOISE FILTER
(f = 3.9kHz)
C
FIGURE 1. ANALOG IN
69
CD22204
DTMF Dialing Matrix
3.579545MHz
1M
COL 0
1209Hz
COL 1
1336Hz
COL 2
1477Hz
COL 3
1633Hz
V
DD
XIN
XOUT
ROW 0
697Hz
1
4
7
*
2
5
8
0
3
6
9
#
A
B
C
D
10
9
6
ROW 1
770Hz
ATB
CD22204
XEN
XEN
11
ROW 2
852Hz
XIN CONNECTED TO V
CD22204
DD
ROW 3
941Hz
10
NOTE: Column 3 is for special applications and is not normally used
in telephone dialing.
11
6
UP TO 10 DEVICES
Digital Inputs and Outputs
All digital inputs and outputs of the DTMF receivers are rep-
resented by the schematic below. Only the “analog in” pin is
different, and is described above. Care must be exercised
not to exceed the voltage or current ratings on these pins as
listed in the “maximum ratings” section.
FIGURE 2. CRYSTAL OSCILLATOR
Outputs D1, D2, D4, D8 and EN
Outputs D1, D2, D4, D8 are CMOS push-pull when enabled
(EN high) and open circuited (high impedance) when dis-
abled by pulling EN low. These digital outputs provide the
hexadecimal code corresponding to the detected digit. The
digital outputs become valid after a tone pair has been
detected and they are then cleared when a valid pause is
timed. The table below describes the hexadecimal codes.
V
DD
CMOS
DIGITAL
CIRCUITRY
DIGITAL
INPUT
DIGITAL
OUTPUT
TABLE 1. OUTPUT CODES
DIGIT
D8
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
D4
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
D2
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
D1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
2
3
4
5
6
7
8
9
0
*
V
SS
FIGURE 3. DIGITAL INPUTS AND OUTPUTS
Input Filter
The CD22204 will tolerate total input noise of a maximum
of 12dB below the lowest amplitude tone. For most
telephone applications, the combination of the high
frequency attenuation of the telephone line and internal
band limiting make special circuitry at the input to these
receivers unnecessary. However, noise near the 56kHz
internal sampling frequency will be aliased (folded back)
into the audio spectrum, so if excessive noise is present
above 28kHz, the simple RC filter shown below may be
used to band limit the incoming signal. The cut off
frequency is 3.9kHz.
#
A
B
C
D
ANALOG
270kΩ
IN
NOISY
SIGNAL
CD22204
DV
0.0015µF
33kΩ
DV signals a detection by going high after a valid tone pair is
sensed and decoded at the output pins D1, D2, D4, and D8.
DV remains high until a valid pause occurs.
FIGURE 4. FILTER FOR USE IN EXTREME HIGH FREQUENCY
INPUT NOISE ENVIRONMENT
N/C Pin
This pin has no internal connection and should be left floating.
70
CD22204
Noise will also be reduced by placing a grounded trace
PARAMETER
Tone Time
SYMBOL MIN
TYP MAX UNITS
around XIN and XOUT pins on the circuit board layout when
using a crystal. It is important to note that XOUT is not
intended to drive an additional device. XIN may be driven
externally; in this case, leave XOUT floating.
For Detection
For Rejection
t
t
40
-
-
-
-
ms
ms
ON
20
ON
Pause Time
Timing Waveforms
For Detection
t
40
-
-
-
-
-
20
46
50
-
ms
ms
ms
ms
µs
OFF
For Rejection
Detect Time
t
OFF
t
t
OFF
ON
TONE BURST 1
t
t
25
35
7
D
Release Time
R
PAUSE
TONE BURST 2
ANALOG
INPUT
Data Setup Time
Data Hold Time
Output Enable Time
t
-
-
SU
t
R
t
4.2
-
5
ms
ns
H
t
D
-
200
300
D1, D2
D4, D8
C
= 50pF, R = 1kΩ
L
L
t
SU
Output Disable Time
-
-
-
-
-
-
150
200
160
200
300
250
ns
ns
ns
t
C = 35pF, R = 500Ω
H
L
L
Output Rise Time
= 50pF
C
DV
L
Output Fall Time
= 50pF
C
L
FIGURE 5.
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Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time with-
out notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
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71
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